U.S. patent application number 09/746506 was filed with the patent office on 2003-03-27 for general information management system.
Invention is credited to Ericson, Petter, Fahraeus, Christer, Wiebe, Linus.
Application Number | 20030061188 09/746506 |
Document ID | / |
Family ID | 27582362 |
Filed Date | 2003-03-27 |
United States Patent
Application |
20030061188 |
Kind Code |
A1 |
Wiebe, Linus ; et
al. |
March 27, 2003 |
General information management system
Abstract
An information management system is intended for management of
digitally represented information which is associated with absolute
positions on an imaginary surface (200). The imaginary surface
(200) contains at least two regions (201-208), each of which is
dedicated to predetermined management of the digitally represented
information. In the system the management of the digitally
represented information is carried out on the basis of the region
affiliation of the absolute positions associated with the
information. The system is suitably based on use of a
position-coding pattern which defines the imaginary surface (200)
and which in parts is applicable on different bases. The system
makes possible both digital recording of information and control of
how the information thus recorded is to be managed. A database, a
method for management of information, a method for compiling a
pattern layout, a product and use are also described.
Inventors: |
Wiebe, Linus; (Malmo,
SE) ; Fahraeus, Christer; (Lund, SE) ;
Ericson, Petter; (Malmo, SE) |
Correspondence
Address: |
BIRCH STEWART KOLASCH & BIRCH
PO BOX 747
FALLS CHURCH
VA
22040-0747
US
|
Family ID: |
27582362 |
Appl. No.: |
09/746506 |
Filed: |
December 22, 2000 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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60177310 |
Jan 21, 2000 |
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60208164 |
May 31, 2000 |
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60208169 |
May 31, 2000 |
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60208170 |
May 31, 2000 |
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60210654 |
Jun 9, 2000 |
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Current U.S.
Class: |
1/1 ;
707/999.001; 707/E17.005 |
Current CPC
Class: |
G06F 3/0317 20130101;
G06F 3/0321 20130101; G06F 3/03545 20130101; G06F 16/20
20190101 |
Class at
Publication: |
707/1 |
International
Class: |
G06F 017/30 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 23, 1999 |
SE |
9904745-8 |
Feb 18, 2000 |
SE |
0000541-3 |
Mar 21, 2000 |
SE |
0000939-9 |
Mar 21, 2000 |
SE |
0000952-2 |
Apr 5, 2000 |
SE |
0001239-3 |
Aug 30, 2000 |
PCT/SE00/01667 |
Claims
What we claim and desire to secure by Letters Patent is:
1. A global information management system, which is intended for
management of information represented in the form of absolute
coordinates and which is based on use of a position-coding pattern
which defines an imaginary surface (100; 200) consisting of all the
positions whose absolute coordinates the position-coding pattern
has the capacity to code, wherein at least two unique regions
(101-104; 201-213) are defined on the imaginary surface (100;200),
each of which is dedicated to a predetermined management of
information, so that the management of information represented by
the absolute coordinates of at least one position on the imaginary
surface (100;200) is carried out dependent upon the region
affiliation of said at least one position.
2. An information management system according to claim 1, in which
said information comprises a sequence of positions on the imaginary
surface (100;200), which positions form message information, such
as interrelated lines.
3. An information management system according to claim 1 or 2, in
which at least one command region (104; 201, 207; 216-219) which
represents an operation is defined on the imaginary surface (100;
200), SO that detection of the absolute coordinates for a position
within this command region (104; 201, 207; 216-219) results in
initiation of said operation.
4. An information management system according to claim 3, in which
said operation is one of the operations to store information, to
send information and to convert information.
5. An information management system according to claim 2, 3 or 4,
in which a primary region (206) on the imaginary surface (100; 200)
is dedicated to a predetermined management of information and
contains said at least one command region (216-219) and at least
one message recording region (214, 215, 220), which is dedicated to
digital recording of a sequence of positions on the imaginary
surface (200), which positions form message information, such as
interrelated lines.
6. An information management system according to claim 5, in which
the primary region (206) contains a plurality of identical standard
regions (213), said at least one message recording region (214,
215, 220) and said at least one command region (216-219) being
included in such a standard region (213).
7. An information management system according to any one of the
preceding claims, further comprising a computer system (3) which is
arranged to store information about the division of the imaginary
surface (100; 200) into said regions.
8. An information management system according to claim 7, in which
the computer system (3) is arranged to store information about an
owner of at least one of said regions.
9. An information management system according to any one of the
preceding claims, further comprising at least one user unit (2)
which is arranged to record said absolute coordinates from a base
(1) which is provided with at least one subset of said
position-coding pattern.
10. An information management system according to claim 9, in which
the absolute coordinates recorded by means of the user unit (2)
represent graphical information which was written using the user
unit (2) on said at least one subset of the position-coding
pattern.
11. An information management system according to any one of the
preceding claims, further comprising at least one base (1) which is
provided with at least one subset of said position-coding pattern,
said at least one subset coding at least one position within at
least one region on the imaginary surface (100; 200).
12. An information management system intended for management of
digitally represented information which is associated with absolute
positions on an imaginary surface (100; 200), wherein the imaginary
surface (100; 200) contains at least two regions (101-104;
201-213), each of which is dedicated to predetermined management of
said information, so that the management of said information is
carried out dependent upon the region affiliation of the absolute
positions associated with said information.
13. An information management system according to claim 12, in
which at least one command region (104; 201, 207; 216-219) is
defined on the imaginary surface (100; 200), which command region
represents an operation, so that detection of at least one absolute
position within said command region (104; 201, 207; 216-220)
results in initiation of said operation.
14. An information management system according to claim 13, in
which said operation is one of the operations to store information,
to send information and to convert information.
15. An information management system according to any one of claims
12-14, comprising a computer system (3) which is arranged to store
information about which absolute positions belong to a particular
region.
16. An information management system according to claim 15, in
which the computer system (3) is arranged to store information
about an owner who is allocated at least one of said regions.
17. An information management system according to any one of claims
12-16, further comprising a held-held device (2) which is arranged
to record at least one absolute position on a base (1) which is
provided with at least one subset of said imaginary surface (100;
200).
18. An information management system according to claim 17, in
which said at least one absolute position which is recorded by the
hand-held device (2) is associated with graphical information which
was written with the hand-held device (2) on the base (1).
19. An information management system according to claim 17 or 18,
in which a position-coding pattern is arranged to define said at
least one absolute position, and in which the hand-held device (2)
is arranged to detect and decode the position-coding pattern to
determine said at least one absolute position on the imaginary
surface (100; 200) and said region affiliation.
20. An information management system according to claim 19, in
which the position-coding pattern comprises marks (A7) which are
arranged with a displacement from their nominal position (A6).
21. An information management system according to any one of the
preceding claims, further comprising at least one base (1) whose
surface is provided with at least one subset of said imaginary
surface (100; 200).
22. A database containing an imaginary surface (100; 200) which
consists of positions defined by absolute coordinates, wherein at
least one position on the imaginary surface (100; 200) is allocated
a rule for information management, so that information which is
associated with the absolute coordinates of said at least one
position is managed on the basis of said rule.
23. A database according to claim 22, in which the imaginary
surface (100; 200) consists of all the positions that a
position-coding pattern has the capacity to code.
24. A database according to claim 22 or 23, in which the imaginary
surface (100; 200) is divided into at least two regions (101-104;
201-213) which are each allocated a rule for information
management.
25. A database according to any one of claims 22-24, in which the
imaginary surface (100; 200) comprises at least one message
recording region (101-103; 202-215, 220) which is allocated a rule
for digital recording of a sequence of positions on the imaginary
surface (100; 200), which positions form message information, such
as interrelated lines.
26. A database according to any one of claims 22-25, in which the
imaginary surface (100; 200) comprises at least one command region
(104; 201, 207; 216-219) which is allocated a rule which represents
an operation, so that detection of the absolute coordinates for a
position within this command region (104; 201, 216-219) results in
initiation of said operation.
27. A database according to claims 25 and 26, in which at least one
message recording region (214, 215, 220) and at least one command
region (216-219) are incorporated in a primary region (206) which
is allocated a rule for predetermined information management.
28. A database according to claim 27, in which the primary region
(206) contains a plurality of identical standard regions (213),
said at least one message recording region (214, 215, 220) and said
at least one command region (216-219) being incorporated in such a
standard region (213).
29. A database according to any one of claims 26-28, in which said
operation is one of the operations to store information, to send
information and to convert information.
30. A database according to any one of claims 22-29, which is
stored completely or partially in a memory (21; 3') in a unit (2;
3) which is incorporated in an information management system.
31. A method for management of information which is represented by
absolute coordinates, comprising the step of defining at least two
unique regions (101-104; 201-213), each of which is dedicated to
predetermined information management, on an imaginary surface (100;
200) which consists of all the positions whose absolute coordinates
a position-coding pattern has the capacity to code, so that
information which is represented by the absolute coordinates of at
least one position on the imaginary surface (100; 200) is managed
dependent upon the region affiliation of said at least one
position.
32. A method according to claim 31, further comprising the step of
giving a party the sole right to use a subset of the
position-coding pattern, which subset codes at least one position
within a predetermined region (101-104; 201-220) on the imaginary
surface (100; 200).
33. A method according to claim 31 or 32, comprising the step of
creating said information by moving a held-held device (2) across a
base (1) which is provided with at least one subset of a
position-coding pattern, which subset codes absolute positions on
the imaginary surface (100; 200), said information being formed as
a sequence of absolute positions on the imaginary surface (100;
200), which absolute positions form message information, such as
interrelated lines.
34. A method according to any one of claims 31-33, comprising the
step of initiating an operation, when said at least one position is
situated within a command region (104; 201, 216-219) on the
imaginary surface (100; 200).
35. A method according to claims 33 and 34, in which said operation
concerns all or parts of the recorded message information.
36. A method according to claim 34 or 35, in which said operation
is one of the operations to store information, to send information
and to convert information.
37. A method for management of digitally represented information
associated with at least one absolute position on an imaginary
surface (100; 200), which contains at least two regions (101-104;
201-220), comprising the steps of determining whether said at least
one absolute position, which is associated with said information,
is situated within one of said regions (101-104; 201-220) and
managing said information in a predetermined way dependent upon to
which region (101-104; 201-220) said at least one absolute position
belongs.
38. A method according to claim 37, comprising the steps of
producing said information by moving a hand-held device (2) across
a base (1) provided with a subset of said imaginary surface (100;
200), of determining the absolute position of the hand-held device
(2) during at least part of said movement and of associating said
information with the absolute position thus determined.
39. A method according to claim 38, in which said information
comprises a graph which represents said movement.
40. A method according to claim 38, in which said information is
characters which correspond to said movement after interpretation
by means of a character interpretation program.
41. A method for compiling a pattern layout which is intended to be
applied on a product (1) and which codes absolute positions on an
imaginary surface (100; 200), which surface (100; 200) consists of
all the absolute positions that a position-coding pattern has the
capacity to code and is divided into regions (101-104; 201-220), of
which at least one first region is allocated a rule for how
information which contains at least one position within the first
region is to be managed, comprising the step of creating the
pattern layout from at least one subset of the position-coding
pattern so that the pattern layout codes positions within said
first region on the imaginary surface (100; 200).
42. A method according to claim 41, in which said at least one
first region comprises a message recording region (101-103;
202-215, 220) which is allocated a rule for digital recording of a
sequence of positions on the imaginary surface (100; 200), which
positions form message information, such as interrelated lines.
43. A method according to claim 41 or 42, in which said regions
(101-104; 201-220) comprise at least one second region, (104; 201,
216-219) which is allocated a rule which represents an operation,
so that detection of the absolute coordinates for a position within
said second region (104; 201, 216-219) results in initiation of
said operation.
44. A method according to claim 43, comprising the step of creating
the pattern layout to code positions within one of a plurality of
identical standard regions (213) on the imaginary surface (100;
200), which standard region (213) contains said at least one first
and at least one second region (214-220).
45. A method according to any one of claims 41-44, comprising the
step of creating the pattern layout from a single coherent subset
of the position-coding pattern.
46. A method according to any one of claims 41-44, comprising the
step of creating the pattern layout by combining at least two
separate subsets of the position-coding pattern.
47. A product which is intended to be used in a system according to
any one of claims 1-11, which product (1) has a message field (1A)
which is provided with a first subset of the position-coding
pattern to enable digital recording of graphical information which
is written on said first subset, and a command field (1B) which is
provided with a second subset of the position-coding pattern, which
second subset defines an operation which is to be carried out with
regard to the recorded graphical information.
48. A product according to claim 47, in which the first subset of
the position-coding pattern in the message field (1A) is continuous
with the second subset of the position-coding pattern in the
command field (1B), so that the product (1) is provided with a
position-coding pattern which codes positions within a coherent
coordinate area on the imaginary surface (100; 200).
49. A product according to claim 47, in which the first subset of
the position-coding pattern in the message field (1A) is
discontinuous with the second subset of the position-coding pattern
in the command field (1B), by the first and second subsets coding
positions within separate coordinate areas on the imaginary surface
(100; 200).
50. Use of positions on an imaginary surface (100; 200) for control
of management of information, which surface (100; 200) consists of
a large number of positions and is divided into regions (101-104;
201-213), in which a rule is associated with each region (101-104;
201-213) for how the information which contains coordinates for at
least one position within this region (101-104; 201-213) is to be
managed.
51. Use according to claim 50, which comprises providing a product
(1) with at least one subset of a position-coding pattern which
codes a large number of positions on the imaginary surface (100;
200), which subset codes at least one position within at least one
of said regions (101-104; 201-220).
52. Use according to claim 51, in which the imaginary surface (100;
200) consists of all the positions which the position-coding
pattern has the capacity to code.
Description
FIELD OF THE INVENTION
[0001] This invention relates to the field of management and
communication of information.
BACKGROUND OF THE INVENTION
[0002] Information is often written down and communicated by means
of pen and paper. Such paper-based information is, however,
difficult to manage and communicate efficiently.
[0003] Computers are used to an increasing extent for managing and
communicating information. The information is entered by means of a
keyboard and stored in the computer's memory, for example on a hard
disk. The entry of the information by means of the keyboard is,
however, slow and it is easy to make mistakes. Nor is it
particularly convenient to read large amounts of text on a computer
screen. Graphical information, such as drawings or images, is
usually entered by means of a separate image reader, such as a
scanner or the like, in a procedure which is time-consuming,
cumbersome, and as often as not gives unsatisfactory results.
However, once the information is in the computer, it is easy to
communicate it to others, for example as an e-mail or SMS via an
Internet connection or as a fax via a fax modem.
[0004] In Applicant's Patent Application PCT/SE00/01895, which
claims priority from Swedish Patent Application No. 9903541-2,
filed on Oct. 1, 1999, and which is incorporated herewith by
reference, a system is described where a pen and paper are used to
write down information in the traditional way, while at the same
time a digital graph is created consisting of several tracks or
lines of the movement of the pen across the paper, which graph can
be transmitted to a computer. Such a system combines the advantage
of management with pen and paper, which many users are used to,
with the computer's superior ability to communicate and store
information. The sheet of paper is provided with a coding pattern,
for example consisting of dots or other symbols. The pen has a
sensor, preferably optical, which records the coding pattern and,
by means of a mathematical algorithm, calculates the position of
the pen on the coding pattern.
[0005] In this way, the traditional pen becomes an excellent input
device for the computer, and the computer can be used to store the
recorded information instead of the sheet of paper having to be
archived in a file. In addition, the information can easily be
communicated by means of the computer.
[0006] The recorded information contains parts which can be used
for different purposes.
[0007] 1) The digital graph contains an image, such as figures or
interrelated lines, which can be interpreted by people, for example
letters, a symbol, a figure or a drawing. This is the actual
message which was written down and which the user wants to manage
in some way, for example to archive or to send to a recipient. This
information, so-called message information, is stored in some
graphical format, for example a vector format or as a collection of
pixels.
[0008] 2) The part of the message information which consists of
letters (handwritten) can be subjected to subsequent processing in
the form of OCR interpretation (Optical Character Recognition) or
ICR interpretation (Intelligent Character Recognition) for
conversion into a character format which can be used by the
computer, for example for searching purposes or for cataloguing.
Symbols can also be interpreted, for example stenography symbols or
icons, to which the user predefines a particular meaning. In the
following, this information is called character information.
[0009] 3) The information can also contain an identification of
which pen was used to write down the information.
[0010] 4) Finally, the graph contains information about where on
the surface the graph was written down, so-called absolute position
information.
[0011] 5) In addition, a hard copy of the recorded information can
be obtained, if the pen makes physical marks on the sheet of
paper.
[0012] Prior-art technique comprises other systems for obtaining
absolute or relative position information when writing on a
surface. However, these previously known systems only describe the
use of such information in order to create message information
and/or character information, that is information belonging to the
groups 1) and 2) above. Such prior art includes, for example,
optical detection of a position-coding pattern on a base according
to U.S. Pat. No. 5,051,736, U.S. Pat. No. 5,442,147, U.S. Pat. No.
5,852,434, U.S. Pat. No. 5,652,412 and EP-B-0 615 209. Position
information can also, as also described in EP-B-0 615 209, be
obtained by means of acceleration sensors, or by means of
inductive/capacitive/magnetic sensors. Other alternatives are a
base incorporating pressure sensors, as described in U.S. Pat. No.
5,790,105, triangulation of signals (light, sound, infrared
radiation, etc.) with the use of a plurality of
transmitters/receivers, as described in U.S. Pat. No. 5,012,049, or
mechanical detection of movement relative to a surface, as
described in U.S. Pat. No. 4,495,646. Position information can also
be obtained by combinations of techniques. For example, a system is
described in WO 00/31682 with combined optical detection of symbols
for the determination of absolute position information at low
resolution, and acceleration sensors, for the determination of
relative position information at high resolution.
[0013] Although, according to prior art, there are several
different techniques for recording message and/or character
information as described above, there is no system for enabling the
user to manage this information in a simple, flexible and
structured way.
[0014] Known systems for managing information, such as the database
system as described in U.S. Pat. No. 5,842,196, comprise as a rule
a central server unit and user units in the form of personal
computers or terminals, which communicate with the server unit. The
server unit contains a database with information stored in data
records. Searching these data records and updating the same with
new information, are time-consuming operations which should be made
as efficient as possible. For this reason the database is often
organized in a tree structure, in which the data records, or data
fields in these, are given searchable indices or key values. It is,
however, unclear how this type of database system would be able to
be combined successfully with the techniques for recording message
and/or character information described above.
[0015] U.S. Pat. No. 5,932,863 describes a technique for improving
the user interface to electronic media. Paper products are provided
with a machine-readable symbol, which is allocated a pre-programmed
command in a computer. When a user reads in the symbol by means of
a hand-held scanner, this is transmitted to the computer, where the
pre-programmed command is executed, for example to cause the
computer to retrieve interactive software from a central databank
and to execute this on the computer. Also in this case, it is
unclear how this type of user interface would be able to be
combined with the techniques for recording message and/or character
information described above.
SUMMARY OF THE INVENTION
[0016] This invention relates to improving management of
information which is recorded by means of a user unit. More
specifically, it is an object of this invention to increase the
possibilities of managing digitally-recorded information.
[0017] It is also desirable to show a technique for information
management that is easy for the user to use.
[0018] A further object is to provide a technique which enables
rapid, simple and unambiguous management of information.
[0019] It is also an object to provide a technique which is
general, but which permits individual handling of different
parties' information.
[0020] These and other objects, which will be apparent from the
following description, have now been achieved completely or
partially by an information management system according to claims 1
and 12, a database according to claim 22, a method for information
management according to claims 31 and 37, a method for compiling a
pattern layout according to claim 41, a product according to claim
47 and use according to claim 50. The dependent claims define
preferred embodiments.
[0021] According to a first aspect, the invention relates to an
information management system.
[0022] According to prior-art technique, a position-coding pattern
is used locally for the sole purpose of recording handwritten
information. The position-coding pattern then needs only to be used
to code positions locally on the writing surface on which the
information is written. According to the invention, absolute
positions are used instead on an imaginary surface which is made up
of all the points or positions which can be coded by means of the
position-coding pattern. Each position is defined by at least two
coordinates. If there are several imaginary surfaces, a third
coordinate can be used to define which imaginary surface is in
question. By dedicating different parts of the imaginary surface to
different types of information management, it is possible both to
record information and to control how the information is to be
managed by using the position-coding pattern. Different bases are
thus provided with different subsets of the position-coding
pattern, depending upon how the information which is written on the
base is to be managed.
[0023] The position-coding pattern covers a total surface which is
imaginary in as much as it is very large and is therefore never
present in its entirety on a base. The imaginary surface is an
imaginary surface which is made up by all the positions that the
position-coding pattern can code. The imaginary surface can be
divided into main regions, which in turn can be divided into
subregions, which in turn can be divided into further subregions,
etc. The main regions can be different sizes and shapes. Together
they do not need to cover all of the imaginary surface, but they
can do so. Each main region can be dedicated to a particular type
of information management. The above-mentioned subregions can be
dedicated to variants of the information management to which the
associated main region is dedicated. The subregions can also be
dedicated to different parties, products, services, operations on
recorded information or the like.
[0024] It must be pointed out that not all of the information which
is managed in the system needs to be represented by absolute
positions on the imaginary surface. The information can be recorded
by a combination of techniques, of which one identifies absolute
positions and the other identifies relative positions. An example
of such a combination is given in the above-mentioned WO 00/31682.
In this case, the information may contain only one or a few
absolute positions, and a sequence of local positions related to
these absolute positions. As the local positions can be converted
to absolute positions, such digitally represented information which
is linked in some way to absolute positions on an imaginary surface
can also be managed in the system according to the invention.
[0025] The system thus increases the possibilities of managing
information. A user can write down and at the same time digitally
record information on a position-coding pattern. The management of
the information recorded digitally in this way is then controlled
by where on the imaginary surface the information is recorded. The
system thus permits information gathering, that is digital
recording of information which is written down on a writing surface
or the like, and information distribution, that is communication of
information to and from a user. All or parts of the digitally
recorded information, for example in the form of message
information, can be sent to a recipient. Alternatively, a user can
be sent further information from a particular party, for example
about a product or service, by recording information on a part of
the imaginary surface designed for the purpose.
[0026] The system is thus easy to use, as the user does not himself
need to define in each situation how the recorded information is to
be managed. The management is controlled instead by the coordinates
of the recorded information, that is its region affiliation on the
imaginary surface. The user can work largely as he does at present
with paper and pen, but still make use of all the possibilities of
electronics. The recorded information can be managed quickly,
easily, unambiguously and transparently for the user in the system
according to the invention.
[0027] The system according to the invention is general, but
permits individual handling of different parties' information,
thanks to the fact that different parties with different needs can
be given access to different regions on the imaginary surface in
the system and can control how their own information is to be
managed.
[0028] As an example, it can be mentioned that a main region can be
dedicated to information which is to be sent to a predetermined
address in a computer network.
[0029] As another example, it can be mentioned than another main
region can be dedicated to information in the form of notes which
are to be stored in a user's computer.
[0030] Different regions on the imaginary surface can be dedicated
to different purposes for different periods of time. Different
regions can be reserved by a party for different periods of time,
for special markets and for special applications.
[0031] The system can be called global, in that the division of the
imaginary surface into different unique regions is applied
throughout the whole system, which, however, does not need to be
global in the sense that it is world-wide.
[0032] The global information management system can be said to
arise and exist when any party utilizes the property of a
position-coding pattern that different coordinate areas or regions
which are coded by different subsets of the pattern can be
dedicated to different management of information purposes.
[0033] In a preferred embodiment, the information management system
comprises a computer system which stores information about the
position of the different regions on the imaginary surface. The
computer system can comprise one or more computers which store the
above-mentioned information. What is essential is to keep track in
a coordinated way of where the different regions are located so
that the regions are utilized consistently in the system.
Information is also suitably stored concerning unused or unreserved
regions and concerning what the different reserved regions are
dedicated to.
[0034] In one embodiment, at least one command region which
represents an operation is defined on the imaginary surface, so
that detection of the absolute coordinates for a point within this
command region results in the initiation, and later execution, of
said operation.
[0035] In addition to the regions which are dedicated to different
management of information purposes, there can thus be one or more
command regions on the imaginary surface. The former regions are
used to record information which is processed in different ways
depending upon the region. The command region is used principally
not for recording information but to define a command or an
operation which is to be carried out. The command region can in the
extreme case comprise a single point, as the command region does
not need to make possible recording of handwritten information. In
the normal case, however, the command region comprises a plurality
of points on the imaginary surface for a corresponding subset of
the position-coding pattern to be read off with high reliability.
The command or operation is typically intended to be carried out
with regard to information which has been or which is to be
recorded by means of a subset of the position-coding pattern which
codes one of said regions which are dedicated to different
management of information purposes.
[0036] According to one example, a user writes information on a
notepad, the writing surface of which has a writing field provided
with a first subset of the position-coding pattern, which first
subset codes coordinates within a region on the imaginary surface
dedicated to notes. Thereafter the user records absolute
coordinates from a command region, which is coded by a second
subset of the position-coding pattern, which second subset is
reproduced in a box on the writing surface of the notepad. The
command can, for example, be to store the recorded information in
the user's computer, in which case the box is marked "store". As
will be described in greater detail below, the detection of the
second subset of the position-coding pattern results in the
information written on the first subset being stored in the user's
computer.
[0037] What was described above regarding the regions for
information management also applies to the command regions.
[0038] The command region can be a universal region on the
imaginary surface, that is a corresponding subset of the
position-coding pattern can be applied on a number of different
bases and combined with other subsets of the position-coding
pattern associated with other regions on the imaginary surface.
[0039] Alternatively, the command region can be part of one of the
above-mentioned regions for information management, for example, a
primary region which is dedicated to transmission of information to
an external unit. The primary region also suitably contains at
least one message recording region, which is dedicated to digital
recording of a sequence of positions on the imaginary surface. The
primary region suitably contains a plurality of identical standard
regions, each of which comprises at least one command region and at
least one message recording region. The primary region is thus
hierarchically structured, which has the advantage that detailed
information about this part of the imaginary surface can be stored
in compact form, for example as an algorithm-based database. In
addition all information which is recorded within a standard region
is considered to belong together, which can be an advantage when
the recorded information is to be managed in the system.
[0040] In a preferred embodiment, the information about the
position of said at least one command region on the imaginary
surface is stored in the above-mentioned computer system, so that
information is collected about where all the different regions on
the imaginary surface are positioned and consistent utilization is
made possible.
[0041] The command or operation which is defined by the command
region can, for example, be one of the commands to store
information, to send information or to convert information. The
information can be sent in different formats and via different
"transport systems". The information can, for example, be sent as
an e-mail message, as an SMS or as a fax. It can be sent from a
user unit, for example in the form of a digital pen, via for
example a mobile phone, a computer or a PDA to a recipient which,
for example, can also be a mobile phone, a PDA, a computer, in
particular a computer connected to the Internet, or a program in a
computer.
[0042] The information is sent preferably in graphical form, that
is as sequences of recorded positions. All the recorded positions
which represent information can be sent, or they can be processed
into a compressed form or some other format. Character recognition
can also be carried out, so that the information can be sent in
character-coded format.
[0043] The information can be stored in a unit which is
synchronized with the user unit, for example a computer, or at a
storage location on a server connected to the Internet.
[0044] The conversion command can comprise a command which means
that the information, for example, is to be translated into a
predetermined language, subjected to character-recognition,
encrypted, or converted in some other way.
[0045] It does not need to be a single party that administers all
the information management in the information management system,
but different parties can have access to different regions on the
imaginary surface. The party that is responsible for the
information management system must, however, as mentioned earlier,
know which regions on the imaginary surface are reserved and which
are free. The computer system stores advantageously information
about an owner of at least one of said information management
regions.
[0046] In addition, the computer system can need to comprise
information about what particular information management regions
and command regions are dedicated to, so that the computer system
can carry out part of the information management. Particular
information which is represented by coordinates of positions within
particular regions can, for example, always be sent to the computer
system, which can carry out particular processing of the
information and then forward it to a recipient.
[0047] In a preferred embodiment, the information management system
can also comprise at least one user unit, preferably in the form of
a hand-held device, such as a digital pen, which is arranged to
record absolute positions from a base provided with at least one
subset of said position-coding pattern, which subset can also be
regarded as at least one subset of the imaginary surface.
[0048] The user unit can comprise a sensor which can detect the
position-coding pattern. As mentioned above, the information can
alternatively be recorded by a combination of techniques, in which
case the user unit can comprise an additional one or more sensors,
for example, an acceleration sensor, a mechanical translation
sensor, etc.
[0049] The user unit can advantageously also have an ordinary pen
point, so that information can be written on a base which is
provided with a subset of the position-coding pattern and can at
the same time be recorded digitally by the sensor. The information
which is recorded by the user unit in the form of absolute
positions thus usually represents message information, that is
graphical information which is written/drawn on the base using the
user unit. However, it can alternatively represent a command (an
operation).
[0050] When a command is detected, it causes the user unit to at
least initiate a predetermined operation, possibly however with a
certain delay. In certain cases the user unit can carry out the
whole operation itself. In other cases the user unit can, for
example, transfer all or parts of the recorded information and
information about which operation is to be carried out to an
external unit, for example a computer or mobile phone, which
completes the operation. This transmission can be carried out
directly or at a later time. By "initiate" is meant here that the
user unit ensures that the operation is carried out, even though it
does not carry out the operation itself, so that the user does not
need to give further commands to the user unit or the external unit
in order for the operation to be carried out. However, the user
many need to supply further information or to confirm the
operation/the information. In its simplest embodiment, the user
unit is not able to recognize or interpret the coordinates
corresponding to different command regions, but it ensures that a
required operation is carried out by sending all the coordinates to
an external unit which can interpret them.
[0051] The information management system can also advantageously
comprise at least one base which is provided with at least one
subset of said position-coding pattern. The base can constitute or
be incorporated in a number of products. Examples of such products
are forms, brochures, newspapers, notepads, calendars, desk mats,
etc, of paper or plastic material, a writing board of plastic
material or a display screen. Products which are particularly
suitable for being provided with coordinates are all forms of
products with writing surfaces. The writing surfaces do not need to
be suitable for writing with an ordinary pen point, but can be
writing surfaces on which writing is carried out by the pen being
moved as in writing. The products are provided with different
subsets of the position-coding pattern, depending upon how the
information is to be managed.
[0052] According to a second aspect, the invention relates to a
database which contains information about the above-mentioned
imaginary surface. In the database at least one position on the
imaginary surface is allocated a rule for information management,
so that information which is associated with the absolute
coordinates for said at least one position is managed on the basis
of this rule.
[0053] This database can, in the information management system
described above, be stored in its entirety in a central
administration unit and/or be divided between a plurality of units.
Different types of database structures can be used in different
units. All types of conventional database structures can be used,
for example relational, network-based, or hierarchical structures.
In a user unit, which generally has limited memory and processor
capacity, the database structure is preferably algorithm-based.
[0054] The data base suitably contains further information
associated with positions on the imaginary surface, such an owner,
a recipient address, an encryption instruction, a link to a program
or document file to be executed or to be sent to a recipient,
etc.
[0055] The advantages of the database according to the invention
are apparent from the above description of the system.
[0056] According to a third aspect, the invention relates to a
method for managing information, the advantages of which are
apparent from the above description of the system.
[0057] According to a fourth aspect of the invention, this relates
to a method for compiling a pattern layout which is intended for
application on a product.
[0058] The method permits a party or user to create a pattern
layout that can be used for digital recording and management of
information in a system or method according to the invention. The
advantages of this method are apparent from the above description
of the system.
[0059] According to a fifth aspect of the invention, this relates
to a product which is intended to be used in an information
management system as described above. The product has a message
field which is provided with a first subset of the position-coding
pattern to enable digital recording of graphical information which
is written on said first subset, and a command field which is
provided with a second subset of the position-coding pattern, which
second subset defines an operation which is to be carried out
concerning the recorded graphical information.
[0060] The advantages of this product are apparent from the above
description of the system.
[0061] According to a sixth aspect of the invention, this relates
to use of positions on at least one imaginary surface divided into
regions for control of management of information. There is a rule
associated with each region for how information which contains the
coordinates of at least one position within the region is to be
managed.
[0062] The advantages of this use are apparent from the above
description of the system.
BRIEF DESCRIPTION OF THE DRAWINGS
[0063] This invention and its distinctive features, objects and
advantages will be described in greater detail in the following
with reference to the accompanying drawings, which for the purpose
of exemplification show currently preferred embodiments.
[0064] FIG. 1 is a schematic diagram that shows an information
management system according to the invention.
[0065] FIG. 2 is a schematic diagram that shows a first imaginary
surface with main regions that are dedicated to different
purposes.
[0066] FIG. 3 is a schematic internal view of a digital pen which
can be used in an information management system according to the
invention.
[0067] FIG. 4 is a schematic diagram that shows in greater detail a
second imaginary surface with main regions that are dedicated to
different purposes.
[0068] FIG. 5 is a schematic diagram that shows in greater detail
subregions in a hierarchically organized main region on the
imaginary surface in FIG. 4.
[0069] FIG. 6 is a schematic diagram that shows an example of the
layout of the subregions at the lowest level of the main region in
FIG. 5.
[0070] FIG. 7 is a schematic diagram that shows a product which is
provided with a position-coding pattern according to a preferred
embodiment.
[0071] FIG. 8 is a schematic diagram that shows how the marks can
be designed and positioned in a preferred embodiment of the
position-coding pattern.
[0072] FIG. 9 is a schematic diagram that shows examples of 4*4
symbols which are used to code a position.
DESCRIPTION OF PREFERRED EMBODIMENTS
[0073] By way of introduction, the overall construction of an
information management system according to the invention will be
described, with reference to FIGS. 1 and 2. Thereafter components
which are part of the system will be described, among other things
with reference to FIG. 3, and a number of examples of applications
with reference to FIG. 2. This is followed by examples of different
forms of communication and localized data processing in the
information management system. Finally, a more detailed example is
given of the layout of the imaginary surface which is part of the
information management system, with reference to FIGS. 4-6.
[0074] FIG. 1 shows an example of how a system according to the
invention can be constructed. The system comprises principally a
plurality of products, a plurality of user units and one or more
external units. For the sake of clarity, however, only one product
1, one user unit 2 and one external unit 3 are shown in FIG. 1.
[0075] The product 1 in FIG. 1 is provided with a message field 1A
to receive graphical information, for example text, numbers or
figures, which are written using the user unit 2, and a command
field 1B for initiating/implementing different operations using the
user unit 2.
[0076] The system permits structured management of the information
which a user records on the product 1 using the user unit 2. The
product 1 is provided with a position-coding pattern which is
interpreted by the user unit 2 as absolute coordinates on the
surface of the product 1. The position-coding pattern, which is
described in greater detail below, is such that it codes positions
on a total surface or imaginary surface which is much larger than
the surface of the product 1. When the user passes the user unit 2
across the surface of the product 1, information is recorded
containing one or more pairs of absolute coordinates. This recorded
information is communicated, automatically (on-line) or upon
command, to the external unit 3 for storage and/or processing.
[0077] In the system according to the invention, management of the
recorded information is dependent upon where on the imaginary
surface the information has been recorded, that is the coordinate
content of the recorded information.
[0078] This system permits structured processing of information.
Different parties with different needs can have access to different
parts of the imaginary surface and can control how their own
information is to be managed. The system is general but also
permits individual management of different parties'
information.
[0079] FIG. 2 shows schematically an example of an imaginary
surface 100 which consists of or is made up by all the points or
positions whose absolute coordinates a position-coding pattern can
code.
[0080] Four different coordinate areas or main regions 101-104 are
defined on the imaginary surface 100. The main regions 101-104 are
different sizes and different shapes. They are spaced from each
other and do not over-lap. The main regions can in turn be divided
into subregions (not shown), which in turn can be divided into
further subregions, etc.
[0081] The main regions can be more or less regular in shape, not
only rectangular as shown in the example, and the relationship
between the size of the main regions and the size of the imaginary
surface can be completely different to the one shown. Nor do the
regions need to be separated from each other, but can physically
overlap each other and be defined by mathematical relations or
associations.
[0082] The different main regions 101-104 are dedicated to
different purposes. In this example, the first main region 101 can
be dedicated to recording notes, the second main region 102 can be
dedicated to recording calendar information, that is information
which is to be stored associated with a particular time or a
particular interval of time, the third main region 103 can be
dedicated to recording handwritten information which is always to
be sent to a predetermined server unit on the Internet and the
fourth main region 104 can be dedicated to one or more specific
commands.
[0083] In an actual information management system the number of
dedicated main regions can be much larger.
[0084] Information about the extent of the imaginary surface and
about the location and extent of the different main regions which
have been dedicated to different information management purposes or
different commands, which are to be carried out with regard to the
information which is managed in the system, is stored completely or
partially in one or more computer systems, for example the external
unit 3 in FIG. 1. Said computer system can be a passive part of the
information management system. It does not need to carry out any
part of the actual information management and thus does not need to
be connected to the other units in the information management
system. The computer system is, however, suitably an interacting
part of the information management system, as will be shown in
greater detail below.
[0085] The Position-Coding Pattern
[0086] The information management system is based, as shown above,
on use of a position-coding pattern. This pattern can be
constructed in various ways, but has the general property that if
an arbitrary part of the pattern of a particular minimum size is
recorded, then the position of this part in the position-coding
pattern can be determined unambiguously.
[0087] The position-coding pattern can be of the type which is
disclosed in the above-mentioned US A-5,852,434, where each
position is coded by a specific symbol.
[0088] It is, however, desirable for the position-coding pattern to
be used to record information at high resolution and in addition to
be used in a system which permits varied processing of the
information. Therefore the pattern should be designed in such a way
that it can code a very large number of positions given by pairs of
absolute coordinates. In addition, the position-coding pattern
should be coded graphically in such a way that it does not dominate
or interfere with the visual impression of the surface of the
product. It should also be possible to detect the position-coding
pattern with high reliability.
[0089] Therefore the position-coding pattern is advantageously of
the type which is disclosed in the Published International Patent
Application WO 00/73983 filed on May 26, 2000, or in the
International Patent Application PCT/SE00/01895 filed on Oct. 2,
2000, both applications being assigned to the present Applicant. In
these patterns each position is coded by a plurality of symbols or
marks, and each symbol contributes to the coding of several
positions. The position-coding pattern is constructed of a small
number of types of symbols.
[0090] An example is shown in PCT/SE00/01085 where a larger dot
represents a "one" and a smaller dot represents a "zero".
[0091] The currently most preferred pattern is shown in
PCT/SE00/01895, where four different displacements of a dot or mark
in relation to a nominal raster point code four different values.
This pattern is constructed of small dots at a nominal spacing of
approximately 0.3 mm. Any part of the pattern which contains
6.times.6 such dots defines a pair of absolute coordinates. Each
pair of absolute coordinates is thus defined by an approximately
1.8 mm.times.1.8 mm large subset of the position-coding pattern. By
means of determination of the position of the 6.times.6 dots on the
sensor in the user unit which is used to read off the pattern, an
absolute position on the imaginary surface can be calculated by
interpolation with a resolution of approximately 0.03 mm. A more
complete description of the position-coding pattern according to
PCT/SE00/01895 is given in the Appendix.
[0092] This position-coding pattern is able to code a large number
of absolute positions. As each position is coded by 6.times.6 dots,
each of which can have one of four values, 4.sup.36 positions can
be coded, which with the above-mentioned nominal distance between
the dots corresponds to a surface of 4.6 million km.sup.2.
[0093] The position-coding pattern can be printed on any base which
allows a resolution of approximately 600 dpi. The base can be any
size and shape, depending upon its planned use. The pattern can be
printed by standard offset printing technology. Ordinary black
carbon-based printing ink or some other printing ink which absorbs
infrared light can advantageously be used. This means that other
inks, including black ink which is not carbon-based and which does
not absorb infrared light, can be used to superimpose other
printing on the position-coding pattern without interfering with
the reading off of this.
[0094] A surface which is provided with the above-mentioned pattern
printed with a carbon-based black printing ink will be perceived by
the eye as only a pale gray shading of the surface (1-3% density),
which is user-friendly and esthetically pleasing.
[0095] Of course, fewer or more symbols can be used to define a
position than described above, and larger or smaller distances
between the symbols can be used in the pattern. The examples are
only given to show a currently preferred realization of the
pattern.
[0096] The position-coding pattern described above can be applied
on all imaginable products on which information is to be recorded
by the recording of coordinates. Examples of such products are
forms, notepads, calendars, desk mats, writing boards, etc. The
products can be different materials, such as paper, plastic, etc.
Alternatively the position-coding pattern can be integrated into or
arranged upon a computer screen. As a result, different positions
on the screen can be read off by means of a digital pen which
detects the pattern. In this way a screen is provided with the same
function as a touch screen, but with the advantages that it is
unaffected by the environment and that the screen can be bent. The
position-coding pattern can alternatively be displayed
electronically on a computer screen. The currently most preferred
embodiment is, however, that the pattern is applied onto paper.
[0097] The User Unit
[0098] FIG. 3 shows an example of a user unit, which in a preferred
embodiment is used to record electronically graphical information
which is produced on a writing surface and to initiate/execute
commands or operations on this information.
[0099] The user unit comprises a casing 11 which is the same shape
as a pen. A short side of the casing defines an opening 12 and is
intended to be held in contact with or a short distance from a base
provided with a position-coding pattern.
[0100] The user unit, below called a digital pen, contains
essentially an optics part, an electronic circuitry part and a
power supply.
[0101] The optics part forms a digital camera and comprises at
least one infrared light-emitting diode 13 for illuminating the
surface which is to be imaged and a light-sensitive area sensor 14,
for example a CCD or CMOS sensor, for recording a two-dimensional
image. The pen may also contain a lens system (not shown). The
infrared light is absorbed by the symbols in the position-coding
pattern and in this way makes them visible to the sensor 14. The
sensor records advantageously at least 100 images per second.
[0102] The power supply for the pen is obtained from a battery 15
which is mounted in a separate compartment in the casing.
Alternatively, however, the pen can be connected to an external
power source.
[0103] The electronic circuitry part comprises a signal processor
16 for determining a position on the basis of the image recorded by
the sensor 14 and more specifically a processor unit with a
microprocessor which is programmed to read in images from the
sensor and to determine in real time absolute coordinates for
points on the imaginary surface on the basis of the imaged subset
of the position-coding pattern. In an alternative embodiment, the
signal processor 16 is realized as an ASIC (Application Specific
Integrated Circuit) or an FPGA (Field Programmable Gate Array).
[0104] The position determination is thus carried out by the signal
processor 16, which thus must have software to enable it to locate
and decode the symbols in an image and to enable it to determine
positions from the codes thus obtained. A person skilled in the art
would be able to design such software from the description in the
above-mentioned Patent Applications WO 00/73983 and
PCT/SE00/01895.
[0105] The signal processor 16 can also have limited information
about the different regions of the imaginary surface and about what
these are dedicated to. The signal processor 16 can, for example,
advantageously contain information which makes it possible for it
to recognize that certain points or regions on the imaginary
surface represent certain commands or operations which are to be
initiated and/or implemented, for example with regard to
information which has been or will be recorded. Preferred commands
which can be recognized by the pen are "store", "send", "to do",
"address" and other similar basic commands. The pen has
advantageously indicating means (not shown), for example a
light-emitting diode, a buzzer or a vibrator, which gives a signal
when the pen detects a command. The signal serves to make the user
aware that a command has been recorded. Of course these indicating
means can also be used to give an indication that the pen has
recorded handwritten information.
[0106] The pen can advantageously also contain information which
makes it possible for it to distinguish between, for example,
information which is to be stored in the pen, information which is
to be transferred to the user's personal computer, information
which is to be sent to a fax number via a modem and information
which is to be sent to a server at a predetermined IP address.
[0107] More specifically, as described above, a main region on the
imaginary surface can be dedicated in order that information which
is recorded by means of a subset of the position-coding pattern
which corresponds to this main region, and is thus represented by
coordinates for points which lie within the main region will always
to be sent to said IP address for further management.
[0108] The digital pen comprises in this embodiment a pen point 17,
using which the user can carry out ordinary pigment-based writing
on the surface provided with the position-coding pattern. The pen
point 17 can be extended and retracted so that the user can control
whether or not it is to be used. A button (not shown) for extending
and retracting the pen point, in the same way as in an ordinary
ball-point pen, can also function as an on/off button for the pen,
so that the pen is activated when the pen point is extended.
[0109] The digital pen can also comprise buttons 18 by which it is
activated and controlled. It also has a transceiver 19 for
short-distance wireless transmission, for example using infrared
light or radio waves, of information to and from the pen. In the
currently most preferred embodiment the transceiver 19 is a
Bluetooth.RTM. transceiver.
[0110] The digital pen is also suitably provided with a pressure
sensor 20 which measures the pressure on the pen point 17 when this
is used.
[0111] The signal processor 16 can comprise software which
determines the angle between the pen point and the paper and also
the rotation of the pen on the basis of the recorded images.
Software for this purpose is described in Applicant's Swedish
Patent Application No. 0000952-2.
[0112] In a preferred embodiment, the signal processor 16
determines the following information on the basis of each recorded
image: a pair of coordinates, the angle between the pen and the
paper, the rotation of the pen, the pressure on the paper and in
addition a time-stamp on the basis of the time of the recording of
the image. Depending upon how the information management system is
constructed, it can, however, be sufficient to record the pair of
coordinates, possibly together with one of the other
parameters.
[0113] The recorded pair of coordinates can be processed and stored
in a compressed format. The signal processor 16 can, for example,
be programmed to analyze a sequence of pairs of coordinates and
convert these into a train of polygons which constitutes a
description of how the pen has been moved across the surface which
is provided with the position-coding pattern.
[0114] All the recorded data can be stored in a buffer memory 21
awaiting transmission to an external unit. The digital pen can
thereby work in stand-alone mode, that is the pen sends the
information when it has the opportunity, for example when it makes
contact with an external unit, whereupon it retrieves recorded
information from the buffer memory 21. It must also be pointed out
that the signal processor 16 does not need to forward all the
information to an external unit, but can be programmed to analyze
the recorded coordinates and only to forward information which is
represented by coordinates within a particular coordinate area. The
information can also be forwarded immediately on-line.
[0115] The signal processor 16 can also have software for
encrypting the information which is sent to external units.
[0116] The pen can have, but thus does not need to have, knowledge
of what all the different regions on the imaginary surface are
dedicated to. In fact, no individual unit in the system needs to
have this knowledge, but it can be distributed over a number of
different units. For the administration of the system there should,
however, be gathered knowledge of which main regions (and
subregions thereof) are already dedicated and which main regions
(and subregions thereof) are free. However, only the party that at
the time has the sole right to use a particular region (main region
or subregion) has information about its precise use. Of course, as
an alternative, all information can be collected in a central unit,
such as in a memory 3' of the unit 3 in FIG. 1.
[0117] It is also desirable for only simpler, less time-consuming
and memory-intensive processing of the recorded information and
processing of security-sensitive information to be carried out in
the pen. More complicated processing can be carried out in a local
computer, with which the pen communicates and in which software is
installed for processing information from the pen, and/or in a
server unit which can contain very powerful software for, among
other things, character recognition (OCR), a larger amount of
memory, for example for database information, and faster signal
processors for more advanced processing of the information.
[0118] Such distribution of the information processing makes it
possible to manufacture pens at a relatively low cost. In addition,
new applications can be added to the information management system
without the existing pens needing to be upgraded. Alternatively,
the user can update his pen at regular intervals so that it
receives information about new dedicated regions and about how
information which is related to these regions is to be managed and
also new functionality.
[0119] The above example is only given to show a currently
preferred realization of the digital pen. In an alternative
embodiment, the pen operates only as an image generator, that is
the images recorded by the sensor 14 are transmitted to an external
unit, for example a computer, which processes the images to
determine the coordinates as above, and which communicates if
necessary with other external units.
[0120] In the embodiment above, the pattern is optically readable
and the sensor is thus optical. The pattern can, however, be based
on a parameter other than an optical parameter. In such a case the
sensor must of course be of a type which can read the parameter
concerned. Examples of such parameters are chemical, acoustic or
electromagnetic marks. Capacitive or inductive marks can also be
used. However, it is preferable for the pattern to be optically
readable, as it is then relatively simple to apply it onto
different products and in particular onto paper.
[0121] Examples of Applications in the Information Management
System
[0122] In the following, the information management system
according to the invention is illustrated by means of a number of
examples of applications with reference to the imaginary surface in
FIG. 2.
[0123] The applications in an information management system
according to this invention can be divided into three groups or
types: 1) Applications with analogue input signal and digital
output signal; 2) Communication applications and 3) Service
applications.
[0124] Applications belonging to the first group use the digital
pen and a writing surface with a position-coding pattern
principally for inputting of information to a computer, a PDA or a
mobile phone.
[0125] A product with a writing surface, for example a notepad, can
be provided on the actual writing surface with a position-coding
pattern taken from a first region, which pattern codes coordinates
for points within a main region which is dedicated to notes, such
as the main region 101 in FIG. 2. The product can also be provided
with a box which is marked "store" and contains a position-coding
pattern from a second main region which is dedicated to commands,
such as the main region 104 in FIG. 2.
[0126] When the user writes on the writing surface, the pen records
a representation of what is written in the form of a sequence of
pairs of coordinates for points within the first region on the
imaginary surface by continually recording images of that part of
the position-coding pattern which is within the field of view of
the pen. The pen stores these absolute coordinates in its buffer
memory. When the user then places the pen in the box marked "store"
or ticks this box, the pen records coordinates for at least one
point in the main region 104 and stores these in the buffer memory.
At the same time the pen notes that these coordinates represent a
command. In the pen's memory it is stored that precisely this
command (will be explained in greater detail below) means that the
information is to be stored in a nearby computer. As soon as the
pen starts communicating with the computer with which it is
synchronized, the pen transfers the recorded coordinate information
to the computer via its transceiver. The computer stores the
received information as an image, which for example can be
displayed directly on the computer's screen. Searching the stored
information can be carried out afterwards on the basis of the time
of storing (or recording) the information and on the basis of key
words which were written in capital letters on the writing surface
and which could thus be stored in character-coded format (ASCII)
after character recognition (OCR).
[0127] Other commands which can be found on a product of the type
described above are, for example, "address book", which is a box
provided with a different subset of the position-coding pattern
which codes a subregion of the main region 104, which subregion is
dedicated to an address book command. When the pen recognizes the
coordinates for this command, it sends address information which
was written by hand, for example in capital letters, on a subset of
the position-coding pattern intended for this purpose to the
computer which stores the address information in a digital address
book. Different subregions of the subregion dedicated to the
address book command on the imaginary surface can be dedicated to
different address information.
[0128] Information with a content which requires interpretation in
order for certain measures to be carried out in the system is
currently written preferably in capital letters in special
character recognition fields, so-called "combs", which are provided
with a subset of the position-coding pattern which is dedicated to
character interpretation. This means that the user is caused to
write legible characters, which facilitates their
interpretation.
[0129] The communication applications, that is applications
belonging to the second group above, are somewhat more demanding.
They also usually require access to the Internet. Loose pages,
pages in a calendar, a notebook or the like can be designed as
forms for the transmission of graphical e-mail, SMS, fax or the
like. Fields are printed on the page which are intended for
indication of address, subject and message text. Address and
subject are intended to be written in capital letters so that they
can easily be converted into character-coded format and can be
understood by other digital units which are designed for managing
information in character-coded format. The information in the
message field can consist of any graphical information. The page is
also provided with a tick box which, when it is ticked, causes the
pen to make contact via its transceiver with the mobile phone with
which it is synchronized. The mobile phone identifies the message
as a graphical e-mail message which is intended for a predetermined
server unit which is incorporated in the information management
system. The identification can be carried out by means of
information which is stored in the pen, or in some unit with which
the mobile phone is in communication, while the mobile phone
preferably only functions as a link or a modem. The mobile phone
transfers the message to the base station by the use of GSM or
GPRS, etc, and then by means of TCP/IP to the predetermined server
unit which decodes the address field and sends the message via the
Internet to the addressee. A confirmation of delivery can be sent
to the mobile phone and shown on its display.
[0130] The above-mentioned page can be provided with a subset of
the position-coding pattern which codes a main region on the
imaginary surface which is dedicated to transmission of (graphical)
e-mail. Different parts of this main region can then represent the
different fields and the tick boxes. This type of hierarchical
layout of a main region will be described in greater detail below
with reference to FIGS. 5-6.
[0131] Alternatively, the different fields and tick boxes can be
provided with different subsets of the position-coding pattern
which code coordinates for points within main regions on the
imaginary surface which are dedicated to address information,
subject indication, transmission, etc. This type of general layout
of main regions on the imaginary surface will be described in
greater detail below with reference to FIG. 4. The advantage of
using a universal "send" box is that this can then be represented
by the same subset each time it is used, irrespective of whether it
is, for example, on a note sheet or on an e-mail form. This is more
economical with the available imaginary surface. Another advantage
is that the decoding in the pen is simple, as the pen only needs to
recognize that it is a "send" box that has been ticked, whereupon
the pen is to initiate an operation.
[0132] The service applications, that is those belonging to the
third group above, are applications where the information
management is controlled via one or more predetermined server
units. An example is an advertisement in a newspaper which is
provided with a subset of the position-coding pattern, which codes
coordinates for points within a main region on the imaginary
surface which is dedicated to information which is to be sent to a
predetermined server unit. This particular subset codes coordinates
for points within a particular subregion of the main region, to
which subregion the advertiser has acquired the sole right. As is
apparent from this, there can thus be larger main regions on the
imaginary surface which are dedicated to a particular information
management purpose. These main regions can then be subdivided into
subregions to which different parties can have the sole right. In
the server unit, which in this example also administers the main
regions, it is noted which party has the right to the different
subregions. A subset of the position-coding pattern can thus also
make possible identification of an owner of the subregion within
which the pattern codes points.
[0133] In the case of the advertisement, a user can place an order
using his digital pen by specifying a recipient address in the
field intended for this and by ticking a "send" box. If the order
requires a payment to be made, a credit card number can be given.
If the order is for the user, no recipient address needs to be
given as an address for the pen previously stored can be used. If
the order concerns a gift to another recipient, a handwritten
greeting to the recipient can be added in a writing area for
free-form graphical information in the advertisement.
[0134] When the user ticks the "send" box, the user unit 2
identifies that information was recorded within the main region 104
and therefore sends the recorded information to the predetermined
server unit on the Internet. In the server unit it is determined
that the recorded information is situated in a particular
subregion, whereupon the owner of this subregion is identified.
Thereafter the decoded information, together with any greeting, is
sent to the owner who handles the delivery of the ordered product
or service.
[0135] Communication Between the Pen and External Units
[0136] Certain operations can be carried out in their entirety by
the pen itself, for example storing of a note in the pen and input
of information for a user program in the pen. These operations can
always be carried out by the pen in stand-alone mode.
[0137] Other operations require communication with the outside
world. These operations can be commenced in stand-alone mode, but
are not completed until the pen is connected to the outside world.
Alternatively, the operations an be carried out on line.
[0138] In local applications, for example recording of notes or
calendar notes, the pen communicates suitably directly with a local
unit, such as a computer, mobile phone or PDA.
[0139] In communication and service applications, the pen can
transmit the recorded information, suitably together with
information about which operation is to be carried out, to a nearby
computer which, for example, arranges the information as an e-mail
message and sends this to a predetermined address or to an address
which is recorded by the pen. Alternatively, the pen can
communicate directly via its transceiver with a nearby external
unit, for example a fax machine, printer or the like, which is also
provided with a transceiver, in order to cause this to carry out
the required operation utilizing the recorded information.
[0140] Alternatively, the pen can communicate via its transceiver
with a mobile phone, which acts as a modem for the pen, for
forwarding the recorded information to, for example, a server unit,
another mobile phone or a fax machine.
[0141] As a further example, the pen can comprise or be integrated
in a mobile phone transceiver so that it can carry out the
operations which require communication directly.
[0142] In the above, wireless transmission of information from the
pen is described. However, the transmission can alternatively be
via cables. For example, the user unit 2 can be connected via a
cable to a network connection unit, such as a mobile phone, a PDA,
a computer or some other suitable unit which has an interface to a
computer network, for example the Internet or a local company
network. Alternatively, the network connection unit can be designed
as a docking unit (not shown) which can be connected via cables to
a communication network, such as a telephone network or a computer
network. Such a docking unit can advantageously be designed as a
pen stand. When the pen is placed in the docking unit, the pen is
caused, automatically or upon command, to communicate with the
outside world. The docking unit can also be designed to charge the
battery 15 (FIG. 3) in the pen. According to another alternative,
the docking unit is designed to establish wireless connection with
the outside world.
[0143] The above communication can be achieved by a subset of the
position-coding pattern coding coordinates for points within a main
region on the imaginary surface which is dedicated to the pen
sending all the recorded information, or parts thereof, to the
external unit when it detects coordinates within this main region.
The pen can be arranged to send information to the external unit
immediately or after a particular period of time. Alternatively,
the pen can send the information after the detection of a "send"
box. The "send" box can, in this case, be located within said main
region, the pen storing information which relates coordinates
within this main region to the address of the external unit, for
example, its Bluetooth.RTM. address.
[0144] Alternatively, as discussed above, the "send" box can be
located in a special command region, the "send" box being allocated
an instruction which causes the pen to send information to the
external unit. In this case, no main region is required which is
dedicated to sending recorded information to the external unit, as
the information can, for example, be recorded in a writing field
whose position-coding pattern codes coordinates for points within a
main region which is dedicated to hand-written notes, an address
field whose position-coding pattern codes coordinates for points
within a main region which is dedicated to OCR interpretation, etc.
Accordingly, the pen only needs to store information which relates
coordinates within the "send" box or a subregion with several
different command boxes, to the address of the external unit.
[0145] Information Processing in the System
[0146] The recorded information can be processed in the system
according to the invention. The processing can be implemented in
different parts of the system, depending upon the application
and/or capabilities of communication with external units.
[0147] The recorded information can be finally processed in the pen
itself.
[0148] Alternatively, only preliminary processing can be carried
out in the pen, such as decoding of a recorded image into a pair of
coordinates, compression of the recorded information or conversion
in the form of character interpretation, translation, encryption,
etc. The recorded information can then be sent to a local unit for
processing in this, for example a local computer or a PDA. The
local unit can contain information about the imaginary surface, or
at least part thereof, and can be designed in such a way that, in
response to the receipt of the recorded information, it identifies
to which region its coordinates belong and determines, based on the
region affiliation, how the information is to be processed.
Alternatively, the pen contains such information about the
imaginary surface, or a part thereof, that it is able to identify
to which region the coordinates belong and to determine, based on
the region affiliation, how the information is to be processed. In
this case, the pen suitably sends a processing instruction to the
local unit.
[0149] The recorded information can alternatively be processed by
an external service provider that only has information about its
part of the imaginary surface. Such an external service provider,
which has the sole right to a part (main region/subregion) of the
imaginary surface and does not have information about other parts,
can, for example, be a telecommunications operator which provides
communication services or a company which offers goods or services
via advertisements.
[0150] The pen can contain information to the effect that a
particular part of the imaginary surface belongs to such an
external service provider, in which case the pen sends the recorded
information directly to this service provider for further
processing.
[0151] Alternatively, the pen can be designed to send the recorded
information to a predetermined central unit, typically a server
unit, which contains information about all or parts of the
imaginary surface. The central unit can be arranged to identify, in
response to the receipt of the recorded information, to which
region its coordinates belong and to determine, based on the region
affiliation, how the information is to be processed. The central
unit can then forward the information to the external service
provider. Alternatively, the central unit can implement the service
or communication application in question.
[0152] According to a further alternative, the pen can be designed
to send the recorded information, preferably only one or a few
pairs of coordinates thereof, to a look-up unit, typically a server
unit or a local computer, which contains information about all or
parts of the imaginary surface. In this embodiment, the look-up
unit is designed to identify, in response to the receipt of
information from the pen, to which region the received information
belongs and to return to the pen an address for the external
service provider which is allocated the identified region. The pen
is designed to send the recorded information to this address for
final processing, in response to the receipt of the address.
[0153] Detailed Example of Imaginary Surface
[0154] FIG. 4 shows schematically, in a similar way to FIG. 2, an
imaginary surface 200 which constitutes or is made up by all the
points or positions whose absolute coordinates can be coded by a
position-coding pattern. A number of different main regions 201-206
are defined on the imaginary surface 200. The main regions are in
general divided into subregions (not shown), which in turn can be
divided into further subregions, etc.
[0155] In the discussion of the embodiment shown in FIG. 4 it is
assumed that the total surface 200 is made up of pairs of
x-y-coordinates of binary type, that is consisting of ones and
zeros, where the pairs of coordinates have a length of 36 bits for
both the x-coordinate and the y-coordinate. The position-coding
pattern thus codes coordinates which make up an imaginary surface
with 4.sup.36 points or positions. The number of positions in this
example can possibly be increased further by interpolation.
[0156] In the example according to FIG. 4, a "send" region 201 is
dedicated to be used for the generation of "send" commands from the
digital pen. The "send" region can, for example, be defined as all
pairs of coordinates whose x-value starts with 0001 and whose
y-value starts with 0001. For example, the four first bits in a
pair of coordinates thus indicate its affiliation to a main region.
With a division according to this example, 256 main regions are
obtained.
[0157] In the example concerned, the four first bits thus indicate
the main region affiliation, and a particular number of the last
bits indicates the size of the subregions in the main region. In
the "send" region 201, the size of the subregions 207 is the
minimum, a so-called atom, consisting of 64*64 positions or
corresponding to the six last bits. With a distance of
approximately 0.3 mm between the dots in the position-coding
pattern, this corresponds to a pattern surface of approximately
20*20 mm.sup.2. The other 26 bits (36-4-6) address the different
subregions 207 (corresponding to a "send" box) in the "send"
region. The total number of subregions is then 4.sup.26, that is
over 4500 billion (4 503 599 627 370 496). Each subregion 207
("send" box) can thereby be identified by a number which consists
of the 5th to the 30th bit of the x- and y-coordinates. The four
first bits in each recorded pair of coordinates thus indicate in
which main region the pen is situated, the following 26 bits
identify a subregion (for example, a particular "send" box) within
the main region, and the six last bits indicate where in the
subregion the pen is situated.
[0158] These "send" boxes suitably belong to different recipients
in a network which is connected to an information management system
according to this invention. Information about such affiliation is
stored in the information management system, either in the pen
itself or in an external unit communicating with the pen, such as a
local computer, a mobile phone or a server unit.
[0159] The second main region 202 is dedicated to notepad
information and also comprises a large number of subregions 208
(corresponding to writing fields). Information about the position
of these subregions 208 is preferably stored in a computer with
which one or more pens communicate, or in the pens themselves. The
position of the subregions 208 is predetermined, so that all users
of the system know in advance that notes made in these subregions
208 belong to the main region 202 which is dedicated to the
notepad.
[0160] For the notepad region 202 it is desirable that each
subregion 208 (writing field) is larger than an A4 page, for
example approximately 1 m.sup.2 in size, corresponding to
approximately 12 bits, to provide for essentially all formats of
notepad. The number of subregions 208 (writing fields) in the main
region 202 for the notepad is thus equal to 4.sup.20, that is
approximately 1 billion (1 099 511 627 776).
[0161] The third main region 203 is dedicated to general
availability. Information about the position of this main region is
stored in a server unit with which one or more pens communicate. No
user can reserve any part of this main region for his own use. This
main region can also be divided into subregions, but the user can
also decide for himself the sizes of the subregions.
[0162] The fourth main region 204 is, in contrast to the general
main region 203, dedicated to giving the owner exclusive
availability, that is the subregions are assumed only to be
available for one pen at a time or in the way determined by the
owner. Information about the position of this main region 204 and
its subregions is stored in a server unit with which one or more
pens communicate. The fact that the owner can reserve parts of this
main region for his own use means that collisions are avoided, as
two or more pens cannot simultaneously use an identical copy of the
same part of the printed position-coding pattern which makes up
this main region, or at least that the owner has full control over
this.
[0163] A large number of private subregions in one or more private
main regions 205 can be regarded as subscription objects, that is
they can be reserved for a user for a shorter or longer period of
time. Information about the positions of the main regions 205 or
their subregions can be stored, together with the identity of a
pen, in a server unit with which one or more pens communicate. In
principle each person and each company in the world can have their
own private area (subregion) with a size of 1 m.sup.2.
[0164] The sixth main region 206 is intended to be available for
local management of communication between a pen and a local
computer, without necessarily having to be in contact with a
computer/server unit in a network. Since the pen suitably
communicates directly with the local computer, the pen should
contain information about the position of this main region 206.
[0165] Of course, this can be achieved by the pen containing
information about the division of all the imaginary surface. It is,
however, desirable to minimize the information that must be stored
in the pen, as this means lower requirements for memory in the pen
and greater speed for its data processing.
[0166] A preferred structure for the main region 206 intended for
local communication is shown in FIG. 5 and described below. It
must, however, be pointed out that the structure described below
can equally well be used for service and communication
applications, particularly when there is a need for the pen to be
able to carry out operations itself on the recorded information and
it must therefore contain detailed information about the imaginary
surface.
[0167] In the embodiment according to FIG. 5, the main region 206
is divided into subregions 210-213 which contain basic elements in
the form of pages 213. Each page 213 is a particular size and has a
number of fields for predefined information management, as will be
described in greater detail in connection with FIG. 6. For example,
each main region 206 can be divided into a number of sections 210,
each of which is divided into a number of shelves 211, each of
which is divided into a number of books 212, each of which contains
the above-mentioned pages 213. At a particular level within the
subregions 210-212, all the pages 213 have an identical size and
layout. For example, the sections 210 can contain different pages,
while each section 210 contains shelves 211 and books 212 with
identical pages 213. Alternatively, each section's 210 shelves 211
can contain different pages 213, while all books 212 within each
shelf 211 have identical pages 213. Alternatively, the different
books 212 can contain different pages 213, while the pages within
each book 212 are identical. As a further alternative, the whole
main region 206 can, of course, contain identical pages 213 in all
the subregions 210-212.
[0168] The embodiment with a large number of identical pages
permits the use of a simplified, preferably algorithm-based,
database in the pen's memory. The pen stores a number of page
templates, which define the size and layout of the pages for the
different subregions 210-212 in the main region 206. Such a page
template can be allocated to the highest subregion level which
contains identical pages. With such a reduced database the pen can
independently and quickly calculate which information is to be sent
to the local computer, for example all information which has been
recorded on one or more pages. Suitably each section, shelf, book
and page has an identifying designation, for example a number. A
particular subregion, for example a page, can thus be addressed
simply by giving a sequence of numbers, as follows:
section.shelf.book.page. For example, 35.100.4.0 can be interpreted
as all the pages in book number 4 on shelf number 100 in section
number 35. In addition, the different fields on each page can be
addressed in a corresponding way:
section.shelf.book.page.field.
[0169] Each section 210 can be dedicated to a particular type of
information management, for example notes, calendar information,
etc. Within each section one or more shelves, books or pages can be
allocated to an owner. For example, a calendar manufacturer can
lease a shelf with 1024 books with 16384 pages of A9 format.
[0170] Alternatively, each hierarchically organized main region can
be dedicated to a particular type of information management, for
example notepads, calendars, graphical messages, etc, or for a
particular owner. It is realized that each such main region can be
divided into any number of subregion levels.
[0171] As mentioned above, each section 210, shelf 211, book 212,
page 213 or field can be allocated particular properties. In
addition to the above-mentioned layout of the pages, these
properties can, for example, indicate how long the pen is to store
information which has been recorded without having been sent to an
external unit, for example the above-mentioned local computer.
Other properties can be that all recorded information is to be sent
to a predetermined address, for example a Bluetooth.RTM. node, that
all recorded information is to be character-interpreted (ICR), that
all recorded information is to be sent directly, that is without
the recording of a "send" box.
[0172] Each page 213 is coded by a subset of the position-coding
pattern, which subset is intended to be applied onto the surface of
the intended product. This subset can be applied either
continuously or discontinuously on the surface of the product, as
will be explained in greater detail with reference to FIG. 6 which
shows an example of the layout of a page 213 on the imaginary
surface. The example shown is not restricted to recording of
information which is to be stored in a local computer, but also
makes possible communication and service applications.
[0173] The page 213 in FIG. 6 is rectangular, and can thus be
identified by the coordinates for two opposite corner points, C1,
C2. The page 213 contains a number of fields 214-220 with
completely or partially predetermined function.
[0174] A central writing field 214 is dedicated to recording of
graphical information. ICR fields 215 are dedicated to character
interpretation of the information recorded therein, where one or
more ICR fields can be predefined to concern address information,
for example an e-mail address, a fax number or a street address or
can be dedicated to decoding only numbers or only letters. "Send"
boxes 216 are dedicated to initiating sending of recorded
information, where certain "send" boxes can have pre-defined
properties, for example initiating the sending of an e-mail
message, a fax message or an SMS message. If a general "send" box
216 is used, this can instead be allocated service selection fields
216', which indicate the different "transport systems" that can be
used, for example e-mail, fax or SMS. Local command fields 217 are
dedicated to initiating operations in the pen's memory, for example
to delete all previously recorded information on the page in
question from the pen's memory, to compress existing information in
the pen's memory, to insert a bookmark in order to make possible
the recreation of the sequence of coordinates which was recorded in
the writing field when the bookmark was recorded, or to show
previously recorded information on the page in question on a
display, for example on a mobile phone or a local computer. The
property field 218 is dedicated to initiating sending of
information stored in the pen to an external unit, for example a
local computer or a server unit. Such a property field 218 can, for
example, initiate sending of the user's credit card number, postal
address, e-mail address, etc. General command fields 219 are
dedicated to initiating operations which are common to many
different applications, for example, that the information which is
to be sent is to be encrypted or allocated a particular priority,
or that the information recorded in the writing field 214 is to be
given certain visual properties, for example regarding color, line
thickness or line type, which is reproduced when the information
recorded in the writing field 214 is displayed, for example on a
computer screen, or when it is printed out. A signature field 220
is dedicated to recording pairs of coordinates, the angle between
the pen and the base, the rotation of the pen and the pressure on
the base.
[0175] In the example above, the page 213 thus contains a plurality
of message fields, such as writing field 214, ICR field 215 and
signature field 220, a plurality of command fields, such as "send"
boxes 216, local command fields 217, property fields 218 and
general command fields 219, and a plurality of selection fields
216', for example for choice of service.
[0176] The pen can, as mentioned above, store information about the
page 213 in the form of an algorithm-based page template. More
specifically, the different fields 214-220 can be identified as one
or more positions on the page 213. For example, each "send" box can
have a particular extent and can be located in a particular
position on each page 213. Similarly, each ICR field can have a
particular extent and a particular position on each page 213.
[0177] An advantage of this type of hierarchical structure is that
the pen can identify and initiate the operations which are
indicated by the above fields 214-220 independently and simply.
Thus the result of these operations can be shown to the user on a
display, for example on a mobile phone, a computer or on or in
association with the pen itself. The user has thus the opportunity
to confirm that the result is correct before the recorded
information is managed further in the system.
[0178] The owner of a particular page, book or shelf has the
opportunity to design a product surface with a position-coding
pattern, based on a page of the above-mentioned type. This can be
carried out in two different ways.
[0179] The product surface can be constructed of a position-coding
pattern which has a discontinuous layout. This can be regarded as
if all or parts of the different fields 214-220 on the above page
213 are "cut out" and arranged into a required appearance. The
actual location of the fields on the product surface is thus not
related to the position of the fields on the imaginary surface, as
different subsets of the position-coding pattern on the surface of
the product are taken from different parts of the imaginary
surface.
[0180] Such a discontinuous layout makes possible any placing and
dimensioning of different fields on the surface of the product, as
position-coding patterns which code parts of a "send" box, a
writing field, etc, can be located anywhere on the surface of the
product. This case is analogous with what was described above in
connection with the command regions in FIGS. 2 and 4.
[0181] The surface of the product can alternatively be constructed
of a position-coding pattern which has a continuous layout. This
can be regarded as if a part of the above page is "cut out" to
create a finished layout, so that the whole surface of the product
is provided with a position-coding pattern which codes coordinates
for a continuous coordinate area on the imaginary surface. Three
such layouts are indicated in FIG. 6 by broken lines. The reference
A concerns a notepad page, the reference B concerns a note sheet of
the type which is marketed under the trademark "Post-It", and the
reference C concerns a form for sending any graphical message.
[0182] The continuous position-coding pattern is preferable in
certain situations. The discontinuous layout of the position-coding
pattern often requires the boundary between adjacent fields on the
surface of the product to have no position-coding pattern for a
certain distance, typically approximately 1 mm, so that the subsets
which code coordinates on each side of the boundary can be detected
unambiguously. Such boundary areas without position-coding pattern
can be undesirable, particularly when the product is small. In
these cases a continuous layout of the position-coding pattern can
be preferable.
[0183] It must also be pointed out that when designing the surface
of the product, regardless of whether the pattern layout is
continuous or discontinuous, the owner can have the opportunity to
define in detail what the properties of each field are to be.
[0184] With both continuous and discontinuous layouts of the
position-coding pattern the advantage is obtained that the
information which is to be sent to the external unit is defined by
the corner points C1, C2 for the page concerned. The pen can thus,
automatically or upon command, send to the external unit all
information which has been recorded within the corner points C1, C2
on the imaginary surface.
[0185] A person skilled in the art will realize that there are many
alternative ways of dividing the imaginary surface. It is common to
the embodiments described above that different regions on the
imaginary surface are dedicated to different purposes. In this way
both recording of information and control of the management of
information can be carried out.
[0186] Appendix
[0187] In the following the description is reproduced of a
preferred position-coding pattern according to the International
Patent Application PCT/SE00/01895.
[0188] FIG. 7 shows a part of a product in the form of a sheet of
paper A1, which on at least part of its surface A2 is provided with
an optically readable position-coding pattern A3 which makes
possible position determination.
[0189] The position-coding pattern comprises marks A4, which are
systematically arranged across the surface A2, so that it has a
"patterned" appearance. The sheet of paper has an X-coordinate axis
and a Y-coordinate axis. The position determination can be carried
out on the whole surface of the product. In other cases the surface
which enables position determination can constitute a small part of
the product.
[0190] The pattern can, for example, be used to achieve an
electronic representation of information which is written or drawn
on the surface. The electronic representation can be achieved while
writing on the surface with a pen, by continually determining the
position of the pen on the sheet of paper by reading off the
position-coding pattern.
[0191] The position-coding pattern comprises a virtual raster,
which is thus neither visible to the eye nor can be detected
directly by a device which is to determine positions on the
surface, and a plurality of marks A4, each of which, depending upon
its position, represents one of four values "1" to "4" as described
below. In this connection it should be pointed out that for the
sake of clarity the position-coding pattern in FIG. 7 is greatly
enlarged. In addition, only a part of the sheet of paper is
shown.
[0192] The position-coding pattern is so arranged that the position
of a partial surface on the total writing surface for any partial
surface of a predetermined size is determined unambiguously by the
marks on this partial surface. A first and a second partial surface
A5a, A5b are shown by broken lines in FIG. 7. The second partial
surface partly overlaps the first partial surface. The part of the
position-coding pattern (here 4*4 marks) which is situated on the
first partial surface A5a codes a first position, and the part of
the position-coding pattern which is found on the second partial
surface A5b codes a second position. The position-coding pattern is
thus partly the same for the adjoining first and second positions.
Such a position-coding pattern is called "floating" in this
application. Each partial surface codes a specific position.
[0193] FIGS. 8a-d show how a mark can be designed and how it can be
positioned relative to its nominal position A6. The nominal
position A6, which can also be called a raster point, is
represented by the intersection of the raster lines A8. The mark A7
has the shape of a circular dot. A mark A7 and a raster point A6
can together be said to constitute a symbol.
[0194] In one embodiment, the distance between the raster lines is
300 .mu.m and the angle between the raster lines is 90 degrees.
Other raster intervals are possible, for example 254 .mu.m to suit
printers and scanners which often have a resolution which is a
multiple of 100 dpi, which corresponds to a distance between points
of 25.4 mm/100, that is 254 .mu.m.
[0195] The value of the mark thus depends upon where the mark is
located relative to the nominal position. In the example in FIG. 8
there are four possible locations, one on each of the raster lines
extending from the nominal position. The displacement from the
nominal position is the same size for all values.
[0196] Each mark A7 is displaced relative to its nominal position
A6, that is no mark is located at the nominal position. In
addition, there is only one mark per nominal position and this mark
is displaced relative to its nominal position. This applies to the
marks which make up the pattern. There can be other marks on the
surface which are not part of the pattern and thus do not
contribute to the coding. Such marks can be specks of dust,
unintentional points or marks and intentional marks, from for
example a picture or figure on the surface. Because the position of
the pattern marks on the surface is so well-defined, the pattern is
unaffected by such interference.
[0197] In one embodiment, the marks are displaced by 50 .mu.m
relative to the nominal positions A6 along the raster lines A8. The
displacement is preferably 1/6 of the raster interval, as it is
then relatively easy to determine to which nominal position a
particular mark belongs. The displacement should be at least
approximately 1/8 of the raster interval, otherwise it becomes
difficult to determine a displacement, that is the requirement for
resolution becomes great. On the other hand, the displacement
should be less than approximately 1/4 of the raster interval, in
order for it to be possible to determine to which nominal position
a mark belongs.
[0198] The displacement does not need to be along the raster line,
but the marks can be positioned in separate quadrants. However, if
the marks are displaced along the raster lines, the advantage is
obtained that the distance between the marks has a minimum which
can be used to recreate the raster lines, as described in greater
detail below.
[0199] Each mark consists of a more or less circular dot with a
radius which is approximately the same size as the displacement or
somewhat less. The radius can be 25% to 120% of the displacement.
If the radius is much larger than the displacement, it can be
difficult to determine the raster lines. If the radius is too
small, a greater resolution is required to record the marks.
[0200] The marks do not need to be circular or round, but any
suitable shape can be used, such as square or triangular, etc.
[0201] Normally, each mark covers several pixels on a sensor chip
and, in one embodiment, the center of gravity of these pixels is
recorded or calculated and used in the subsequent processing.
Therefore the precise shape of the mark is of minor significance.
Thus relatively simple printing processes can be used, provided it
can be ensured that the center of gravity of the mark has the
required displacement.
[0202] In the following, the mark in FIG. 8a represents the value
1, in FIG. 8b the value 2, in FIG. 8c the value 3 and in FIG. 8d
the value 4.
[0203] Each mark can thus represent one of the four values "1 to 4
". This means that the position-coding pattern can be divided into
a first position code for the x-coordinate and a second position
code for the y-coordinate. The division is carried out as
follows:
1 Mark value x-code y-code 1 1 1 2 0 1 3 1 0 4 0 0
[0204] The value of each mark is thus converted into a first value,
here bit, for the x-code and a second value, here bit, for the
y-code. In this way two completely independent bit patterns are
obtained by means of the pattern. Conversely, two or more bit
patterns can be combined into a common pattern which is coded
graphically by means of a plurality of marks in accordance with
FIG. 8.
[0205] Each position is coded by means of a plurality of marks. In
this example, 4*4 marks are used to code a position in two
dimensions, that is an x-coordinate and a y-coordinate.
[0206] The position code is constructed by means of a number series
of ones and zeros, a bit series, which has the characteristic that
no four-bit-long bit sequence occurs more than once in the bit
series. The bit series is cyclic, which means that the
characteristic also applies when the end of the series is connected
to its beginning. A four-bit sequence has thus always an
unambiguously determined position number in the bit series.
[0207] The bit series can be a maximum of 16 bits long if it is to
have the characteristic described above for bit sequences of four
bits. In this example, however, only a seven-bit-long bit series is
used, as follows:
[0208] "0 0 0 1 0 1 0".
[0209] This bit series contains seven unique bit sequences of our
bits which code a position number in the series as follows:
2 Position number in the series Sequence 0 0001 1 0010 2 0101 3
1010 4 0100 5 1000 6 0000
[0210] To code the x-coordinate, the bit series is written
sequentially in columns over all the surface which is to be coded,
where the left column K.sub.0 corresponds to the x-coordinate (0).
In one column the bit series can thus be repeated several times in
succession.
[0211] The coding is based on differences or position displacements
between adjacent bit series in adjacent columns. The size of the
difference is determined by the position number (that is the bit
sequence) in the bit series with which adjacent columns
commence.
[0212] More specifically, if we take the difference .DELTA..sub.n
modulo seven between, on the one hand, a position number which is
coded by a four-bit sequence in a first column K.sub.n and which
can thus have the value 0 to 6, and, on the other hand, a position
number which is coded by an adjacent four-bit sequence at a
corresponding "height" in an adjacent column K.sub.n+1 the
difference will be the same regardless of where, that is at what
"height", on the two columns the difference is taken. Using the
difference between the position numbers for two bit sequences in
two adjacent columns, it is thus possible to code an x-coordinate
which is independent of and constant for all y-coordinates.
[0213] As each position on the surface is coded by a partial
surface consisting of 4*4 marks in this example, there are four
vertical bit sequences available and thus three differences, each
with the value 0 to 6, for coding the x-coordinate.
[0214] The pattern is divided into code windows F with the
characteristic that each code window consists of 4*4 marks. There
are thus four horizontal bit sequences and four vertical bit
sequences available, so that three differences can be created in
the x-direction and four position numbers can be obtained in the
y-direction. These three differences and four position numbers code
the position of the partial surface in the x-direction and the
y-direction. Adjacent windows in the x-direction have a common
column, see FIG. 7. Thus the first code window F.sub.0,0 contains
bit sequences from the columns K.sub.0, K.sub.1, K.sub.2, K.sub.3,
and bit sequences from the rows R.sub.0, R.sub.1, R.sub.2, R.sub.3.
As differences are used in the x-direction, the next window
diagonally in the x-direction and y-direction, the window F.sub.1,1
contains bit sequences from the columns K.sub.3, K.sub.4, K.sub.5,
K.sub.6, and the rows R.sub.4, R.sub.5, R.sub.6, R.sub.7.
Considering the coding in just the x-direction, the code window can
be considered to have an unlimited extent in the y-direction.
Correspondingly, considering the coding in just the y-direction,
the code window can be considered to have an unlimited extent in
the x-direction. Such a first and second code window with unlimited
extent in the y-direction and x-direction respectively together
form a code window of the type shown in FIG. 7, for example
F.sub.0,0.
[0215] Each window has window coordinates F.sub.x, which give the
position of the window in the x-direction, and F.sub.y, which give
the position of the window in the y-direction. Thus the
correspondence between the windows and columns is as follows:
[0216] K.sub.i=3F.sub.x
[0217] R.sub.i=4F.sub.y
[0218] The coding is carried out in such a way that for the three
differences, one of the differences .DELTA..sub.0 always has the
value 1 or 2, which indicates the least significant digit S.sub.0
for the number which represents the position of the code window in
the x-direction, and the other two differences .DELTA..sub.1,
.DELTA..sub.2, have values in the range 3 to 6, which indicates the
two most significant digits S.sub.1, S.sub.2, for the coordinate of
the code window. Thus no difference can be zero for the
x-coordinates, as that would result in too symmetrical a code
pattern. In other words, the columns are coded so that the
differences are as follows: (3 to 6); (3 to 6); (1 to 2); (3 to 6);
(3 to 6); (1 to 2); (3 to 6); (3 to 6); (1 to 2); (3 to 6); (3 to
6); . . .
[0219] Each x-coordinate is thus coded by two differences
.DELTA..sub.1, .DELTA..sub.2 of between 3 and 6 and a subsequent
difference .DELTA..sub.0 which is 1 or 2. By subtracting one (1)
from the least difference A.sub.0 and three (3) from the other
differences, three digits are obtained, S.sub.2, S.sub.1, S.sub.0,
which in a mixed base directly give the position number of the code
window in the x-direction, from which the x-coordinate can then be
determined directly, as shown in the example below. The position
number of the code window is:
[0220] S.sub.2(4*2)+S.sub.1*2+S.sub.0*1
[0221] Using the principle described above, it is thus possible to
code code windows 0, 1, 2, . . . , 31, using a position number for
the code window consisting of three digits which are represented by
three differences. These differences are coded by a bit pattern
which is based on the number series above. The bit pattern can
finally be coded graphically by means of the marks in FIG. 8.
[0222] In many cases, when a partial surface is inputted consisting
of 4*4 marks, a complete position number which codes the
x-coordinate will not be obtained, but parts of two position
numbers, as the partial surface in many cases does not coincide
with one code window but covers parts of two adjacent code windows
in the x-direction. However, as the difference for the least
significant digit S.sub.0 of each number is always 1 or 2, a
complete position number can easily be reconstructed, as it is
known what digit is the least significant.
[0223] The y-coordinates are coded in accordance with approximately
the same principle as that used for the x-coordinates by means of
code windows. The cyclic number series, that is the same number
series as is used for the x-coding, is written repeatedly in
horizontal rows across the surface which is to be position coded.
Precisely as for the x-coordinates, the rows are made to start in
different positions, that is with different bit sequences, in the
number series. For the y-coordinates, however, differences are not
used, but the coordinates are coded by values which are based on
the start position of the number series in each row. When the
x-coordinate has been determined for a partial surface with 4*4
marks, the start positions in the number series can in fact be
determined for the rows which are included in the y-code for the
4*4 marks.
[0224] In the y-code, the least significant digit S.sub.0 is
determined by letting this be the only digit which has a value in a
particular range. In this example, one row of four starts in
position 0 to 1 in the number series, in order to indicate that
this row concerns the least significant digit S.sub.0 in a code
window, and the three other rows start in any of the positions 2 to
6 in order to indicate the other digits S.sub.1 S.sub.2 S.sub.3 in
the code window. In the y-direction there is thus a series of
values as follows:
[0225] (2 to 6); (2 to 6); (2 to 6); (0 to 1); (2 to 6); (2 to 6);
(2 to 6); (0 to 1); (2 to 6); . . .
[0226] Each code window is thus coded by three values between 2 and
6 and a subsequent value between 0 and 1.
[0227] If zero (0) is subtracted from the low value and two (2)
from the other values, a position in the y-direction S.sub.3
S.sub.2 S.sub.1 S.sub.0 in mixed base is obtained in a
corresponding way as for the x-direction, from which the position
number of the code window can be determined directly, which is:
[0228] S.sub.3*(5*5*2)+S.sub.2*(5*2)+S.sub.1*2+S.sub.0*1
[0229] Using the method above, it is possible to code 4*4*2=32
position numbers in the x-direction for the code windows. Each code
window comprises bit sequences from three columns, which gives
3*32=96 columns or x-coordinates. In addition, it is possible to
code 5*5*5*2=250 position numbers in the y-direction for the code
windows. Each such position number comprises horizontal bit
sequences from 4 rows, which gives 4*250=1000 rows or
y-coordinates. In total it is thus possible to code 96000
coordinate positions.
[0230] As the x-coding is based on differences, it is, however,
possible to select the position in which the first number series in
the first code window is to start. If it is taken into account that
this first number series can start in seven different positions, it
is possible to code 7*96000=672000 positions. The start position of
the first number series in the first column K.sub.0 can be
calculated when the x- and y-coordinates have been determined. The
above seven different start positions for the first series can code
different pages or writing surfaces on a product.
[0231] Theoretically, a partial surface with 4*4 symbols, which
each have four values, can code 4.sup.4*4 positions, that is
4,294,967,296 positions. In order to make possible floating
determination of the position of a partial surface, there is thus a
redundancy factor in excess of 6000(4294967296/672000).
[0232] The redundancy consists partly in the restrictions on the
size of the differences, and partly in only 7 bits out of 16 being
used in the position code. This latter fact can, however, be used
to determine the rotational position of the partial surface. If the
next bit in the bit series is added to the four-bit sequence, a
five-bit sequence is obtained. The fifth bit is obtained by reading
off the adjacent bit immediately outside the partial surface which
is being used. Such an additional bit is usually easily
available.
[0233] The partial surface which is read off by the sensor can have
four different rotational positions, rotated through 0, 90, 180 or
270 degrees relative to the code window. In those cases where the
partial surface is rotated, the reading off of the code will,
however, be such that the code read off will be inverted and
reversed in either the x-direction or the y-direction or both, in
comparison to if it had been read off at 0 degrees. This assumes,
however, that a slightly different decoding of the value of the
marks is used according to the table below.
3 Mark value x-code y-code 1 0 0 2 1 0 3 1 1 4 0 1
[0234] The above-mentioned five-bit sequence has the characteristic
that it only occurs the right way round and not in inverted and
reversed form in the seven-bit series. This is apparent from the
fact that the bit series (0 0 0 1 0 1 0) contains only two "ones".
Therefore all five-bit sequences must contain at least three zeros,
which after inversion (and any reversing) result in three ones,
which cannot occur. Thus if a five-bit sequence is found which does
not have a position number in the bit series, it can be concluded
that the partial surface should probably be rotated and the new
position tested.
[0235] In order to further illustrate the invention according to
this embodiment, here follows a specific example which is based on
the described embodiment of the position code.
[0236] FIG. 9 shows an example of an image with 4*4 marks which are
read off by a device for position determination.
[0237] These 4*4 marks have the following values:
4 4 4 4 2 3 2 3 4 4 4 2 4 1 3 2 4
[0238] These values represent the following binary x- and
y-codes:
5 x-code: 0 0 0 0 1 0 1 0 0 0 0 0 1 1 0 0
[0239]
6 y-code: 0 0 0 1 0 1 0 0 0 0 1 0 1 0 1 0
[0240] The vertical bit sequences in the x-code code the following
positions in the bit series: 2 0 4 6. The differences between the
columns are -2 4 2, which modulo 7 gives: 5 4 2, which in mixed
base codes the position number of the code window:
(5-3)*8+(4-3)*2+(2-1) 16+2+1=19. The first coded code window has
the position number 0. Thus the difference which lies in the range
1 to 2 and which appears in the 4*4 marks of the partial surface is
the twentieth such difference. As additionally there are in total
three columns for each such difference and there is a start column,
the vertical sequence furthest to the right in the 4*4 x-code
belongs to the 61st column (column 60) in the x-code (3*20+1=61)
and the vertical sequence furthest to the left belongs to the 58th
column (column 57).
[0241] The horizontal bit sequences in the y-code code the
positions 0 4 1 3 in the number series. As these horizontal bit
sequences start in the 58th column, the start position of the rows
is these values minus 57 modulo 7, which gives the start positions
6 3 0 2. Converted to digits in mixed base, this becomes 6-2, 3-2,
0-0, 2-2 4 1 0 0, where the third digit is the least significant
digit in the number concerned. The fourth digit is then the most
significant digit in the next number. It must in this case be the
same as in the number concerned. (The exception is when the number
concerned consists of highest possible digits in all positions.
Then it is known that the commencement of the next number is one
larger than the commencement of the number concerned.)
[0242] The position number is in mixed base
0*50+4*10+1*2+0*1=42.
[0243] The third horizontal bit sequence in the y-code thus belongs
to the 43rd code window which has a start position 0 or 1, and as
there are four rows in total for each such code window, the third
row is number 43*4=172.
[0244] In this example, the position of the top left corner of the
partial surface with 4*4 marks is (58,170).
[0245] As the vertical bit sequences in the x-code in the 4*4 group
start at row 170, the whole pattern's x-columns start in the number
series' positions ((2 0 4 6) -169) mod 7=1 6 3 5. Between the last
start position (5) and the first start position the numbers 0-19
are coded in mixed base, and by adding the representations of the
numbers 0-19 in mixed base the total difference between these
columns is obtained. A primitive algorithm for doing this is to
generate these twenty numbers and directly add their digits. Call
the sum obtained s. The page or writing surface is then given by
(5-s)modulo7.
[0246] An alternative method for determining which bit is the least
significant in a partial surface, in order to be able to identify a
code window in this way, is as follows. The least significant bit
(LSB) is defined as the digit which is the lowest in a partial
surface's differences or row position number. In this way, the
reduction (redundancy) of the maximum useable number of coordinates
is relatively small. For example, the first code windows in the
x-direction in the example above can all have LSB=1 and other
digits between 2 and 6, which gives 25 code windows, the next can
have LSB=2 and other digits between 3 and 6, which gives 16 code
windows, the next can have LSB=3 and other digits between 4 and 6,
which gives 9 code windows, the next can have LSB=4 and other
digits between 5 and 6, which gives 4 code windows, the next can
have LSB=5 and other digits 6, which gives 1 code window, that is a
total of 55 code windows, compared to 32 in the example above.
[0247] In the example above, an embodiment has been described where
each code window is coded by 4*4 marks and a number series with 7
bits is used. This is, of course, only one example. Positions can
be coded by more or fewer marks. There does not need to be the same
number in both directions. The number series can be of different
lengths and does not need to be binary, but can be based on a
different base, for example hex code. Different number series can
be used for coding in the x-direction and coding in the
y-direction. The marks can represent different numbers of values.
The coding in the y-direction can also be carried out by
differences.
[0248] In a practical example, a partial surface is used consisting
of 6*6 marks and where the bit series as a maximum can consist of
2.sup.6 bits, that is 64 bits. However, a bit series consisting of
51 bits is used, and consequently 51 positions, in order to have
the possibility of determining the rotational position of the
partial surface. An example of such a bit series is:
7 0 0 0 0 0 1 1 0 0 0 1 1 1 1 1 0 1 0 1 0 1 1 0 1 1 0 0 1 1 0 1 0 0
0 1 0 1 0 0 1 1 1 0 1 1 1 1 0 0 1 0
[0249] Such a partial surface consisting of six by six marks can
code 4.sup.6*6 positions, which with the above raster dimensions of
0.3 mm is an extremely large surface.
[0250] In a similar way as described above for the seven-bit
series, according to this invention the characteristic is utilized
that the partial surface is enlarged to include one bit on each
side of the partial surface, at least at its center, so that for
the third and fourth rows in the partial surface of 6*6 symbols, 8
symbols are read off, one on each side of the partial surface, and
similarly in the y-direction. The above-mentioned bit series which
contains 51 bits has the characteristic that a bit sequence of 6
bits occurs only once and that a bit sequence of 8 bits which
contains said bit sequence of 6 bits occurs only once and never in
an inverted position or reversed and inverted. In this way, the
rotational position of the partial surface can be determined by
reading off 8 bits in row 3, row 4, column 3 and/or column 4. When
the rotational position is known, the partial surface can be
rotated to the correct position before the processing is
continued.
[0251] It is desirable to obtain a pattern which is as random as
possible, that is where areas with excessive symmetry do not occur.
It is desirable to obtain a pattern where a partial surface with
6*6 marks contains marks with all the different positions in
accordance with FIGS. 8a to 8d. In order to increase the randomness
further or avoid repetitive characteristics, a method can be used
which is called "shuffle". Each bit sequence in a code window
starts in a predetermined start position. However, it is possible
to displace the start position in the horizontal direction for each
row, if the displacement is known. This can be carried out by each
least significant bit (LSB) being allocated a separate displacement
vector for the adjacent rows. The displacement vector states by how
much each row is displaced in the horizontal direction. Visually it
can be regarded as if the y-axis in FIG. 7 is "spiky".
[0252] In the example above, with a 4*4 code window, the
displacement vector can be 1, 2, 4, 0 for LSB=0 and 2, 2, 3, 0 for
LSB=1. This means that after subtracting the numbers 2 and 0
respectively, the above displacement is to be subtracted (modulo
five) from the bit sequence's position number, before the
calculating continues. In the example above, for the y-coordinate,
the digits 4 1 0 0 (S.sub.2, S.sub.1, S.sub.0, S.sub.4) are
obtained in mixed base, where the second digit from the right is
the least significant digit, LSB. As the displacement vector 1, 2,
4, 0 is to be used (LSB=0) for the digits 4 and 1, 2 is subtracted
from 4 to give S.sub.2=2 and 4 is subtracted from 1 (modulo five)
to give S.sub.1=2. The digit S.sub.0=0 remains unchanged (the
displacement vector's component for the least significant digit is
always zero). Finally, the digit S.sub.4 belongs to the next code
window, which must have LSB=1, that is the second displacement
vector is to be used. Thus 2 is subtracted from 0 (modulo five)
which gives S.sub.4=3.
[0253] A similar method can be used to change the codes for the
x-coordinates. However, there is less need to change the
x-coordinates, as they are already relatively randomly distributed,
as the difference zero is not used, in the example above.
[0254] In the example above, the mark is a dot. Naturally it can
have a different appearance. It can, for example, consist of a line
or an ellipse, which starts at the virtual raster point and extends
from this to a particular position. Other symbols than a dot can be
used, such as a square, rectangle, triangle, circle or ellipse,
filled-in or not.
[0255] In the example above, the marks are used within a square
partial surface for coding a position. The partial surface can be
another shape, for example hexagonal. The marks do not need to be
arranged along the raster lines in an orthogonal raster but can
also have other arrangements, such as along the raster lines in a
raster with 60 degree angles, etc. A polar coordinate system can
also be used.
[0256] Rasters in the form of triangles or hexagons can also be
used. For example, a raster with triangles enables each mark to be
displaced in six different directions, which provides even greater
possibilities, corresponding to 6.sup.6*6 partial surface
positions. For a hexagonal raster, a honeycomb pattern, each mark
can be displaced in three different directions along the raster
lines.
[0257] As mentioned above, the marks do not need to be displaced
along the raster lines but can be displaced in other directions,
for example in order to be located each in a separate quadrant of a
square raster pattern. In the hexagonal raster pattern the marks
can be displaced in four or more different directions, for example
in six directions along the raster lines and along lines which make
60 degrees with the raster lines.
[0258] In order for the position code to be detected, it is
necessary for the virtual raster to be determined. This can be
carried out, in a square raster pattern, by examining the distance
between the different marks. The shortest distance between two
marks must originate from two adjacent marks with the values 1 and
3 in the horizontal direction or 2 and 4 in the vertical direction,
so that the marks lie on the same raster line between two raster
points. When such a pair of marks has been detected, the associated
raster points (the nominal positions) can be determined using
knowledge of the distance between the raster points and the
displacement of the marks from the raster points. Once two raster
points have been located, additional raster points can be
determined using the measured distance to other marks and from
knowledge of the distance between the raster points.
[0259] If the marks are displaced 50 .mu.m along the raster lines,
which are a distance of 300 .mu.m apart, the least distance between
two marks will be 200 .mu.m, for example between marks with the
values 1 and 3. The next smallest distance arises between, for
example, marks with the values 1 and 2, and is 255 .mu.m. There is
therefore a relatively distinct difference between the least and
the next smallest distance. The difference in any diagonals is also
great. However, if the displacement is larger than 50 .mu.m, for
example more than 75 .mu.m (1/4), diagonals can cause problems and
it can be difficult to determine to which nominal position a mark
belongs. If the displacement is less than 50 .mu.m, for example
less than approximately 35 .mu.m (1/8), the least distance will be
230 .mu.m, which does not give a very large difference to the next
distance, which is then 267 .mu.m. In addition, the demands on the
optical reading off increase.
[0260] The marks should not cover their own raster point and should
therefore not have a larger diameter than twice the displacement,
that is 200%. This is, however, not critical, and a certain
overlapping can be permitted, for example 240%. The least size is
determined initially by the resolution of the sensor and the
demands of the printing process used to reproduce the pattern.
However, the marks should not have a smaller diameter than
approximately 50% of the displacement in practice, in order to
avoid problems with particles and noise in the sensor.
[0261] In the embodiment above, the raster is an orthogonal grid.
It can also have other forms, such as a rhombic grid, for example
with 60 degree angles, a triangular or hexagonal grid, etc.
[0262] Displacement in more or less than four directions can be
used, for example displacement in three directions along a
hexagonal virtual raster. In an orthogonal raster only two
displacements can be used, in order to facilitate the recreation of
the raster. However, a displacement in four directions is
preferred, but six or eight directions are also possible.
[0263] In the embodiment above, the longest possible cyclic number
series is not used. Thus a degree of redundancy is obtained, which
can be used in various ways, for example to carry out error
correcting, replace missing or hidden marks, etc.
* * * * *