U.S. patent application number 09/317518 was filed with the patent office on 2003-01-09 for data entry device recording input in two dimensions.
Invention is credited to JIN, GUO, WU, CHARLES YIMIN.
Application Number | 20030006956 09/317518 |
Document ID | / |
Family ID | 23234036 |
Filed Date | 2003-01-09 |
United States Patent
Application |
20030006956 |
Kind Code |
A1 |
WU, CHARLES YIMIN ; et
al. |
January 9, 2003 |
DATA ENTRY DEVICE RECORDING INPUT IN TWO DIMENSIONS
Abstract
A data entry device having an integral input element capable of
recording input movement in two dimensions (including Chinese
strokes and characters, Roman letters and Arabic numerals) and
delivering resultant signals to a processor. The processor is
programmed for identifying a handwriting input represented by the
signals.
Inventors: |
WU, CHARLES YIMIN;
(SINGAPORE, SG) ; JIN, GUO; (SUNNYVALE,
CA) |
Correspondence
Address: |
MOTOROLA INC
600 NORTH US HIGHWAY 45
LIBERTYVILLE
IL
60048-5343
US
|
Family ID: |
23234036 |
Appl. No.: |
09/317518 |
Filed: |
May 24, 1999 |
Current U.S.
Class: |
345/156 ;
178/18.01; 345/161 |
Current CPC
Class: |
G06F 3/0233 20130101;
G06V 10/17 20220101 |
Class at
Publication: |
345/156 ;
345/161; 178/18.01 |
International
Class: |
G09G 005/00; G09G
005/08 |
Claims
1. A data entry device comprising: an array of switching elements
capable of recording input movement between at least four discrete
points arranged in two dimensions and providing a series of
discrete inputs; a memory having stored therein handwriting input
identifiers and at least one series of discrete inputs for each
handwriting input identifier; a processor coupled to the array of
switching elements and the memory and programmed for searching the
handwriting input identifiers with a series of discrete inputs
received from the array of switching elements for identifying a
handwriting input represented by the series of discrete inputs.
2. The data entry device of claim 1 wherein the array is an array
of finger-operated switches.
3. The data entry device of claim 2, wherein the array comprises at
least four and not more than sixteen switches.
4. The data entry device of claim 2, wherein the array comprises at
least four and not more than eight switches arranged at points of a
compass.
5. The data entry device of claim 2, wherein the array comprises
four switches arranged at northeast, southeast, southwest and
northwest sectors of the input device.
6. The data entry device of claim 1, wherein the array comprises a
joystick element.
7. The data entry device of claim 6, wherein the joystick element
includes a push switch.
8. The data entry device of claim 7, wherein the data entry device
generates the series of discrete inputs when the push switch is
active and the joystick element is moved in a horizontal plane.
9. The data entry device of claim 1, wherein the handwriting input
identifiers are stored as a table of Roman character
identifiers.
10. The data entry device of claim 1, wherein the handwriting input
identifiers are stored as a table of stroke identifiers.
11. The data entry device of claim 10, wherein the memory further
comprises a table of ideographic character identifiers, and the
processor is programmed to index the table of ideographic character
identifiers using at least one handwriting input identifier from
the table of stroke identifiers.
12. The data entry device of claim 11, wherein the table of
ideographic character identifiers is a table of Chinese character
identifiers.
13. The data entry device of claim 11, wherein the table of
ideographic character identifiers is a table of Japanese character
identifiers.
14. A method of data entry comprising: providing a data entry
device capable of recording input movement between at least four
discrete points arranged in two dimensions; receiving from the data
entry device a series of discrete inputs identifying a series of
discrete points of the data entry device; storing in memory a table
of characters having at least one series of discrete inputs for
each character; indexing the table of characters with a series of
discrete inputs received, thereby identifying a character
represented by the series of discrete inputs.
15. The method of claim 14, wherein the data entry device has at
least four and not more than sixteen discrete points.
16. The method of claim 14 wherein the data entry device has at
least four and not more than eight discrete points arranged at
points of a compass.
17. The method of claim 14 wherein the discrete points are arranged
at northeast, southeast, southwest and northwest sectors of the
input device.
18. The method of claim 14, wherein the step of receiving comprises
moving a pointer element across the input device and generating the
discrete inputs from movement of the pointer relative to the input
device.
19. A data entry device comprising: a two-dimensional input device
comprising: a joystick element; analog elements mounted in first
and second dimensions providing analog movement signals responsive
to movement of the joystick element in first and second dimensions
of a horizontal plane; an analog-to-digital converter coupled to
the input device; and a processor coupled to the analog-to-digital
converter for receiving digitized inputs from the input device, the
processor having instructions that cause the processor to perform
pre-processing operations for segmenting into strokes digitized
inputs received from the input device, and to perform recognition
operations recognizing the strokes as handwritten input and
generating character identifications therefrom.
20. The data entry device of claim 19, further comprising a push
switch integral with the joystick element and responsive to pushing
of the joystick element.
21. The data entry device of claim 20, wherein the processor is
responsive to the push switch for segmenting into strokes digitized
input received while the switch is pushed.
Description
FIELD OF THE INVENTION
[0001] This invention relates to a method which permits a user to
input data (including Chinese strokes and characters, Roman letters
and Arabic numerals) using a compact input device in a novel and
convenient manner.
BACKGROUND OF THE INVENTION
[0002] Many proposals and designs exist for using keypad on small
hand-held devices for entry of Chinese strokes as part of character
input process. In operation, a user simply types in the strokes by
pressing the keys in a sequence according to the natural writing
order of the strokes of the character he wishes to generate.
[0003] Generally, strokes of Chinese characters can be classified
into certain number of basic stroke types. A typical example of
that number is 26. We refer to such a number as N. These N basic
strokes can be further grouped into 5 to 9 stroke categories
according to various defining criteria. From now onwards, we refer
to the stroke categories simply as strokes.
[0004] The prevailing method for entry of Chinese strokes on a
keypad requires that each kind of stroke be assigned to a specific
key on the keypad. A user types in a stroke by pressing the
corresponding key. One example of such a scheme can be found in US
patent application No. 09/220,308 of Guo et al., filed on Dec. 23,
1998 and assigned to the assignee of the present application, where
9 strokes are defined and assigned to 9 corresponding keys on the
phone keypad respectively. Such an example can also be found in
Motorola's CD928C cellular telephone.
[0005] In operation, a user enters the strokes of a character by
pressing on the corresponding keys one at a time. A set of
candidate characters is generated and presented on a display as
matching alternatives. The displayed set of candidate characters is
updated with every entry of a stroke. The user selects the
character he or she wants from the set of candidate characters.
[0006] Two disadvantages with the above method lie in, first, the
separately defined keys and second, the less intuitive relationship
between the stroke writing process and the key pressing process.
Due to the first constraint, for every intended stroke a user has
to select a specific key among several corresponding keys. When
fast or blind typing of strokes is required, a user may encounter
many misfires when doing the key selecting and pressing at a fast
pace or in a dark environment. The method requires the conversion
from the natural stroke writing process to the key pressing
process. The relationship between these two is not very
straightforward nor highly intuitive. Therefore, in addition to
decoding characters into strokes, a user's mind also needs to
constantly engage in matching strokes to associated keys. For a
casual user, in order to be assured of a correct result, the user's
eyes have to monitor not only the set of candidate characters, but
also the key pressing on the keypad. It makes the whole character
entry process inefficient and stressful.
[0007] There also exists a method for inputting Roman letters on a
small keypad, as can be found on many fixed-line phones or cell
phones. In this method, generally, nine of the ten numerical keys
are employed to input Roman letters, with each key assigned to a
certain number of Roman letters. Typically, numerical key 1 is
assigned to ABC, key 2 is assigned to DEF, . . . , key 8 is
assigned to WXYZ. In operation, a user presses key 1 once to enter
A, twice to enter B, three times to enter C. The user presses on
key 2 to enter D or E or F, on key 3 to enter G or H or I, and so
on.
[0008] This method involves two steps when inputting a letter.
First, a specific key is to be selected from the keypad for the
intended letter. Second, the user needs to press that particular
key for an exact number of times in order to retrieve the letter.
The latter step can be avoided by using a disambiguation scheme
such as that described in Arnott, J. L et al, "Probabalistic
Character Disambiguation for Reduced Keyboards Using Small Text
Samples", Augmentative and Alternative Communication, 1992.
[0009] Although this method is fairly straightforward, with almost
no learning curve needed, it has two disadvantages. First, for a
casual user, it requires intensive visual checking on the keypad
when doing key selecting and pressing. Second, it is neither
compatible to the way a user types on a normal size keyboard nor
analogous to the way the user writes on paper. Hence, it affects
the efficiency in user's content composing and results in slower
input speed.
[0010] Other methods of data entry involve writing characters on a
tablet using a stylus and performing hand recognition on the input
penstrokes. Devices manufactured for this method require a tablet
of significant area and generally require a special stylus. The
tablet area does not permit use of the method on very small devices
such as small mobile telephones. The stylus is an inconvenient
additional element, as it can be lost. Two-handed operation is
necessary: one hand to hold the device and the other hand to
operate the stylus. Such a method is not optimal for a busy
user.
[0011] There is therefore a demand for an improved method for data
entry where fewer keys are needed, and where there is an intuitive
relationship between the writing and the key pressing process, so
as to achieve better ergonomic efficiency.
SUMMARY OF THE INVENTION
[0012] According to one aspect of the present invention, a data
entry device is provided comprising an array of switching elements
capable of recording input movement between at least four discrete
points arranged in two dimensions and providing a series of
discrete inputs. The array of switching elements may be
touch-sensitive or proximity-sensitive switches or pushbuttons and
may be activated with a pen, finger or stylus, or they may be
discrete points of operation of a joystick, trackball, mouse or
similar device. They may be arranged at points of a compass or in a
two-dimensional matrix array.
[0013] A table of handwriting input identifiers (e.g. strokes,
character components, characters or pseudo-characters) is stored in
memory with at least one series of discrete inputs for each
handwriting input identifier. The table of handwriting input
identifiers is indexed (e.g. by a look-up operation or a search
operation) with a series of discrete inputs received from the array
of switching elements. In this manner, a handwriting input
represented by the series of discrete inputs is identified and may
be displayed to the user or stored or otherwise used as original
data entry.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 is a block diagram illustrating an embodiment of a
data entry device in accordance with the invention.
[0015] FIGS. 2a-2f are diagrams showing different examples of
stroke inputs using a four-switch input device.
[0016] FIG. 3 is a flow diagram illustrating operation of the
program controlling the microprocessor of FIG. 1.
[0017] FIGS. 4, 5 and 6 are a front view, rear view and elevation
view respectively of a joystick-type device for use in place of the
input device of FIG. 1.
[0018] FIG. 7 is a diagram of examples of Roman letter input using
a four-switch input device.
[0019] FIG. 8 is a block diagram of an alternative embodiment of
the invention.
DETAILED DESCRIPTION OF THE DRAWINGS
[0020] Referring to FIG. 1, a data entry device 10 (such as a
cellular telephone, a wireless messaging communicator, a personal
digital assistant, a memo-writer or other device) is shown
comprising a microprocessor 11, an input device 12, a display 13
(or other output device such as a RF or IR link), a program memory
14 and a data memory 15.
[0021] The input device may take a number of forms, any of which is
capable of recording input movement between at least four discrete
points arranged in two dimensions. In the preferred embodiment it
comprises four push keys 20 in a matrix or square of about 1.5 cm
in height and 1.5 cm width, with one key at each corner. For
convenience's sake, the top-left key is numbered 1, the top-right
2, the bottom-left 3, and the bottom-right 4. Each key can be
sensitive to pressure or sensitive to merely the presence of the
fingertip on or near the key. The four keys provide four inputs
into the microprocessor. The four inputs are illustrated as four
discrete lines, but it will be understood that four data states can
be represented by two data lines (with or without a "data active"
line).
[0022] The data entry device 10 may have further buttons (not
shown) for other functions. For example, it preferably has a 12-key
keypad for entry of digits 0-9 and for calling. Scrolling keys may
be provided for menu control.
[0023] The memory 15 is illustrated as having two tables 25 and 26.
Tables are not essential, but it will be explained below that
tables are a useful and convenient manner of translating inputs
from the input device 12 into primitive handwriting elements and
(if required by the ultimate character set of the language in
question) for translating primitive handwriting elements into data
characters.
[0024] In operation, a user enters vector or movement strokes into
the input device 12 by passing his or her finger across the keys 20
in two dimensions in a horizontal plane. The input device 12
generates a series or sequence of discrete inputs to the
microprocessor 11, dependent on the keys activated. This is
explained in greater detail below with reference to language
examples. The microprocessor, under the control of program code
stored in program memory 14, performs a look-up or search operation
in the memory 15 to uniquely identify the intended character or to
identify the most likely intended character.
[0025] Where a character is uniquely identified by the
microprocessor 11, it is displayed on display 13. Where several
likely intended characters are identified, one or more is or are
displayed on display 13. Where one character only is displayed, the
character that is deemed to be the most likely intended character
is displayed. Where several candidate characters are displayed,
these are displayed in a selection list in decreasing order of
likelihood of usage. Likelihood of intended usage is determined by
frequency information in the memory 15, showing the frequency of
usage of a character in the language in question (or the relative
frequency of usage from among several candidates) or the frequency
of usage of a character in the context of the character in the
language (e.g. taking into account the previous N characters). A
more detailed explanation is set out below.
EXAMPLE 1
Chinese input
[0026] In one example, an apparatus is described for inputting
Chinese strokes.
[0027] In operation, if a user wishes to input a left-right
horizontal stroke, the user moves his or her thumb horizontally
across key1 and key2. The signal that key1 and key2 have been
consecutively visited in a particular sequence is sent to the
microprocessor 11 for interpretation as horizontal stroke. In the
same manner, for a top-down vertical stroke, the user moves his or
her thumb across key1 and key2.
[0028] The method presented here defines 6 fundamental strokes,
namely "horizontal", "vertical", "slash", "back slash", "clockwise"
and "counter-clockwise". There now follows, with reference to FIGS.
2a-2f, a brief description of the six fundamental strokes and how
they can be entered via sequence of keys. In the following table
(Table 1), "No." is a serial number for the fundamental strokes;
"Type" is the name of the fundamental strokes; "Var" is the number
of variations of thumb move paths; and "Path" is the thumb move
paths defined by the sequence of keys being visited.
1TABLE 1 No. Type Var Path Description 1 Horizontal 3 12 34 32
left-right, stroke "HENG" or "TI" 2 Vertical 2 13 24 top-down,
stroke "SHU" 3 Slash 1 23 top-right to bottom- left, stroke "PIE" 4
Backslash 1 14 top-left to bottom- right, stroke "DIAN" or "NA" 5
Clockwise 5 124 123 241 1241 1231 clockwise turn, stroke "ZHE" 6
Counter- 5 134 234 132 142 1342 counter-clockwise clockwise turn,
stroke "ZHE"
[0029] Strokes 1-6 are illustrated in FIGS. 2a-2f respectively. A
stroke is classified as "clockwise turn" type if and only if the
first turn of the stroke is of clockwise direction, no matter how
many turns may follow thereafter and no matter what direction they
are. The same applies to the "counter-clockwise turn" stroke type.
A thumb move path is the sequence of keys which have been visited
during a preset time period from the first key of the sequence
being visited until a pre-defined time-off is detected. A time-off
is the time elapse from the moment the previous key is visited to
the moment the next key is visited.
[0030] Upon entering strokes using discrete thumb, finger, stylus,
trackball, mouse or other two-dimensional stroke inputs, i.e.
discrete signals representative of discrete vectors, the
microprocessor 11 translates the vector inputs into strokes using
Table 1 and then performs a tabular look-up or other search in
table 26 in memory 15 for Chinese characters corresponding to the
stroke inputs. A two-stage translation is preferred, as this
reduces the size of table 26, but it is not necessary. Chinese
character identifiers can alternatively be stored in table 26 in a
manner indexable by a raw vector input sequence.
[0031] A method for storing and performing look-up of Chinese
characters from primitive stroke data is described in co-pending
patent application No. 08/806,504 of Chen, assigned to the assignee
of the present invention and incorporated herein by reference,
which describes a table of digit streams representative of
characters in a desired language and character addresses
corresponding to the digit streams. The digit streams are
equivalent to sequences of strokes (e.g. strokes 1-6 above).
Alternatively, in accordance with the teaching of the present
invention, the digit streams can be key sequences representative of
stroke vectors.
[0032] Also described in the co-pending patent application, and
illustrated in FIG. 3 herein, is a further table 27 of characters
located at addresses corresponding to character addresses from
table 26. A character is read from table 27 located at a character
address obtained from table 26. Characters in the table 27 that
have a common stroke sequence (or common digit stream) are stored
in order of relatively decreasing frequency of use. This scheme
allows for changing the relative addresses of characters in the
table 27 to adjust for relative frequency of use of characters. A
further table 28 can optionally be provided to perform bigram
look-up operations. The output of table 27 (or table 28 if used) is
standard hexGB coding of one or more Chinese characters. A further
look-up is used to obtain and display the pictorial representation
of the character.
[0033] The above method has the following two notable and
advantageous features. First, it makes use of only four keys.
Therefore, the keypad can be relatively small in size. The four
keys are distinctively positioned, the chance of getting confused
with different keys and thus resulting misfires on wrong keys has
been greatly reduced.
[0034] Second, this method does not require a one-to-one match from
an actual writing stroke to a designated key. Instead, it
associates the thumb move path over the keys with the actual
writing trajectory of the intended stroke. This builds an intuitive
relationship between the stroke writing and key pressing processes.
In addition, the definition of six fundamental strokes allows 17
different kinds of entry variations in total, which cover all N
basic stroke types. It has an unprecedented feature that the
majority of basic strokes can be drawn on the 4-key keypad. This
scheme makes it possible that a user only needs to look at the set
of candidate characters and make a selection among them without the
need of watching closely the movement of the thumb over the keys on
the keypad. It allows a user to input strokes in a natural and
convenient manner.
[0035] Some editing functions have also been defined by the thumb
move path over the keys, as described below.
2TABLE 1 continued No. Type Var Path Description 7 DEL 1 21 delete
8 UNDO 1 212 undo 9 ENTER 1 143 return, newline 10 CASE 1 41 in
Chinese mode: do radical expansion in Roman mode: toggle between
upper and lowercase 11 MODE 1 11 toggle among Chinese/Roman/Number
12 OK 1 22 confirmation on selection 13 SPACE 1 44 insert a space
14 ONOFF 1 33 toggle among input mode/scroll mode 15 LEFT 2 21 43
left-arrow scroll 16 RIGHT 2 12 34 right-arrow scroll 17 UP 2 31 42
up scroll 18 DOWN 2 13 24 down scroll
EXAMPLE 2
Roman or Alphanumeric Data Entry
[0036] A further embodiment of the invention is now described with
reference to entry of Roman letters and Arabic numerals
(alphanumeric data entry). The embodiment will again be described
using a 4-key keypad.
[0037] In operation, to enter a Roman letter, the user draws a
stroke with his thumb on the four keys. Different schemes can be
used to represent Roman letters using a single stroke (i.e.
pen-down to pen-up strokes) or a small number of strokes. Graffiti
(trademark) is an example of a scheme.
[0038] A list of strokes is defined for each of the 26 uppercase
Roman letters, as shown in Table 2. The first column is the
corresponding uppercase Roman letter, the second column is the
number of variations of strokes. The third column is the strokes
defined as the sequence of keys to be pressed during the time
period from the first key of the sequence is visited until a
pre-defined time-off is detected. Here a time-off is defined as the
maximum time elapse allowed from the moment a key is visited to the
moment its subsequent key is visited.
3TABLE 2 Letter Var Strokes A 4 314 324 1314 2324 B 2 131443 3143 C
1 2134 D 4 131243 23424 4234 24234 E 6 13121212 13343434 1341212
1341334 13121234 13123434 F 2 211312 131212 G 2 134124 2134124 H 3
131224 13124 132412 I 1 24 J 3 243 1243 12243 K 1 13214 L 1 134 M 2
13142324 314324 N 3 3142 13142 1324 O 8 12431 13421 24312 34213
31243 21342 43124 42134 P 2 13123 3123 Q 8 124314 134214 2431214
3421314 3124314 2134(2)14 4312414 R 4 1312 312 31214 131214 S 1
2143 T 2 1224 124 U 1 1342 V 2 132 142 W 1 132142 X 3 2314 1423
3214 Y 2 1323 1424 Z 1 1234
[0039] On a well-designed keypad, the strokes can be drawn on four
keys by moving around the thumb or a finger. This is illustrated in
FIG. 4 for the first four letters of the Roman alphabet. Thus, the
letter "A" can be drawn in four (or more) ways and can be drawn as
a single pen-down (or thumb-down) stroke (as in "Graffiti") or
using two pen-down strokes, each starting at the apex. A dotted
line in FIG. 4 illustrates the thumb being lifted, generally to
return the thumb to a key to begin a new stroke at another key.
Note that the table does not distinguish between two keys being
visited in a thumb-down sequence and two keys being visited in a
thumb-up sequence. These distinctions are shown only for ease of
understanding.
[0040] Note also that other sequences can be added to the sequences
shown, provided the time-out timer permits. Thus, for example, a
horizontal cross-stroke can be added to the sequence of stroke
vectors that represent the letter "A" (e.g. 232434 or 32434). In
this particular example, such an additional stroke is redundant,
because the extra stroke 3-4 adds nothing to disambiguate the input
sequence, which is already uniquely identified by the first two
strokes 2-3-2-4 or 3-2-4. Thus it can be seen that it is not
necessary to include further strokes of a letter in Table 1.
[0041] A timer is started for each letter entry. Preferably the
timer begins with the first key-press of a new character. All
strokes entered before the time-out are considered as a single
entry (character or numeral). Any additional strokes not necessary
for character recognition (e.g. the cross-stroke of the letter "A")
are simply disregarded. This has the advantage that a user does not
need to learn a special style of input (e.g. the user does not need
to drop the cross-stroke on the letter "A"). In addition, the timer
is reset as soon as a character is uniquely decoded and the
immediate following stroke entered is not a legitimate stroke, thus
allowing a user to immediately begin entry of the next character.
However, if the immediate following stroke entered before the
time-out is a legitimate stroke although not necessary, it is still
disregarded, but the timer will not be reset until either after the
time-out or the immediate following stroke entered is not a
legitimate stroke.
[0042] Ultimately the exact choices for stroke sequences in Table 2
is a matter for compromise and is dependent on handwriting habits
and preferences of typical users.
[0043] Preferably no two letters of the Roman alphabet can be
represented by the same sequence of keys, but this is not
essential. If there are ambiguities (e.g 3143 for "A" and for "B"),
these ambiguities will need to be resolved using disambiguation
techniques such as through n-grams.
[0044] The above method has the following advantageous features.
First, it uses a small number of keys. Hence, the keypad can be
designed relatively small to allow very compact implementations.
Second, this method uses an intuitive relationship between the
actual letter writing and key pressing. In addition, the multiple
definitions of strokes provide reasonable variations to give users
more freedom in writing than, for example rigid adherence to a
single-stroke scheme (such as "Graffiti"). The scheme makes it
possible to do blind typing of Roman letters on a small keypad.
[0045] Based on the same concept, the ten Arabic digits 0-9 can
also be input by stroke sequences, as presented below.
4TABLE 2 continued Digit Var Strokes 1 2 13 24 2 1 1234 3 3 12343
12143 12123 4 2 13424 23424 5 1 14312 6 1 13423 7 2 124 123 8 2
21432 12341 9 1 21324 0 8 12431 13421 24312 34213 31243 21342 43124
42134
[0046] It can be easily seen that there are some overlaps between
the strokes defined for letters and those for digits. Therefore, a
mode switch between these two is preferably introduced to avoid
confusions.
Hardware Variations
[0047] Referring to FIGS. 5, 6 and 7, a front view, rear view and
elevation view respectively of an alternative input device 50 are
shown. The alternative input device has a joystick element 100
(which term is to be understood as including other button or lever
devices moveable in two dimensions in a horizontal plane, including
mouse-buttons). The joystick element 100 is mounted on a
spring-loaded mounting illustrated as a ball-and-socket mounting
101 by way of example. The mounting is biased such that the
joystick element returns to a central resting position (not shown)
when not under thumb or finger pressure. Springs 104-107 are shown
as providing bias, but it will be understood that these need not be
discrete helical springs and may be replaced by a single
elastomeric member. Four discrete contacts 110-113 are shown at
four equally spaced compass points around the center (north-west,
north-east, south-east and south-west respectively).
[0048] As shown in FIG. 6, there is a silvered circle 120 on the
rear of the ball of the ball-and-socket mounting 101 and there is a
ground contact 121 fixed relative to the ball-and socket mounting
and positioned centrally behind the ball.
[0049] In operation, a user moves the joystick element 100 with his
or her thumb or finger and the ball rotates such that the silvered
circle 120 makes contact between the ground contact 121 and one of
the discrete compass-point contacts 110-113. In this way, the input
device of FIG. 5 can generate a series of discrete inputs just like
the four-key input device 12 of FIG. 1. A north-west movement of
the joystick generates the same input as key 1 of input device 12,
and so on.
[0050] It will be understood by one of ordinary skill in the act
that other joystick elements can achieve the same result. For
example, a ball-and-socket arrangement with an asymmetric ball can
be used that activates four or more microswitches similar to the
buttons of input device 12 of FIG. 1. The joystick does not need to
have a ball-and-socket at all.
[0051] It will also be understood by one of ordinary skill in the
art that more than four contacts can be used for the input device
12 of FIG. 1 or the input device 50 of FIG. 5. For example, six,
eight, twelve or sixteen compass point contacts can be used.
Alternatively, a matrix of 3.times.3 or 4.times.4 buttons or
contacts could be used. Tables 1 and 2 would need to be
reformulated accordingly, and there would be many more stroke
variations permissible for each item in these tables.
Alternatively, the joystick button input device of FIG. 5 does not
have a ball-and-socket, but is fixed on its mounting and uses
orthogonal strain gauge elements to provide a continuous (i.e.
progressive, non-discrete) 2-dimensional output (e.g. two analog
voltage outputs) which is divided into discrete values by the
microprocessor 11 or by an interface into the microprocessor 11
(e.g. an analog-to-digital converter).
[0052] Referring to FIG. 7, a microswitch 150 is shown mounted
beneath the ball-and-socket mounting 101 of the input device 50 of
FIG. 5. The microswitch 150 is a push-to-make switch and can be
used for a number of purposes.
[0053] In one embodiment, the microswitch 150 is used as a pen-down
indicator. In this variation, a single input stroke is measured
from pen-down to pen-up. This has the advantage of disambiguating
between pen-down and pen-up segments. All contiguous pen-down
segments can be captured and used for character recognition,
regardless of whether they are captured within a time-out time or
after expiry of a time-out timer. This allows for greater
flexibility in user-variations of time duration when entering
strokes or characters. A "data active" line on the input device 12
of FIG. 1 can perform the same function, such that all continuous
thumb-down movements cause an activation of at least one button and
cause activation of the "data active" line, whereas a thumb-up
event gives no data active signal. Instead of a data active line,
timing measurements by the processor 11 can be used to measure the
time lapse between button presses (if any) and so determine if
there has been a thumb-up event.
[0054] If an input device 50 such as that of FIG. 7 is used that
gives a continuous analog output, the preprocessing technique of
U.S. Pat. No. 5,740,273 followed by the recognition technique of
U.S. Pat. No. 5,742,705 can be used to interpret and recognize
Roman letters or Chinese characters written as pen-down writing
segments. This is illustrated in FIG. 8.
[0055] In FIG. 8, a joystick element 200 is shown having strain
gauges (or other analog elements) 201 and 202 that provide analog
movement indications for movement of the joystick element 200 in
orthogonal x and y dimensions in a horizontal plane. Integral with
the joystick element 200 is a push switch 204, preferably a
push-to-make switch.
[0056] The analog elements 201 and 202 are connected to
analog-to-digital (A/D) converters 210 and 211 (or to a single
shared A/D converter), which are coupled to a processor 220. The
switch 204 is also coupled to the processor 220.
[0057] The processor 220 has a program stored in program memory
that causes it to perform a scaling (normalizing) function 221 on
the inputs from the A/D converters 210 and 211, for example as
described in U.S. Pat. No. 5,740,273. Inputs from the A/D
converters are accepted by the scaling function 221 when the switch
204 indicates a "push" condition (equivalent to a pen-down state).
Following the scaling function, an optional smoothing function 222
is carried out and a segmentation function 223. The segmentation
function segments the two-dimensional input into segments at
natural bends in the input, thereby providing a sequence of raw
stroke segments. A matching function 224 matches the segments
against pre-stored templates from template store 230 in a manner
known in the art, for example as described in U.S. Pat. No.
5,742,705.
[0058] The arrangement of FIG. 8 is particularly useful for entry
and recognition of ideographic characters (e.g. Chinese
characters), but is not limited thereto, and is useful for Roman
character entry or Grafitti (trade mark) type of stroke entry. The
smoothing, segmenting and matching steps can be modified (or
omitted where unnecessary) to suit the type of data entry.
[0059] This method makes inputting of alphanumeric letter on a
small input device in a convenient and efficient manner, and it
also leads to very compact implementations.
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