U.S. patent application number 09/410986 was filed with the patent office on 2001-12-13 for dual mode, dual information, document bar coding and reading system.
Invention is credited to BREWINGTON, GRACE T., PAUL, PETER.
Application Number | 20010050308 09/410986 |
Document ID | / |
Family ID | 23627089 |
Filed Date | 2001-12-13 |
United States Patent
Application |
20010050308 |
Kind Code |
A1 |
PAUL, PETER ; et
al. |
December 13, 2001 |
DUAL MODE, DUAL INFORMATION, DOCUMENT BAR CODING AND READING
SYSTEM
Abstract
A dual level encryption method, and document, for providing and
obtaining a substantially increased amount of optically readable
information from an otherwise conventional and highly visible
printed bar code pattern area on a document without interfering
with the conventional optical reading of the conventional
information in the bar code, comprising integrally printing a
second and very much finer pattern of encoded optically machine
readable glyph code or other such indicia within the bar code
pattern area, containing a much higher level of information, to
provide two different levels of information within the same area.
Scanning the bar code pattern with a conventional bar code reader
extracts conventional bar coded information embedded in the bar
code without interference from the second indicia. Scanning the
same bar code pattern area with a different, higher resolution,
optical scanner extracts the much greater amount of information
from the second, much finer, optically readable indicia
pattern.
Inventors: |
PAUL, PETER; (WEBSTER,
NY) ; BREWINGTON, GRACE T.; (FAIRPORT, NY) |
Correspondence
Address: |
JOHN E BECK
XEROX CORPORATION
XEROX SQUARE 20A
ROCHESTER
NY
14644
|
Family ID: |
23627089 |
Appl. No.: |
09/410986 |
Filed: |
October 1, 1999 |
Current U.S.
Class: |
235/375 |
Current CPC
Class: |
G06K 19/06028
20130101 |
Class at
Publication: |
235/375 |
International
Class: |
G06F 017/00 |
Claims
What is claimed is:
1. An encoded document encoded with a plural mode, plural
information level, integrated encoding system, wherein said
document is printed with two separately readable but integrally
printed first and second optically readable indicia patterns; said
first indicia pattern comprising an otherwise conventional bar code
pattern of spaced-apart optically readable bars encoded with a
first set of encoded information readable by a conventional bar
code reader, and said second optically readable indicia pattern
comprising a finer second pattern encoded with a second set of
encoded information which contains a higher level of information
than said first set of encoded information, said second, finer,
pattern of optically readable indicia being integral said bar code
pattern and not optically readable by a conventional bar code
reader but optically readable by a fine pattern optical reader,
said fine pattern of optically readable indicia integral said bar
code pattern being smaller in dimension than said spacing between
said optically readable bars of said bar code pattern or the width
of said bars.
2. The encoded document of claim 1, wherein said indicia of said
second pattern of optically readable indicia integral said bar code
pattern is at least 20 times smaller in area than the area of said
spacing between said optically readable bars of said bar code
pattern.
3. The encoded document of claim 1, wherein said second optically
readable indicia pattern is printed in thin glyphs integrally
printed within said bar code pattern.
4. The encoded document of claim 1, wherein said second optically
readable indicia pattern is a pattern of fine optically readable
indicia which is within said optically readable bars of said bar
code pattern.
5. The encoded document of claim 1, wherein said second optically
readable indicia pattern comprises a multiple fine spaced optically
readable indicia pattern printed in between said spaced-apart
optically readable bars of said bar pattern.
6. The encoded document of claim 1, wherein at least one of said
optically readable bars of said bar code pattern is formed by a
dense pattern of said second optically readable indicia.
7. The encoded document of claim 1, wherein said second optically
readable indicia pattern is a different color than said bar code
pattern.
8. A dual encryption method for providing and obtaining a
substantially increased amount of optically readable information
from an otherwise conventional and highly visible bar code pattern
on a document without interfering with the conventional optical
reading of the conventional information in said bar code,
comprising integrally embedding a second and finer pattern of
encoded optically machine readable indicia within said bar code
pattern, containing a higher level of information, to provide two
different levels of information within a conventional bar code
pattern, and scanning said bar code pattern with a conventional bar
code reader to extract conventional bar coded information embedded
in said bar code pattern, and also scanning said same bar code
pattern with a second and different optical scanner to extract said
second optically readable indicia pattern therefrom.
9. The dual encryption method of claim 8, wherein said second and
much finer optical indicia pattern is a thin glyph code
pattern.
10. The dual encryption method of claim 8, wherein said second
pattern comprises optical indicia at least 20 times smaller than
said bar code pattern.
11. The dual encription method of claim 8 wherein said second and
different optical scanner is responsive to different colors than
said bar code reader.
Description
[0001] Disclosed is an embodiment of a plural-mode, plural
information level, document encoding system and document. The
document is printed with an integrated encoding of conventional bar
coding information with its first level of bar code pattern
information for optical reading by a conventional bar code reader,
and integrally printed within the bar code pattern is a much finer
and higher level information indicia pattern which does not
interfere with the conventional bar code reading, yet is optically
readable by a second, much higher resolution, optical reading
system, to provide a much higher level of information from that
second, much finer information indicia pattern. A high data density
channel is thereby provided while maintaining the backward
compatibility of the dual symbology to legacy bar code readers that
are already in fielded systems.
[0002] It will be noted that many bar code readers can read
multiple bar code symbologies, including readers that can read both
one dimensional and two dimensional bar codes. There does not
exist, however, a symbology which can be read by different kinds of
readers at different data density levels.
[0003] Also in this manner, the user may be directed by the highly
visible and well-recognized bar code pattern to provide scanning in
the correct area or location of the document in which the other,
much higher data density, indicia also exists, containing far more
embedded information than can be provided by the bar code indicia
itself, yet without any incompatibility or interference between
these two optical data encoding and data reading systems.
[0004] The widespread prior art uses of digitally readable bar
codes or their equivalents on almost any object or document is so
ubiquitous as not to require discussion herein. They include common
1D and 2D bar codes, "checkerboard" codes, the UPS or "bulls eye"
codes, etc.. Thus, it will be appreciated as to the terms "bar
codes" and the "bars" of "bar codes", as those terms are used in
this particular application, that such "bars" can be circular as
well as linear in shape.
[0005] An important advantage of bar codes is that they are highly
visible, distinctive, and universally known and recognizable. Thus,
they provide a clear visual pointer to what area of a document or
object bearing a bar code needs to be scanned.
[0006] However, for bar codes to be correctly read by any of
various conventional bar code readers, which are typically simple
low-resolution optical scanners with very limited image processing
or enhancement, the bar coding pattern on the document requires a
precisely defined pattern of multiple bars with clear, defined,
"white spaces" in between the bars, with sharp, clear, boundary
definitions and high contrast. Thus, the underprinting or
overprinting of the bar code pattern areas of documents with other
indicia is not normally allowed or considered appropriate.
[0007] Further by way of background, "glyph" encoding (also known
under the proprietary names "DataGlyph" or "Smart Paper") of
various printed documents is also known in the art for various
applications. "Glyphs" are an embedded digitally readable font, in
particular a very fine pattern of machine readable indicia,
preferably in very fine patterns of angled slash-mark appearing
fonts like "///.backslash..backslash.////.backslash.-
.backslash.//.backslash.// ", etc., (only very much smaller than as
shown here) to be printed on various hardcopy documents. The
proposed substitution of glyphs for bar codes has been suggested in
some glyph literature. However, "glyphs" are by their very nature
typically intended to be optically invisible to the naked eye, not
recognizable, not within a clearly defined or bounded area of a
document, and are not well known to the public.
[0008] Xerox Corp. U.S. Pat. No. 5,291,243 issued Mar. 1, 1994
(D/92224) to Dean A. Heckman, et al, discloses a system of
integrated two color security patterns for checks or other security
document printing, to prevent forgery. That patent specifically
discusses providing buried glyph copies of any of the desired check
data in the check background pattern image [e.g., Col. 12 line 58
to Col. 13 line 38], and specifically cites and incorporates by
reference several of the below-cited patents. This and other
references provide teachings for those skilled in the art of how to
combine a fine, high-density, pattern of glyph encoded information
into other patterns, backgrounds, text, or pictures, which glyph
patterns are deliberately, effectively invisible to the naked eye,
but machine-readable with surprising accuracy by known special
glyph readers scanning the document or analyzing the electronic
image thereof and readily separating the glyph pattern from its
image background pattern.
[0009] Also particularly noted by way of background descriptions of
Glyphs is Xerox Corp. European patent Application No. 92311676.8
published Jun. 30, 1993 as Publication No. 0 549 315 A1 by David L.
Hecht, et al. (D/91764). The paragraph bridging Cols. 5-6 suggests
the use of distinctly colored glyphs. Some additional examples of
prior art on Glyphs in general includes an EPO Glyphs application
Publication No. 459 792 published Dec. 4, 1991 (D/89190), which
lists several glyph utilities and applications. Its parent U.S.
application continuation issued in the U.S. on Jan. 23, 1996 as
U.S. Pat. No. 5,486,686.
[0010] Other issued Xerox Corp. Glyph patents include U.S. Pat.
Nos. 5,091,966, 5,128,525; 5,168,147; 4,716,438; 4,728,984;
4,757,348; 4,970,554, 5,060,980, 5,157,726, 5,221,833; 5,245,165;
5,278,400; 5,315,098; 5,317,646, 5,448,375, 5,449,895; 5,449,896,
5,453,605, 5,489,763, 5,521,372; 5,537,223; 5,572,010; 5,576,532;
5,611,575; 5,684,885; 5,706,099; 5,717,197; 5,761,686 and
5,771,245.
[0011] A further broadly glyph-related patent is Xerox Corp. U.S.
Pat. No. 4,786,940 by J. Daniele. Also noted is J. Daniele U.S.
Pat. No. 5,444,779 issued Aug. 22, 1995 (D/93027).
[0012] However, as noted, glyphs are effectively invisible to the
naked human eye, and are not widely publicly understood, even if
observed (unlike bar codes) and thus do not visually instruct a
person wishing to scan a document as to where to scan the document
in order to extract the imbedded (printed) information, i.e., which
side and which area of the document to scan to extract the embedded
glyph information. Likewise, there is normally no particular
identified place on a document to print glyph information, much
less a defined area of the document where the entire image
background will normally (and very desirably for glyph information
clarity and readability) be pure solid black and pure solid white
areas.
[0013] It will be appreciated that the term "document" as used
herein in reference to the printing of bar codes and glyphs thereon
is not limited to conventional sheets of paper or plastic. In this
application it also broadly encompasses packaging, labels, and
various other printable image substrates.
[0014] A specific feature of the specific embodiments disclosed
herein is to provide an encoded document encoded with a plural
mode, plural information level, integrated encoding system, wherein
said document is printed with two separately readable but
integrally printed first and second optically readable indicia
patterns; said first indicia pattern comprising an otherwise
conventional bar code pattern of spaced-apart optically readable
bars encoded with a first set of encoded information readable by a
conventional bar code reader, and said second optically readable
indicia pattern comprising a second pattern encoded with a second
set of encoded information which contains a higher level of
information than said first set of encoded information, said
second, pattern of optically readable indicia being integral said
bar code pattern and not optically readable by a conventional bar
code reader but optically readable by a fine pattern optical
reader, said fine pattern of optically readable indicia integral
said bar code pattern being several times smaller in dimension than
said spacing between said optically readable bars of said bar code
pattern or the width of said bars.
[0015] Further specific features disclosed in the embodiment
herein, individually or in combination, include those wherein said
indicia of said second pattern of optically readable indicia
integral said bar code pattern is at least 20 times smaller in area
than the area of said spacing between said optically readable bars
of said bar code pattern; and/or wherein said second optically
readable indicia pattern is printed in thin glyphs integrally
printed within said bar code pattern and/or wherein said second
optically readable indicia pattern is a pattern of fine optically
readable indicia which is within said optically readable bars of
said bar code pattern; and/or wherein said second optically
readable indicia pattern comprises a multiple fine spaced optically
readable indicia pattern printed in between said spaced-apart
optically readable bars of said bar pattern; and/or wherein at
least one of said optically readable bars of said bar code pattern
is formed by a dense pattern of said second optically readable
indicia; and/or wherein said second optically readable indicia
pattern is a different color than said bar code pattern.
[0016] Another disclosed feature of the embodiment is a dual
encryption method for providing and obtaining a substantially
increased amount of optically readable information from an
otherwise conventional and highly visible bar code pattern on a
document without interfering with the conventional optical reading
of the conventional information in said bar code, comprising
integrally embedding a second and finer pattern of encoded
optically machine readable indicia within said bar code pattern,
containing a higher level of information, to provide two different
levels of information within a conventional bar code pattern, and
scanning said bar code pattern with a conventional bar code reader
to extract conventional bar coded information embedded in said bar
code pattern, and also scanning said same bar code pattern with a
different, higher resolution, optical scanner to extract said
second optically readable indicia pattern therefrom; and/or wherein
said second and much finer optical indicia pattern is a thin glyph
code pattern; and/or wherein said second pattern comprises optical
indicia at least 20 times smaller than said bar code pattern.
[0017] As to specific components of the subject apparatus, or
alternatives therefor, it will be appreciated that, as is normally
the case, some such components are known per se in other apparatus
or applications which may be additionally or alternatively used
herein, including those from art cited herein. All references cited
in this specification, and their references, are incorporated by
reference herein where appropriate for appropriate teachings of
additional or alternative details, features, and/or technical
background. What is well known to those skilled in the art need not
be described here.
[0018] Various of the above-mentioned and further features and
advantages will be apparent from the specific apparatus and its
operation described in the examples below, and from the claims.
Thus, the present invention will be better understood from this
description of specific embodiments, including the drawing figures
wherein:
[0019] FIG. 1 is an example of a conventional, highly-visible bar
code pattern area for document, which bar code has integral
effectively invisible (to the naked eye) fine glyph patterns of
high-density information, in accordance with the present invention.
This integrally dual encrypted document is shown with that bar
coded area of the document being moved (illustrated solid movement
arrows) past a conventional bar code reader and also past a
separate, special, glyph code reader (both are shown
schematically), or alternatively (as shown by their respective
dashed line arrows) the document may be stationary and be
separately scanned by the bar code reader and/or the special glyph
code reader;
[0020] FIG. 2 shows a highly magnified small area portion of one of
the bars of the bar code shown in FIG. 1, showing one example of
the subject glyph data which may be integrally embedded therein,
here, as glyph-shaped white spaces, which are invisible to the
conventional bar code reader and do not interfere with its
operation;
[0021] FIG. 3 is similar to FIG. 2 except that in this case the
fine glyph pattern is shown printed in black and embedded into a
small area of a white space in between adjacent bars of the bar
code of FIG. 1 (shown to the same enlargement and showing the same
portion of a glyph code data stream); and
[0022] FIG. 4 is a flowchart illustrating one example of a dual
mode, dual data density system for the embodiment of FIGS. 1-3 or
other dual (low and high density) encoding and reading systems.
[0023] Referring to FIGS. 1-4, as noted, the particular bar code
pattern and the particular glyphs illustrated therein are merely
exemplary, and others are known, including those noted in the
references cited above, and/or including those in distinctive
colors (which, of course, cannot be shown in patent drawings). The
illustrated bar code pattern is one very well known to those
skilled in the art as well as members of the public at large. It
should also be noted that the embodiments of FIGS. 2 and 3 can be
alternatives, or they can both be used in the same bar code
pattern. As also noted above, the generation, printing, reading and
interpretation of both bar codes and glyphs is well known in the
art and need not be re-described herein.
[0024] Referring to FIG. 1, as described above, an example of an
otherwise conventional bar code pattern 10 is illustrated on a
broken-away minor portion of a document 12. The bars themselves are
10A, and the "white spaces" between the bars are 10B.
[0025] Note that a bar code footprint or area also typically
includes a "quiet zone" of white space preceding the first solid
black line and following the last solid black line of the bar code
pattern. This "quiet zone" is typically 6.4 mm (0.25 inches), and
may (or may not) be specified by the ANS3.182 standard. In
addition, a "quiet zone" of white space at the ends on the bar code
lines (at the "top" and the "bottom" of the bar code) is also
normally defined. It is important to note that both of those
standard border regions of the bar code can be part of the bar code
footprint, pattern, or area as described or claimed herein. For
example, where we indicate that the glyphs or other higher data
density indicia should preferably not extend beyond the bar code
footprint.
[0026] It will also be appreciated, as well as known, that bar
codes are normally printed with completely solid black bar code
lines, with a pattern of wide black lines and narrower solid black
lines separated by "white spaces" therebetween. However, since the
U.S. Patent Office does not allow the use of solid black lines of
such width in patent drawings, the solid black bar code lines
throughout the drawings here are illustrated with the U.S. Patent
Office approved crosshatching symbol for black.
[0027] As described above, either the document 12 can be moved
relative to a conventional bar code reader (exemplified here
schematically at 50) or vice versa. This is respectively
illustrated by the solid line movement arrow 11 on the document 12
and the alternative dashed line movement arrow 52 associated with
the conventional bar code reader 50. The conventional bar code
reader 50 may of course have the usual, simple, low-resolution,
conventional optical sensor 54, which may be conventionally
connected to any various alternative information processors 100 in
a known manner.
[0028] However, also shown schematically in FIG. 1 is a known type
of high-resolution scanner or glyph reader 60, with an associated
illustrative dashed line movement arrow 62, for separately or
simultaneously scanning the bar code pattern 10. The glyph reader
60 may have a much finer pattern of multiple, optical sensors 64.
These respective embedded information readers 50 and 60 may be
either separate or combined scanning units or, alternatively, be
stationary mounted for separate or integrated sequential movement
of the document 12 bar code area 10 past the glyph sensor 60 and/or
the bar code reader 50.
[0029] As explained in the above-cited references, the exemplary
type of glyph information indicia encoding shown herein has a
narrow and slanted strokes font, which is orientation insensitive
and uncritical. Thus, the relative position or movement of the bar
code pattern 10 relative to the glyph reader 60 can vary
considerably from that illustrated in FIG. 1 and still provide
accurate reading out of the embedded glyph symbols.
[0030] Turning now to FIG. 2, this is a greatly enlarged (by
several orders of magnitude) minor portion of one of the black bars
10A of FIG. 1, showing a normally optically invisible (to the naked
eye) exemplary pattern of white or colored (non-black) glyphs 16
which can be buried integrally within a minor portion of one bar
10A of the bar code pattern 10. Extrapolating also doing this over
any desired amount of the rest of the entire bar or bar code
footprint or area demonstrates the very high information level
which can be embedded in this manner within the bar code area. It
will be seen that the individual glyph strokes or binary characters
may be greatly smaller than the area of a narrow standard bar code
line 10A, in the range 10-500 or more times smaller in area, and
preferably more than 20 times smaller in area, than any bar 10A,
and also preferably substantially spaced apart from one another.
The result is that none of the glyphs 16 are optically visible or
detectable by a conventional low-resolution bar code sensor 50, nor
do they change the macro optical characteristics of the bar code,
and thus they do not effect the reading out of the bar coded
information in any respect.
[0031] FIG. 3 shows a similar glyph high-density information
encoding 18 in a similarly highly magnified view of a very minor
portion of the bar code pattern 10 of FIG. 1. However, in this case
the information is shown being glyph encoded in one of the white
spaces 10B in between the dark bars 10A of the bar code pattern 10
by printing (conventionally) the glyph pattern therein (with the
same or other dark printing ink or toner, or a different
material).
[0032] Again, in this FIG. 3 embodiment, (which may be in addition
to, or an alternative to, the FIG. 2 encryption of glyph patterns),
the dark (or colored) printed glyphs 18 are so small in individual
areas and so well spaced as compared to the area of underlying
unprinted white or other light background, that they are optically
invisible to the conventional bar code reader 50.
[0033] As is well known, glyph patterns are detectable even with
their lines being generated by only a few printed pixels. The
glyphs can be of only a single pixel line in width and still be
detectable by the known glyph recognition software, which can be
programmed into the information processor 100 from the signals
detected by the glyph reader 60. The glyphs can be conventionally
generated as high-resolution, binary amplitude modulated pixels in
standard printing systems.
[0034] It is of course, desirable, and readily accomplished with
the present invention, to simultaneously print the first or bar
code pattern and the integral second or glyph pattern
simultaneously in the same printing process with the same (or
different) printing ink or toner by electronically superimposing
the two images before electronic printing. As shown by the
above-cited U.S. Pat. No. 5,291,243, and other patents above, this
can be accomplished in a known manner by electronically merging the
two images before they are printed.
[0035] It will be appreciated that the glyphs reader thresholding
and/or background suppression settings may be different for reading
white or colored glyphs on a black bar background area as compared
to reading dark or colored glyphs on a white or light colored
inter-bar space.
[0036] Multi-color printing and scanning can be used to enhance the
distinction and readability of the second and higher level of
information buried in the bar code. In addition, multi-color
printing can be used to provide increased data density. For
example, by using a very specific limited spectrum color for the
glyphs in contrast to the typical black of the bar code pattern.
The use of color for more precisely spectral signature distinction
can be utilized in glyphs of a glyph code providing either a
bistate or polystate characteristics, as suggested in, for example,
the paragraph bridging columns 5-6 of the above-cited EPO
Publication Number 0 549 315 A1. However, different colors should
not be necessary for the low-resolution of the standard bar code
reader to reject interference from a glyph code which can be 1 or 2
orders of magnitude or more finer than the bar code pattern.
[0037] Another alternative is to modify the glyph pattern by
introducing an extra space or spaces between the glyph strokes or
characters so as to have even less effect on the solid black or
solid white background on which they are printed. Also, the glyph
pattern may be printed either along the axis of the bar code lines
10A, or transverse thereto. In any case, it is desirable that the
glyphs not extend beyond the perimeters defined by the bar code
pattern and its surrounding "quiet zone".
[0038] The symbology has the property that an optical low pass
filter operation (which is what the low resolution bar code reader
does when it reads) can "blur" the fine symbols (such as glyphs)
together to form a readable bar code signal. That is, the high
density information itself may be printed densely enough, and in
the right areas, to itself provide "bars" as seen by the bar code
reader, (as opposed to printing otherwise solid bars with voids in
the space of glyphs). That is, a "blurred" version of the combined
printed high density indicia can provide the bar code "bars". For
that embodiment, for glyph symbology, wider glyphs comprised of
"slashes" made up of two or three pixels per row may be needed. For
other high density symbols (not just conventional glyphs), various
invented symbology may be used where a "blurred" high density
symbology results in a readable bar code. Since a bar code reader
has low optical resolution, it only reads a "blurred" version of
the composite symbology which results in a readable bar code.
[0039] Another embodiment is where an invented symbology with
spectrally limited high density symbology results in a readable bar
code. Typically, bar code readers use red light emitting diodes
(LEDs) (or other spectrally limited sources, or sensors) to read
the bar codes. Thus, since the bar code reader can only "see" red,
red "looks" white and green "looks" black to the bar code
reader.
[0040] Note that different high density symbology could be used in
the bar code bars and/or in the bar code spaces. For example,
glyphs could be used in the bar code bars, while high resolution
binary amplitude modulated pixels could be used in the bar code
spaces. Thus, resulting in a hybrid information system.
[0041] It may be seen that the above-described system allows
encoding and decoding in a machine-readable format of both
high-density and low-density data, within the same area of a
conventional bar coded document. The low-density (bar code) symbols
may be decoded with a conventional low-density bar code reader,
while the high-density data can be read with an advanced reader
using a higher optical resolution power to download a much larger
amount of information from the same document area, yet without
interfering with correct reading of the bar coded data. The very
small area and the spacing of the glyphs will not effect luminance
and uniformity over the bars 10A or the white spaces 10B to any
significant extent. The optical appearance of the bar code to the
naked eye and the bar code reader will be essentially the same as a
solid black and white bar code pattern, even though many thousands
of glyph characters may be buried therein.
[0042] It will be appreciated that there are many documents for
which it is not appropriate, for visual impression purposes, to
impose a bar code thereon. However, there are also a great many
documents in which bar codes are already present on the document
for other reasons. The high visibility of bar codes and the public
knowledge that they contain information which needs to be scanned,
provides an easy visual instruction for the scanning on the bar
code area by an unit which can also extract a great deal more
information from the same bar coded area, by the disclosed system,
providing the document has been encoded therewith.
[0043] It will be appreciated that in addition to the illustrated
one-dimensional glyph code that two-dimensional glyph codes, such
as wedge-shaped or small square block glyphs, may be utilized in
some cases. However, the illustrated or other narrow glyphs are
preferable.
[0044] It should be noted that standard one-dimensional bar code
readers, and the requisite one-dimensional bar code symbology, are
designed to be very robust to distortions and reading errors, such
as bar codes printed on curved or odd-shaped surfaces, wrinkles,
contamination, etc.. This robustness or insensitivity is actually
taken advantage of in the subject embedding of the high-density
data therein, by making the latter undetectable to the bar code
reader. The high-density data of the glyph encoding is, in effect,
optically invisible or hidden from the standard bar code reader.
The high-density data itself can be designed to be more robust by
including error correction codes etc.. Data glyph-like symbols with
error correction codes have been shown to be very robust to
distortions, as discussed in various of the above-cited patent
references.
[0045] The present system, by maintaining complete backward
compatibility to existing conventional bar code readers, does not
require the modification or purchase of different equipment for bar
code reading, yet allows for additional high-data density
information to be encoded without any impact on the existing bar
code system. One example would be special added tracking control
data for inventory control over documents, which would only need to
be read by a limited number of people with glyph readers capable of
reading those glyph codes or other high-density indicia within the
bar code. Thus, for example, a print shop operator who wishes to
include an additional document verification system would not have
to replace existing bar-code-based finisher or other controls for
the print shop, but could have such additional information glyph
encoded on the documents within the existing bar code
information.
[0046] While the embodiments disclosed herein are preferred, it
will be appreciated from this teaching that various alternatives,
modifications, variations or improvements therein may be made by
those skilled in the art, which are intended to be encompassed by
the following claims.
* * * * *