Registers – Coded record sensors – Particular sensor structure
Reexamination Certificate
2000-06-02
2003-05-20
Lee, Diane I. (Department: 2876)
Registers
Coded record sensors
Particular sensor structure
C235S462080, C235S462110, C382S237000
Reexamination Certificate
active
06565003
ABSTRACT:
FIELD OF THE INVENTION
The invention relates generally to an improved method for locating and reading two-dimensional barcodes printed within an image.
BACKGROUND OF THE INVENTION
Contrary to the frequent predictions that we will one day live in a “paperless society”, paper, and other printed mediums, are playing an increasingly important role as an inexpensive, effective and convenient means for communication. A fundamental limitation with paper, however, is that from a computer standpoint, it is currently an output-only format. While paper may be the preferred medium for displaying information for human use, it is difficult, if not impossible, for a computer to recover data reliably once it has been printed. Optical character recognition (OCR) attempts to solve this problem in a relatively simple domain, such as text rendered using standard fonts, but has met with only limited success thus far. While accuracy rates of ninety-nine (99%) percent are perhaps achievable and may seem impressive, a page with 3,000 characters will still incur an average of thirty (30) OCR errors and hence requires expensive and time consuming manual post-processing.
Another approach uses computer readable barcodes which may be included directly on paper (or other printed medium such as microfilm). Once encoded, such barcodes can be used by the computer to recover information evident to the human reader but difficult for a computer to recognize (e.g., printed text), information implicit to the creation of page but essentially invisible to the human reader (e.g., spreadsheet formulas), or any other information desired, whether or not dependent on the actual character text on the paper.
Computer readable barcodes, wherein digital data is recorded directly on paper, are known and have been utilized to provide document or product identification given a fixed set of values using simple numeric encoding and scanning technologies. Document or product identification systems which have been employed in the past include barcode markers and scanners which have found use in a wide range of arenas. With respect to paper documents, special marks or patterns in the paper have been used to provide information to a related piece of equipment, for example the job control sheet for image processing as taught by Hikawa in U.S. Pat. No. 5,051,779. Similarly, identifying marks comprising encoded information have been printed on the face of preprinted forms as described in U.S. Pat. No. 5,060,980 to Johnson, et al. The Johnson, et al. system provides for a user entering hand drawn information in the fields on a paper copy of the form and then scanning the form to provide insertions to the fields in the duplicate form that is stored electronically in the computer. Still another system is described in U.S. Pat. No. 5,091,966 of Bloomberg, et al., which teaches the decoding of glyph shape codes, which codes are digitally encoded data on paper. The identifying codes can be read by a computer and thereby facilitate computer handling of the document, such as identifying, retrieving and transmitting such document.
Besides the various shaped barcodes described above, two-dimensional barcodes called “data strips” having a plurality of rows of “data lines” that represent information digitally encoded on printed media are also known in the art. Each data line row consists of a series of black and white pixels each representing binary “0”s and “1”s. The ordering of the bits in each row determines the digital data stored therein. The data stored within the totality of the rows define the data contained in the two-dimensional barcode. Typically, to read the barcode, the user passes a hand scanner, which simultaneously reads the information in each data line row, vertically along the length of the barcode to read all of the data line rows.
An example of a prior art system using a data strip two-dimensional barcode having rows of data lines with paper media, is found in U.S. Pat. Nos. 4,692,603, 4,754,127 and 4,782,221 of Brass, et al. In this system, two-dimensional barcodes consist of data line rows which are used to encode computer programs and data on paper and are scanned by use of a hand scanner. In addition to encoding the computer programs and data, these data lines also contain tracking and synchronization bits, hereinafter referred to as “clock bits”. The requirement for use of numerous clock bits directly within each data line row, significantly reduces the amount of digital data that can be stored within each row. Further, if data line rows having clock bits are damaged, which is common if such barcodes are photocopied or transmitted by facsimile systems, such clock bits would be lost making it difficult, if not impossible, to decode the information encoded in the barcode. Other examples of two-dimensional barcodes include: (1) U.S. Pat. No. 5,083,214 to Knowles, which describes a two-dimensional barcode system that requires clock bits embedded within the encoded data itself; and (2) U.S. Pat. No. 4,924,078 to Sant'Anselmo et al., which describes a two-dimensional barcode system in which an orientation and/or timing cell border is included within the body of the barcode itself.
In addition, in co-pending patent application “A Clock-Free Two-Dimensional Barcode and Method for Printing and Reading the Same”, (Ser. No. 08/569,280, filed Dec. 8, 1995) (“the '280 Application”), the contents of which are explicitly incorporated by reference herein, a clock-less two-dimensional barcode with a border on at least one of the four sides of the barcode is described, which border is placed outside the confines of the barcode itself. The two-dimensional barcodes are sometimes called “PanaMarks”®. As depicted in
FIG. 1A
herein, two-dimensional barcode
10
is printed in the low right hand comer of printed page
11
, although this position is completely arbitrary. In the embodiment depicted in
FIG. 1A
, the remaining portion of printed page 11 is occupied by printed text
12
. However, as one skilled in the art will appreciate, any type of computer-generated printed material, for example a spreadsheet or graphics, can be substituted for the printed text
12
. The two-dimensional barcode
10
depicted in
FIG. 1B
herein includes a border
13
that is present on all four of its sides. As is fully described in the '280 Application, although the border
13
is only needed on one of the four sides of the two-dimensional barcode
10
, for aesthetic reasons it is typically included on all four sides.
Also, in co-pending patent application “A Borderless Clock-Free Two-Dimensional Barcode and Method for Printing and Reading the Same”, (Ser. No. 09/088,189, filed Jun. 1, 1998) (“the '189 Application”), the contents of which are explicitly incorporated by reference herein, a clock-less two-dimensional barcode without a border (shown in
FIG. 2
herein) is described, along with methods of printing and reading the same. Two alternate symbologies for the barcode are presented in the '189 Application, a first symbology which requires that the four corner bits
21
to be black (when printed on a white background), and a second symbology in which no black corner bits
21
are required. As such, two alternate methods for reading the barcode of
FIG. 2
are described in the '189 Application, a first method which operates on the barcode which does not require corner bits, as described by the flowchart in
FIG. 8A
therein and the description related thereto, and a second method which operates on the barcode which is required to have corner bits, as described by the flowchart in
FIG. 8B
therein and the description related thereto. Although the two methods of reading the barcode described in the '189 Application provide satisfactory results, it was found that when the barcode was printed on a page with a complex background, the results provided by the locate step
70
of
FIGS. 8A and 8B
of the '189 Application, which is described therein in conjunction with
FIGS. 9A and 9B
, were less than optimal, particularly in
Amster Rothstein & Ebenstein
Lee Diane I.
Matsushita Electric - Industrial Co., Ltd.
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