Error detection/correction and fault detection/recovery – Pulse or data error handling – Digital data error correction
Reexamination Certificate
1999-02-24
2003-05-06
Moise, Emmanuel L. (Department: 2133)
Error detection/correction and fault detection/recovery
Pulse or data error handling
Digital data error correction
C714S755000, C714S784000, C714S786000, C235S437000, C235S456000, C235S462070
Reexamination Certificate
active
06560741
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to high-density printed codes and, in particular, to high-density printed codes that have improved damage-tolerance. In addition, the invention concerns high-density printed codes capable of storing multiple biometrics and text for positive identity identification. Further, the invention concerns off-line positive identity identification apparatus capable of operating in combination with high-density printed codes storing multiple biometrics.
BACKGROUND OF THE INVENTION
Numerous technologies have been developed over the past two decades that are capable of storing significant amounts data (on the order of a kilobyte or more) in a small, compact space (a few square inches or less). Such technologies include so-called “smart cards”; CD-ROM-based optical storage media; magnetic stripe cards; and two-dimensional high-capacity printed bar codes and matrix codes. Depending on the overall information capacity of the medium, each of these technologies may be suitable for storing biometric information for use in positive identity verification applications. Each of these technologies has its advantages and disadvantages in this specific application and other applications.
One of the primary advantages of two-dimensional high-capacity printed bar codes and matrix codes results from the fact that they can be created using conventional printing techniques (including laser printers). One application among many for these codes is in positive identity verification programs where such codes are used to identify human beings. Due to the often enormous number of identification documents that may be created in positive identity verification programs, the fact that two-dimensional printed codes can be formed by conventional printing techniques provides a significant cost advantage over “smart cards,” CD-ROM-based optical storage media; and magnetic stripe cards. Further, error-corrected two-dimensional printed codes are far more robust than smart cards with respect to the ability to tolerate electromagnetic fields, radiation and mechanical stress and CD-ROM-based optical storage media with respect to the ability to withstand scuffing and scratching. “Smart cards” incorporate circuitry and chips that may be damaged should the card be flexed, limiting the suitability of the card for low-cost applications.
Within the art of printed codes, over the past decade, numerous two-dimensional printed paper-based codes have been introduced. These codes represent a substantial improvement over prior one-dimensional bar codes in a number of areas. Most importantly, these codes are capable of storing hundreds of bytes of information, approaching a kilobyte, in a few square inches. In contrast, prior one-dimensional bar codes were capable of storing only a few characters, on the order of ten or twelve, in roughly the same space.
Such codes also exhibit improved error detection and correction capability. For example, one such code, PDF417, disclosed in U.S. Pat. No. 5,304,786, employs the Reed-Solomon error correcting method to improve the damage-tolerance of the code.
Using the Reed-Solomon error correcting method, additional codewords are appended to the end of the data codewords appearing in the PDF417 symbol. If a substantial contiguous portion of the code were to be destroyed or otherwise rendered unreadable (a likely possibility due to the often rugged conditions these codes encounter, e.g., on the outside of a shipping parcel, or on a part on an assembly line), the data represented in the data codewords can still be recovered by reading the Reed-Solomon error correction codewords included in the symbol.
One drawback of PDF417 is the fact that it employs an (n, k) bar code encoding methodology based on 929 codewords. As a result, each PDF417 codeword has a data capacity of 9.25 bits. Given the length of the codeword (17 bits), this results in a substantial overhead (redundant portion of the code). In addition, PDF417 is capable of storing only about 1500 bytes of information with minimal levels of error correction, and much less in the case with acceptable levels of error correction.
Another code is the data strip code disclosed and claimed in U.S. Pat. No. 4,782,221. The data strip code disclosed and claimed in U.S. Pat. No. 4,782,221 is capable of storing up to a kilobyte or more of information in a small space but is vulnerable to data loss in the case of large area destruction due to the relatively limited error correction capability of the code.
Other two-dimensional printed codes include matrix codes, e.g., Datamatrix, or the UPS Maxicode, which have been used in small parts identification and package sortation. These codes have features that facilitate discrimination of the code from a background that is particularly useful when the code is being scanned by a reading device placed above a conveyer belt on which the part or parcel is moving. These codes, while particularly useful in such applications, have not been found to be suitable where large amounts of information are sought to be encoded in a relatively small amount of space.
Overcoming the limitations of these prior printed codes is particularly important because a major application for such codes is off-line positive identity verification. In such applications, biometrics that provide a positive identity verification capability are encoded in the two-dimensional code. Such codes, when operating with apparatus capable of decoding the code, permit positive identity verification to occur independent of a central database storing such identity verification information. This lends a great deal of flexibility in instances where temporary installations are used by governments, e.g., in voting; voting might occur in an installation not having a fixed identity verification apparatus or connection to a central identity database. Having a printed code encoding identity information permits positive identity verification to occur without a permanent positive identity verification apparatus in place.
In order to function effectively in such off-line positive identity verification applications, two-dimensional printed codes must be capable of storing biometric information used in positive identity verification. In addition, the codes storing biometric information must be tailored to fit on standard-sized identity verification papers like, e.g., conventionally-sized ISO cards or passports. These standards are set forth in the International Civil Aviation Organization document entitled Machine Readable Travel Documents 9303 Parts 1-4. Document 9303 Parts 1-4 identifies a number of standard-sized travel documents including machine readable official travel document 1 (MROTD1) card (the ubiquitous ISO CR-80 credit-card sized card which is 2.125×3.375 inches and in the MRTOD1 application allocates 0.98×3.13 inches to a two-dimensional printed code); the oversized identification card (designated MROTD2 and which allocates 0.72×2.52 inches for a two-dimensional printed code); and a conventional passport page (which allocates 0.72×3.14 inches for a two-dimensional printed code.
These standards illustrate that even with the advent of machine-readable codes, standards organizations are still unwilling to dedicate all or most of a document to a machine-readable code and instead specify standards that leave large areas in which to print human-readable information. As a result, real estate on such documents is precious and most be used efficiently, indicating the desirability of even higher density two-dimensional printed codes.
Due to the requirements of known compression techniques for compressing files storing biometric information, known two-dimensional codes have relatively limited capability for providing highly-accurate positive identity verification where such identification is dependent on storing multiple biometrics. For example, known data compression techniques create files that are on the order of 500-750 bytes per fingerprint template (uncompressed) and 900-1100 bytes (compressed) for a p
Gerety Eugene P.
Sardi Stephen G.
Strempski Richard A.
Datastrip (IOM) Limited
Kalow & Springut LLP
Moise Emmanuel L.
LandOfFree
Two-dimensional printed code for storing biometric... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Two-dimensional printed code for storing biometric..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Two-dimensional printed code for storing biometric... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3090577