Datastrip offers new take on bar codes
- By Michelle Speir
- Aug 12, 2002
Bar codes are everywhere. The ubiquitous striped rectangles show up on everything from groceries to government documents. But they have one major limitation: the amount of data they can hold.
The bar codes most of us are familiar with are one-dimensional. The data is read horizontally by gauging the width of the bars. You could truncate bars vertically — or portions of the bars could be damaged — without losing data as long as at least one small horizontal portion remains intact.
Two-dimensional bar codes, however, contain information in the vertical dimension as well as the horizontal. Instead of having a striped appearance, two-dimensional bar codes look like TV screen "snow." And they can hold much more information than conventional bar codes.
Datastrip Products Inc., maker of the DS Verify2D bar code scanner, uses a type of 2-D bar code called 2D Superscript. Such bar codes, used for standard identification cards, are strips measuring 0.75 inches by 3 inches and can hold 2.1K of information. Larger 2D Superscript bar codes can contain up to 3K of information. Data density can also vary from 150 to 1,000 bytes per square inch, depending on the printing technology used to print the strips.
Thanks to the large capacity, 2D Superscript bar codes can contain biometric information and photographs in addition to text. The typical strip for an ID card can hold one to two fingerprints, or one fingerprint and another biometric identifier in addition to a color photo and hundreds of words.
2D Superscript also features error correction, which allows full data recovery when as much as 50 percent of the bar code has been damaged. This is made possible by Reed-Solomon codes, mathematical codes that form the basis of error correction for products including computer hard disks and music CDs.
Conveniently, these bar codes can be printed using any standard 300-dots-per-inch printer, and possible government use includes passports, national ID cards, border control, voter registration cards, driver's licenses, military ID cards and more.
The bar code system also has a privacy advantage: All personal data is stored on the card, not in a database.
Hardware That Makes It Happen
The DS Verify2D device is a handheld computer with an integrated fingerprint sensor and high-resolution flatbed scanner. It weighs about 3 pounds and measures 11.5 inches by 5 inches by 2 inches.
The system can be used as a stand-alone product or as part of a PC-based solution.
The device contains a 200 MHz Hitachi Data Systems SH2 processor with a 66 MHz bus running Microsoft Corp. Windows CE 3.0. It has 32M of synchronous dynamic RAM and 32M of flash memory. (The operating system is stored in the flash memory.)
The display is a 3-inch color thin-film transistor LCD panel. Four LED indicators directly below the display indicate successful verification, verification failure or error, battery charging and system power.
The integrated scanner features 600 dpi resolution both horizontally and vertically with a scan window measuring 2.11 inches by 5 inches. It accepts most standard laminated and non-laminated ID cards, passports and other qualified documents.
Our unit came with an integrated fingerprint scanner from Antheus Technology Inc., but customers can order DS Verify2D with any brand of fingerprint sensor they choose.
The device includes two USB 1.1 ports, one RS-232 serial port, one selectable RS-232/RS-485 serial port and one infrared port. There is also a speaker for audio feedback and one Type II PC Card slot.
An alphanumeric keypad is located on the front of the unit, along with arrow keys and five function keys. The keypad is not designed for regular typing, but the letter keys are arranged in the traditional qwerty keyboard pattern, which makes it easier to use.
DS Verify2D also features an integrated smart card slot compatible with ISO 7816 cards, but we did not test this capability.
Power comes from either the replaceable lithium-ion battery or the AC power adapter. You can also order an extra battery and charger for about $70.
Datastrip doesn't offer out-of-the-box functionality. Instead, DS Verify2D comes with a software development kit. Accordingly, we tested a stand-alone demonstration version that enabled us to experience the bar code and fingerprint verification process.
It took only a few seconds for the scanner to read the bar code on our sample ID cards. Vertical placement of the ID card was irrelevant as long as the left edge of the card was flush with the left edge of the scanner.
Next, the system instructed us to place our registered finger on the fingerprint sensor, naming the specific finger. A red LED indicator on the sensor then lit up to indicate it was active.
The fingerprint verification process was a little slow, but that's no surprise considering the limited memory and processing power in this system. Of more pressing concern, however, was that after dozens of attempts with two different fingers and three different cards, the system did not once verify our tester's fingerprint.
The caveat is that when we made the ID cards during a meeting with Datastrip representatives, we tested them on a DS Verify2D machine, and they did work. The problem was only with the test unit we received.
The system read the text information and the photos with no problems, though, so the cards were not faulty.
A company representative theorized that the problem was with the Antheus fingerprint scanning technology and not with the system, because other information on the cards was read correctly.
We would caution users not to rely on the photo identification alone, though, because the photo quality on the display screen may not be good enough to prevent similar-looking people from impersonating one another.
Clearly, 2-D bar codes hold great potential not only for security applications, but also for recordkeeping applications such as insurance or employee information. They may be coming soon to an airport near you.