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I was thinking OCR software wouldn't be as reliable as reading from the barcode... |
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The information density of a 2D barcode can be much greater than that of text. With suitable software, a half-megapixel (640x480) camera photographing a really big 2D barcode could reliably capture more than 4Kbytes of usable data--possibly 8Kbytes or more (16K would probably be achievable, though image compression would be a no-no). Getting even 4K worth of data using OCR, assuming 6 bits per character, would mean each character would be represented by about 64 pixels. Not a problem if the camera is perfectly aligned, but if anything isn't perfect OCR under such cases will be difficult at best. |
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Incidentally, many newer barcode readers--including 2D readers for anything but PDF-814 format--don't use lasers except as an indicator for the user for where to place the barcode to be scanned. PDF-814 is designed so that a scanner can read bits and pieces and assemble them all together; its information density is reduced considerably by that feature. Modern scanners use a CCD camera to photograph an entire barcode at once and then use some digital magic to determine whether there's an interesting-looking barcode in the picture. |
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Sounds reminiscent of VCR-Plus, in which some sequence of digits translated into a start time, end time and channel number. I assume these bar codes translate into a departure time and place, arrival time and place. Is this translation via an algorithm (preferred?) or a database? |
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