Datamatrix and PDF417 data integrity test

摘要

We conducted a test to evaluate data integrity of selected two-dimensional, high-density, high-capacity coding symbologies for use in selected automatic identification applications. The test was part ot the US Army`s Project Manager for Annnunition Logistics Automatic Ammunition Identification Technology Project. Specific symbologies tested were Datamatrix, from International Data Matrix, Inc., and PDF417, from Symbol Technologies, Inc. As a reference, Code 39 symbology was also evaluated under the same conditions. The statistical objective of the test was to determine if Datamatrix and/or PDF417 symbologies could be expected to exhibit one error or less in two million characters scanned and decoded. The level of confidence was set to 95%. Symbols for Datamatrix and PDF417 included 50, 100, 250, and 350 encoded characters for each of three levels or error correction. Each Code 39 symbol contained 15 to 25 characters. Based on a population of 1080 symbols per symbology, sample size was calculated to be 31,438,998 characters per symbology. An automated test apparatus was used to assure uniformity of test conditions. The apparatus included robotic loading and unloading of carrier sheets onto scanning stations. Scanning for Datamatrix symbols was performed using fixed mounted RS-170 CCD cameras. PDF417 and Code 39 symbols were scanned using hand-held rastering visible laser scanners mounted in fixed positions and software triggered. Decoding of all symbols occurred in decoders supplied with the scanners using the respective manufacturer`s proprietary decoding algorithms. Over 94 million characters were decoded during the test. Analysis of test results indicate no errors attributable to either Datamatrix or PDF417 symbologies. Eleven errors were recorded for Code 39.