Method and apparatus for decoding multi-level bar codes or bi-level bar codes.

摘要

This is a bar code decoding method and apparatus that decodes the bar codes from digital video data. The apparatus will decode multi-level bar codes, as well as bi-level bar codes, but only a single format bar code at any given time. Data acquisition is via an optical scanner that generates a data signal that is converted into a run-length pixel count of pixels per bar or space. An array of twelve latches sequentially stores the run-length data while a programmable, high-speed math module sums the pixel count for a predetermined number of elements. Multi-level thresholds are established and the pixel count of a given element is compared to a multiple range of pixel counts used to define the number of modules per element. The module count of each element is compared to a predetermined start or stop code pattern. Look-up tables are then used for character decoding based on the module count of each element after the start code has been detected. <IMAGE>