| 摘要 |
A code reader and method which is capable of reading "black-on-black" codes such as bar codes which are molded in the surface of an object. The code is illuminated so as to provide light-to-shadow transitions which are read by an imaging device such as a video camera. The resultant video signal transitions representing light-to-dark transitions are differentiated and converted to a train of pulses which are submitted to a delay line sequencing network to develop a series of timing signals. These timing signals are utilized to operate a sampling network to derive 0-bit and 1-bit code information which is submitted serially to a serial-to-parallel shift register to permit code reading by a microcomputer function. Legality checks are carried out with respect to sampling and the developed work and quiescent zones are developed with respect to the start and stop of a given code sequence.
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