| 摘要 |
A novel bar code and optical reader for scanning the same. The bar code consists of two parallel channels of marks and spaces representing bit sequences, a given bit in one sequence being associated with a bit in the other sequence, forming successive bit pairs. The data is encoded in the logical exclusive-or combination of the bit pairs. An alternating clock scheme is further used to encode the data, which limits the width of any mark or space to twice the minimum width. The optical reader includes two optical detectors connected to a microprocessor which records the time intervals between mark/space transitions in each channel. These time intervals are used to reconstruct the bit sequences in each channel; the bit sequences may then be correlated and the XOR operation performed, yielding the encoded data.
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