| 摘要 |
Systems (apparatus and methods) for reading bar code data detect light reflected and/or refracted from a target. The detected light is converted into an electrical signal containing width values that are indicative of widths of light areas and dark areas of the target. Systems for pre-screening data read by a bar code reader determine whether sequences of width values are consistent with potential bar code data by comparing the relative widths of subsequences of light areas and dark areas. If the relative widths are consistent with bar code data, the width values of the sequence being pre-screened are output to a decoder, which attempts to read the sequence of width values. If the relative width values are inconsistent with bar code data, the sequence of width values is not output to the decoder, thereby decreasing the amount of processing the decoder would otherwise be required to perform.
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