| 摘要 |
<p>The present invention relates to apparatus for reading a two-dimensional bar code having bars located nominally at a predetermined pitch comprising means (20) for scanning the bar code with a plurality of spaced apart scan lines, means for generating for each scan line a sequence of elements of image data, recognition means (6) for recognising the bar code from the sequences of elements of image data, and transferring means (5) for selectively transferring the sequences of elements of image data to the recognition means (6).
<??>Apparatus in accordance with the invention is characterised in that the transferring means (5) comprises indicator generating means (21, 22, 23, 24, 25, 26, 30, 31, 32, 33, 34) for generating for each of the sequences of elements of image data an indicator representing the likelihood that the sequence represents the scanning of a portion of a bar, and profile vector constructing means (28) for constructing a plurality of profile vectors from selected ones of the indicators. The apparatus also includes comparison means in the programmed logic array (35) for determining for each profile vector which of the sequences of elements of image data, the indicators of which are used to construct the profile vector, represent the scanning of a portion of a bar and which of the sequences represent the scanning of a space between adjacent bars. The apparaturs further includes in the programmed logic array (35) means for selectively transferring to the recognition means (6) only those sequences of elements of image data which represent the scanning of a portion of a bar and disregarding all other sequences.
<??>The invention also relates to a method of reading a two-dimensional bar code having bars located nominally at a predetermined pitch utilising apparatus as above. </p> |
