| 摘要 |
<p>PURPOSE:To prevent the occurrence of read errors due to dirt or the like, by using a two-dimensional sensor to detect the code consisting of plural ring- shaped marks provided on the outside circumference of a pipe or bar material. CONSTITUTION:A pipe (or bar) material 1 is moved in the direction of an arrow; and when its end part 1a reaches a pipe end detector 2 consisting of a light projector 3 and a photodetector 4, a strobe 6 starts the light emission at intervals of a certain time for a certain time. A two-dimensional sensor 7 is operated synchronously with this light emission, and a still picture is projected onto a monitor television 8 and a picture processing device 9. The still picture is stored in the picture processing device 9, and this operation is continued until a read start mark 5a and a read end position mark 5n are caught on the whole of a screen 10. The picture processing device 9 checks the number of picture elements in every one column and detects marks 5a and 5n if this number is a prescribed or higher proportion, and the device 9 checks the number of picture elements similarly in each window part 11 of bits 5b-5m of a code 5 to output level ''1'' or ''0''. Thus, errors due to dirt are prevented.</p> |
