| 摘要 |
PURPOSE:To perform inspection accurately regardless of a pattern, by stopping the position correcting operation in the direction of position deviation, when the amount of the data of the position deviation is less than a specified threshold value. CONSTITUTION:Binary coded video signals are stored into the shift registers of image memories 91A and 91B. Every time the image datum of one bit is inputted, the image signal is shifted by every one bit. When the signal is taken out of each position of the shift registers of the memories 91A and 91B, an image which is deviated in the X and Y directions with respect to a reference image is obtained. The images are taken out with delay circuits 92A and 92B and inputted into an exclusive OR circuit 93. The disagreed parts of the images, which are deviated by several bits, are detected and counted with a counter circuits 94. The counter circuit, of minimum count is identified with computing circuits 95A and 95B. When the rare of change in each of X and Y is less than a specified preset value, the output of the position deviation in that direction from a changing-rate computing circuit 96A or 96B is forcibly judged to be no deviation. The signal of the judgment is outputted to a position-deviation correcting circuit 97. In this way, inspection can be performed accurately regardless of a pattern to be inspected.
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