JPS5627481A - Pattern checker - Google Patents

Abstract

PURPOSE:To attain a close check by easily limiting any number of check areas in any shape by comparing the number of detected check areas to an allowable number and by storing the number of defectives in every check area. CONSTITUTION:The surface of cheched pattern 201 is scanned in two dimensions and from video input unit 204 of a TV camera, etc., an analog video signal in time series which corresponds to light and darkness is output. This signal output is converted into a digital signal, pattern end detecting circuit 208 detects a change point from the pattern to the background and with a position signal from scan synchronizing signal generating circuit 227, it is stored in pattern end memory 209 as coordinate values. Further, the number of defectives in every check area is integrated by defective integrating circuit 220, coordinate values in memory 209 are read by processor 230 and in each check area, the number of detected defectives is compared to an allowable number to correct coordinate values in reference level sampling area memory 214. Additionally, any number of check areas in any shape are stored in check area limitation memory 215 to make a close check.