| 摘要 |
PURPOSE:To detect defects at a high speed by picking up the image of a detected subject, storing detected contents, comparing them each other at a specific position around a testing reference position and detecting the magnitude of the defect based on the compared result. CONSTITUTION:Arithmetic is executed with intersection points P0 and P1 of an edge line L and a scan line L3 as a reference. Namely a point symmetric address is obtained in the direction of the scan line L3 at every picture element with respect to the intersection point P0, and its light and dark value Z is extracted. Then, according to expressions I and II the arithmetic is executed. Here, Za1-Zan, Zb1-Zbn, and DELTAZ1-DELTAZn show light and dark values of picture elements al-an, those of picture elements b1-bn and light and dark differences, respectively. Then a comparator circuit compares a total sum SIGMADELTAZn with a preset threshold. If it is over the threshold the tested subject is a reject having defects: Otherwise, it is decided to be an acceptance. |
