| 摘要 |
PURPOSE:To inspect the presence or absence and the shape of a through hole without requiring inputting of data of an inspecting position, etc., by detecting the defect in size and position of the through hole from above a pattern to be inspected. CONSTITUTION:A video signal 41 of a photoelectric conversion circuit 1 obtained when a pattern to be inspected is read is A/D converted at 2, and converted to a binary-coded image signal 43 at 3. A reverse image signal 44 inverted at 4 is turned to thin lines thereby to extract the central line of the inspected pattern at 5. A closed area surrounded by a line image signal 45 is extracted at 6. An identification number is assigned to each area. An inspecting area signal 47 is output at 7. A counter circuit 11 counts for every area the number of '1' patterns of a synchronous binary-coded image signal 48 synchronized with the signal 47 and delayed from the signal 43 at 8, thereby to calculate the area of a through hole. An area value signal 49 is compared with a reference value, and a size defect signal 50 is generated at 12. On the other hand, whether or not the position of the through hole is good is decided at 10 from a branch point signal 51 detected when a branch point of the signal 45 is extracted at 9, based on the generating position and generating pitch of the branch point. As a result, a position defect signal 52 is output. |
