| 摘要 |
PROBLEM TO BE SOLVED: To detect even the defect of a pattern edge part with high accuracy by comparing the position of an edge decided in a 1st area with the position of an edge decided in a 2nd area and deciding the quality of an image pattern from the difference value of both edge positions. SOLUTION: An object to be checked is photographed (S1) and the reference coordinates are decided (S2). A check processing area is selected according to the reference coordinates (S3). A pixel near an optional edge candidate is defined as a 1st area in a digital image, and an edge is decided with approximation in the 1st area (S4). A check processing area includes the 1st area, a 2nd area larger than the 1st area is selected and an edge of the 2nd area is approximated by a straight line or circular arc to decide this edge (S5). The distance between the 1st and 2nd areas is calculated for comparing the edge positions of both areas with each other (S6). The calculation value, i.e. the comparison result of both edge positions is compared with the quality decision value that is previously set for deciding the quality of an image pattern (S7). |
