| 摘要 |
PROBLEM TO BE SOLVED: To detect a flaw with high accuracy by clearly discriminating between irregularity and an original uneven flaw by binarizing the change quantity of luminosity of each pixel and that of operated luminosity on the basis of a predetermined threshold value. SOLUTION: The inspection region 2 set on the surface of an IC mold 1 is photographed as a light and shade variable density image and the luminosity of each pixel is binarized on the basis of a threshold value C1 discriminating between voids 3 and a normal part. The regions (probes) P1 , P2 of a pixel becoming luminosity equal to or less than the threshold value C1 are extracted and the center-of-gravity coordinates positions G1 , G2 thereof are stored in a memory. Next, differential operation calculating the change quantity of the luminosity of the respective pixels of the region 2 is performed and the change quantity of luminosity is binarized on the basis of the threshold value discriminated between voids 3 and the normal part. Probes P3 -P6 becoming the change quantities of luminosity equal to or more than the threshold value C2 are extracted and the center-of-gravity coordinates positions G3 -G6 thereof are stored. Subsequently, the coincidence of the distances between the stored positions G1 , G2 and G3 -G6 is judged to be voids on the basis of the threshold value C3 and, as a result, the distance between the positions G1 , G3 becomes a threshold value C3 and it is judged that there is the center of gravity of voids 3. |
