| 摘要 |
PURPOSE:To correctly detect a defective part without generating the erroneous detection caused by the nonuniformity of the luminance due to the irradiation unevenness, etc., as for a method for detecting the defective part on the surface of a workpiece from a dark part which appears on the image of an image pick-up means, by using an optical inspection device equipped with the image pick-up means which receives the reflected light from the surface of the workpiece. CONSTITUTION:The parameter value based on the luminance difference from the picture element on the periphery, e.g. the square value of the luminance difference is calculated for each picture element of an image. Even if the dark part (c) caused from the nonuniformity of the luminance, added with a dark part (b) caused by a defective part appears on a gray image taken in from an image pick-up means, the parameter value drastically increases in the dark part (b) in comparison with that in the dark part (c), since the luminance change is steep in the dark part (b). When the image of parameter value is binarized. The dark part (b3) appears only at the part corresponding to the defective part. This dark part is detected as the dark part caused by the defective part. |
