| 摘要 |
PURPOSE: To correct the binarized threshold value for an image, having a saturated level substantially over the entire region thereof except a part of shadow image having unsaturated level, depending on the fluctuation in the illuminance thereof in order to detect a defect in a work to be inspected. CONSTITUTION: A search line 4 for tracking the outline position 3 of an image 1A a shadow image 2 is predetermined using a reference work of same type. Minimum values (lower limit level) 7 of image data are then determined at a plurality of local regions along the line 4 and averaged to determine a reference reflection level Lo. A binarized threshold value THo of image is also set for detect detection. Position of the search line 4 is then determined front the outline position 3 of the image 1A of work to be inspected and the reflection level Li is determined similarly for that image. Finally, the binarized threshold value THi for the image is corrected according to a formula; THi=(Li/ Lo)×THo. |
