| 摘要 |
PURPOSE: To enhance the detecting sensitivity of the defect of a surface under inspection in a surface inspecting apparatus using a reverse reflection screen. CONSTITUTION: Two light sources 1a and 1b are arranged at positions holding a camera 2 at the upper and lower sides with respect to the surface of a material under inspection 10. A light source switching device 4, which changes the irradiations of the light sources 1a and 1b, in provided. The images of the light sources 1a and 1b are picked up which the camera 2. The differential image is formed from two images and processed with an image processor 6. Thus, the sensitivity is doubled. |
