| 摘要 |
PURPOSE:To detect easily a surface defect of a surface to be inspected having processed stripes in a fixed direction by detecting the variation of a component of the reflected light quantity in the direction parallel to the processing stripes of the object to be inspected out of the reflected light from the object. CONSTITUTION:Luminous flux L is irradiated to an object 1 to be inspected having processed stripes 2 to detect the reflected light by a photodetector 3 such as television camera. The photodetector 3 is arranged to the direction perpendicular to the inspecting surface, and a sampling line 4 is made parallel to the direction of the stripes 2. Thus the variation N of the reflected light quantity due to the surface roughness can be decreased. Thereby, SN ratio of the variation S of the reflected light quantity level due to the defect part to the variation N of the reflected light quantity level at the normal part is increased, and the defect detection ability is improved. |
