JPH0623645B

PURPOSE:To make it possible to certainly confirm the position of large component parts, by a method wherein lights having different wavelengths are allowed to selectively irradiate parts and the obtained pickup images are allowed to be incident on an image input apparatus through a pair of filters which are arranged in parallel to each other so as to be inclined by 45 deg. to an optical axis and have selective reflectivity/transmissivity corresponding to the wavelengths of lights. CONSTITUTION:The light emitted from an illuminator 13 reaches a light source filter 14 and only light having a predetermined wavelength passes therethrough to be incident on an irregular reflection illuminator 12 to be irregularly reflected while a part of the light is irregularly reflected from the surface of an irregular reflection illuminator 11 and the pickup images of parts generated by said irregularly reflected lights are inputted to an image input apparatus 11 through region converting bodies 15a, 15b to certainly confirm the position of the parts on the basis of the good pickup images having a contrast. In other words, by confirming two corner parts of the parts 3, the position and posture of the parts 3 can be known.