Abstract: A method and apparatus for providing a uniform illumination to a part provides a backlight unit in the form of a light panel located beneath the part. A reflector, generally hemispherical in shape, is located over the part to receive reflected light from the backlight. A first plane-polarizing material is positioned over the backlight, also beneath the part, and a second plane polarizer is located adjacent an aperture at the apex of the hemispherical reflector. A camera, mounted external of the reflector, is positioned to receive light passing through the second polarizer. Transmitted light from the backlight is polarized by the first polarizing material as it is transmitted to the reflector. Light directly received by the camera is filtered-out by the second polarizer, while reflected light that illuminates the part can substantially pass through the second polarizer into the camera.

Abstract: A system and method for inspecting the surface of an object using structured illumination is provided. A structured illuminator having a diffuser assembly, grid pattern and beam splitter projects the grid pattern on the surface. The projected grid pattern is viewed by a camera, which is aligned on-axis with the projection and substantially perpendicular to the surface. The structured grid pattern makes more-pronounced any surface defects. The projected image, defined by the grid pattern and received by the camera, is analyzed using a two-step technique that, first locates and scores the individual features of the grid, and then compares the locations of the actual features as viewed, to ideal locations for such features.