Method and apparatus for illumination and imaging of a surface employing cross polarization

Abstract

An apparatus for illumination and imaging of a surface includes an apparatus for illuminating the surface, an apparatus for obtaining an image of the illuminated surface and providing an output signal representative of the obtained image, and an apparatus for limiting the exposure time of the image-obtaining apparatus to a selected fast exposure time less than the video frame rate of the image-obtaining apparatus. The image-obtaining apparatus may be a CCD-based camera. The CCD-based camera and the illumination apparatus may be mounted in a shroud having an opaque side wall. A first polarizing film may be provided intermediate the illumination apparatus and the surface, and a second polarizing film, having a polarization orientation orthogonal to that of the first polarizing film, may be provided intermediate the surface and the image-obtaining apparatus. Tip switches may be provided to prevent activation of the illumination apparatus and the image obtaining apparatus except when a lower edge of the shroud side wall is in contact with the surface.

Dependencies are inferred from the claim text.