Abstract: A method of and apparatus for scanning annularly arranged images on a disc film arranged for rotation about its axis so as to present sequentially the images at a scanning station, is provided.To correct for keystone distortion of a scanned image, a dove prism or equivalent mirror box is located on the optical axis and is rotated about such axis at half the speed of rotation of the disc.

Abstract: An optical scanner (10) scans a color transparency (11) with a spot of light from a scanning beam. The light transmitted by the transparency, which is modulated according to the color content and density of the transparency, enters a beam splitter (21, 28) for separation into spectrally-different components. Each component is passed to a photoresponsive detecting device (12, 13, 14). To compensate for scratches and dirt on the transparency, which scatter the transmitted light away from the beam splitter, an internally reflective mirror box (30, 47, 48) defines the optical path to the beam splitter so that scattered light is recovered and enters the beam splitter. The optical path to each photoresponsive device is also contained by a mirrored enclosure (31, 31a, 31b, 32, 32a, 32b).

Abstract: An optical beam splitter is provided which removes aberrations such as coma and transverse chromatic aberration by subjecting all transmitted rays to equal and opposite amounts of induction of coma and transverse chromatic aberration, by curing residual astigmatism by providing a terminal astigmatism correcting lens in each transmitted ray path, and by avoiding ghost images by ensuring adequate separation between the main image and any ghost images. The splitter thus permits the use of high resolution, low sensitivity, linear charge coupled devices in image analysis.