Polaroid Corporation

Timothy R Crawford

Robert Francis Hartmann

Patrick J Hegarty

Joseph V Demarinis

Thomas H Campbell

A scanning system for a film recorder utilizes multiple digital-to-analog converters (DACs) to produce a linear output for a vertical deflection circuit which drives a vertical yoke circuit for controlling a CRT beam in a film recorder. The system contains a coarse DAC, a fine DAC, and a delta DAC which provides a signal representing the analog change from line to line. A summing circuit, a difference amplifier, a A/D converter, and a calibration sequence controlled by a DSP create a table to effectively increase the resolution and linearity of the deflection output signal.

Scanning system for film recorder

A method and apparatus for compensating for color and brightness variations in a white-light printer is described where the white-light printer automatically adjusts exposure of a photosensitive medium to optimize a printed image thereon. The white-light printer generates compensation factors used by the white-light printer to individually correct for primary colors within an image by monitoring chromatic transmission through the same or equivalent color filters as are being used to expose the photosensitive medium. A method is disclosed where the video output is set at maximum and brightness, or Luma, is varied and measured in foot-Lamberts. The Luma that gives 'white', a film table is recorded, and that Luma is fixed such that proper white, black, and grays are attained. A similar procedure is repeated for each primary color, thereby compensating for color and brightness variations due to differing CRTs and the warm-up state of each CRT.

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Needham, MA, United States of America

Timothy R Crawford