Accession Number : ADD009056

Title :   Minimum Resolvable Contrast Measurement Device.

Descriptive Note : Patent,


Personal Author(s) : Task,Harry L ; Kuperman,Gilbert G

Report Date : 10 Nov 1981

Pagination or Media Count : 6

Abstract : An apparatus is disclosed for creating images of nonperiodic patterns, which patterns are variable in contrast with respect to a uniform and constant level of background luminance. Two beams of uniform luminance are projected through individual, orthogonally oriented linear polarizers, and then into a common cube beam splitter to be divided and interlaced. One combined output beam from the splitter is projected through a rotatable linear polarizer onto the image sensing optical detector undergoing test. The second beam is projected toward a detection system. The patterned region of the second beam passes through a second rotatable linear polarizer, synchronized to the first rotatable polarizer, and onto a CCD array detector system. Contrast between the pattern and the background is represented by the two electrical voltage levels in the array output, irrespective of the spatial frequencies in the pattern. Two unpatterned background regions from either of the interlaced beams are projected through individual and orthogonal linears polarizers to individual luminance detectors. Each detector, in turn, regulates its corresponding beam intensity to compensate for drift in the beam generating elements. (Author)

Descriptors :   *Patents, *Television systems, *Test equipment, Contrast, Resolution, Beam splitting, Polarization, Optical images, Comparison, Background radiation, Nonperiodic variations, Sensitivity, Charge coupled devices

Subject Categories : Test Facilities, Equipment and Methods
      Printing and Graphic Arts

Distribution Statement : APPROVED FOR PUBLIC RELEASE