Optics: measuring and testing – Range or remote distance finding – With photodetection
Patent
1979-10-02
1981-08-25
Hix, L. T.
Optics: measuring and testing
Range or remote distance finding
With photodetection
354 38, 354 50, 356222, 250214P, G03B 7083
Patent
active
042855845
ABSTRACT:
A photometer for use in combination with a camera determines the optimum film exposure interval with the exposure interval corrected for differences in illuminance between a subject of principal interest in the central portion of the scene to be photographed and the subjects of secondary interest in the foreground and background portions of the scene. The photometer includes a photo-responsive array divided into three light receiving segments each having a field of view that generally corresponds to, respectively, the central portion, the foreground portion, and the background portion of the scene. Electronic circuitry, either in analog or digital form, is provided to select the maximum output of the background and foreground segments of the photo responsive array and compare the so-selected maximum output with the output of the central segment to increase the exposure interval when either the background or the foreground portion of the scene are more brightly illuminated than the subject of principal interest and decrease the exposure interval when the background or foreground portion of the scene are less brightly illuminated than the subject of principal interest. A photometer in accordance with the present invention is suitable for use with both conventional shutter mechanisms and time-integrating shutters.
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"The Theory of the Multicell Exposure Meter", R. Euling, Photographic Science and Engineering, vol. 6, No. 3, May-Jun. 1962, pp. 121-129.
Hix L. T,.
Polaroid Corporation
Roman Edward S.
Schreyer Stafford D.
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