Photography – With exposure objective focusing means – focusing aid – or... – Having auxiliary illumination
Patent
1999-03-31
2000-02-15
Adams, Russell
Photography
With exposure objective focusing means, focusing aid, or...
Having auxiliary illumination
396 98, 396120, 396125, G03B 1300
Patent
active
06026246&
ABSTRACT:
A far-side signal (I.sub.2) output from a PSD which has received reflected light from an object to be subjected to distance measurement is input to a clamp circuit through a second signal processing circuit, and the far-side signal (I.sub.2) or a clamp signal (Ic) at a predetermined level, i.e., a signal (I.sub.2 c) at a higher level is output from the clamp circuit. An arithmetic circuit and an integration circuit receive a near-side signal (I.sub.1) output from the PSD and the signal (I.sub.2 c) output from the clamp circuit and calculate an output ratio signal (I.sub.1 /(I.sub.1 +I.sub.2 c)). A CPU obtains a distance signal from the output ratio signal in accordance with a transformation formula which changes depending on the threshold value for determining whether to clamp the signal.
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Miwa Yasuhiro
Yoshida Hideo
Adams Russell
Fuji Photo Optical Co., Ltd.
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