Apparatus and method for determining exposure condition of ophthalmic photographing

Abstract

Abstract An ophthalmic photographing apparatus for determining the exposure condition of ophthalmic photographs, includes an illuminating optical system for illuminating a subject to be photographed, a photographing optical system for photographing the subject, an exposure control system comprising light detecting means for detecting intensities of light reflected at a plurality of zones of the subject, boundary level setting means for dividing a region between the highest and lowest values of the light intensities detected by the detecting means into a plurality of sub-regions and determining a boundary value between each two adjacent sub-regions, exposure condition setting means for setting a selected one of the sub-regions, comparator means for comparing output of the detecting means with the boundary value related to the selected sub-region to thereby select the outputs included in the selected sub-region, and exposure control means for controlling exposure in accordance with the selected outputs of the detecting means. A method for determining exposure condition of ophthalmic photographing comprising the steps of detecting intensities of light reflected at a plurality of zones in a subject to be photographed, dividing a region between highest and lowest values of the detected light intensities into a plurality of sub-regions, selecting one of the sub-regions and extracting the detected light quantities included in the selected sub-region, calculating a mean value of the extracted light intensities, and determining the exposure in accordance with the mean value of the extracted light quantities.

Inventors

• 👤 Susumu Takahashi

Bibliographic Details