Retinal camera
AssigneeOlympus Opitical Co., Ltd.
InventorsHiroshi Fujiwara, Kazuyuki Minami
Life of this patent
Estimating the term…
Abstract
To make it possible to simply and positively estimate on the spot the quality of the retinal photographing result, a retinal camera provided with an automatic exposure controlling device, an estimate reference signal generating means, a quality estimating means estimating the quality of the photographing result and an estimation indicating means indicating the estimation result. The automatic exposure controlling device comprises an integrator integrating the output from a light receiving element, a keyboard putting in exposure conditions, an exposure data signal generating means, a reference voltage generating means, a comparative calculating means and a flash light emission controlling means.
Claims15
A retinal camera comprising:
- automatic exposure controlling means for emitting a flash emission starting signal to initiate a flash output, a flash emission stopping signal indicative of a predetermined amount of light from said flash being received, and an exposure data signal indicative of exposure conditions;
- estimate reference signal generating means, connected to said automatic exposure controlling means, for producing an estimate reference signal indicative of a time that should elapse between said flash emission starting signal and said flash emission stopping signal if a proper subject is exposed by said camera, based on said exposure data signal and said flash emission starting signal from said automatic exposure controlling means;
- quality estimating means, connected to said automatic exposure controlling means and said estimate reference signal generating means, for determining whether said flash emission stopping signal from said automatic exposure controlling means is produced within a predetermined time threshold of said estimate reference signal and producing an estimating signal indicative thereof, thereby estimating if a proper subject is exposed by said camera;
- and
- estimation indicating means connected to said quality estimating means, for indicating said estimation result on the basis of the estimating signal emitted from said quality estimating means.
A retinal camera for photographing an object that is to be irradiated by a photographic flash, comprising:
- light receiving means for receiving a reflection of a flash from said object to be photographed and producing an output indicative thereof;
- automatic exposure controlling means, connected to said light receiving means, and including:
- (a) integrator means for integrating the output from said light receiving means, and
- (b) means for determining rate of rising of an output of said integrator means at a predetermined time point,
- said automatic exposure controlling means for emitting a flash emission starting signal to initiate said flash, and for producing a flash emission stopping signal when said output of said integrator means reaches a predetermined level and an exposure data signal;
- estimate reference signal generating means, connected to said automatic exposure controlling means, for producing an estimate reference signal indicative of a time beginning at said flash emission starting signal, and after which said flash emission stopping signal should be received, if a proper subject is exposed by said camera, as a reference for estimating the quality of a photographing result, and based on said exposure data signal and said flash emission starting signal from said automatic exposure controlling means, and for producing signals indicative of an upper limit value and a lower limit value indicative of a permissible range around said estimate reference signal;
- quality estimating means, connected to said automatic exposure controlling means and said estimate reference signal generating means, for comparing the integrated output from said integrator means with said two signals corresponding to said lower limit value and said upper limit value from said estimate reference signal generating means;
- and
- estimation indicating means, connected to said quality estimating means, for indicating an estimation result based on said estimating signal from said quality estimating means.
Dependencies are inferred from the claim text.