Stabilized range finder for use with an electronically controlled camera
First Claim
1. A stabilized range finding device for an electronically controlled camera of the type having light projector means for projecting light toward an object to be photographed, light receiver means for receiving light reflected from the object and for outputting two channel signals changing in accordance with the intensity and incident position of the reflected light, and calculating means for calculating a distance datum on the basis of the two channel signals, the range finding device comprising:
- (a) a plurality of light emitting diodes as said light projecting means, each driven during sequential intervals to project emitted light toward different areas of said object and each driven to emit a first predetermined number of times during its driven interval;
(b)O a position sensitive detector included within said light receiver means for outputting said two channel signals;
(c) a microcomputer as said calculating means for executing a photographic image taking sequence;
(d) means for linearly amplifying said tow channel signals and for outputting said two channel signals as analog signals;
(e) means for A/D converting said two channel analog signals into digital signals and for sending said digital signals for respective channels to said calculating means; and
(f) stabilizing means controlled by said calculating means for invalidating said digital signals produced prior to a second lesser predetermined number of times.
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Accused Products
Abstract
A range finding device having a plurality of LEDs for projecting toward a scene to be photographed a plurality of spot beams of light disposed in a horizontal line, and a PSD for receiving light reflected from the object. Two channel signals from the PSD are amplified by gain control amplifiers and converted into digital signals. The two channel digital signals are obtained for each LED, and the ratio between the two digital signals is used for calculating a distance datum. Of a plurality of distance data obtained for respective LEDs, an optimum one is selected. For the calculation of a distance datum, there is used a microcomputer which controls an image taking sequence. The gain of the gain control amplifier is automatically adjusted by the measured data obtained in accordance with pulsed light emitted during the initial period of driving the LED. Digital signals obtained prior to the light emission of the LED are used for calculating an offset correction value. Each LED emits a pulsed light beam at a predetermined interval. An average value of digital signals for the pulsed light beams is used for calculating a distance datum. Several pulsed light beams during the initial period are not used for range finding or gain control. If the gain of the gain control amplifier is not proper, the range finding is interrupted and a distance datum specific to the then-existing gain value is used.
26 Citations
12 Claims
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1. A stabilized range finding device for an electronically controlled camera of the type having light projector means for projecting light toward an object to be photographed, light receiver means for receiving light reflected from the object and for outputting two channel signals changing in accordance with the intensity and incident position of the reflected light, and calculating means for calculating a distance datum on the basis of the two channel signals, the range finding device comprising:
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(a) a plurality of light emitting diodes as said light projecting means, each driven during sequential intervals to project emitted light toward different areas of said object and each driven to emit a first predetermined number of times during its driven interval; (b)O a position sensitive detector included within said light receiver means for outputting said two channel signals; (c) a microcomputer as said calculating means for executing a photographic image taking sequence; (d) means for linearly amplifying said tow channel signals and for outputting said two channel signals as analog signals; (e) means for A/D converting said two channel analog signals into digital signals and for sending said digital signals for respective channels to said calculating means; and (f) stabilizing means controlled by said calculating means for invalidating said digital signals produced prior to a second lesser predetermined number of times. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A stabilized range finding device for an electronically controlled camera, comprising:
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a light emitting element for projecting pulsed light a first predetermined number of times toward an object to be photographed; a light receiving element for receiving pulsed light reflected from said object and for outputting a signal corresponding of the intensity and incident position of said reflected pulsed light; calculating means for calculating a distance datum to be used for focusing said camera in accordance with said signal from said light receiving element; and control means for invalidating said signal obtained from said light receiving element that is produced prior to a second lesser predetermined number of times.
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Specification