Fuji Electric Co., Ltd.

Fuji Electric Corporate Research and Developement Ltd.

Konishiroku Photo Industry Co., Ltd.

Fuji Electric Corporate Research & Development Co., Ltd.

Fuji Elec. Co. Ltd.

Takashi Nishibe

Shotaro Yokoyama

Kiziro Suzuki

Takashi Tsutsumi

Akio Izumi

Seiichi Isoguchi

Koji Watanabe

Hiromu Haruki

Yoshio Tsuruta

An object detecting system for an optical instrument having a pair of image sensors which receive light from objects in the field of view through different optical paths, each image sensor producing a group of image data representing the images of the objects in the field of view. Subgroups are formed from the groups of image data, wherein each subgroup represents image data corresponding to a portion of the field of view, and pairs of subgroups are formed with each pair of subgroups including one subgroup formed from each group of image data and both subgroups in each pair representing the same portion of the field of view. Consecutive overlapping segments of image data from each subgroup in each pair of subgroups are tested for high correlation between corresponding segments of image data from the subgroups of each pair. Clusters of segments of image data with high correlation are distinguished and one of the distinguished clusters is selected on the basis of a predetermined set of criteria.

Object-detecting system for optical instrument

Distance measuring unit for an automatic focusing camera

A light sensor device which uses semiconductors, can assure linearity even with low light intensity, and has a fast response time provides a voltage output proportional to a photoelectric current obtained from the output of an operational amplifier by accumulating the photoelectric current from a photodiode using the operational amplifier and an integration capacitance connected in parallel to the operational amplifier.

Light sensor having an integration circuit

An optical sensing circuit having a photodiode, a differential amplifying circuit, and a comparator. The differential amplifying circuit is provided with an integral capacity. Adjusting capacities are connected in parallel to or disconnected from the integral capacity. A composite capacitance of the integral capacity and the adjusting capacities is adjusted by a control circuit so that the composite capacitance increases with increase of light intensity. This makes it possible to improve sensitivity of the optical sensing circuit for the light intensity and to widen the dynamic range for light sensitivity.

Optical sensing circuit including an integral capacity

An object detector for an optical instrument that is suitable for detecting an object of image pickup in the case of the automatic focusing of the optical instrument such as a camera. The object detector is capable of selecting or adjusting angles of oblique direction with respect to the optical axis easily to detect an object.

Object detector for an optical instrument

An image position detecting device for detecting relative positions of images of an object on a pair of image sensors. A pair of image data groups are derived from the pair of image sensors. The image position detecting device includes window-size designating means, correlative value calculating means, and highest-correlation detecting means. The window-size designating means determines the number of data to be contained in windows, which define partial data groups from the image data groups depending on an optical parameter of the optical instrument. The correlative value calculating means calculates a correlative value representing the correlation between a pair of partial data groups defined by the windows. The highest-correlation detecting means detects the combination of the partial data groups with a correlative value which represents the highest correlation, and changes the combination of the partial data groups by successively displacing the windows for both the image data groups. With such an arrangement, an index is obtained from the positions of the windows for the combination of the partial data groups with the highest correlation to indicate the relative positions of the images on the pair of image sensors.

Image position detecting device

A method and apparatus for measuring the output of the measurement signal output by an optical sensor, for determining the intensity of the lights incident on the sensors. A plurality of setting values corresponding in a functional relationship to a plurality of estimated light intensity values being stored, prior to the measurement, in a memory. An address specifying means for causing the memory to output one of the plurality of setting values prestored therein during the time the address is specified. A count means for counting clock pulses with a predetermined period during the time duration of the measurement signal. A detecting means for detecting a comparison between the count value of the clock pulses and the setting value prestored in the memory and then causing the address specifying means to specify a new address in the memory in response to the detection result.

Method and apparatus for measuring sensor output

A circuit for generating clock signals includes a reference clock signal generator and a 1/N frequency divider for generating 1/N frequency divided clock signals. An up-counter counts the 1/N frequency divided clock signals until the occurrence of a first event. A programmable counter receives both an inverted count result as an initial value from the up-counter and the reference clock signals and counts the reference clock signals up to a predetermined count. When the programmable counter reaches the predetermined count it outputs a carry signal and is reset back to the initial value. As the programmable counter again counts from the initial value to the predetermined count, it again outputs a carry signal. These plurality of carry signals can be counted to provide a count corresponding to the amount of time between the occurrence of plurality of events.

Clock signal generating circuit

A method and apparatus for aligning image sensors with an optical system in an optical apparatus utilizing photosensors incorporated in the image sensors with high precision. The reference light beams are focused on the image sensors each having a specified photosensor for receiving a respective light beam. Signal outputs from the specified photosensors of the image sensors are measured. The position of the image sensors is adjusted relative to the position of the optical system in response to the measured signal outputs.

Method and apparatus for aligning image sensors with an optical system

A light intensity detecting circuit using a charge storage type of optical sensor having a parallel capacitor eliminates the influence of the dark current of the optical sensor and/or the influence of the offset of the comparator included in the detecting circuit so that the accuracy of the light intensity detection is improved over that of the prior art. To eliminate the influence of the dark current of the optical sensor in an image sensor, there is provided an optically shielded mimic sensor having the same structure as that of the optical sensor including a corresponding parallel capacitor. In order to eliminate the influence of the offset of the comparator, there is provided a time constant circuit having a capacitor that may be composed partially of the parallel capacitor of the mimic sensor corresponding to the parallel capacitor of the optical sensor; with potential applying means for operating the time constant circuit.

Light intensity detecting circuit with dark current compensation

A device for detecting the focal deviation value for focusing an optical apparatus includes a pair of optical lenses for receiving light from the focal object, which produces a pair of images that travel along two spatially isolated optical paths. These images are detected by a pair of photoelectric transducer arrays or photodiode arrays, which produce a pair of image signals that represents the distribution of light intensity in each image. Each image signal is composed of a plurality of image signal values. These signal values are used by a correlation evaluator, which extracts pairs of partial image signals corresponding to a predetermined number of consecutive image signal values, evaluates the correlation between any pair of extracted partial image signals, detects the position of the pair of extracted partial image signals and produces a corresponding focal deviation value for focusing the optical apparatus. The number of signal values in each image signal is not more than 1.5 times the predetermined number of consecutive image signal values of each extracted partial image signal. The device will produce a focal deviation value which shows the best correlation between extracted partial image signals.

Device for detecting the focal value for the focusing of optical

A method and system for finding an exact focus of a taking lens of a single lens camera or the like. The method detects the relative position between two images on the basis of light intensity distribution of the images from a pair of light sensor arrays that receive the images through light paths separated from each other in space. The relative position depends on whether a taking lens of a camera is in front-focus condition or in back-focus condition. Partial image data consisting of n data respectively are sampled from the two image data as verification data. A number of combinations of the data are used to calculate evaluation values indicative of the level of correlation between the respective verification data. Correct focus exhibits the highest correlation. The method overcomes the problem that the combination having the highest correlation may not be correctly determined due to abnormal shape or envelope of the plotted distribution of the evaluation value.

Method for detecting relative position of an image pair including

A device for measuring the intensity of light received by a photosensor comprises a photosensor for receiving light and producing a corresponding current and a circuit for integrating the current so that the intensity of the received light is indicated as the time required for the integration value of the integrating circuit to reach a predetermined value. If the intensity of the light is determined to be high at the start of the integration operation the integration value is set to the smaller of two predetermined values. If the intensity of the light is low, the integration value is set to a larger value.

Device for measuring light intensity received by a photosensor

A time interval measuring system includes circuitry for generating a signal indicating the beginning and end of a time interval, a clock to generate a periodically increasing clock signal, and a counter to count the clock signal between the beginning and end of the interval. The periodically increasing clock signal comprises a series of pulses each of which has a pulse period which is longer than the pulse period of the preceding pulse by a predetermined ratio greater than one.

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Kanagawa, Japan

Takashi Nishibe