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.

Shotaro Yokoyama

Takashi Nishibe

Kenichi Mori

Kiziro Suzuki

Takashi Tsutsumi

Seiichi Isoguchi

Kazuo Matsuzaki

Akira Amano

Koji Watanabe

Yoshio Tsuruta

Hiromu Haruki

Takashi Nishinbe

A method of detecting a phase difference between a pair of images of an object which are formed on a pair of optical sensor arrays through different optical paths, with presence of flare in one of the images, is disclosed. The method includes the steps of: preparing a sensor data group representing a pattern of each image and consisting of sensor data received from each optical sensor array; correcting the sensor data group so as to eliminate a difference in the average value of the sensor data between the optical sensor arrays; preparing a plurality of combinations each having two subgroups corresponding to the pair of optical sensor arrays, each subgroup consisting of a predetermined number of a series of sensor data, which are selected from the sensor data group corrected, such that a portion of the sensor data group from which the subgroup is selected is sequentially shifted; and selecting one of the combinations having a maximum degree of correlation between the subgroups, and detecting a phase difference from positions on the optical sensor arrays which correspond to the subgroups of the selected combination.

Method of detecting phase difference between a pair of images

An image data circuit compensates sensitivity differences in image detection between a pair of image sensors. The image sensors each include a plurality of charge storage type optical sensing elements. Correction data indicative of sensitivity difference between the image sensors is stored in permanent memory. A clock pulse generator circuit generates clock pulses for counting charge storage periods indicated by output signals from the optical sensing elements. A pair of counter circuits counts the clock pulses and outputs count values corrected with the correction data and corresponding to the charge storage periods. A pair of quantizing circuits converts the output signals to image data based on the corrected count values.

Image data circuit for correcting sensitivity differences between image

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

An acceleration measuring device consists of a sealed-off, diode vacuum tube which in turn contains a cold cathode and an anode positioned at opposing longitudinal end regions of the vacuum tube via an inter-electrode space C. An inert argon gas is sealed in the vacuum tube at the pressure of 1 mm Hg. Because the acceleration measuring device utilizes field effect electron emission phenomenon, i.e., quantum mechanical tunneling by the Schottky effect, from the cold cathode, one obtains electron-emission characteristics which are essentially temperature independent. The vacuum tube also includes one or more areas connected to the inter-electrode space, local density of the gas in which connected areas changes in response to acceleration experienced by the acceleration measuring device, whereby the density of the gas in the inter-electrode space is altered. Since the density of the gas in the inter-electrode space between the mutually opposing electrodes corresponds essentially linearly to the impedance against the electron flow towards the anode, the anode current is inversely proportional to the density of the gas in the inter-electrode space. The magnitude of the acceleration is measured by detecting the variation of the anode current.

Acceleration measuring device

For correction of an error caused in a period of a clock signal for digitizing a plurality of time signals, e.g., from an image sensor, a clock signal generating device generates a reference signal Sr indicative of a reference time of time signals TS from an OR-date (20). The device counts a reference clock signal .phi. in a frequency divider (30) until the reference signal Sr is generated, and outputs a divided clock signal .phi..sub.n with frequency dividing ratio 1/N from the frequency divider (30). It then counts the signal .phi..sub.n and stores the count value as a reference value S in a reference value counter (40). The device outputs an output clock signal .phi..sub.o from an output counter (50) each time the signal .phi. received after generation of the signal Sr reaches a predetermined value. It accumulates in an accumulator (60) the count value of the frequency divider (30) at the time of generation of the signal Sr in response to the signal .phi..sub.o, and it sets a reference value of the counter (50) for counting the signal .phi., to generate the signal .phi..sub.o usually at S, and at 1+S when an accumulated value in the accumulator (60) reaches the parameter N of the frequency dividing ratio.

Clock signal generating device

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

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 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

In a focus detection system in which light from an object is incident on at least two photosensor arrays via an optical system to form two images on the photosensor arrays, the relative displacement between the two images is determined in order to detect whether the optical system is in focus or not. A correction term which is formed by f(i.sub.0 +2) and f(i.sub.0 +1) or f(i.sub.0 -2) and f(i.sub.0 -1) is added to f(i.sub.0-1)-f(i.sub.0) or f(i.sub.0 +1)-f(i.sub.0), so that the amount of image deviation between the two images is obtained. Here i.sub.0 is the value of i when a function f(i) is minimized, the function f(i) expressing the inconsistency between the two images, corresponding to an amount of relative displacement i.times.p between the two images obtained discretely. The symbol p represents the pitch of the at least two photosensor arrays.

Method and system for detecting whether an optical system is in focus

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 weighted event counting circuit comprises a cascade connection circuit composed of a plurality of frequency dividing circuit means and a plurality of coincidence detecting circuit means inserted between the frequency dividing circuit means, and input circuit means to supply digital data representing the occurrence of plural events to the coincidence detecting circuit means. The number of occurrence times of the plural events is counted and totalized with weighting.

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Kanagawa, Japan

Shotaro Yokoyama