Canon Kabushiki Kaisha

Mitsutoshi Owada

Yukichi Niwa

Noriyuki Asano

Tokuichi Tsunekawa

Kazuya Hosoe

Makoto Masunaga

Masahiko Ogawa

Shuichi Tamura

Shin Tsuda

Takaaki Yamagata

This specification discloses an image scanning system in which an object image formed by an optical system is electrically scanned by utilization of a photosensor array device and the image scanning output then obtained is quantized to thereby provide quantized image data. According to the improvement of the present invention, there are obtained two different quantized image data, namely, first quatized image data quantized by a voltage level determined on the basis of the image scanning output from the sensor device and second quantized image data quantized by a predetermined fixed voltage level.

Image scanning system

A so-called active-type focus detection device applicable to optical instruments such as camera is provided with light emitting means and photoelectric detector means disposed at two positions conjugate with the pre-arranged focal plane of an image-forming optical system whose focus adjusted condition is to be detected or two positions optically equivalent to the two conjugate positions, and the light emitted from the light emitting means is projected toward an object to which the camera is to be focused, through the image-forming optical system. The light then reflected by the object is received by the photoelectric detector means through the image-forming optical system and the focused condition of the image-forming optical system with respect to the object is detected in accordance with the electrical output of the photoelectric detector means. According to a preferred embodiment of the present invention, the light emitted from the light-emitting means is projected upon the object by utilization of the maximum half area of the effective aperture of the image-forming optical system while, of the light that is reflected into the image-forming optical system by the object, the light passing through the maximum other half area of the effective aperture of the image-forming optical system is directed to the photoelectric detector means, whereby the position of incidence of the light flux on the light-receiving surface of the photoelectric detector means is varied correspondingly to the focus adjusted condition of the image-forming optical system with respect to the object and the variation in position of incidence of the light flux on the light-receiving surface of the photoelectric detector means is detected in accordance with the electrical output of the photoelectric detector means, thereby detecting the focus adjusted condition of the image-forming optical system with respect to the object.

Focus detection device

An optical sensor device for use in optical instruments is disclosed. The optical sensor device is provided with an optical sensing region having at least one sensor element responsive to incident light for producing a charge, first and second charge storing regions each having the same number of charge storage elements as that of said sensor elements for accumulating the charges produced from said sensor elements, a first gate region for controlling the transfer of charge from said optical sensing region to said first charge storing region, and a second gate region for controlling the transfer of charges from the optical sensing region to the second charge storing region. Upon alternate application of a voltage to said first and second gate regions, the charges produced from said optical sensing region are alternately accumulated on said first and second charge storing regions.

Optical sensor device with reduction of ambient light effects

A photo-sensor device comprises a light receiving part composed of a plurality of photo-sensor elements for converting photosignals into electrical signals. A portion of the light receiving part is shielded by light shielding means so that in reading out the output from the device, there can be obtained also a signal of dark current information from the shielded photo-sensor elements.

Photo-sensor device and image scanning system employing the same

This specification discloses an image scanning system in which an object image formed by an optical system is electrically scanned by utilization of a photosensor array device and the image scanning output then obtained is quantized to thereby provide quantized image data. According to the improvement of the present invention, there are obtained two different quantized image data, namely, first quantized image data quantized by a voltage level determined on the basis of the image scanning output from the sensor device and second quantized image data quantized by a predetermined fixed voltage level.

A distance measuring device is disclosed. This device has light projecting means. Light is projected from this projecting means to a target, and the concurrently reflected light from the target is received by photoelectric light receiving means which is provided with a plurality of photosensitive elements independent of each other and arranged in such predetermined distances from the above described light projecting means as to correspond to individual object distances different from each other. From the concurrent state of output of said photoelectric light receiving means there can be detected a distance to the above described target.

Distance measuring device

This invention relates to a device for focus detection or distance detection in which one or more images of a target formed by an optical system are received by photoelectric light receiving means to obtain a photoelectric output regarding the imaging condition of the image of the target and this photoelectric output is electrically processed through a processing circuit to thereby provide an electrical output representing the focus adjusted condition of the optical system with respect to the target or the distance to the target. According to the improvements of the present invention, such device is provided with projector means for illuminating a limited part of the detection view field determined by the focal length of the optical system and the dimensions of the effective light receiving surface of the photoelectric light receiving means, detection means for detecting whether or not the signal put out by the photoelectric light receiving means regarding the imaging condition of one or more images of the target is a sufficiently proper signal to ensure accurate focus detection or distance detection by the processing circuit, and control means for controlling the projector means in accordance with the detection output from the detection means. When proper detection is not ensured during the focus detection or the distance detection, the projector means is driven by the control means in accordance with the detection output of the detection means and the projection image of the projected light formed thereby on the target is utilized to effect focus detection or distance detection.

Device for focus detection or distance detection

A range detecting method and apparatus of a construction, in which first and second images of an object to be formed by a range finding optical system with a relative positional parallax corresponding to the object distance are scanned purely electrically by the use of one or more photo-sensor arrays, then analog image element signals concerning these first and second images obtained at this time are sequentially converted into two-value signals, after which the two-value signals are stored, as inputs, in first and second digital storing device where the coincidence and non-coincidence of these digital image scanning signals stored in these first and second storing devices are detected by means of a coincidence detecting device, while one of these image scanning signals are relatively shifted bit by bit with respect to other image scanning signals, and the shift bit quantities required until the digital image scanning signals of the same bit numbers concerning these first and second images may become optimumly coincided, thereby finding out the object distance from the shift bit quantities.

Range detecting method and apparatus

A range detecting method and apparatus in which a first and a second image of an object each having a relative positional parallax corresponding to the object distance formed by a range finding optical system are purely electrically scanned by the use of one or more photosensor arrays and the resulting image scan signals in analog form relating to the first and second images are applied to first and second analog storing devices for storage therein, in which coincidence or non-coincidence between the analog image scan signals is detected by coincidence detecting drive while one of these image scan signals is shifted bit by bit relative to the other image scan signal, thereby counting an amount of shift bits required until the image scan signals of the same bit number relating to the first and second images are rendered most appropriately coincident with each other, whereby the object distance may be known from such amount of shift bits.

Growing community of inventors

Yokohama, Japan

Mitsutoshi Owada