Canon Kabushiki Kaisha

Kunihiko Yamada

Hirofumi Suda

Akihiro Fujiwara

Masamichi Toyama

Kitahiro Kaneda

Katsuji Yoshimura

Hideo Homma

Masahide Hirasawa

Naoya Kaneda

Mitsuo Niida

Yuji Tsuda

Ryunosuke Iijima

Kunio Imai

Kenji Kyuma

Hideyuki Arai

Shigeru Ogino

Hiroyuki Shimizu

Toshio Kaji

Kouichi Ueda

Yukihiro Adachi

In a quantity-of-light adjusting apparatus having an iris and an ND filter which limit incident light, a control method for the quantity-of-light adjusting apparatus, and a computer program product providing a control program for the quantity-of-light adjusting apparatus, a state of limitation of the incident light by the iris is changed at a first changing speed, and, when a state of limitation of the incident light by the ND filter is changed, the state of limitation of the incident light by the iris is changed at a second changing speed different from the first changing speed.

Quantity-of-light adjusting apparatus

A focus adjusting apparatus of an optical image formation system performs focus adjustment by: splitting light coming from an object into at least two rays along light paths of different lengths and projecting an image of the object; sensing the split rays and converting them into an image signal; filtering a first signal component out of the image signal and outputting a first value corresponding to an amount of the first signal component; filtering a second signal component, having a frequency different from the first signal component, out of the image signal and outputting a second value corresponding to an amount of the second signal component; judging a focus condition of the projected image by comparing the first value with the second value; and controlling the optical system to adjust the focus condition in accordance with a signal derived from the judging step.

Automatic focus adjusting apparatus and method utilized by an image sensing apparatus

An exposure control device having a light measuring area setting circuit which sets a light measuring area on an image sensing plane, a discriminating circuit which discriminates from each other varied states of the image sensing plane through video signal parts corresponding to the inside and the outside of the light measuring area and an exposure compensating circuit which compensates the state of exposure to light is arranged to shift the set position of the light measuring area to trace an object's image at least when the exposure compensating circuit is in operation. The operating modes of the device includes a first light measuring mode in which a quantity of light is measured on the basis of the average video signal level of the whole image sensing plane, a second light measuring mode in which the light quantity is measured with weight attached to a video signal part obtained from the inside of the light measuring area, and a third light measuring mode in which the light quantity is measured with weight attached to the video signal of the light measuring area by shifting the light measuring area to trace the object. The three light measuring modes are adaptively switched from one over to another.

Exposure control device

There is disclosed an integrated circuit for focus control, which is obtained by integrating, on a single chip, a filter circuit for extracting a predetermined signal component, which changes in accordance with a focusing state, from an image pickup signal, a gate circuit for extracting a focus signal, corresponding to a portion in a focus detection region in a photographing frame, from a focus signal extracted by the filter circuit, an arithmetic circuit for generating an evaluation signal of the focusing state by performing predetermined signal processing for the focus signal extracted by the gate circuit and corresponding to the portion in the focus detection region, a region setting circuit for controlling the positions or the number of focus detection regions in the photographing field by controlling the gate circuit, and an interface for connecting the respective circuits to an external circuit, and allowing the circuits to be controlled by a command from the control circuit.

Automatic focusing apparatus

An image processing apparatus provided with an electronic zooming device for electronically enlarging the image around a selected position in the image area, and a display control circuit for displaying an area to be enlarged, in the image area, prior to the image enlargement in the electronic zooming operation.

Image pickup apparatus provided with enlargement process means for enlarging image signals output from an image pickup device

Automatic focusing apparatus for a video camera

An exposure control device for performing exposure control on the basis of a video signal obtained from a light measuring area set within an image sensing plane is provided with a determining circuit which determines the position of a photographed object within the image sensing plane from the values of a specific component of the video signal obtained from the inside and outside of a detection area the position of which is variably set within the image sensing plane. The light measuring area is set in the object's position within the image sensing plane detected by the determining circuit. The exposure control device is provided further with a changing circuit which detects the size of the object on the image sensing plane and changes the size of the light measuring area accordingly, and a weighting circuit which performs for light measurement a weighting operation on video signals obtained from the inside and outside of the light measuring area.

An automatic focusing device for automatically controlling the focused state of an optical system on the basis of a video signal obtained within a focus detecting area which is set on an image sensing plane comprises: a tracing area setting circuit arranged to movably set, within said image sensing plane, an inner tracing area and an outer tracing area which surrounds the inner tracing area; a computing circuit arranged to compute information on a difference in a given frequency component of the video signal obtained from the inner and outer tracing areas in each of their different positions to which they are moved within the image sensing plane; determining means for determining the position or size of an object's image formed within the image sensing plane from the difference information computed by the computing circuit; and a circuit which is arranged to shift the focus detecting area to the position of the object's image determined by the determining circuit and to change the size of the focus detecting area according to the size of the object's image.

Automatic focusing device

An image sensing apparatus includes a diaphragm for an image sensing optical system, the aperture of the diaphragm being formed in a shape which is substantially asymmetrical in a horizontal or vertical direction, a in-focus detecting circuit for making a decision as to near focus state, in focus and far focus on the basis of a signal waveform which corresponds to an edge portion of a subject image passed through the diaphragm, and a driving circuit for performing focus adjustment of the image sensing optical system on the basis of an output of the in-focus detecting circuit.

Image sensing apparatus

Exposure control device having a plurality of light detecting areas

An automatic focusing device which is capable of movably setting within an image sensing plane a focus detecting area for detecting the focused degree of an object image formed on the image sensing plane by a photo-taking optical system comprises a position detecting circuit for detecting the position of an object within the focus detecting area, a computing circuit for computing on the basis of information from the position detecting circuit a setting position for setting the focus detecting area, and a control circuit which is arranged to move the focus detecting area according to the output of the computing circuit and to vary and control at least one of the size, the moving range and the moving response speed of the focus detecting area according to information on the depth of field of the photo-taking optical system.

Image sensing device having a selectable detecting area

In the automatic focusing device having an object image variation detecting circuit for quantitatively detecting a variation of an object image on the image pickup plane of an image pickup element so that the focusing operation is controlled in accordance with the amount of variation of the object image detected by the object image variation detecting circuit, there are provided a stop control circuit for controlling the period for stopping the focusing operation when panning depending on whether the amount of variation of the object image is large or small, a characteristic varying circuit for varying the frequency band of the picked-up image signal to be used in the focus detection depending on whether the amount of variation of the object image at the time of the focusing operation is large or small, and a pass characteristic varying circuit for varying the focus detection area on the image pickup plane depending on whether the amount of variation of the object image is large or small.

Automatic focusing device with adaptive signal filtering

A video camera is provided in which an effective image plane is not affected even if a command to write data is supplied from a microcomputer to a signal processing portion in an effective video period. A plurality of control registers are provided in an interface portion. If a command to write data is supplied from the microcomputer to the signal processing portion in an effective video period for a video signal, data, which must be transferred, and address are temporarily stored in the registers and the stored signals are transferred to the signal processing portion in a retrace line period for a next video signal. As a result of the structure, data is written on the signal processing portion in the retrace line period for the next video signal even if the command to write data is supplied from the microcomputer to the signal processing portion. Therefore, if data different from the data which must be transferred is supplied from the microcomputer to the register on which the data for the signal processing portion has been written, the effective image plane is not affected.

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Tokyo, Japan

Kunihiko Yamada