Automatic focusing apparatus for a video camera

An automatic focus control apparatus using a one-chip integrated circuit for focus control, comprising:

• (A) focusing means for performing focusing;
• (B) image pickup means;
• (C) an auto-focus integrated circuit for outputting a plurality of evaluation signals, which have characteristics different from each other and change in accordance with a focusing state, on the basis of an image pickup signal output from said image pickup means, said integrated circuit comprising
• a) gate means for setting a predetermined focus detection region in a photographing filed, and for allowing only the portion of the image pickup signal in the focus detection region to pass therethrough as a focus detection region signal,
• b) filter means for extracting a plurality of predetermined frequency components including a difference between maximum and minimum values of luminance components of the focus detection regions, which change in accordance with the focusing state, from the focus detection region signal,
• c) filter control means for controlling said filter means to extract different frequency components in the even and odd scanning lines respectively;
• d) arithmetic means for generating the plurality of evaluation signals by performing predetermined processing for the predetermined frequency components extracted by said filter means, and
• e) interface means for connecting said one-chip integrated circuit to control means and for supplying the plurality of evaluation signals generated by said arithmetic means to said control means;
• and
• (D) control means, connected to said integrated circuit via said interface means, for performing automatic focus control of said focusing means on the basis of the plurality of evaluation signals,
• wherein said one-chip integrated circuit includes at least part of camera signal processing means for producing a video signal by performing a predetermined process on the image pickup signal output from said image pickup means.

An automatic focus control apparatus comprising;

• (A) extraction means for extracting a plurality of predetermined frequency components including a difference between maximum and minimum values of luminance components of focus detection regions, which change in accordance with a focusing state, from an image pickup signal corresponding to a portion in a plurality of predetermined focus detection regions set on a photographing field, said extracting means extracts different frequency components in the even and odd scanning lines respectively;
• (B) peak detection means for detecting peak values of the frequency components in each horizontal scanning line within the portion in the focus detection regions;
• (C) integration means for integrating an output from said peak detection means in the focus detection regions;
• and
• (D) control means for controlling the focusing state on the basis of peak values output from said peak detection means in the focus detection regions, and an output from said integration means, said control means controlling a hill-climbing operation of a focusing lens, detection of an in-focus point of said focusing lens and restarting operation of said focusing lens.

An automatic focusing apparatus comprising:

• filter means for extracting different frequency components used in focus detection from an image pickup signal output from image pickup means in the even and odd scanning lines respectively;
• gate means for extracting focus signals corresponding to focus detections regions in a photographing field from a focus signal extracted by said filter means;
• extraction means for extracting a plurality of focus signals including a difference between maxiinum and minimum values of luminance components of the focus detection regions in the photographing field;
• estimating means for estimating the extracted focus signals on the basis of outputs from said extraction means;
• and
• driving means for driving a focusing lens to an in-focus point on the basis of the estimated extracted focus signals estimated by said estimating means.

An auto-focus integrated circuit, comprising:

• (A) filter means for extracting different frequency components including a difference between maximum and minimum values of luminance components of focus detection regions, which changes in accordance with a focusing state, from an image signal in the even and odd scanning lines respectively;
• (B) gate means for extracting a predetermined signal component, corresponding to a portion in a predetermined focus detection region in a photographing filed, of the signal output from said filter means;
• (C) arithmetic means for generating a plurality of evaluation signals, which have characteristics different from each other, by performing predetermined processing on the predetermined signal component extracted by said filter means;
• and
• (D) interface means for connecting said integrated circuit to an external control circuit and for supplying to said external control circuit the evaluation signal output from said arithmetic means to perform an automatic focusing operation, wherein said integrated circuit includes at least a part of camera signal processing means for performing a predetermined process on an output signal from an image sensor.

An auto-focus control integrated circuit chip for focus control, comprising:

• (a) extracting means for extracting different frequency components including a difference between maximum and minimum values of luminance components of focus detection regions, which changes in accordance with the focusing state, from an image signal corresponding to a focus detection region in the even and odd scanning lines respectively;
• (b) gate control means for operably controlling a size and/or a position of the focus detection region in a photographing field;
• (c) arithmetic means for generating a plurality of focus evaluation signals which have characteristics different from each other by performing predetermined processings, for the predetermined frequency components extracted by said extracting means;
• (d) interface means, arranged in said auto-focus control integrated circuit chip and connected to an external control circuit, for supplying the plurality of the focus evaluation signals generated by said arithmetic means to said external control circuit and for performing automatic focus control on the basis of the evaluation signals;
• and
• (e) camera signal processing means for performing a predetermined camera process on the image signal.

An auto-focus integrated circuit comprising:

• (A) extracting means for extracting different frequency components including a difference between maximum and minimum values of luminance components of focus detection regions from an image signal in a focus detecting region set in an image frame in the even and odd scanning lines respectively;
• (B) region control means for operably controlling a size or a position of the focus detection region in response to an instruction from an external control circuit;
• (C) focus detecting means for detecting a focus state on the basis of the predetermined frequency components extracted by said extracting means and outputting a focus evaluating signal corresponding to the focus state;
• (D) processing means for performing at least a part of a camera processing operation on the image signal;
• and
• (E) interface means, connected to the external control circuit, for supplying the focus evaluating signals to said external control circuit to cause said external control circuit to perform a focusing operation.