# US 5,345,264 A · Video signal processing circuit for a video camera using a luminance signal

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- Number: US 5,345,264 A
- Document ID: US5345264A
- Status: Granted
- Kind: A
- Application number: 08/021,590
- Filed: 1993-02-24
- Granted: 1994-09-06
- Earliest claimed: 1992-02-27
- Assignees: Sanyo Electric Co., Ltd.
- Inventors: Haruhiko Murata; Yukio Mori; Akihiro Maenaka; Masao Takuma; Kiyotada Kawakami; Toru Asaeda; Toshiyuki Okino; Toshiya Iinuma; Akio Kobayashi; Toshinobu Haruki
- Web page: https://patentgrep.com/patent/US5345264A

## CPC

- H04N 23/68: for stable pick-up of the scene, e.g. compensating for camera body vibrations
- H04N 23/673: {based on contrast or high frequency components of image signals, e.g. hill climbing method}
- H04N 23/6811: {based on the image signal}
- H04N 23/683: {performed by a processor, e.g. controlling the readout of an image memory}
- H04N 23/72: Combination of two or more compensation controls
- H04N 25/60: Noise processing, e.g. detecting, correcting, reducing or removing noise
- H04N 25/75: Circuitry for providing, modifying or processing image signals from the pixel array
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION

## Abstract

Auto focus control and/or auto exposure control is carried out by using a luminance signal before gamma correction, before addition of aperture signal but after hand shake correction. Auto white balance control is carried out by using a color signal after hand shake correction. Consequently, precise auto focus control, auto exposure control and/or auto white balance control can be done. The field memory for electronic zooming and/or hand shake correction is also used as a field memory for noise reduction. Consequently, a video signal processing circuit which is inexpensive and simple can be implemented.

## Claims

### Claim 1

A video signal processing circuit for a video camera, comprising:
Y/C separating means for separating a video signal obtained by AD conversion of an output from an image pickup device to a luminance signal and a color signal for outputting; and
auto focus accumulating means for accumulating, at a prescribed period, high frequency component of the luminance signal outputted from said Y/C separating means before gamma correction, for outputting the result as an auto focus reference signal for automatic focus adjustment.

### Claim 2 (depends on 1)

The video signal processing circuit for a video camera according to claim 1, wherein the luminance signal to be accumulated by said auto focus accumulating means is the luminance signal before addition of an aperture signal.

### Claim 3 (depends on 1)

The video signal processing circuit for a video camera according to claim 1, wherein
the video signal processing circuit including said auto focus accumulating means is formed by one IC chip.

### Claim 4

A video signal processing circuit for a video camera, comprising:
Y/C separating means for separating a video signal obtained by AD conversion of an output from an image pickup device to a luminance signal and a color signal for outputting; and
auto exposure accumulating means for accumulating, at a prescribed period, low frequency component of the luminance signal outputted from said Y/C separating means before gamma correction, for outputting the result as an auto exposure reference signal for automatic exposure adjustment.

### Claim 5 (depends on 4)

The video signal processing circuit for a video camera according to claim 4, wherein the luminance signal to be accumulated by said auto exposure accumulating means is the luminance signal before addition of an aperture signal.

### Claim 6 (depends on 4)

The video signal processing circuit for a video camera according to claim 4, wherein
the video signal processing circuit comprising said auto exposure accumulating means is formed by one IC chip.

### Claim 7

A video signal processing circuit for a video camera, comprising:
hand shake correcting means for correcting hand shake of a video signal obtained by AD conversion of an output from an image pickup device for outputting;
Y/C separating means for separating the video signal after hand shake correction output from said hand shake correcting means to a luminance signal and a color signal for outputting; and
auto focus accumulating means for accumulating, at a prescribed period, high frequency component of the luminance signal output from said Y/C separating means for outputting the result as an auto focus reference signal for automatic focus adjustment.

### Claim 8

A video signal processing circuit for a video camera, comprising:
hand shake correcting means for correcting hand shake of a video signal obtained by AD conversion of an output from an image pickup device for outputting;
Y/C separating means for separating the video signal after hand shake correction output from said hand shake correcting means to a luminance signal and a color signal for outputting; and
auto exposure accumulating means for accumulating, at a prescribed period, low frequency component of the luminance signal output from said Y/C separating means for outputting the result as an auto exposure reference signal for automatic exposure adjustment.

### Claim 9

A video signal processing circuit for a video camera, comprising:
hand shake correcting means for correcting hand shake of a video signal obtained by AD conversion of an output from an image pickup device for outputting;
Y/C separating means for separating the video signal after hand shake correction output from said hand shake correcting means to a luminance signal and a color signal for outputting; and
auto white balance accumulating means for accumulating, at a prescribed period, the color signal output from said Y/C separating means for outputting the result as an auto white balance reference signal for automatic tone adjustment.