# US 5,351,080 A · Color temperature control by comparing chrominance signals with reference levels

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- Number: US 5,351,080 A
- Document ID: US5351080A
- Status: Granted
- Kind: A
- Application number: 07/923,305
- Filed: 1992-07-31
- Granted: 1994-09-27
- Earliest claimed: 1986-02-21
- Assignees: Canon Kabushiki Kaisha
- Inventors: Kenji Kyuma; Teruo Hieda; Kazunori Masuda; Hirohumi Takei
- Web page: https://patentgrep.com/patent/US5351080A

## CPC

- H04N 23/88: for colour balance, e.g. white-balance circuits or colour temperature control
- G01J 1/42: using electric radiation detectors (optical or mechanical part G01J1/04; by comparison with a reference light or electric value G01J1/10)
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION
- G01J: MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY (light sources F21, H01J, H01K, H05B; investigating properties of materials by optical means G01N)

## Abstract

A color temperature information forming device has converting means of a plurality of kinds arranged to obtain chrominance signals of a plurality of different kinds by photoelectric converting rays of light of different wave length zones included in an incident light and to accumultate and produce the plurality of chrominance signals. The device detects the level of at least one kind of the chrominance signal among the chrominance signals of the plurality of kinds produced from the plurality of converting means and forms color component information according to the detected level.

## Claims

### Claim 1

A color image pick-up apparatus, comprising:
(a) image pick-up means for producing color image signals;
(b) light sensing means for producing chrominance signals of plurality of kinds;
(c) color temperature control means for producing color temperature control signals according to a binary combination of comparison results obtained by a binary gate circuit which receives comparison output signals obtained by comparing levels of said chrominance signals with respective predetermined reference levels; and
(d) correcting means for correcting said color image signals according to said color temperature control signals.

### Claim 2 (depends on 1)

An apparatus according to claim 1, wherein said image pick-up means includes a CCD.

### Claim 3 (depends on 1)

An apparatus according to claim 1, wherein said chrominance signals include an R-signal, a B-signal and a G-signal.

### Claim 4 (depends on 1)

An apparatus according to claim 1, wherein said correcting means includes an amplifier and is arranged to variably control the levels of said color image signals in accordance with said color temperature control signals.

### Claim 5

A color image pick-up apparatus, comprising:
(a) image pick-up means for producing color image signals;
(b) light sensing means for producing chrominance signals of a plurality of kinds;
(c) color temperature control means for producing color temperature control signals obtained by a logical operation of a logic circuit wherein said logic circuit receives comparison output signals obtained by comparing levels of said chrominance signals with respective predetermined reference levels; and
(d) correcting means for correcting said color image signals according to said color temperature control signals.

### Claim 6 (depends on 5)

An apparatus according to claim 5, wherein said image pick-up means includes a CCD.

### Claim 7 (depends on 5)

An apparatus according to claim 5, wherein said chrominance signals include an R-signal, a B-signal and a G-signal.

### Claim 8 (depends on 5)

An apparatus according to claim 5, wherein said correcting means includes an amplifier and is arranged to variably control the levels of said color image signals in accordance with said color temperature control signals.