Video camera with white balance control having the function of inhibiting auto while balance control under a special light source or of a special object

• US 5,267,026 A
• Filed: 08/29/1991
• Issued: 11/30/1993
• Est. Priority Date: 08/31/1990
• Status: Expired due to Term

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Kawahara, Hiroyuki, Tatsumi, Shingo
• Primary Examiner(s): Powell, Mark R.
• Application Number:
  US07/752,029
• Time in Patent Office: 824 Days
• Field of Search: 358/29, 358/29 C
• US Class Current: 348/223.1
• CPC Class Codes: H04N 23/88 for colour balance, e.g. white-balance circuits or colour temperature control

Abstract

In a video camera capable of regulating the white balance by relative regulation of the gains of plural color signals obtained from the light coming from an object, a control signal for controlling the white balance regulating operation is formed according to color temperature information, and the formation of the control signal is suspended according to the result of discrimination whether the control signal is within a predetermined range, whereby the time required for regulating operation is shortened. Also in case the object color is identified to contain a deviation to a particular color, the control signal is replaced by another value. In this manner the white balance control utilizing the image signal is enabled ever under a special light source for a special object.

Claims

1. A video camera, comprising:

a) image pickup means for forming plural color signals according to the light from an object;

b) regulation means for relative regulation of the gains of said plural color signals thereby regulating the white balance thereof;

c) control signal forming means for forming, according to color temperature information, a control signal for controlling said regulation means;

d) discrimination means for discriminating, whether said control signal is within a predetermined range; and

e) termination means for stopping the function of said control signal forming means in response to the result of discrimination by said discrimination means, and for subsequently inhibiting the function of said control signal forming means irrespective of said control signal.

2. A video camera according to claim 1, further comprising:

substitution means for substituting the value of the control signal, formed by said control signal forming means, with another value according to the result of discrimination by said discrimination means.

3. A video camera according to claim 2, wherein said substitution means is adapted to substitute the value of control signal, formed by said forming means, with a value within said predetermined range and close to the value of said control signal, according to the result of discrimination by said discrimination means.

4. A video camera according to claim 2, wherein said substitution means is adapted to substitute the value of said control signal with a predetermined value corresponding to a particular light source, according to the result of discrimination by said discrimination means.

5. A video camera according to claim 1, further comprising:

fixation means for fixing the value of said control signal according to the result of discrimination by said discrimination means.

6. A video camera according to claim 1, further comprising:

timer means for measuring the time from the start of function of said control signal forming means;

wherein said termination means is adapted to terminate the function of said control signal forming means, according to the output of said timer means.

7. A video camera according to claim 1, wherein said control signal forming means is adapted to form said control signal according to said plural color signals formed by said image pickup means.

8. A video camera according to claim 7, wherein said control signal forming means is adapted to form said control signal, utilizing the plural color signals transmitted by said regulation means.

9. A video camera according to claim 8, wherein said control signal forming means includes plural integration circuits for respectively integrating plural color signals transmitted by said regulation means.

10. A video camera, comprising:

a) image pickup means for forming plural color signals according to the light from an object;

b) plural regulation means for respectively regulating the gains of said plural color signals;

c) control signal forming means for forming plural control signals for controlling said plural regulation means, utilizing said plural color signals;

d) discrimination means for discriminating whether the combination of said plural control signals belong to a predetermined group of combinations; and

e) control means for substituting the values of said plural control signals with other values and stopping the function of said control signal forming means, in response to the result of discrimination by said discrimination means, said control means subsequently inhibiting the function of said control signal forming means irrespective of said control signal.

11. A video camera according to claim 10, wherein said control means is adapted to substitute the combination of said plural control signals with a combination belonging to said group and close to the first-mentioned combination, according to the result of discrimination by said discrimination means.

12. A video camera according to claim 10, wherein said control means is adapted to substitute the combination of said plural control signals with a predetermined combination corresponding to a predetermined light source, according to the result of discrimination by said discrimination means.

13. A video camera, comprising:

a) image pickup means for forming plural color signals according to the light from an object;

b) regulation means for relative regulation of the gains of said plural color signals thereby regulating the white balance thereof;

c) control signal forming means for forming, according to color temperature information, a control signal for controlling said regulation means;

d) discrimination means for detecting that the color of said object has a deviation to a particular color; and

e) substitution means for substituting the value of the control signal formed by said forming means with another value, in response to the result of detection by said detection means, and for subsequently maintaining the another value irrespective of said control signal.

14. A video camera according to claim 13, wherein said substitution means is adapted to substitute the value of said control signal, formed by said forming means with a predetermined value corresponding to a predetermined light source, according to the result of detection by said detection means.

15. A video camera according to claim 13, wherein said substitution means includes a memory for storing the value of the control signal formed by said forming means, and is adapted to substitute the value of the control signal, formed by said forming means, with a past value of the control signal stored in said memory.

16. A video camera according to claim 13, wherein said detection means includes plural integration circuits for respectively integrating said plural color signals formed by said image pickup means.

17. A video camera according to claim 13, wherein said detection means includes plural integration circuits for respectively integrating plural color signals transmitted by said regulation means, and plural comparator circuits for respectively comparing the outputs of said plural integration circuits with predetermined values.

18. A video camera according to claim 13, wherein said control signal forming means is adapted to form said control signal according to said plural color signals formed by said image pickup means.

19. A video camera according to claim 18, wherein said control signal forming means is adapted to form said control signal, utilizing plural color signals transmitted by said regulation means.

20. A video camera according to claim 19, wherein said control signal forming means includes plural integration circuits for respectively integrating plural color signals transmitted by said regulation means.