System and method for controlling exposure of a video camera by utilizing luminance values selected from a plurality of luminance values

• US 5,880,782 A
• Filed: 12/27/1995
• Issued: 03/09/1999
• Est. Priority Date: 12/30/1994
• Status: Expired due to Term

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Koyanagi, Masakazu, Tomitaka, Tadafusa
• Primary Examiner(s): Garber, Wendy
• Assistant Examiner(s): Vu, Ngoc-Yen, Vu, Ngoc-Yen
• Application Number:
  US08/578,076
• Time in Patent Office: 1,168 Days
• Field of Search: 348/222, 348/223, 348/224, 348/225, 348/229, 348/234, 348/235, 348/236, 348/237, 348/362, 348/363, 348/364, 348/365, 348/366, 348/169, 348/255, 348/256, 396/233, 396/234, 396/242, 396/243
• US Class Current: 348/364
• CPC Class Codes: G01S 3/7864 T.V. type tracking systems
• CPC Class Codes: H04N 23/70 Circuitry for compensating brightness variation in the scene
• CPC Class Codes: H04N 23/71 Circuitry for evaluating the brightness variation
• CPC Class Codes: H04N 23/72 Combination of two or more compensation controls

Abstract

A video camera system and method for automatically controlling the exposure of a desired object image. A plurality of average luminance values are respectively determined by a plurality of light measurement units. A plurality of reference luminance values are obtained from a plurality of reference value circuits. Selected ones of the average luminance values and the reference luminance values are utilized to form control signals. Such control signals control the video camera so as to maintain a proper exposure of the desired object.

Claims

1. A video camera system, comprising:

picture information temporary storage means having a temporary memory for dividing a video signal obtained from a video camera into luminance information and color information, and for storing picture information including said luminance information and color information in said temporary memory;

object recognizing and tracking means for recognizing, extracting and tracking a displayed object in accordance with said picture information stored in said temporary memory;

tracked object extraction and light measurement means for extracting and integrating only luminance information of said tracked object so as to calculate a first average value;

recognized color extraction and light measurement means for extracting color information having a same color as said tracked object, and integrating corresponding luminance information so as to calculate a second average value; and

exposure control means for controlling an iris and/or an automatic gain controller of said video camera by utilizing said first average value obtained by said tracked object extraction and light measurement means or said second average value obtained by said recognized color extraction and light measurement means and by utilizing a luminance reference value, and for adjusting the luminance of said tracked object so as to be substantially constant.

2. The video camera system according to claim 1, further comprising means for providing a command signal and wherein said tracked object extraction and light measurement means includes means for generating said luminance reference value used for exposure control upon receiving the command signal.

3. The video camera system according to claim 1, wherein said recognized color extraction and light measurement means integrates said luminance information having substantially the same color as a recognized color in said picture information which is other than noise in a black object and environment color in a white object to calculate the second average value.

4. The video camera system according to claim 1, further comprising means for providing a command signal and wherein said recognized color extraction and light measurement means initializes a recognized color in response to the command signal.

5. The video camera system according to claim 1, further comprising a storage switch arranged on said video camera, said storage switch being adapted to initiate and/or terminate exposure operations of said video camera system.

6. The video camera system according to claim 1, further comprising a storage switch arranged on one of a cable and a radio remote control for said video camera, said storage switch being adapted to initiate and/or terminate exposure operations of said video camera system.

7. The video camera system according to claim 1, further comprising a recording start switch of said video camera, said recording start switch being adapted to initiate and/or terminate exposure operations of said video camera system.

8. The video camera system according to claim 1, further comprising a recording start switch arranged on one of a cable and a radio remote control for said video camera, said recording start switch being adapted to initiate and/or terminate exposure operations of said video camera system.

9. A video camera system, comprising:

picture information temporary storage means having a temporary memory for dividing a video signal obtained from a video camera into luminance information and color information, and for storing picture information including said luminance information and color information in said temporary memory;

object recognizing and tracking means for recognizing, extracting and tracking a displayed object in accordance with said picture information stored in said temporary memory;

tracked object extraction and light measurement means for extracting and integrating only luminance information of said tracked object so as to calculate a first average value;

recognized color extraction and light measurement means for extracting color information having a same color as said tracked object, and integrating said corresponding luminance information so as to calculate a second average value;

centralized light measurement means for integrating luminance information of a first area in a center portion of a screen so as to calculate a third average value;

spot light measurement means for integrating luminance information in a second area around the center portion of said screen which is smaller than said first area so as to calculate a fourth average value;

light-measuring method selection means for selecting said first average value obtained by said tracked object extraction and light measurement means, said second average value obtained by said recognized color extraction and light measurement means, said third average value obtained by said centralized light measurement means, or said fourth average value obtained by said spot light measurement means in accordance with an object condition; and

exposure control means for controlling an iris and/or an automatic gain controller of said video camera by using the selected luminance average value and a luminance reference value, and for adjusting the luminance of said tracked object so as to be substantially constant.

10. The video camera system according to claim 9, wherein said light-measuring method selection means selects said second average value of said recognized color extraction and light measurement means, said third average value of said centralized light measurement means, or said fourth average value of said spot light measurement means when said tracked object cannot be extracted so as to recover an operating state in which exposure control may be performed by said tracked object extraction and light measurement means.

11. The video camera system according to claim 9, wherein said light-measuring method selection means selects said third average value of said centralized light measurement means or said fourth average value of said spot light measurement means when said tracked object is undetectable on the screen.

12. The video camera system according to claim 9, further comprising means for storing characteristic values of said tracked object and wherein said light-measuring method selection means selects said third average value of said centralized light measurement means or said fourth average value of said spot light measurement means prior to initialization in which the characteristic values are stored in said means for storing characteristic values.

13. A video camera exposure control method, comprising:

dividing a video signal obtained from a video camera into luminance information and color information, and storing picture information including said luminance information and color information in a temporary memory;

recognizing, extracting and tracking a displayed object in accordance with said picture information stored in said temporary memory;

extracting and integrating only luminance information of said tracked object so as to calculate a first average value;

extracting color information having a same color as said tracked object, and integrating corresponding luminance information so as to calculate a second average value; and

controlling an iris and/or an automatic gain controller of said video camera by utilizing said first average value or said second average value and by utilizing a luminance reference value, and adjusting the luminance of said tracked object so as to be substantially constant.

14. The video camera exposure control method according to claim 13, wherein the step of extracting only said luminance information of said tracked object includes generating said luminance reference value used for exposure control upon receiving a command signal.

15. The video camera exposure control method according to claim 13, wherein the step of extracting said color information integrates said luminance information having substantially the same color as a recognized color in said picture information which is other than noise in a black object and environment color in a white object to calculate the average value.

16. The video camera exposure control method according to claim 13, wherein the step of extracting said color information initializes a recognized color in response to a command signal.

17. The video camera exposure control method according to claim 13, wherein the video camera includes a storage switch arranged thereon and being adapted to initiate and/or terminate exposure operations of said video camera.

18. The video camera exposure control method according to claim 13, wherein the video camera includes a storage switch arranged on one of a cable and a radio remote control for said video camera, said storage switch being adapted to initiate and/or terminate exposure operations of said video camera system.

19. The video camera exposure control method according to claim 13, wherein the video camera includes a recording start switch of said video camera, said recording start switch being adapted to initiate and/or terminate exposure operations of said video camera system.

20. The video camera exposure control method according to claim 13, wherein the video camera includes a recording start switch arranged on one of a cable and a radio remote control for said video camera, said recording start switch being adapted to initiate and/or terminate exposure operations of said video camera system.

21. A video camera exposure control method, comprising:

dividing a video signal obtained from a video camera into luminance information and color information, and storing picture information including said luminance information and color information in a temporary memory;

recognizing, extracting and tracking a displayed object in accordance with said picture information stored in said temporary memory;

extracting and integrating only luminance information of said tracked object so as to calculate a first average value;

extracting color information having a same color as said tracked object, and integrating said corresponding luminance information so as to calculate a second average value;

integrating said luminance information of a first area in a center portion of a screen so as to calculate a third average value;

integrating said luminance information in a second area around the center portion of said screen which is smaller than said first area so as to calculate a fourth average value;

selecting said first average value, said second average value, said third average value, or said fourth average value in accordance with an object condition; and

controlling an iris and/or an automatic gain controller of said video camera by using the selected luminance average value and a luminance reference value, and adjusting the luminance of said tracked object so as to be substantially constant.

22. The video camera exposure control method according to claim 21, wherein the selecting step selects said second average value, said third average value, or said fourth average value when said tracked object cannot be extracted so as to recover an operating state in which exposure control may be performed by the step of extracting and integrating only said luminance information of said tracked object.

23. The video camera exposure control method according to claim 21, wherein the selecting step selects said third average value or said fourth average value when said tracked object is undetectable on the screen.

24. The video camera exposure control method according to claim 21, further comprising the step of storing characteristic values of said tracked object and wherein the selecting step selects said third average value or said fourth average value prior to initialization in which the characteristic values are stored during the storing step.

25. A video camera system, comprising:

picture information temporary storage means having a temporary memory for dividing a video signal obtained from a video camera into luminance information and color information, and for storing picture information including said luminance information and color information in said temporary memory;

object recognizing and tracking means for recognizing, extracting and tracking a displayed object in said picture information stored in said temporary memory;

tracked object extraction and light measurement means for extracting luminance information of said tracked object, for integrating only the extracted luminance information, and for averaging the integrated luminance information so as to produce a first average value;

recognized color extraction and light measurement means for extracting objects having a same color as said tracked object, for integrating corresponding luminance information of said objects, and for averaging the integrated information so as to produce a second average value;

reference generating means for generating reference luminance value signals; and

exposure control means for controlling an exposure operation of said video camera by utilizing selected ones of said first and second average values and said luminance reference values so that the luminance of said tracked object is properly adjusted.

26. A video camera system, comprising:

picture information temporary storage means having a temporary memory for dividing a video signal obtained from a video camera into luminance information and color information, and for storing picture information including said luminance information and color information in said temporary memory;

tracked object extraction and light measurement means for extracting luminance information of a tracked object from the picture information stored in said temporary memory, for integrating the extracted luminance information, and for averaging the integrated luminance information so as to produce a first average value;

recognized color extraction and light measurement means for extracting other objects having a same color as said tracked object, for integrating corresponding luminance information of said other objects, and for averaging the integrated information so as to produce a second average value;

centralized light measurement means for integrating luminance information of a first area in a center portion of a screen, and for averaging the integrated luminance information so as to produce a third average value;

reference generating means for generating a plurality of reference luminance value signals;

light-measuring method selection means for selecting (i) one of said first average value from said tracked object extraction and light measurement means, said second average value from said recognized color extraction and light measurement means, and said third average value from said centralized light measurement means, and (ii) one of said reference luminance value signals in accordance with current operating conditions; and

exposure control means for controlling an exposure operation of said video camera by utilizing the selected ones of said first, second and third average values and said reference luminance value signals so that the luminance of said tracked object is properly adjusted.

27. A video camera system according to claim 26, further comprising spot light measurement means for integrating luminance information in a second area around the center portion of said screen which is smaller than said first area, and for averaging the integrated information so as to produce a fourth average value.

28. A video camera exposure control method, comprising the steps of;

dividing a video signal obtained from a video camera into luminance information and color information, and for storing picture information including said luminance information and color information in a temporary memory;

recognizing, extracting and tracking a displayed object from said picture information stored in said temporary memory;

extracting luminance information of said tracked object, integrating only the extracted luminance information, and averaging the integrated luminance information so as to produce a first average value;

extracting objects having a same color as said tracked object, integrating corresponding luminance information of said objects, and averaging the integrated information so as to produce a second average value;

generating reference luminance value signals; and

controlling an exposure operation of said video camera by utilizing selected ones of said first and second average values and said reference luminance value signals so that the luminance of said tracked object is properly adjusted.

29. A video camera exposure control method, comprising the steps of:

dividing a video signal obtained from a video camera into luminance information and color information, and storing picture information including said luminance information and color information in a temporary memory;

extracting luminance information of a tracked object from the picture information stored in said temporary memory, integrating the extracted luminance information, and averaging the integrated luminance information so as to produce a first average value;

extracting other objects having a same color as said tracked object, integrating corresponding luminance information of said other objects, and averaging the integrated information so as to produce a second average value;

integrating luminance information of a first area in a center portion of a screen, and averaging the integrated luminance information so as to produce a third average value;

generating a plurality of reference luminance value signals;

selecting (i) one of said first average value, said second average value and said third average value, and (ii) one of said reference lumninance value signals in accordance with current operating conditions; and

controlling an exposure operation of said video camera by utilizing the selected ones of said first, second and third average values and said reference luminance value signals so that the luminance of said tracked object is properly adjusted.

30. The video camera exposure control method according to claim 29, further comprising the step of integrating said luminance information in a second area around the center portion of said screen which is smaller than said first area, and averaging the integrated luminance information so as to produce a fourth average value.