Exposure time control for a solid-state color camera

• US 4,532,550 A
• Filed: 01/31/1984
• Issued: 07/30/1985
• Est. Priority Date: 01/31/1984
• Status: Expired due to Term

• Current Assignee: RCA Corporation
• Original Assignee: RCA Corporation
• Inventors: Johnson, Cydney A., Bendell, Sidney L.
• Primary Examiner(s): Rubinson, Gene Z.
• Assistant Examiner(s): Lev, Robert
• Application Number:
  US06/575,570
• Time in Patent Office: 546 Days
• Field of Search: 358/209, 358/211, 358/212, 358/213, 358/214, 358/215, 358/216, 358/217, 358/225, 358/227, 358/228, 358/102, 358/113, 358/134, 357/30
• US Class Current: 348/230.1
• CPC Class Codes: H04N 23/73 by influencing the exposure time

Abstract

A television camera includes a solid-state imager which forms a signal representative of the image during an integration interval. The integration interval is followed by a pull-down interval during which the integrated signal is transferred out of the photo-responsive region of the solid state imager. A shutter is provided which periodically prevents light from falling upon the photo-responsive region of the imager. The shutter is controllable for controlling the integration interval. Thus, by effectively adjusting the integration interval special effects such as "true" stop motion may be provided from a television scene.

Claims

1. A television camera, comprising:

solid-state image transducing means including a photosensitive surface for generating signal in response to received radiant energy from a scene during an integration interval; and

optical shutter means arranged to block radiant energy from said scene from reaching said photosensitive surface during all of a television field except during a portion of said integration interval, said optical shutter means being automatically controllable in response to the level of said received radiant energy for varying that portion of said integration interval during which radiant energy is blocked.

2. The camera according to claim 1 wherein said solid-state image transducing means is a charge-coupled device.

3. The camera according to claim 2 wherein said charge-coupled device is a frame transfer imager.

4. A television camera, comprising:

solid-state image transducing means including a photosensitive surface for generating signal in response to received radiant energy from a scene during an integration interval; and

first and second shutters arranged to block radiant energy from said scene from reaching said photosensitive surface during all of a television field except during a portion of said integration interval, the relative positions of said first and second shutters being automatically adjustable in response to the level of said received radiant energy to vary that portion of said integration interval during which radiant energy is blocked.

5. The camera according to claim 4 wherein said solid-state image transducing means is a charge-coupled device.

6. The camera according to claim 5 wherein said charge-coupled device is a frame transfer imager.

19. The camera according to claim 4 wherein said first and second shutters comprise rotating blade shutters.

7. A television camera, comprising:

solid-state image transducing means including a photosensitive surface for generating signal in response to received radiant energy from a scene during an integration interval;

a first shutter having a first blade for blocking radiant energy from said scene from reaching said photosensitive surface during recurrent fixed duration portions of a television field which do not include said integration interval; and

a second shutter having a second blade cooperatively arranged with said first shutter and automatically controlled such that radiant energy is blocked during recurrent variable duration portions of a television field which include said integration interval.

8. The camera according to claim 7 wherein said solid-state image transducing means is a charge-coupled device.

9. The camera according to claim 8 wherein said charge-coupled device is a frame transfer imager.

20. The camera according to claim 9 wherein said first and second shutters comprise rotating blade shutters.

10. A camera, comprising:

image transducing means including a photosensitive surface for generating signal in response to received radiant energy from a scene;

a first shutter for blocking radiant energy from said scene from reaching said photosensitive surface during a portion of a television field;

first motor means, coupled to said first shutter, for driving said first shutter;

first servo control means, coupled to said first motor means, for maintaining a predetermined speed and phase of said first shutter;

a second shutter coaxially arranged with said first shutter for varying the portion of a television field during which radiant energy is blocked;

second motor means, coupled to said second shutter, for driving said second shutter; and

second servo control means, coupled to said second motor means, for maintaining the speed of said second shutter and for controlling the phase of said second shutter with respect to said first shutter to vary that portion of a television field during which radiant energy is blocked.

11. The camera according to claim 10 wherein said image transducing means is a charge-coupled device.

12. The camera according to claim 11 wherein said charge-coupled device is a frame transfer imager.

13. The camera according to claim 12 wherein at least a part of said portion of a television field is the transfer interval when signal is transfered from an imaging area of said device to a storage area of said device.

14. A television camera, comprising:

image transducing means including a photosensitive surface for generating signal in response to received radiant energy from a scene;

first light control means for controlling the relative amount of radiant energy from said scene that impinges on said photosensitive surface;

first feedback means for automatically controlling said first light control means to compensate for the brightness of said scene, said first feedback means being switchable into a manual operating mode whereby the relative amount of radiant energy is fixed;

second light control means for controlling the relative time that radiant energy from said scene impinges on said photosensitive surface; and

second feedback means for automatically controlling said second light control means to compensate for the brightness of said scene, said second feedback means being switchable into a manual operating mode whereby said relative time is fixed.

15. The television camera according to claim 14 wherein said first light control means is an iris control and said second light control means is a variable aperture shutter.

16. The television camera according to claim 15 wherein said image transducing means is a charge-coupled device.

17. The camera according to claim 16 wherein said charge-coupled device is a frame transfer imager.

18. The camera according to claim 17 wherein at least a part of said portion of a television field is the transfer interval when signal is transfered from an imaging area of said device to a storage area of said device.

21. The camera according to claim 14 wherein changes in the amount of light impinging upon said photosensitive surface in response to manual operation of one of said first and second feedback means, is compensated for by automatic operation of the other of said first and second feedback means.