Video assist system for motion-picture camera

• US 4,928,171 A
• Filed: 10/30/1987
• Issued: 05/22/1990
• Est. Priority Date: 10/30/1987
• Status: Expired due to Fees

• Current Assignee: Panavision International LP (Panavision Incorporated)
• Original Assignee: Panavision Incorporated
• Inventors: Kline, Donald
• Primary Examiner(s): Groody, James J.
• Assistant Examiner(s): Kostak, Victor R.
• Application Number:
  US07/115,145
• Time in Patent Office: 935 Days
• Field of Search: 358/97, 358/214, 358/140, 358/311, 358/185, 358/244, 358/244.1, 358/215, 358/216, 358/228, 352/131
• US Class Current: 348/64
• CPC Class Codes: H04N 23/00 Cameras or camera modules comprising electronic image sensors; Control thereof
• CPC Class Codes: H04N 5/2228 Video assist systems used in motion picture production, e.g. video cameras connected to viewfinders of motion picture cameras or related video signal processing
• CPC Class Codes: Y10S 348/91 Flicker reduction

Abstract

A video assist system operates in parallel with a motion-picture camera by recording and scanning periodic frames of the motion-picture image. Each recorded frame is transferred to intermediate storage where data from that frame may be processed at a rate which is independent of the motion-picture capture rate. Data for each recorded frame is translated into an intermediate signal format in which each line of a television ("TV") image signal is transmitted at a standard TV signal rate, but in which an entire frame is transmitted at the motion-picture capture rate. The intermediate signal format is presented to a frame buffer which allows conversion to a standard TV signal format.

Claims

1. A video assist system for use in conjunction with a motion-picture camera having a predetermined capture rate for a motion-picture image, said system comprising

memory means for recording infalling light in synchrony with said motion-picture camera as a plurality of periodic image frames at said predetermined means for retrieving a plurality of said periodic image frames from said memory means at a periodic rate which is independent of said capture rate.

2. A video assist system as in claim 1, wherein said means for retrieving comprises means for translating data from said memory means into an intermediate signal format having a line transmission rate and a frame transmission rate substantially independent of said line transmission rate.

3. A video assist system as in claim 1, wherein said means for retrieving comprises means for translating data from said memory means into an intermediate signal format having periodic frames and lines within said periodic frames, said intermediate signal format comprising a frame transmission rate substantially greater than the inverse of a frame transmission time.

4. A video assist system as in claim 3, wherein said line transmission rate is substantially equal to a television standard line transmission rate, and wherein said frame transmission rate is substantially equal to a predetermined motion-picture file capture rate.

5. A video assist system as in claim 1, wherein said means for retrieving comprises means for translating data from said memory means into an intermediate signal format having periodic frames and lines within said periodic frames, said intermediate signal format comprising

line format means comprising a line transmission rate;

and

frame format means comprising a plurality of said line format means within a frame transmission time, and further comprising non-transmission format means comprising a substantial absence of said line format means.

6. A video assist system as in claim 1, wherein said memory means comprises CCD means for receiving infalling light and for generating image data therefrom.

7. A video assist system as in claim 1, wherein said predetermined capture rate is set by an operator of said motion-picture camera.

8. A video assist system for use in conjunction with a motion-picture camera having a predetermined capture rate for a motion-picture image, said system comprising

memory means for recording infalling light in synchrony with said motion-picture camera as a plurality of periodic image frames at said predetermined capture rate;

and

means for retrieving a plurality of said periodic image frames from memory means with a line retrieval rate which is independent of said capture rate and with a frame retrieval rate which is an integer multiple of said capture rate.

9. A video assist system as in claim 8, wherein said predetermined capture rate is set by an operator of said motion-picture camera.

10. A video assist system for use in conjunction with a motion-picture camera having a predetermined capture rate for a motion-picture image, said system comprising

memory means for recording periodic frames of said motion-picture image;

means for translating data from said memory means into an intermediate signal format having a line transmission rate and a frame transmission rate substantially independent of said line transmission rate; and

means for converting said intermediate signal format into a standard television signal format.

11. A video assist system as in claim 10, wherein said line transmission rate corresponds to a predetermined output rate of said memory means.

12. A video assist system as in claim 11, wherein said frame transmission rate corresponds to a standard television signal format frame transmission rate.

13. A video assist system as in claim 10, wherein said means for converting comprises a line buffer for storing image data corresponding to said intermediate signal format.

14. A video assist system as in claim 13, wherein said line buffer comprises

means for synchronizing an input to said line buffer with a first horizontal sync signal from an external video signal source;

and

means for synchronizing an output from said line buffer with a second horizontal sync signal.

15. A video assist system as in claim 10, wherein said means for converting comprises a frame buffer for storing image data corresponding to said intermediate signal format.

16. A video assist system as in claim 10, comprising means for receiving said intermediate signal format and for storing image data corresponding to said intermediate signal format.

17. A video assist system for use in conjunction with a motion-picture camera having a predetermined capture rate for a motion-picture image, said system comprising

means for recording a first image of a past scene;

means for capturing a second image of a present scene; and

means for displaying said first and second images in conjunction, whereby said first and second images may be directly compared.

18. A video assist system for use in conjunction with a motion-picture camera having a predetermined capture rate for a motion-picture image, said system comprising

memory means for recording a scan line of image pixels corresponding to at least part of an image pointed to by said motion-picture camera in a predetermined order;

and

means for retrieving said scan line in reverse order from said predetermined order.

19. A video assist system for use in conjunction with a motion-picture camera having a predetermined capture rate for a motion-picture image, said system comprising

means for synchronizing an input to a line buffer with a first horizontal sync signal from an external video signal source corresponding to at least part of an image pointed to by said motion-picture camera;

and

means for synchronizing an output from said line buffer with a second horizontal sync signal.

20. A video assist system for use in conjunction with a motion-picture camera having a predetermined capture rate for a motion-picture image, said system comprising

means for periodically converting image frames, corresponding to at least part of an image pointed to by said motion-picture camera, into image data;

memory means for storing said image data;

means for amplifying said image data to a predetermined brightness; and

means for retrieving said image data in a television signal format.

21. A video assist system for use in conjunction with a motion-picture camera having a predetermined capture rate for a motion-picture image, said system comprising

means for measuring infalling light, corresponding to at least part of an image pointed to by said motion-picture camera, at a plurality of image points and for generating image data therefrom;

means for storing said image data;

means for automatically amplifying said image data to a predetermined brightness;

frame buffer means for recording said image data;

means for retrieving said image data from said frame buffer means, and for generating therefrom a signal substantially in a television signal format.

22. A video assist system for use in conjunction with a motion-picture camera having a predetermined capture rate for a motion-picture image, said system comprising

CCD means for receiving infalling light, corresponding to at least part of an image pointed to by said motion-picture camera, and for generating image data therefrom;

automatic gain control means for automatically amplifying said image data to a predetermined brightness;

line buffer means for recording at least one horizontal scan line of said image data;

frame buffer means for recording at least one frame of said image data;

means for retrieving said image data from said frame buffer means, and for generating therefrom a signal substantially in a television signal format.

23. A method of operating a video assist system in conjunction with a motion-picture camera having a predetermined capture rate for a motion-picture image, comprising the steps of

recording infalling light in synchrony with said motion-picture camera as a plurality of periodic image frames in memory means at said predetermined capture rate;

and

retrieving a plurality of said periodic image frames from memory means at a periodic rate which is independent of said capture rate.

24. A method as in claim 23, wherein said predetermined capture rate is set by an operator of said motion-picture camera.

25. A method of operating a video assist system in conjunction with a motion-picture camera having a predetermined capture rate for a motion-picture image, comprising the steps of

recording infalling light in synchrony with said motion-picture camera as a plurality of periodic image frames in memory means at said predetermined capture rate;

and

retrieving a plurality of said periodic image frames from memory means with a pixel retrieval rate which is independent of said capture rate and with a frame retrieval rate which is an integer multiple of said capture rate.

26. A method as in claim 25, wherein said predetermined capture rate is set by an operator of said motion-picture camera.

27. A method of operating a video assist system in conjunction with a motion-picture camera having a predetermined capture rate for a motion-picture image, comprising the steps of

recording periodic frames of said motion-picture image in memory means;

translating data from said memory means into an intermediate signal format having a line transmission rate and a frame transmission rate substantially independent of said line transmission rate; and

converting and intermediate signal format into a standard television signal format.

28. A method of operating a video assist system in conjunction with a motion-picture camera having a predetermined capture rate for a motion-picture image, comprising the steps of

recording a first image of a past scene;

capturing a second image of a present scene; and

displaying said first and second images in conjunction;

wherein said first and second images may be directly compared.

29. A method as in claim 28, comprising the step of

altering said present scene until said first and second images are substantially identical.

30. A method of operating a video assist system in conjunction with a motion-picture camera having a predetermined capture rate for a motion-picture image, comprising the steps of

recording a horizontal scan line of image pixels in memory means in a predetermined order;

and

retrieving said horizontal scan line in reverse order from said predetermined order.

31. A method of operating a video assist system in conjunction with a motion-picture camera having a predetermined capture rate for a motion-picture image, comprising the steps of

synchronizing an input to a line buffer with a first horizontal sync signal from an external video signal source;

and

synchronizing an output from said line buffer with a second horizontal sync signal.

32. A video assist system for generating a flicker-free image corresponding to at least part of an image pointed to by a motion picture camera having a film shutter operating in a periodic cycle at a predetermined rate, said system comprising

means for generating a shutter pulse signal each time said film shutter of said motion-picture camera reaches a predetermined point in said periodic cycle, the timing of said film shutter not being controlled by the video assist system;

means, coupled to said means for generating, for generating a frame of image data for each said shutter pulse signal;

means for storing said frame of image data in a memory;

means for retrieving said image data from said memory in a continuous sequence at a periodic rate which is independent of said rate.

33. A video assist system as in claim 32, wherein said predetermined rate is set by an operator of said motion-picture camera.

34. A video assist system as in claim 32, wherein said means for generating comprises a CCD.

35. A video assist system as in claim 32, wherein said memory comprises a dual-port memory.

36. A video assist system as in claim 32, wherein said means for storing and said means for retrieving operate substantially simultaneously, whereby said image data which is retrieved from said memory substantially corresponds to said image pointed to by said motion-picture camera.

37. A video assist system as in claim 32, comprising

means for generating a television signal from said image data which is retrieved from said memory.