Phase responsive composite video signal control system

• US 4,642,682 A
• Filed: 04/27/1984
• Issued: 02/10/1987
• Est. Priority Date: 04/27/1984
• Status: Expired

• Current Assignee: Colorgraphics Systems Incorporated
• Original Assignee: VTA Technologies, Inc.
• Inventors: Orsburn, Michael L., Hemsky, Robert L., Bacon, James I.
• Primary Examiner(s): Shepperd, John W.
• Application Number:
  US06/604,845
• Time in Patent Office: 1,019 Days
• Field of Search: 358/28, 358/80, 358/76, 358/54, 358/27, 358/32, 358/22, 358/39, 358/81, 358/82
• US Class Current: 358/520
• CPC Class Codes: H04N 9/11 Scanning of colour motion picture films, e.g. for telecine
• CPC Class Codes: H04N 9/64 Circuits for processing colour signals H04N9/77 takes precedence; camera processing pipelines for processing colour signals H04N23/84

Abstract

A phase responsive video parameter control system operative for correcting hue, saturation, and luminance of a phase encoded component of a composite video signal. A digital phase detector detects the instantaneous hue of the video image, and provides a signal which selects which one of a plurality of color intervals or bands the detected instantaneous hue falls in. Prestored digital correction values associated with the selected color interval are retrieved from memory and converted into analog correction signals which modify the phase, amplitude, and DC level of the composite video signal. New digital correction values, which reflect operator control panel adjustments, may be loaded into memory during the vertical retrace interval, thereby allowing frame-by-frame color correction.

Claims

1. A phase responsive video signal correction system for correcting a video parameter of an image represented by a composite video signal, comprising:

phase detecting means responsive to detect relative phase between a phase encoded component of an uncorrected composite video signal and a reference signal in each one of a plurality of ranges of phases representable by said composite video signal;

correction signal means responsive to said detected relative phase for generating a correction signal related to said detected relative phase; and

means responsive to said correction signal for correcting said uncorrected composite video signal to provide a corrected composite video signal.

2. The system of claim 1, wherein said correcting means selectively corrects a chrominance portion of said uncorrected composite video signal.

3. The system of claim 2, wherein said correcting means selectively corrects the hue of a particular hue represented by said uncorrected composite video signal.

4. The system of claim 2, wherein said correcting means selectively corrects the saturation of a particular hue represented by said uncorrected composite video signal.

5. The system of claim 1, wherein said correcting means selectively corrects a luminance portion of said uncorrected composite video signal.

6. The system of claim 5, wherein said correcting means selectively corrects a luminance portion of a particular hue represented by said uncorrect composite video signal.

7. The system of claim 1, wherein said correction signal means is programmably variable.

8. A phase responsive video parameter control system for controlling a video parameter of a portion of a video image represented by a phase-encoded input video signal, said portion of said video image being at least partially defined by a predetermined hue, comprising:

memory means for storing a plurality of correction signals, each of said correction signals corresponding to a desired value of said video parameter for each one of a plurality of color intervals, each of said color intervals corresponding to one of a plurality of ranges of phase differences between said input video signal and a subcarrier reference signal;

phase detecting means responsive to said phase-encoded video signal for detecting said predetermined hue by detecting relative phase between said phase encoded video signal and said subcarrier reference signal and for providing a correction value selection signal related to the detected instantaneous hue of said video image;

correction value selecting means responsive to said correction value selection signal for selecting and retrieving a particular one of said plurality of correction signals associated with a particular one of said color intervals stored in said memory means and for providing said particular correction signal as an output, said particular correction signal being related to a particular desired value of said video parameter for said detected instantaneous hue; and

means responsive to said particular correction signal for controlling said video parameter to said particular desired value.

9. The system of claim 8, further comprising means for dividing each cycle of said subcarrier reference signal into said plurality of color intervals, and wherein said correction value selecting means selects and retrieves a particular one of said correction signals associated with a particular one of said color intervals.

10. The system of claim 9, wherein said dividing means comprises:

phase locked loop means for locking to the frequency of said subcarrier reference signal, said phase locked loop including a voltage controlled oscillator having an output signal having a frequency at least about N times the frequency of said subcarrier reference signal, N being the number of discrete color intervals; and

digital counter means responsive to said output signal of said oscillator to count to N once each cycle of said subcarrier reference signal.

11. The system of claim 9, wherein said memory means is responsive to said dividing means to repetitively provide said plurality of said correction signals in a predetermined sequence corresponding to said color intervals, and

wherein said correction value selecting means comprises latching means responsive to said correction value selection signal to temporarily store a particular one of said correction signals being provided by said memory means at a time of occurrence of said correction value selection signal.

12. The system of claim 8, further comprising operator control means for providing updated correction signals in response to actuation by an operator to indicate a desired change in control, and

means for periodically storing said updated correction signals in said memory means during an external access mode.

13. The system of claim 12, wherein said storing means is operative during a video signal vertical retrace interval.

14. The system of claim 8, wherein said video parameter is the hue of said detected instantaneous hue.

15. The system of claim 8, wherein said video parameter is the saturation of said detected instantaneous hue.

16. The system of claim 8, wherein said video parameter is the luminance of said detected instantaneous hue.

17. The system of claim 8, wherein said phase detecting means and said correction value selecting means are responsive to select said particular correction signal at least once each cycle of said subcarrier reference signal.

18. The system of claim 8, wherein each of said correction signals corresponds to a desired value of said video parameter for a plurality of predetermined ranges of hues, each of said predetermined ranges of hues comprising a plurality of particular instantaneous hues.

19. The system of claim 18, further comprising means for dividing each cycle of said subcarrier reference signal into a plurality of discrete color intervals, each of said color intervals corresponding to one of said predetermined ranges of hue, and wherein each of said color intervals is associated with a particular one of said correction signals stored in said memory means.

20. A hue responsive video parameter control system for controlling a video parameter of a portion of a video image, said portion of said video image being at least partially defined by a predetermined hue, comprising:

operator hue selection means for selecting a particular predetermined hue of said video image in response to actuation by an operator;

hue detecting means responsive to an input video signal to detect said selected particular predetermined hue and to provide a hue detect signal;

memory means for storing a plurality of correction signals, each one of said plurality of correction signals corresponding to a different one of a plurality of predetermined hues;

means responsive to said hue detect signal for retrieving a correction signal related to a desired value of a video parameter for said selected particular predetermined hue from said memory means; and

means for applying said retrieved correction signal to said input video signal to correct said video parameter to said desired value.

21. The system of claim 20, further comprising operator correction signal control means for selectively varying said correction signal.

22. The system of claim 20, further comprising memory means for storing a plurality of correction signals, each one of said plurality of correction signals corresponding to a different one of a plurality of predetermined hues.

23. The system of claim 22, further comprising second memory means for storing a plurality of sets of said correction signals, each one of said sets corresponding to a particular plurality of said correction signals associated with a particular video image.

24. The system of claim 20, further comprising memory means for storing a plurality of sets of correction signals, each of said sets being associated with a different video image,

each of said sets comprising a plurality of correction signals, and

wherein said memory means is responsive to provide a particular one of said sets of correction signals in response to receipt of a scene change signal indicative of a change in video images.

25. The system of claim 24, wherein said scene change signal is provided by an operator.

26. The system of claim 24, wherein said scene change signal is provided automatically by a control unit during provision of a series of video images.

27. A hue responsive video signal correction system for correcting a video parameter of an image represented by an uncorrected input color video signal, comprising:

hue detecting means responsive to said input color video signal for detecting hue of said input color video signal in one of a plurality of ranges of hues representable by said input color video signal; and

means responsive to said hue detecting means and comprising a single channel circuit for correcting a parameter of said uncorrected input color video signal to provide a corrected color video output signal.

28. The system of claim 27, wherein said video parameter is the hue of said portion of said video image.

29. The system of claim 27, wherein said video parameter is the saturation of said portion of said video image.

30. The system of claim 27, wherein said video parameter is the luminance of said portion of said video image.

31. The system of claim 27, further comprising memory means for storing a plurality of correction signals, each of said plurality of correction signals being related to a different predetermined hue, and wherein said correcting means selects a particular one of said plurality of correction signals stored in said memory means related to a particular predetermined hue.

32. The system of claim 31, wherein said memory means is an addressable digital memory, wherein said correction signals are digital signals, and wherein said hue detecting means selects a particular address of said addressable memory to select said particular one of said correction signals.

33. The system of claim 27, wherein said video parameter is the hue of said portion of said video image, and further comprising:

quadrature signal means for converting said input color video signal into a pair of quadrature-related chrominance component signals;

quadrature signal correction means for modifying the amplitude of one of said chrominance component signals to provide a modified chrominance component signal; and

quadrature component signal mixing means for mixing said modified chrominance component signal with the other one of said chrominance component signals to provide said corrected color video output signal.

34. The system of claim 33, wherein said quadrature signal correction means comprises analog multiplier means.

35. The system of claim 33, wherein said quadrature signal means comprises phase shifting means responsive to shift said phase-encoded video signal by ninety degrees to provide one of said pair of quadrature-related chrominance component signals.

36. The system of claim 27, wherein said input color video signal is a composite video signal including a luminance signal and a chrominance signal, and further comprising filter means for separating said chrominance signal from said composite video signal and for providing said chrominance signal to said hue detecting means.

37. The system of claim 27, wherein said hue detecting means comprises:

means responsive to said input color video signal for providing a chroma detect signal once each cycle of said input color video signal, said chroma detect signal having an edge aligned with the coincidence of said input color video signal with a predetermined reference voltage level;

first digital counter means responsive to count to a predetermined count once each cycle of said reference signal, said first counter means being reset to a predetermined nominal count once each cycle of said reference signal; and

means responsive to said chroma detect signal for holding a digital count of said first counter means at a time of occurrence of said edge of said chroma detect signal, said digital count representing a value related to the instantaneous hue of said image.

38. The system of claim 37, wherein said hue detecting means further comprises phase locked loop means for locking to the frequency of said reference signal.

39. The system of claim 38, wherein said phase locked loop includes an oscillator having an output frequency greater than the frequency of said reference signal, and further comprising second digital counter means responsive to an output signal of said oscillator to count to a predetermined count once each cycle of said reference signal,

said first digital counter means being responsive to count upon each occurrence of a first particular output signal from said second digital counter means and to reset upon each occurrence of a second particular output signal from said second digital counter means,

whereby said first digital counter divides each cycle of said reference signal into said plurality of ranges of hues.

40. The system of claim 39, wherein said digital count held by said holding means selects a particular one of said plurality of ranges, whereby a particular one of a plurality of desired values of said video parameter is selected.

43. A phase responsive video signal correction system for correcting a video parameter of an image represented by a color video signal, comprising:

phase detecting means responsive to detect relative phase between a phase encoded component of an uncorrected color video signal and a reference signal;

correction signal means for generating a plurality of correction signals, each of said correction signals being related to a different one of a plurality of ranges of relative phase between said uncorrected color video signal and said reference signal;

correction signal selecting means responsive to said detected relative phase detected by said detecting means for selecting a particular one of said correction signals corresponding to one of said ranges of relative phase; and

means responsive to said selected correction signal for correcting said uncorrected color video signal to provide a corrected output color video signal.

44. A video signal color correction system for correcting a video parameter of an image represented by an input color video signal, comprising:

means for defining a plurality of color control ranges, each of said color control ranges comprising those hues of the visible color spectrum which fall within a region of the spectrum defined by a first boundary of a predetermined first hue and a second boundary of a predetermined second hue;

detecting means for detecting when said input color video signals have hues within one of said color control ranges and responsive to provide a hue detect signal;

operator control means for providing color control signals indicative of an adjustment of a selected video parameter related to hues within said color control ranges; and

means responsive to said hue detect signal for applying said color control signals to said input color video signal.

45. A video signal color correction system for correcting a video parameter of an image represented by a color video signal, comprising:

memory means for storing a plurality of correction signals, each of said correction signals corresponding to a color correction for a video parameter having a hue within a predetermined color interval;

means responsive to said input color video signal for selecting one of said correction signals stored in said memory means as a function of the instantaneous hue of the video image; and

correction means responsive to said selected one of said correction signals for correcting said input color video signal to provide a color corrected video output signal.

46. A video signal color correction system for correcting a video parameter of an image represented by an input color video signal, comprising:

means for providing a plurality of color correction regions on a vectorscope representation of said color video signal;

memory means for storing a selectively variable correction signal corresponding to corrections for a video parameter;

means for detecting when said color video signal is within one of said color correction regions;

means for retrieving said correction signal from said memory means in response to said detecting means; and

correction means responsive to said retrieved correction signal for correcting said input color video signal to provide a corrected video output signal.

41. The system of claim 46, further comprising memory means for storing said plurality of desired values of said video parameter.

42. The system of claim 41, wherein said memory means is an addressable memory, and wherein said correcting means selects a particular address of said addressable memory to obtain said particular one of said plurality of desired values.

47. A phase responsive luminance control system for controlling the luminance of a portion of a video image represented by a phase-encoded video signal, said portion of said video image being at least partially defined by a predetermined hue, comprising:

phase detecting means responsive to detect said predetermined hue by detecting relative phase between said phase-encoded video signal and a reference signal in each one of a plurality of ranges of phases representable by said phase-encoded video signal;

luminance controlling means responsive responsive to said detected relative phase for generating a correction signal related to said detected relative phase; and

means responsive to said correction signal for controlling luminance in a video signal corresponding to said phase encoded video signal.

48. The system of claim 47, wherein said phase encoded video signal is a composite video signal including a luminance signal portion and a chrominance signal portion, and wherein said luminance controlling means is operative to control said luminance signal portion.

49. The system of claim 47, wherein said luminance controlling means is programmably variable.

50. A phase responsive chrominance control system for controlling the chrominance of a portion of a video image represented by a chrominance signal, said portion of said video image being at least partially defined by a predetermined hue, comprising:

phase detecting means responsive to detect said predetermined hue by detecting relative phase between said chrominance signal and a reference signal in each one of a plurality of ranges of phases representable by said chrominance signal;

correction signal means responsive to said detected relative phase for generating a correction signal related to said detected relative phase; and

means responsive to said correction signal for controlling said chrominance signal to provide a corrected chrominance signal.

51. The system of claim 50, wherein said controlling means comprises phase-shifting means for shifting the phase of said chrominance signal, whereby the hue of said portion of said video image is controlled.

52. The system of claim 51, wherein said phase-shifting means comprises quadrature signal means for converting said chrominance signal into a pair of quadrature-related chrominance component signals, and further comprising:

quadrature signal correction means responsive to said correction signal for modifying the amplitude of one of said chrominance component signals to provide a modified chrominance component signal; and

quadrature component signal mixing means for mixing said modified chrominance component signal with the other one of said chrominance component signals to provide said corrected chrominance signal.

53. The system of claim 50, wherein said controlling means comprises amplitude adjusting means for adjusting the amplitude of said chrominance signal, whereby the saturation of said portion of said video image is controlled.

54. The system of claim 50, wherein said correction signal means is programmably viable.

55. A phase responsive video signal correction system for correcting a video parameter of an image represented by a composite video signal, comprising:

phase detecting means responsive to detect relative phase between a phase encoded component of an uncorrected composite video signal and a reference signal;

correction signal means responsive to said detected relative phase for generating a correction signal related to said detected relative phase; and

means responsive to said correction signal for selectively correcting a luminance portion of a particular hue represented by said uncorrected composite video signal to provide a corrected composite video signal.

56. A phase responsive video parameter control system for controlling a video parameter of a portion of a video image represented by a phase-encoded video signal, said portion of said video image being at least partially defined by a predetermined hue, comprising:

memory means for storing a plurality of correction signals, each of said correction signals corresponding to a desired value of said video parameter for a particular instantaneous hue;

phase detecting means responsive to said phase-encoded video signal for detecting said predetermined hue by detecting relative phase between said phase encoded video signal and a subcarrier reference signal and for providing a correction value selection signal related to a detected instantaneous hue of said video image;

means for dividing each cycle of said subcarrier reference signal into a plurality of discrete color intervals, each of said color intervals being related to a particular one of said correction signals stored in said memory means;

correction value selecting means responsive to said correction value selection signal for selecting and retrieving a particular one of said plurality of correction signals associated with a particular one of said color intervals stored in said memory means and for providing said particular correction signal as an output, said particular correction signal being related to a particular desired value of said video parameter for said detected instantaneous hue; and

means responsive to said particular correction signal for controlling said video parameter to said particular desired value.

57. A phase responsive video parameter control system for controlling a video parameter of a portion of a video image represented by a phase-encoded video signal, said portion of said video image being at least partially defined by a predetermined hue, comprising:

memory means for storing a plurality of correction signals, each of said correction signals corresponding to a desired value of said video parameter for a particular instantaneous hue;

phase detecting means responsive to said phase-encoded video signal for detecting said predetermined hue by detecting relative phase between said phase encoded video signal and a subcarrier reference signal and for providing a correction value selection signal related to a detected instantaneous hue of said video image;

correction value selecting means responsive to said correction value selection signal for selecting and retrieving a particular one of said plurality of correction signals stored in said memory means and for providing said particular correction signal as an output, said particular correction signal being related to a particular desired value of said video parameter for said detected instantaneous hue;

means responsive to said particular correction signal for controlling said video parameter to said particular desired value;

operator control means for providing updated correction signals in response to actuation by an operator to indicate a desired change in control; and

means for periodically storing said updated correction signals in said memory means during an external access mode.

58. A phase responsive video parameter control system for controlling a video parameter of a portion of a video image, said portion of said video image being at least partially defined by a predetermined hue, comprising:

means for developing a phase-encoded video signal representative of a video image to be controlled;

operator hue selection means for selecting a particular predetermined hue of said video image in response to actuation by an operator;

phase detecting means responsive to said phase-encoded video signal to detect said selected particular predetermined hue by detecting relative phase between said phase-encoded video signal and a subcarrier reference signal;

means responsive to said detected relative phase for generating a correction signal related to a desired value of a video parameter for said selected particular predetermined hue;

memory means for storing a plurality of correction signals, each one of said plurality of correction signals corresponding to a different one of a plurality of predetermined hues;

second memory means for storing a plurality of sets of said correction signals, each one of said sets corresponding to a particular plurality of said correction signals associated with a particular video image; and

means responsive to said correction signal for correcting said video parameter to said desired value.

59. A phase responsive video parameter control system for controlling a video parameter of a portion of a video image, said portion of said video image being at least partially defined by a predetermined hue, comprising:

means for developing a phase-encoded video signal representative of a video image to be controlled;

operator hue selection means for selecting a particular predetermined hue of said video image in response to actuation by an operator;

phase detecting means responsive to said phase-encoded video signal to detect said selected particular predetermined hue by detecting relative phase between said phase-encoded video signal and a subcarrier reference signal;

memory means for storing a plurality of sets of a plurality of correction signals, each one of said sets being associated with a different video image, said memory means being responsive to provide a particular one of said sets of correction signals in response to receipt of a scene change signal indicative of a change in video images;

means responsive to said detected relative phase for retrieving from said memory means one of said correction signals related to a desired value of a video parameter for said selected particular predetermined hue; and

means responsive to said correction signal for correcting said video parameter to said desired value.