Color correction system and method with scene-change detection

• US 4,823,184 A
• Filed: 09/08/1987
• Issued: 04/18/1989
• Est. Priority Date: 04/09/1984
• Status: Expired due to Term

• Current Assignee: Cintel SRL
• Original Assignee: Corporate Communications Consultants, Inc. (Aduddell Industries, Inc.)
• Inventors: Chayka, Stanley J., Belmares-Sarabia, Armand
• Primary Examiner(s): Shepperd, John W.
• Application Number:
  US07/094,241
• Time in Patent Office: 588 Days
• Field of Search: 358/27, 358/21 R, 358/31, 358/105, 358/136
• US Class Current: 348/650
• CPC Class Codes: H04N 1/6011 with simulation on a subsidiary picture reproducer H04N1/622 takes precedence; matching two or more picture reproducers H04N1/6052
• CPC Class Codes: H04N 19/142 Detection of scene cut or scene change
• CPC Class Codes: H04N 19/179 the unit being a scene or a shot
• CPC Class Codes: H04N 19/87 involving scene cut or scene change detection in combination with video compression
• CPC Class Codes: H04N 5/147 Scene change detection
• CPC Class Codes: H04N 9/64 Circuits for processing colour signals H04N9/77 takes precedence; camera processing pipelines for processing colour signals H04N23/84
• CPC Class Codes: H04N 9/73 Colour balance circuits, e.g. white balance circuits or colour temperature control camera processing pipelines for colour balance H04N23/88

Abstract

A color correction system with an improved scene-change detection module is disclosed. The scene-change detection module processes video picture signals representative of images stored by an image recording medium to detect the start of a new scene. The module advantageously includes circuits which sense a change in each of at least two different parameters of the video picture signals. The changes are analyzed in relation to a preselected condition. The module also includes circuits which generate a change detect signal when the change in at least one of the two parameters satisfies the preselected condition. Preferably, an area discrimination circuit is employed to limit the portion of the video picture in which the signals are sampled for scene-change detection purposes. One of the parameters that may be analyzed is a signal indicative of the color content of the video picture. Another parameter that may be analyzed corresponds to signals in a particular frequency range, which frequency range is below the range of frequencies for chrominance signals. As an alternative, the scene-change detection module may analyze just signals in a preselected frequency range when trying to find the start of a new scene. Each parameter may be analyzed by determining its average level in at least a portion of one video field, determining its average level in at least a portion of another video field, and then comparing the difference in average levels with a predetermined standard.

Claims

1. A system for color correcting video picture signals representative of images stored by an image recording medium, comprising:

transport means for moving the image recording medium and supplying video picture signals representative of each of the images stored by the image recording medium, said video picture signals being capable of producing pictures corresponding to the images;

discrimination means for discriminating video picture signals forming one area of the picture from video picture signals forming the remainder of the picture, said one area being smaller than the entire area of the picture;

scene change detecting means for processing said video picture signals and detecting a change of scene in said pictures, said detecting means including means for analyzing a change in each of at least two different parameters of said video picture signals in relation to a predetermined standard, said detecting means being connected to said discrimination means and analyzing only video picture signals in said one area, said detecting means including means for generating a change detect signal when the change in at least one of said parameters satisfies said predetermined standard; and

color correction means for developing color correction signals for the video picture signals forming the pictures in various scenes.

2. A system as recited in claim 1, wherein one of said two different parameters corresponds to a signal indicative of the color content of the picture and wherein said analyzing means includes means for analyzing the change in said color indicative signal.

3. A system as recited in claim 1, wherein one of said two different parameters corresponds to signals in a preselected frequency range, said preselected frequency range being below the range of frequencies for chrominance signals, and wherein said analyzing means includes means for analyzing the change in said signals in said preselected frequency range.

4. A system as recited in claim 3, wherein said preselected frequency range is between about 1.5 megahertz and about 2.5 megahertz.

5. A system as recited in claim 1, further comprising:

means for generating signals indicative of said predetermined standard and for generating signals indicative of the change in each of said two parameters; and

display means for displaying the pictures formed by the video picture signals along with the signals indicative of said predetermined standard and the signals indicative of the change in each of said two parameters.

6. A method for color correcting video picture signals representative of images stored by an image recording medium, comprising the steps of:

moving the image recording medium and supplying video picture signals representative of each of the images stored by the image recording medium, said video picture signals being capable of producing pictures corresponding to the images;

discriminating video picture signals forming one area of the picture from video picture signals forming the remainder of the picture, said one area being smaller than the entire area of the picture;

detecting a change of scene in said pictures by analyzing only video picture signals in said one area, said detecting step including the step of analyzing a change in each of at least two different parameters of said video picture signals in relation to a predetermined standard;

generating a change detect signal when the change in at least one of said parameters satisfies said predetermined standard; and

developing color correction signals for the video picture signals forming the pictures in various scenes.

7. A method as recited in claim 6, wherein one of said two different parameters corresponds to a signal indicative of the color content of the picture and wherein said detecting step includes analyzing the change in said color indicative signal.

8. A method as recited in claim 6, wherein one of said two different parameters corresponds to signals in a preselected frequency range, said preselected frequency range being below the range of frequencies for chrominance signals, and wherein said detecting step includes analyzing the change in said signals in said preselected frequency range.

9. A method as recited in claim 8, wherein said preselected frequency range is between about 1.5 megahertz and about 2.5 megahertz.

10. A method as recited in claim 6, further comprising the steps of:

generating signals indicative of said predetermined standard;

generating signals indicative of the change in each of said two parameters; and

displaying the pictures formed by the video picture signals together with the signals indicative of said predetermined standard and the signals indicative of the change in each of said two parameters.

11. A color correction system for color correcting video picture signals representative of images stored by an image recording medium, comprising:

means for moving the image recording medium and producing video picture signals representative of each of the images stored by the image recording medium;

display means responsive to said video picture signals for displaying pictures corresponding to each of the images stored by the image recording medium;

scene analysis means for analyzing at least one of the video picture signals in each of a plurality of pictures to detect a scene change, said scene analysis means automatically producing a scene-change signal in response to a scene change, said scene analysis means including means for determining a first average level of selected video signals within a predetermined range of frequencies in a portion of a first field, means for determining a second average level of said selected video signals in said portion of a second field, means for evaluating the difference between the first and second average levels based upon a predetermined standard, and means for automatically producing said scene-change signal if the predetermined standard is satisfied;

color correction means for selectively producing color correction signals for said video picture signals;

first storage means for selectively storing said color correction signals in response to a first manual command;

position signal means for producing position signals indicative of the position of each of the images stored by the image recording medium;

means for determining the location of an initial image of a new scene from the scene-change signal and from the position signals, said location determining means producing a location signal representative of the location of the initial image of the new scene;

second storage means for selectively storing said signal representative of the location of the initial image of the new scene in response to a second manual command;

readout means for reading from said first and second storage means said color correction signals and said location signals, respectively; and

combining means for selectively combining color correction signals read from said first storage means with said video picture signals, said combining means being responsive to the location signals read from said second storage means and to the position signals from said position signal means.

12. A system as recited in claim 11, wherein said predetermined range of frequencies is below the range of frequencies for chrominance signals.

13. A system as recited in claim 12, wherein said predetermined range of frequencies corresponds to the detail lines of a monochrome video picture.

14. A system as recited in claim 11, further comprising means for selectively ignoring said scene-change signal.

15. A method for color correcting video picture signals representative of images stored by an image recording medium, comprising the steps of:

moving the image recording medium;

producing video picture signals representative of each of the images stored by the image recording medium;

displaying pictures corresponding to each of the images stored by the image recording medium;

analyzing at least one of the video picture signals in each of a plurality of pictures to detect a scene change, said analyzing step including the steps of determining a first average level of selected video signals within a predetermined range of frequencies in a portion of a first field, determining a second average level of said selected video signals in said portion of a second field, and evaluating the difference between the first and second average levels based upon a predetermined standard;

automatically producing a scene-change signal if the predetermined standard is satisfied;

selectively producing color correction signals for at least one of said video picture signals;

selectively storing said color correction signals in response to a first manual command;

producing position signals indicative of the position of each of the images stored by the image recording medium;

determining the location of an initial image of a new scene from said scene-change signal and from said position signals;

producing a location signal representative of the location of the initial image of the new scene;

selectively storing said location signal in response to a second manual command;

reading said color correction signals and said location signals; and

selectively combining said color correction signals with said video picture signals in response to said location signals and said position signals.

16. A method as recited in claim 15, wherein said predetermined range of frequencies is below the range of frequencies for chrominance signals.

17. A method as recited in claim 16, wherein said predetermined range of frequencies corresponds to the detail of an image in a video picture.

18. An apparatus for electrically analyzing video signals which form a plurality of video pictures to detect a scene change, said apparatus comprising:

bandpass filter means for transmitting video signals within a preselected pass band;

scene sensing means responsive to the video signals transmitted by said bandpass filter means, said scene sensing means including means for determining a first average level of said transmitted video signals in at least a portion of a second field, means for comparing the difference between the first and second average levels to a predetermined standard, and means for producing an output signal indicative of a scene change if the predetermined standard is satisfied.

19. An apparatus as recited in claim 18, wherein said preselected pass band is centered at approximately 2.0 megahertz and has a width of about 1.0 megahertz around the center frequency.

20. A method for electrically analyzing video signals which form a plurality of video pictures to detect a scene change, said method comprising the steps of:

transmitting video signals within a preselected pass band;

sensing a scene change by analyzing said transmitted video signals, said sensing step including the steps of determining a first average level of said transmitted video signals in at least a portion of a first field, determining a second average level of said transmitted video signals in at least a portion of a second field, comparing the difference between the first and second average levels to a predetermined standard; and

producing an output signal indicative of a scene change if the predetermined standard is satisfied.