Ambient light derived from video content by mapping transformations through unrendered color space

• US 20090175536A1
• Filed: 01/05/2005
• Published: 07/09/2009
• Est. Priority Date: 01/05/2004
• Status: Active Grant

• Current Assignee: Top Victory Investments Limited (TPV Technology Co., Ltd. (f/k/a Nanjing Huadong Electronics Information & Technology))
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Kuppens, Simon J. M., Gutta, Srinivas, Vanden Broek, Huub
• Granted Patent: US 7,932,953 B2
• Time in Patent Office: Days
• US Class Current: 382/166
• 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

Extracting and processing video content encoded in a rendered color space to be emulated by an ambient light source, comprising extracting color information from a video signal and transforming the color information through unrendered color space using tristprimary matrices to form a second rendered color space to drive the ambient light source. Video signal decoding into frames can allow extracting average or other color information from an selected screen regions to reduce bitstream load, and negative gamma correction helps prevent garish or inappropriate chromaticities and luminance.

Claims

1. A method for extracting and processing video content encoded in a rendered color space (RGB) to be emulated by an ambient light source (88), comprising:

[1] Extracting color information from a video signal (AVS) that encodes at least some of said video content in said rendered color space;

[2] Transforming said color information to an unrendered color space (XYZ);

[3] Transforming said color information from said unrendered color space to a second rendered color space (R′

G′

B′

) so formed as to allow driving said ambient light source.

2. The method of claim 1, wherein step [1] additionally comprises decoding said video signal into a set of frames.

3. The method of claim 1, wherein step [1] additionally comprises extracting an average color (R_AVG) from said color information.

4. The method of claim 1, wherein step [1] additionally comprises at least one extraction of said color information from an extraction region (R1).

5. The method of claim 4, wherein step [1] additionally comprises using said extraction of said color information to broadcast ambient light (L4) from said ambient light source adjacent said extraction region.

6. The method of claim 5, wherein step [1] additionally comprises extracting an average color (R_AVG) from said color information.

7. The method of claim 1, additionally comprising performing a gamma correction to said second rendered color space.

8. The method of claim 1, wherein steps [2] and [3] additionally comprise matrix transformations of primaries (RGB, R′

G′

B′

) of said rendered color space and second rendered color space to said unrendered color space using first and second tristimulus primary matrices (M₁, M₂); and

deriving a transformation of said color information into said second rendered color space (R′

G′

B′

) by matrix multiplication of said primaries of said rendered color space, said first tristimulus matrix, and the inverse of said second tristimulus matrix (M₂)<sup>−

1</sup>.

9. The method of claim 8, wherein said unrendered color space is one of CIE XYZ;

ISO RGB defined in ISO Standard 17321;

Photo YCC; and

CIE LAB.

10. The method of claim 8, wherein step [1] additionally comprises extracting an average color (R_AVG) from said color information.

11. The method of claim 10, wherein step [1] additionally comprises at least one extraction of said color information from an extraction region (R1).

12. The method of claim 11, wherein step [1] additionally comprises using said extraction of said color information to broadcast ambient light (L4) from said ambient light source adjacent said extraction region.

13. The method of claim 1, wherein steps [1], [2], and [3] are substantially synchronous with said video signal (AVS).

14. The method of claim 1, additionally comprising broadcasting ambient light (L1) from said ambient light source using said color information in said second rendered color space.

15. A method for extracting and processing border region video content from a rendered color space (RGB) to be emulated by an ambient light source (88), comprising:

[1] Extracting color information from a video signal (AVS) that encodes at least some of said video content in said rendered color space, after decoding said video signal into individual frames;

[2] Extracting an average color (R_AVG) from said color information from an extraction region (R1) in each of said individual frames;

[3] Transforming said average color to an unrendered color space (XYZ);

[4] Transforming said average color from said unrendered color space to a second rendered color space (R′

G′

B′

) so formed as to allow driving said ambient light source;

[5] using said average color to broadcast ambient light (L4) from said ambient light source adjacent said extraction region.

16. The method of claim 15, wherein steps [1], [2], [3], [4], and [5] are substantially synchronous with said video signal (AVS).

17. The method of claim 15, wherein steps [3] and [4] additionally comprise matrix transformations of primaries (RGB, R′

G′

B′

) of said rendered color space and second rendered color space to said unrendered color space using first and second tristimulus primary matrices (M₁, M₂); and

deriving a transformation of said color information into said second rendered color space (R′

G′

B′

) by matrix multiplication of said primaries of said rendered color space, said first tristimulus matrix; and

the inverse of said second tristimulus matrix (M₂)<sup>−

1</sup>.

18. A method for extracting and processing border region video content from a rendered color space (RGB) to be emulated by an ambient light source (88), using a colorimetric estimate, comprising:

[1] Extracting color information from a video signal (AVS) that encodes at least some of said video content in said rendered color space, after decoding said video signal into individual frames;

[2] Extracting a colorimetric estimate from said color information from an extraction region (R1) in each of said individual frames;

[3] Transforming said colorimetric estimate to an unrendered color space (XYZ);

[4] Transforming said colorimetric estimate from said unrendered color space to a second rendered color space (R′

G′

B′

) so formed as to allow driving said ambient light source;

[5] using said calorimetric estimate to broadcast ambient light (L4) from said ambient light source adjacent said extraction region.

19. The method of claim 18, wherein steps [1], [2], [3], [4], and [5] are substantially synchronous with said video signal (AVS).

20. The method of claim 18, wherein steps [3] and [4] additionally comprise matrix transformations of primaries (RGB, R′

G′

B′

) of said rendered color space and second rendered color space to said unrendered color space using first and second tristimulus primary matrices (M₁, M₂); and

deriving a transformation of said color information into said second rendered color space (R′

G′

B′

) by matrix multiplication of said primaries of said rendered color space, said first tristimulus matrix, and the inverse of said second tristimulus matrix (M₂)<sup>−

1</sup>.