DEVICE AND METHOD FOR PROCESSIGN COLOR IMAGE DATA

• US 20100020242A1
• Filed: 11/20/2007
• Published: 01/28/2010
• Est. Priority Date: 11/30/2006
• Status: Active Grant

• Current Assignee: Dynamic Data Technologies LLC
• Original Assignee: NXP B.V. (NXP Semiconductors NV)
• Inventors: Lammers, Matheus J. G., De Greef, Petrus M.
• Granted Patent: US 8,441,498 B2
• Time in Patent Office: Days
• US Class Current: 348/642
• CPC Class Codes: G09G 2320/0606 Manual adjustment
• CPC Class Codes: G09G 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• CPC Class Codes: G09G 5/02 characterised by the way in which colour is displayed details of colour display specific for CRTs G09G1/28; specific for flat matrix panels other than liquid crystal displays G09G3/2003; specific for liquid crystal displays G09G3/3607
• CPC Class Codes: H04N 9/67 for matrixing camera processing pipelines for matrixing of colour signals H04N23/85

Abstract

The present invention relates to a video processing device comprising a luminance and saturation detector (LSHD) for detecting the luminance values (lum) and the saturation values (sat) of pixels of an input video signal (IN); and a white-point, saturation and hue modulator (WSH) for transforming luminance and saturation properties (lum, sat) of the pixels of the input video signal (IN) into white-point, saturation and hue correction factors (W, Wc; S, Sc; H, Hc). The video device also comprises a color gamut matrix generating unit (CGMG) for generating a color gamut matrix in the perception domain based on the white-point, saturation and hue correction factors (Wc, Sc, Hc) of the white-point, saturation and hue modulator (WSH); a color gamut mapping unit (20) for multiplying the pixels of the input video signal (IN) with a color gamut matrix generated by the color gamut matrix generating unit (CGMG); and a clipping unit (31) for clipping the results of the a color gamut mapping unit (20) which are out of a predefined range.

Claims

1. A video processing device, comprising:

a luminance and saturation detector (LSHD) for detecting the luminance values (lum) and the saturation values (sat) of pixels of an input video signal;

a white-point, saturation and hue modulator (WSH) for transforming luminance and saturation properties (lum, sat) of the pixels of the input video signal into white-point, saturation and hue correction factors;

a color gamut matrix generating unit (CGMG) for generating a color gamut matrix in the perception domain based on the white-point, saturation and hue correction factors of the white-point, saturation and hue modulator (WSH);

a color gamut mapping unit for multiplying the pixels of the input video signal with a color gamut matrix generated by the color gamut matrix generating unit (CGMG); and

a clipping unit for clipping the results of the a color gamut mapping unit which are out of a predefined range.

2. The video processing device according to claim 1, wherein the luminance and saturation detector (LSHD) comprises:

a RGB squaring unit (RGB_SQ) for squaring amplitudes of sub-pixels of the input video signal;

a RGB shuffler unit (RGB_SH) for ranking the squared sub-pixels based on their amplitude value;

a luminance and saturation calculation unit (LSH) for calculating a value of the luminance (L_D), an internal saturation (Si) and a saturation correction factor (Cs); and

a saturation correction unit (Sc) for outputting a corrected saturation value (Sd).

3. The video processing device according to claim 2, wherein the white-point, saturation and hue modulator (WSH) comprises:

a white point modulator (WPM) for determining a white-point correction factor (Wc) based on the luminescence value (Ld) from the luminance and saturation calculation unit (LSH),

a saturation modulator (SM) for determining a saturation correction factor (Sc) based on the saturation value (Sd) from the luminance and saturation calculation unit (LSH); and

a hue modulator (HM) for determining a hue correction factor (Hc) based on the saturation value (Sd) from the luminance and saturation calculation unit (LSH).

4. The video processing device according to claim 3, wherein the color gamut matrix generating unit (CGMG) is adapted to generate the color gamut matrix based upon measured characteristics of a display module.

5. The video processing device according to claim 4, further comprising a memory for storing display module specific parameters.

6. A method of processing color image data, comprising the steps of:

detecting the luminance values (lum) and the saturation values (sat) of pixels of an input video signal by a luminance and saturation detector (LSHD);

transforming luminance and saturation properties (lum, sat) of the pixels of the input video signal into white-point, saturation and hue correction factors by a white-point, saturation and hue modulator (WSH);

generating a color gamut matrix in the perception domain based on the white-point, saturation and hue correction factors of the white-point, saturation and hue modulator (WSH) by a color gamut matrix generating unit (CGMG);

multiplying the pixels of the input video signal with the color gamut matrix generated by the color gamut matrix generating unit (CGMG) by a color gamut mapping unit; and

clipping the results of the a color gamut mapping unit which are out of a predefined range by a clipping unit.

7. (canceled)