Granted Patent B2

US 8,467,604 · App. 12/676,358 · Granted Jun 18, 2013

Abstract

Claims (27)

1. An image processor comprising:

an instruction-executing unit;

a color format converter for converting, under control of the instruction-executing unit, a pixel, which is expressed in an RGB color space, into a converted pixel, which is expressed in a YUV color space;

a color shift vector generator for generating, under control of the instruction-executing unit, a color shift vector, which is expressed in the YUV color space, on the basis of the converted pixel, the color shift vector generator being arranged to generate the color shift vector on the basis of a color enhancement definition, which comprises a definition of at least one type of color enhancement, wherein respective color zones in the YUV color space are associated with respective types of color enhancement, the color shift vector generator being arranged to detect if the converted pixel falls within a color zone and, if so, to generate the color shift vector in accordance with the type of color enhancement associated with that color zone, and wherein the color enhancement definition defines an order of priority for different types of color enhancement, the color shift vector generator being arranged to apply the type of color enhancement that has the highest priority among those respective types of color enhancement that are associated with respective color zones in which the converted pixel falls;

an inverse color format converter for converting, under control of the instruction-executing unit, the color shift vector into a color enhancement vector, which is expressed in the RGB color space; and

an adder for adding , under control of the instruction-executing unit, the color enhancement vector to the pixel so as to obtain a color enhanced pixel.

2. An image processor as claimed in claim 1 , wherein the color shift vector generator is arranged to generate the color shift vector on the basis of a color zone that has a trapezium shape.

3. An image processor as claimed in claim 1 , comprising:

an image analyzer for analyzing, under control of the instruction-executing unit, at least one image that the image processor receives so as to establish the color enhancement definition depending on colors that are predominant in the at least one image.

4. An image processor as claimed in claim 3 , comprising:

a histogram builder for establishing, under control of the instruction-executing unit, a color histogram on the basis of the at least one image, the color histogram indicating colors that are predominant in the at least one image; and

a histogram analyzer for establishing, under control of the instruction-executing unit, the color enhancement definition on the basis of the color histogram.

5. An image processor as claimed in claim 3 , comprising:

a controller for applying, under control of the instruction-executing unit, control parameters to the image analyzer on the basis of which the image analyzer establishes the color enhancement definition as a function of the colors that are predominant in the at least one image.

6. An image processor as claimed in claim 1 , the color shift vector generator comprising:

a color shift operator for providing, under control of the instruction-executing unit, a gross color shift vector and a weighting coefficient for a converted pixel that falls within a color zone in the YUV color space, the weighting coefficient depending on a relative position of the converted pixel within the color zone in accordance with a weighting profile; and

a color shift vector composer for composing, under control of the instruction-executing unit, the color shift vector on the basis of the gross color shift vector and the weighting coefficient.

7. An image processor as claimed in claim 6 , comprising:

an image analyzer for analyzing, under control of the instruction-executing unit, at least one image that the image processor receives so as to establish the color enhancement definition and the weighting profile depending on colors that are predominant in the at least one image.

8. A method of color enhancement comprising:

converting a pixel, which is expressed in an RGB color space, into a converted pixel, which is expressed in an YUV color space;

generating a color shift vector on the basis of the converted pixel and on the basis of a color enhancement definition, which comprises a definition of at least one type of color enhancement, wherein respective color zones in the YUV color space are associated with respective types of color enhancement and wherein each type of color enhancement is assigned a priority order, the color shift vector being expressed in the YUV color space, wherein if the converted pixel falls within more than one color zone, applying the type of color enhancement that has a highest priority among those respective types of color enhancement that are associated with respective color zones in which the converted pixel falls;

converting the color shift vector into a color enhancement vector, which is expressed in the RGB color space;

and

adding the color enhancement vector to the pixel so as to obtain a color enhanced pixel.

9. A video system comprising an image processor according to claim 1 and a display device for displaying a color enhanced image that comprises color enhanced pixels, which the image processor provides.

10. A computer program product for a programmable processor, the computer program product comprising a set of instructions recorded in computer readable storage media that, when loaded into the programmable processor, causes the programmable processor to carry out the method according to claim 8 .

Assignments (7)