Detection, correction fading and processing in hue, saturation and luminance directions

• US 20060251323A1
• Filed: 01/24/2006
• Published: 11/09/2006
• Est. Priority Date: 05/05/2005
• Status: Abandoned Application

• Current Assignee: Genesis Microchip Inc. (STMicroelectronics NV)
• Original Assignee: Genesis Microchip Inc. (STMicroelectronics NV)
• Inventors: Swartz, Peter, MacKinnon, Andrew
• Application Number:
  US11/339,313
• Publication Number:
  US 20060251323A1
• Time in Patent Office: Days
• US Class Current: 382/167
• CPC Class Codes: H04N 1/6075 Corrections to the hue
• CPC Class Codes: H04N 1/62 Retouching, i.e. modification of isolated colours only or in isolated picture areas only
• 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 9/643 Hue control means, e.g. flesh tone control

Abstract

A method, system and apparatus for color management that directly acts upon the hue, saturation, and luminance value of a pixel instead of its U and V value. Additionally, instead of dividing the color space into uniform areas, the color space is divided into multiple user-defined regions. The detection of a pixel is based on its hue, saturation, and luminance value, so a single set of values can define the correction for an entire hue.

Claims

1. A method for processing a pixel, comprising:

converting the pixel'"'"'s color space from Cartesian coordinates to polar coordinates;

determining whether the pixel lies within a 3-dimensional region described by a set of region parameters;

applying a correction factor based upon the pixel'"'"'s location in the 3-dimensional region; and

converting the pixel'"'"'s polar coordinates to Cartesian coordinates.

2. A method as recited in claim 1, wherein the color space is hue, saturation, and luminance (YUV) color space.

3. A method as recited in claim 2, wherein the 3-dimensional region comprises:

a two dimensional U,V plane; and

a Y axis in a third dimension, wherein the two dimensional U,V, plane includes a color correction region that further includes a fade area that is a specified distance from an edge of the color correction region wherein the specified distance is computed in the U, V, and Y directions.

4. A method as recited in claim 3, further comprising:

when the pixel location is in the fade area, then determining a fade factor based on the distance computed in the hue, saturation and luminance directions.

5. A method as recited in claim 3, further comprising:

when the pixel'"'"'s location is in the color correction region, then calculating a color correction factor based upon the pixel'"'"'s location.

6. A method as recited in claim 5, further comprising:

applying gain and offset parameters in the hue, saturation and luminance directions to determine a correction amount for applying to the pixel.

7. A method as recited in claim 6, further comprising:

converting the pixel'"'"'s polar hue and saturation coordinates to Cartesian UV coordinates while leaving the pixel'"'"'s modified luminance unchanged.

8. A method as recited in claim 7, further comprising:

reducing the correction amount by the fade factor; and

applying the reduced correction amount to the pixel