Hexagonal color pixel structure with white pixels
View Patent ↗A digital color imager provides an extended luminance range, enabling a method for an easy transformation into all other color spaces having luminance as a component. White pixels are added to hexagonal red, green and blue pixels. These white pixels can alternatively have an extended dynamic range as described by U.S. Pat. No. (6,441,852 to Levine et al.). Especially the white pixels may have a larger size than the red, green, or blue pixels used. This larger size can be implemented by concatenation of “normal” size hexagonal white pixels. The output of said white pixels can be directly used for the luminance values Y of the destination color space. Therefore only the color values have to be calculated from the RGB values, leading to an easier and faster calculation. As an example chosen by the inventor the conversion to YCbCr color space has been shown in detail.
1. A method to convert pixel color values of a digital color imager into another color space having luminance as a component is comprising:
providing a digital color imager comprising hexagonal red, green, blue and white pixels;
use sensor output of white pixels for luminance value Y;
calculate color values of destination color space from the output of the red, green and blue pixels using a correspondent conversion matrix.
2. The method of claim 1 wherein said red, green and blue hexagonal pixels have correspondent color filters.
3. The method of claim 2 wherein all said pixels have an equilateral hexagonal shape.
4. The method of claim 2 wherein the arrangement of said red, green, blue, and white pixels is performed in a way that each white pixel must be adjacent to one red, one green and one blue pixel and each red, green, or blue pixel must be surrounded by white pixels only.
5. The method of claim 2 wherein said pixels have non-equilateral hexagonal shapes.
6. The method of claim 2 wherein said white pixels are XDR-type pixels.
7. The method of claim 2 wherein said red pixels are XDR-type pixels.
8. The method of claim 2 wherein said blue pixels are XDR-type pixels.
9. The method of claim 2 wherein said green pixels are XDR-type pixels.
10. The method of claim 2 wherein said white red, green, or blue pixels have all a same size.
11. A method to convert pixel color values of a digital color imager into another color space having luminance as a component is comprising:
providing a digital color imager comprising hexagonal red, green, and blue pixels and additionally white pixels, wherein said white pixels have been concatenated from hexagonal white pixels;
use sensor output of white pixels for luminance value Y;
calculate color values of destination color space from the output of the red, green and blue pixels using a correspondent conversion matrix.
12. The method of claim 11 wherein said red, green and blue hexagonal pixels have correspondent color filters.
13. The method of claim 11 wherein said hexagonal pixels have an equilateral hexagonal shape.
14. The method of claim 11 wherein the arrangement of said red, green, blue, and white pixels is performed in a way that each white pixel must be adjacent to one red, one green and one blue pixel and each red, green, or blue pixel must be surrounded by white pixels only.
15. The method of claim 11 wherein said pixels have non-equilateral hexagonal shapes.
16. The method of claim 11 wherein said white pixels are XDR-type pixels.
17. The method of claim 11 wherein said red pixels are XDR-type pixels.
18. The method of claim 11 wherein said blue pixels are XDR-type pixels.
19. The method of claim 11 wherein said green pixels are XDR-type pixels.
20. The method of claim 11 wherein said white pixels, before concatenation, and said red, green, or blue pixels have all a same size.
21. The method of claim 11 wherein said white pixels are concatenated from two white pixels wherein the concatenation is performed using white hexagonal pixels having the same size as said red, green or blue pixels.
22. The method of claim 11 wherein said white pixels are concatenated from two or three white pixels wherein the concatenation is performed using white hexagonal pixels having the same size as said red, green or blue pixels.
23. The method of claim 11 wherein said white pixels have a shape of concatenated whole hexagonal pixels being concatenated with portions of hexagonal pixels.
24. A method to convert pixel color values of a digital color imager into YCbCr color space:
providing a digital color imager comprising hexagonal red, green, blue and white pixels;
use sensor output of white pixels for luminance value Y;
calculate color values Cb and Cr from the output of the red, green and blue pixels using transformation parameters.
25. The method of claim 24 wherein said calculation of the Cb and Cr components of YCbCr color space is performed according to the following equation:
[
Cb
Cr
]
=
[
-
0.169
-
0.331
0.5
0.5
-
0.419
-
0.81
]
⨯
[
R
G
B
]
,
wherein R is the output of the red sensor, G is the output of the green sensor and B is the output of the blue sensor.
26. The method of claim 24 wherein said red, green and blue hexagonal pixels have correspondent color filters.
27. The method of claim 24 wherein all said pixels have an equilateral hexagonal shape.
28. The method of claim 24 wherein the arrangement of said red, green, blue, and white pixels is performed in a way that each white pixel must be adjacent to one red, one green and one blue pixel and each red, green, or blue pixel must be surrounded by white pixels only.
29. The method of claim 24 wherein said pixels have non-equilateral hexagonal shapes.
30. The method of claim 24 wherein said white pixels are XDR-type pixels.
31. The method of claim 24 wherein said red pixels are XDR-type pixels.
32. The method of claim 24 wherein said blue pixels are XDR-type pixels.
33. The method of claim 24 wherein said green pixels are XDR-type pixels.
34. The method of claim 24 wherein said white red, green, or blue pixels have all a same size.
35. The method of claim 24 wherein said white pixels have a same size as the red, green, or blue pixels used.
36. A method to convert pixel color values of a digital color imager into YCbCr color space:
providing a digital color imager comprising hexagonal red, green, and blue pixels and additionally white pixels, wherein said white pixels have been concatenated from hexagonal white pixels;
use sensor output of white pixels for luminance value Y;
calculate color values Cb and Cr from the output of the red, green and blue pixels using transformation parameters.
37. The method of claim 36 wherein said calculation of the Cb and Cr components of YCbCr color space is performed according to the following equation:
[
Cb
Cr
]
=
[
-
0.169
-
0.331
0.5
0.5
-
0.419
-
0.81
]
⨯
[
R
G
B
]
,
wherein R is the output of the red sensor, G is the output of the green sensor and B is the output of the blue sensor.
38. The method of claim 36 wherein said red, green and blue hexagonal pixels have correspondent color filters.
39. The method of claim 36 wherein said hexagonal pixels have an equilateral hexagonal shape.
40. The method of claim 36 wherein the arrangement of said red, green, blue, and white pixels is performed in a way that each white pixel must be adjacent to one red, one green and one blue pixel and each red, green, or blue pixel must be surrounded by white pixels only.
41. The method of claim 36 wherein said hexagonal pixels have non-equilateral hexagonal shapes.
42. The method of claim 36 wherein said white pixels are XDR-type pixels.
43. The method of claim 36 wherein said red pixels are XDR-type pixels.
44. The method of claim 36 wherein said blue pixels are XDR-type pixels.
45. The method of claim 36 wherein said green pixels are XDR-type pixels.
46. The method of claim 36 wherein said white pixels, before they were concatenated, and the red, green, or blue pixels have all a same size.
47. The method of claim 36 wherein said white pixels are concatenated from two white pixels wherein the concatenation is performed using white pixels having the same size as said red, green or blue pixels.
48. The method of claim 36 wherein said white pixels are concatenated from two or three white pixels wherein the concatenation is performed using white pixels having the same size as said red, green or blue pixels.
49. The method of claim 36 wherein said white pixels have a same size as the red, green, or blue pixels used.
50. The method of claim 36 wherein said white pixels have a shape of concatenated whole hexagonal pixels being concatenated with portions of hexagonal pixels.