Color image reproduction of scenes with preferential color mapping and scene-dependent tone scaling
First Claim
1. A method for enhancing the color and lightness characteristics of a digital color image, the digital color image having pixel values from which digital luminance and color difference values can be deduced, comprising the steps of:
- a) deducing digital luminance and digital color difference values for pixels of the digital color image;
b) using the pixels of the digital color image to calculate an image dependent transform;
c) using the image dependent transform to modify the digital luminance values for pixels of the digital color image to form modified luminance values;
d) calculating a preferred color transform that modifies the original digital color difference values in a manner that consistently and smoothly moves the values toward or away from predetermined digital color difference values; and
e) using the color transform to modify the original color difference values for pixels of the digital color image to produce modified color difference values.
5 Assignments
0 Petitions
Accused Products
Abstract
A method for enhancing the hue and lightness characteristics of a digital color image, the digital color image having pixel values from which digital luminance and color difference values can be deduced, includes the steps of: deducing digital luminance and digital color difference values for pixels of the digital color image; using the pixels of the digital color image to calculate an image dependent transform; using the image dependent transform to modify the digital luminance values for pixels of the digital color image to form modified luminance values; calculating a color transform that modifies the original digital color difference values in a manner that consistently and smoothly moves the values toward or away from predetermined digital color difference values; and using the color transform to modify the original color difference values for pixels of the digital color image to produce modified color difference values.
285 Citations
54 Claims
-
1. A method for enhancing the color and lightness characteristics of a digital color image, the digital color image having pixel values from which digital luminance and color difference values can be deduced, comprising the steps of:
-
a) deducing digital luminance and digital color difference values for pixels of the digital color image;
b) using the pixels of the digital color image to calculate an image dependent transform;
c) using the image dependent transform to modify the digital luminance values for pixels of the digital color image to form modified luminance values;
d) calculating a preferred color transform that modifies the original digital color difference values in a manner that consistently and smoothly moves the values toward or away from predetermined digital color difference values; and
e) using the color transform to modify the original color difference values for pixels of the digital color image to produce modified color difference values. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54)
a) specifying one or more regions of color space in which digital color difference values will be transformed;
b) selecting one or more test colors within each specified region of color space for which preferred digital color difference values are to be defined;
c) deducing original digital color difference values for the test colors, d) determining preferred digital color difference values for the test colors; and
e) forming a preferred color transform that modifies the original digital color difference values in a manner that consistently and smoothly moves said values toward or away from the preferred digital color difference values.
-
-
17. The method of claim 16 wherein the test colors are derived by exposing a photographic film to an original scene;
- developing and scanning the exposed photographic film to produce a digital image; and
transforming the digital image to a colorimetric digital scene representation.
- developing and scanning the exposed photographic film to produce a digital image; and
-
18. The method of claim 16 wherein the test colors are derived by capturing an image of the original scene with an electronic camera to produce a digital image and transforming the digital image to a calorimetric digital scene representation.
-
37. A computer program product for performing the method of claim 1.
-
38. A computer program product for performing the method of claim 2.
-
39. A computer program product for performing the method of claim 3.
-
40. A computer program product for performing the method of claim 4.
-
41. A computer program product for performing the method of claim 5.
-
42. A computer program product for performing the method of claim 6.
-
43. A computer program product for performing the method of claim 7.
-
44. A computer program product for performing the method of claim 8.
-
45. A computer program product for performing the method of claim 9.
-
46. A computer program product for performing the method of claim 10.
-
47. A computer program product for performing the method of claim 11.
-
48. A computer program product for performing the method of claim 12.
-
49. A computer program product for performing the method of claim 13.
-
50. A computer program product for performing the method of claim 14.
-
51. A computer program product for performing the method of claim 15.
-
52. A computer program product for performing the method of claim 16.
-
53. A computer program product for performing the method of claim 17.
-
54. A computer program product for performing the method of claim 18.
-
19. Apparatus for enhancing the color and lightness characteristics of a digital color image, the digital color image having pixel values from which digital luminance and color difference values can be deduced, comprising:
-
a) means for deducing digital luminance and digital color difference values for pixels of the digital color image;
b) means for using the pixels of the digital color image to calculate an image dependent transform;
c) means for using the image dependent transform to modify the digital luminance values for pixels of the digital color image to form modified luminance values;
d) means for calculating a preferred color transform that modifies the original digital color difference values in a manner that consistently and smoothly moves the values toward or away from predetermined digital color difference values; and
e) means for using the preferred color transform to modify the original color difference values for pixels of the digital color image to produce modified color difference values. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36)
a) means for specifying one or more regions of color space in which digital color difference values will be transformed;
b) means for selecting one or more test colors within each specified region of color space for which preferred digital color difference values are to be defined;
c) means for deducing original digital color difference values for the test colors, d) means for determining preferred digital color difference values for the test colors; and
e) means for forming the preferred color transform that modifies the original digital color difference values in a manner that consistently and smoothly moves said values toward or away from the preferred digital color difference values.
-
-
35. The apparatus of claim 34 wherein the means for selecting one or more test colors includes means for exposing a photographic film to an original scene;
- means for developing and scanning the exposed photographic film to produce a digital image; and
means for transforming the digital image to a calorimetric digital scene representation.
- means for developing and scanning the exposed photographic film to produce a digital image; and
-
36. The apparatus of claim 35 wherein the means for selecting one or more test colors includes means for capturing an image of the original scene with an electronic camera to produce a digital image and means for transforming the digital image to a calorimetric digital scene representation.
Specification