Method, apparatus and system for converging images encoded using different standards
View Patent ↗A method for transforming an image expressed in terms of a first image encoding to a second image encoding, includes converting a set of original scene exposure-factor values into corresponding first and second image encoding values. A transform is then derived between the first image encoding values and the second image encoding values. The transform is then applied to an image encoded in said first image encoding. Examples of different encoding that can be transformed include Rec. 709, sRGB and other known image encoding standards. A system for performing such transformations as well as an electronic device that is capable of performing such transformations are also disclosed.
1. A method comprising:
calculating, by a processing device, a set of original scene exposure factor values defined in terms of reference color primaries and a reference white point from a captured image of achromatic patches;
converting, by device, the set of original scene exposure factor values into a set of first image encoding values and a set of second image encoding values, wherein the set of first image encoding values and the set of second image encoding values each have reference color primaries and a reference white point in common with the set of original scene exposure factor values;
deriving, by the processing device, a transform between the set of first image encoding values and the set of second image encoding values; and
applying, by the processing device, the derived transform to an image encoded in the first image encoding.
2. The method of claim 1 , wherein the first image encoding comprises Rec. 709 encoding.
3. The method of claim 1 , wherein the first image encoding comprises sRGB encoding.
4. The method of claim 2 , wherein the second image encoding comprises sRGB encoding.
5. The method of claim 3 , wherein the second image encoding comprises Rec. 709 encoding.
6. The method of claim 1 , wherein the set of original scene exposure-factor values correspond to achromatic stimuli.
7. The method of claim 1 , wherein the converting the set of original scene exposure factor-values into the set of first image encoding values or the set of second image encoding values comprises using an optoelectronic transfer characteristic.
8. The method of claim 7 , wherein the optoelectronic transfer characteristic corresponds to the REC. 709 encoding standard.
9. The method of claim 7 , wherein the optoelectronic transfer characteristic relates to the sRGB-encoding standard.
10. The method of claim 9 , wherein the optoelectronic transfer characteristic is a device dependent sRGB.
11. The method of claim 1 , further comprising capturing an image of achromatic patches with an image capture device.
12. The method of claim 11 , wherein the processing device comprises the image capture device.
13. The method of claim 1 , wherein the set of original scene exposure factor values sample a usable range of exposure-factor values.
14. A device comprising:
memory configured to store instructions and data; and
a processor communicatively coupled to the memory, wherein the processor is configured to:
calculate a set of original scene exposure factor values defined in terms of reference color primaries and a reference white point from a captured image of achromatic patches;
convert the set of original scene exposure factor values into a set of first image encoding values and a set of second image encoding values, wherein the set of first image encoding values and the set of second image encoding values each have reference color primaries and a reference white point in common with the set of original scene exposure factor values;
derive a transform between the set of first image encoding values and the set of second image encoding values; and
apply the transform to an image encoded in the first image encoding.
15. The device of claim 14 , wherein the first image encoding comprises RGB encoding and the second image encoding comprises Rec. 709 encoding.
16. The device of claim 14 , wherein the first image encoding comprises Rec. 709 encoding and the second image encoding comprises sRGB encoding.
17. The device of claim 14 , wherein the processor is configured to convert the set of original scene exposure factor-values into the set of first image encoding values or the set of second image encoding values by using an optoelectronic transfer characteristic.
18. A non-transitory computer-readable medium storing instructions configured to cause a computing device to perform operations comprising:
calculating a set of original scene exposure factor values defined in terms of reference color primaries and a reference white point from a captured image of achromatic patches;
converting the set of original scene exposure factor values into a set of first image encoding values and a set of second image encoding values, wherein the set of first image encoding values and the set of second image encoding values each have reference color primaries and a reference white point in common with the set of original scene exposure factor values;
deriving a transform between the set of first image encoding values and the set of second image encoding values; and
applying the transform to an image encoded in the first image encoding.
19. The non-transitory computer-readable medium of claim 18 , wherein the first image encoding comprises sRGB encoding and the second image encoding comprises Rec. 709 encoding.
20. The non-transitory computer-readable medium of claim 18 , wherein the set of original scene exposure-factor values correspond to achromatic stimuli.
21. The non-transitory computer-readable medium of claim 18 , wherein the converting the set of original scene exposure factor-values into the set of first image encoding values or the set of second image encoding values comprises using an optoelectronic transfer characteristic.