Method and apparatus for converting color spaces and multi-color display apparatus using the color space conversion apparatus

• US 8,274,527 B2
• Filed: 02/25/2005
• Issued: 09/25/2012
• Est. Priority Date: 02/26/2004
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd. (Samsung Group)
• Original Assignee: Samsung Electronics Co. Ltd. (Samsung Group)
• Inventors: Ok, Hyunwook, Lee, Seongdeok, Choe, Wonhee, Kim, Changyeong, Park, Dusik
• Primary Examiner(s): McDowell, Jr., Maurice L
• Application Number:
  US11/064,951
• Publication Number:
  US 20050190967A1
• Time in Patent Office: 2,769 Days
• Field of Search: 348/571, 348/34, 345/604, 345/600, 345/603, 382/167
• US Class Current: 345/600
• CPC Class Codes: G09G 5/02 characterised by the way in which colour is displayed details of colour display specific for CRTs G09G1/28; specific for flat matrix panels other than liquid crystal displays G09G3/2003; specific for liquid crystal displays G09G3/3607
• CPC Class Codes: H04N 1/54 Conversion of colour picture signals to a plurality of signals some of which represent particular mixed colours, e.g. for textile printing
• CPC Class Codes: H04N 9/67 for matrixing camera processing pipelines for matrixing of colour signals H04N23/85

Abstract

A method and apparatus for converting an m-dimensional color space comprising first through m-th input color components to an n-dimensional color space comprising first through n-th output color components. specified A method of converting an m-dimensional color space having first through m-th input color components into an n-dimensional color space having first through n-th output color components, m being less than n, includes: extracting first through nth intermediate color components by linearly combining the first through m-th input color components; determining whether m+1-th through n-th intermediate color components are within a specified dynamic range and compensating the first through n-th intermediate color components when signal values of the m+1-th through n-th intermediate color components are not within the dynamic range to obtain the first through n-th output color components.

Claims

1. A method of converting an m-dimensional color space having first through m-th input color components into an n-dimensional color space having first through n-th output color components, m being less than n, the method comprising:

extracting, using at least one processing device, respective first through m-th intermediate color components and extracting respective m+1-th through n-th intermediate color components by linearly combining the first through m-th input color components;

analyzing the m+1-th through n-th intermediate color components determining whether m+1-th through n-th intermediate color components are within a specified dynamic range for the m+1-th through n-th output color components; and

compensating the first through n-th intermediate color components, to obtain the first through n-th output color components, based on a result of the analyzing and consideration of a dynamic range of the m+1-th through n-th intermediate color components being different from a dynamic range of the first through m-th input color components.

2. The method of claim 1, wherein the extracting the first through n-th intermediated color components includes:

determining a first coefficient group used to calculate the first through m-th intermediate color components by linearly combining the first through m-th input color components;

determining a second coefficient group used to calculate the m+1-th through n-th intermediate color components by linearly combining the first through m-th input color components; and

calculating the first through n-th intermediate color components using the first through m-th input color components and the first and second coefficient groups.

3. The method of claim 2, wherein the calculating the first through n-th intermediate color component includes:

calculating the dynamic range of the m+1-th through n-th intermediate color components;

determining a scaling ratio for scaling the dynamic range of the m+1-th through n-th intermediate color components; and

scaling the m+1-th through n-th intermediate color components using the scaling ratio.

4. The method of claim 3, wherein the determining the scaling ratio includes:

determining the grayscale of the first through m-th input color components using a specified algorithm; and

determining the scaling ratio such that the scaling ratio is complementary to the grayscale.

5. The method of claim 4, wherein the grayscale is calculated by ((the maximum of the first through m-th input color components) minus (the minimum of the first through m-th input color components)) divided by the maximum of the first through m-th input color components, and the scaling ratio is calculated using (1−

p*grayness), wherein p satisfies 0<

p<

1.

6. The method of claim 1, wherein the compensating the first through n-th intermediate color components includes:

when more than one of the m+1-th through n-th intermediate color components are less than a first specified value, compensating the color components less than the first specified value; and

when more than one of the m+1-th through n-th intermediate color components are greater than a second specified value, compensating the color components greater than the second specified value.

7. The method of claim 6, wherein the compensating the color components less than the first specified value includes:

adding the absolute value of the color component less than the first specified value to the m+1-th through n-th intermediate color components;

adding the absolute value of the color component less than the first specified value to a complementary color component which is complementary to the color component less than the first specified value; and

setting the value of the color component less than the first specified value to the first specified value.

8. The method of claim 6, wherein the compensating the color components greater than the second specified value includes:

dividing values of the m+1-th through n-th intermediate color components by the value of the color component greater than the second specified value; and

setting the value of the color component greater than the second specified value to the second specified value.

9. The method of claim 1, wherein the first through m-th input color components are RGB color components (m=3), and the m+1-th through n-th output color components are CMY color components (n=6) obtained by applying a conversion matrix, [0 ½

½

;

½

0 ½

;

½

½

0], to a vector comprising the first through m-th input color components.

10. An apparatus for converting an m-dimensional color space having first through m-th input color components to an n-dimensional color space having first through n-th output color components, m being less than n, comprising:

an intermediate color component extractor extracting respective first through m-th intermediate color components and extracting respective m+1-th through n-th intermediate color components by linearly combining the first through m-th input color components;

a dynamic range comparator analyzing the m+1-th through n-th intermediate color components determining whether the m+1-th through n-th intermediate color components are within a specified dynamic range for the m+1-th through n-th output color components; and

a color component compensator compensating the first through n-th intermediate color components, to obtain the first through n-th output color components, based on a result of the analyzing and consideration of a dynamic range of the m+1-th through n-th intermediate color components being different from a dynamic range of the first through m-th input color components.

11. The apparatus of claim 10, wherein the intermediate color component extractor includes:

a first coefficient group determiner determining a first coefficient group used to calculate the first through m-th intermediate color components by linearly combining the first through m-th input color components; and

a second coefficient group determiner determining a second coefficient group used to calculate the m+1-th through n-th intermediate color components by linearly combining the first through m-th input color components, new line, and the central controller calculates the first through n-th intermediate color components using the first through m-th input color components and the first and second coefficient groups.

12. The apparatus of claim 11, wherein the intermediate color component extractor further comprises a scaling ratio determiner determining a scaling ratio for scaling the dynamic range of the m+1-th through n-th intermediate color components and the central controller scales the m+1-th through n-th intermediate color components using the scaling ratio.

13. The apparatus of claim 12, wherein the scaling ratio determiner determines the grayscale of the first through m-th input color components using a specified algorithm and determines the scaling ratio such that the scaling ratio is complementary to the grayscale.

14. The apparatus of claim 13, wherein the grayscale is calculated using (the maximum of the first through m-th input color components—

the minimum of the first through m-th input color components) divided by the maximum of the first through m-th input color components, and the scaling ratio is calculated using (1−

p*grayness), where p satisfies 0<

p<

1.

15. The apparatus of claim 10, wherein the color component compensator includes:

a small color component compensator compensating color components less than the first specified value when more that one of the m+1-th through n-th intermediate color components are less than a first specified value; and

a big color component compensator compensating color components greater than the second specified value when more that one of the m+1-th through n-th intermediate color components are greater than a second specified value.

16. The apparatus of claim 15, wherein the small color component compensator adds the absolute value of the color component less than the first specified value to the m+1-th through n-th intermediate color components, adds the absolute value of the color component less than the first specified value to a complementary color component complementary to the color component less than the first specified value and sets the value of the color component less than the first specified value to the first specified value.

17. The apparatus of claim 15, wherein the big color component compensator divides values of the m+1-th through n-th intermediate color components by a value of the color component greater than the second specified value and sets the value of the color component greater than the second specified value to the second specified value.

18. The apparatus of claim 10, wherein the first through m-th input color components are RGB color components (m=3), and the m+1-th through n-th output color components are CMY color components (n=6) obtained by applying a conversion matrix, [0 ½

½

;

½

0 ½

;

½

½

0], to a vector comprising the first through m-th input color components.

19. A color display apparatus for displaying an image signal having first through n-th output color components, comprising:

an intermediate color component extractor extracting respective first through m-th intermediate color components and extracting respective m+1-th through n-th intermediate color components by linearly combining first through m-th input color components, m being less than n;

a dynamic range comparator analyzing the m+1-th through n-th intermediate color components determining whether the m+1-th through n-th intermediate color components are within a specified dynamic range for the m+1-th through n-th output color components;

a color component compensator compensating the first through n-th intermediate color components, to obtain the first through n-th output color components, based on a result of the analyzing and consideration of a dynamic range of the m+1-th through n-th intermediate color components being different from a dynamic range of the first through m-th input color components; and

a display unit including n optical sources emitting light of wavelengths corresponding to the n output color components.

20. The apparatus of claim 19, wherein the intermediate color component extractor includes:

a first coefficient group determiner determining a first coefficient group used to calculate the first through m-th intermediate color components by linearly combining the first through m-th input color components;

a second coefficient group determiner determining a second coefficient group used to calculate the m+1-th through n-th intermediate color components by linearly combining the first through m-th input color components; and

a scaling ratio determiner determining a scaling ratio used to scale the dynamic range of the m+1-th through n-th intermediate color components, wherein the central controller calculates the first through n-th intermediate color components using the first through m-th input color components and the first and second coefficient groups, and scales the m+1-th through n-th intermediate color components by using the scaling ratio.

21. The apparatus of claim 20, wherein the scaling ratio determiner determines the grayscale of the first through m-th input color components by ((the maximum of the first through m-th input color components) minus (the minimum of the first through m-th input color components)) divided by the maximum of the first through m-th input color components, and the scaling ratio is calculated using (1−

p*grayness), wherein p satisfies 0<

p<

1.

22. The apparatus of claim 19, wherein the color component compensator includes:

a small color component compensator compensating color components less than the first specified value when more that one of the m+1-th through n-th intermediate color components are less than a first specified value; and

a big color component compensator compensating color components greater than the second specified value when more that one of the m+1-th through n-th intermediate color components are greater than a second specified value.

23. The apparatus of claim 22, wherein the small color component compensator adds the absolute value of the color component less than the first specified value to the m+1-th through n-th intermediate color components, adds the absolute value of the color component less than the first specified value to a complementary color component complementary to the color component less than the first specified value and sets the value of the color component less than the first specified value to the first specified value.

24. The apparatus of claim 22, wherein the big color component compensator divides values of the m+1-th through n-th intermediate color components by a value of the color component greater than the second specified value and sets the value of the color component greater than the second specified value to the second specified value.

25. The apparatus of claim 19, wherein the first through m-th input color components are RGB color components (m=3), and the m+1-th through n-th output color components are CMY color components (n=6) obtained by applying a conversion matrix, [0 ½

½

;

½

0 ½

;

½

½

0], to a vector comprising the first through m-th input color components.

26. A method of displaying an image signal having first through n-th output color components, the method comprising:

extracting, using at least one processing device, respective first through m-th intermediate color components and extracting respective m+1-th through n-th intermediate color components by linearly combining first through m-th input color components, m being less than n;

analyzing the m+1-th through n-th intermediate color components determining whether the m+1-th through n-th intermediate color components are within a specified dynamic range for the m+1-th through n-th output color components;

compensating the first through n-th intermediate color components, to obtain the first through n-th output color components, based on a result of the analyzing and consideration of a dynamic range of the m+1-th through n-th intermediate color components being different from a dynamic range of the first through m-th input color components; and

emitting light of wavelengths corresponding to the n output color components.

27. A color conversion method, the method comprising:

extracting, using at least one processing device, a CMY signal having cyan (C), magenta (M), and yellow (Y) color components from an input RGB signal having red (R), green (G), and a blue (B) color components by linearly combining the input R, G, and B color components;

calculating respective intermediate color components of the R, G, B, C, M, and Y color components and scaling the respective intermediate components of the C, M, and Y color components;

determining at least one dynamic range of the scaled C, M, and Y intermediate color components, and analyzing at least one of the scaled C, M, and Y intermediate color components to detect a signal with a dynamic range which exceeds the determined dynamic range, which is a dynamic range for the m+1-th through n-th output color components; and

compensating at least one of the R, G, B, intermediate color components and at least one of the scaled C, M, and Y intermediate color components using the detected signal based upon consideration of a dynamic range of the C, M, and Y intermediate color components being different from a dynamic range of the input R, G, and B color components.

28. A color conversion method, the method comprising:

determining first and second coefficient groups usable to extract from an input RGB signal having red (R), green (G), and blue (B) color components intermediate color components of a CMY signal having cyan (C), magenta (M), and yellow (Y) color components and of an RGB signal having red (R), green (G), and blue (B) color components, the CMY signal and the RGB signal being extracted from the input RGB signal;

linearly combining, using at least one processing device, R, G, and B color components of the input R, G, and B signal and, using the first and the second coefficient groups, to extract intermediate color components of the R, G, B, C, M, and Y color components;

scaling the intermediate color components of the C, M, and Y color components;

analyzing the scaled intermediate color components of the C, M, and Y color components determining whether signal values of the scaled intermediate color components of the C, M, and Y color components are within a specified dynamic range for the m+1-th through n-th output color components; and

compensating at least one of the intermediate color components of the R, G, and B color components and at least one of the scaled intermediate color components of the C, M, and Y color components based on at least one of a small color component and a large color component of the scaled intermediate color components based on a result of the analyzing and consideration of a dynamic range of the m+1-th through n-th intermediate color components being different from a dynamic range of the first through m-th input color components.

29. A method of converting an m-dimensional color space having first through m-th input color components into an n-dimensional color space having first through n-th output color components, m being less than n, the method comprising:

extracting, using at least one processing device, first through n-th intermediate color components by linearly combining the first through m-th input color components, including performing a compensating of the first through m-th input color components to generate the first through m-th intermediate color components thereby reducing image degradations due to manufacturing variances; and

compensating the first through n-th intermediate color components based on an analyzing of the m+1-th through n-th intermediate color components determining that signal values of the m+1-th through n-th intermediate color components are not within a specified dynamic range for the m+1-th through n-th output color components, wherein a dynamic range of the m+1-th through n-th intermediate color components is different from a dynamic range of the first through m-th input color components.

30. A method, the method comprising:

analyzing at least one of an m+1-th through n-th intermediate color components, of respectively extracted first through m-th and m+1-th through n-th intermediate color components, with the analyzing determining whether the at least one m+1-th through n-th intermediate color components includes a signal value outside a specified dynamic range for the m+1-th through n-th output color components; and

compensating, using at least one processing device, at least one of the first through m-th intermediate color components, to obtain the first through n-th output color components, based on a result of the analyzing and consideration of a dynamic range of the m+1-th through n-th intermediate color components being different from a dynamic range of the first through m-th input color components.

31. The method of claim 30, wherein the compensating of the at least one of the first through m-th intermediate color components further comprises compensating of the at least one of the m+1 through n-th intermediate color components based on the determining.

32. The method of claim 30, further comprising scaling the extracted m+1-th through n-th intermediate color components based on a scaling ratio derived from a determined grayscale of the extracted first through m-th intermediate components, and

wherein the determining comprises determining whether at least one of the scaled m+1-th through n-th intermediate color components is within the specified dynamic range.