Apparatus for and method of color compensation

• US 20040017380A1
• Filed: 07/21/2003
• Published: 01/29/2004
• Est. Priority Date: 07/26/2002
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Oh, Jae-Hwan, Kim, Moon-Cheol
• Granted Patent: US 7,348,992 B2
• Time in Patent Office: Days
• US Class Current: 345/600
• CPC Class Codes: H04N 1/6005 with luminance or chrominance signals, e.g. LC1C2, HSL or YUV
• CPC Class Codes: H04N 1/608 within the L, C1, C2 colour signals
• CPC Class Codes: H04N 1/628 Memory colours, e.g. skin or sky

Abstract

An apparatus for color compensation includes a chroma deflection generation unit to calculate a chroma deflection based on an input chroma signal and a predetermined first reference value, a hue deflection generation unit to calculate a hue deflection based on an input hue signal and a predetermined second reference value, a chroma deflection function generation unit to calculate a luminance deflection based on an input luminance signal and a predetermined third value, and a tone mapping function generation unit to output the chroma signal, hue signal and luminance signal after individually compensating these signals based on the chroma deflection, hue deflection and luminance deflection. According to the present invention, when color is distorted due to transmission flaws, the color can be compensated to be an appropriate color.

Claims

1. An apparatus for color compensation of an input signal comprising:

a chroma deflection generation unit to calculate a chroma deflection based on an input chroma signal detected from the input signal and a predetermined first reference value;

a hue deflection generation unit to calculate a hue deflection based on an input hue signal detected from the input signal and a predetermined second reference value;

a luminance deflection generation unit to calculate a luminance deflection based on an input luminance signal detected from the input signal and a predetermined third value; and

a skin tone mapping function generation unit to output a compensated chroma signal, a compensated hue signal and a compensated luminance signal after individually compensating the input chroma, hue, and luminance signals based on the chroma deflection, the hue deflection and the luminance deflection.

2. The apparatus for color compensation of claim 1, further comprising a color space conversion unit to respectively calculate the input chroma signal, the hue signal and the luminance signal by converting a color signal of the input signal in a color space, and transmits the chroma, hue, and luminance signals to the corresponding chroma deflection function generation unit, hue deflection function generation unit and luminance deflection function unit.

3. The apparatus for color compensation of claim 1, wherein the first, second and third reference values are provided based on empirical data collected after statistically processing data obtained through experiment.

4. The apparatus for color compensation of claim 3, wherein the chroma deflection is calculated based on a difference between the input chroma signal and the first reference value.

6. The apparatus for color compensation of claim 3, wherein the hue deflection is calculated based on a difference between the input hue signal and the second reference value.

8. The apparatus for color compensation of claim 3, wherein the luminance deflection is calculated based on a difference between the input luminance signal and the third reference value.

9. The apparatus for color compensation of claim 8, wherein the skin tone mapping function unit outputs the compensated luminance signal compensated after summing the input luminance signal and the luminance deflection.

5. The apparatus for color compensation of claim 5, wherein the skin tone mapping function unit outputs the compensated chroma signal compensated by summing the input chroma signal and the chroma deflection.

7. The apparatus for color compensation of claim 7, wherein the skin tone mapping function unit outputs the compensated chroma signal compensated by summing the input hue signal and the hue deflection.

10. A method of color compensation of an input signal comprising:

calculating a chroma deflection based on an input chroma signal detected from the input signal and a predetermined first reference value;

calculating a hue deflection based on an input hue signal detected from the input signal and a predetermined second reference value;

calculating a luminance deflection based on an input luminance signal and a predetermined third reference value; and

outputting the compensated chroma, hue and luminance signals after individually compensating the input chroma, hue, and luminance signals based on the calculated chroma deflection, hue deflection, and luminance deflection.

11. The method of color compensation of claim 10, further comprising:

calculating the input chroma signal, the hue signal and the luminance signal by converting a color signal of the input signal in a color space; and

individually transmitting the calculated chroma, hue, and luminance signals as the input chroma, hue, and luminance signals for use in the calculating the chroma deflection, the hue deflection, and the luminance deflection.

12. The method of color compensation of claim 10, wherein the first, second and third reference values are provided based on empirical data collected after statistically processing data obtained through experiment.

13. The method of color compensation of claim 12, wherein the chroma deflection is calculated based on a difference between the input chroma signal and the first reference value.

14. The method of color compensation of claim 13, the outputting the compensated chroma, hue, and luminance signals comprises summing the input chroma signal and the chroma deflection.

15. The method of color compensation of claim 12, wherein the hue deflection is calculated based on a difference between the input hue signal and the second reference value.

16. The method of color compensation of claim 15, the outputting the compensated chroma, hue, and luminance signals comprises summing the input hue signal and the hue deflection is output.

17. The method of color compensation of claim 12, wherein the luminance deflection is calculated based on a difference between the input luminance signal and the third reference value.

18. The method of color compensation of claim 17, the outputting the compensated chroma, hue, and luminance signals comprises summing the luminance signal and the luminance deflection.

19. An apparatus for color compensating an input image having image properties, comprising:

a first deflection calculation unit to detect a first amount of deflection of a first one of the image properties from a first reference value;

a second deflection calculation unit to detect a second amount of deflection of a second one of the image properties from a second reference value; and

a compensation unit which compensates the first and second image properties of the input image using the first and second amounts of deflection so as to output a compensated image.

20. The apparatus of claim 19, further comprising a third deflection calculation unit to detect a third amount of deflection of a third one of the image properties from a third reference value, wherein the compensation unit compensates the first, second, and third image properties of the input image using the first, second, and third amounts of deflection so as to output the compensated image.

21. The apparatus of claim 19, wherein one of the first and second image properties is luminance, and the other one of the first and second image properties is chroma.

22. The apparatus of claim 20, wherein one of the first through third image properties is luminance, another one of the first through third image properties is chroma, and a remaining one of the first through third image properties is hue.

23. The apparatus of claim 19, further comprising a color space conversion unit to convert the input image into the first and second properties for use by the first and second deflection calculation units.

24. The apparatus of claim 23, wherein the color space conversion unit converts the input image to be mapped into first and second properties in a color space comprising one of RGB, YIQ, YUV, YCbCr and HLS.

25. The apparatus of claim 20, further comprising a color space conversion unit to convert the input image into the first through third properties for use by the first through third deflection calculation units.

26. The apparatus of claim 25, wherein the color space conversion unit converts the input image to the first through third properties mapped in a color space comprising one of RGB, YIQ, YUV, YCbCr and HLS.

27. The apparatus of claim 19, further comprising a display unit to display the compensated image.

28. The apparatus of claim 20, further comprising a display unit to display the compensated image.

29. The apparatus of claim 19, wherein the first deflection calculation unit compares the first property to first through third ranges to determine the first amount,

the first range including the first reference value and for which the first amount is zero,

the second range being disposed outside of the first range and for which the first amount is non-zero;

and

a third range being disposed outside of the first and second ranges and for which the first amount is zero.

30. The apparatus of claim 29, wherein:

the second range includes a midpoint at which the first amount is at one of a maximum and a minimum,

from the midpoint towards the first range, the first amount one of increases and decreases, and

from the midpoint towards the third range, the first amount the other one of increases and decreases.

31. The apparatus of claim 20, wherein:

the first deflection calculation unit compares the first property to first through third ranges to determine the first amount,

the first range including the first reference value and for which the first amount is zero,

the second range being disposed outside of the first range and for which the first amount is non-zero; and

the third range being disposed outside of the first and second ranges and for which the first amount is zero.

the second deflection calculation unit compares the second property to fourth through sixth ranges to determine the second amount,

the fourth range including the second reference value and for which the second amount is zero,

the fifth range being disposed outside of the fourth range and for which the second amount is non-zero; and

the sixth range being disposed outside of the fourth and fifth ranges and for which the second amount is zero, and

the third deflection calculation unit compares the third property to seventh through ninth ranges to determine the third amount,

the seventh range including the third reference value and for which the third amount is zero,

the eighth range being disposed outside of the seventh range and for which the third amount is non-zero; and

the ninth range being disposed outside of the seventh and eighth ranges and for which the third amount is zero.

32. The apparatus of claim 31, wherein:

the second, fifth, and eighth ranges each include a midpoint at which the corresponding one of first, second, and third amount is at one of a maximum and a minimum,

from the midpoint towards the corresponding first, fourth, and seventh ranges, the corresponding first, second, and third amounts one of increases and decreases, and

from the midpoint towards the corresponding third, sixth, and ninth ranges, the corresponding first, second, and third amounts the other one of increases and decreases.

33. A computer readable medium encoded with processing instructions for performing a method of color compensating an input image having image properties performed by a computer, the method comprising:

calculating a first amount of deflection of a first one of the image properties from a first reference value;

calculating a second amount of deflection of a second one of the image properties from a second reference value; and

compensating the first and second image properties of the input image using the first and second amounts of deflection so as to output a compensated image.

34. The computer readable medium of claim 33, wherein:

the method further comprises calculating a third amount of deflection of a third one of the image properties from a third reference value, and

the compensating to output the compensated image comprises compensating the first, second, and third image properties of the input image using the first, second, and third amounts of deflection so as to output the compensated image.

35. The computer readable medium of claim 33, wherein one of the first and second image properties is luminance, and the other one of the first and second image properties is chroma.

36. The computer readable medium of claim 34, wherein one of the first through third image properties is luminance, another one of the first through third image properties is chroma, and a remaining one of the first through third image properties is hue.

37. The computer readable medium of claim 33, wherein the method further comprises converting the input image into the first and second properties for use in the calculating the first and second amounts.

38. The computer readable medium of claim 37, wherein the converting the input image comprises converting the input image to the first and second properties mapped into a color space comprising one of RGB, YIQ, YUV, YCbCr and HLS.

39. The computer readable medium of claim 34, wherein the method further comprises converting the input image into the first through third properties for use in the calculating the first through third amounts.

40. The computer readable medium of claim 39, wherein the converting the input image comprises converting the input image into the first through third properties mapped into a color space comprising one of RGB, YIQ, YUV, YCbCr and HLS.

41. The computer readable medium of claim 33, wherein the method further comprises outputting the compensated image to a display unit to display the compensated image.

42. The computer readable medium of claim 34, wherein the method further comprises outputting the compensated image to a display unit to display the compensated image.

43. The computer readable medium of claim 33, wherein the calculating the first amount comprises comparing the first property to first through third ranges to determine the first amount,

the first range including the first reference value and for which the first amount is zero,

the second range being disposed outside of the first range and for which the first amount is non-zero;

and

a third range being disposed outside of the first and second ranges and for which the first amount is zero.

44. The computer readable medium of claim 43, wherein:

the second range includes a midpoint at which the first amount is at one of a maximum and a minimum,

from the midpoint towards the first range, the first amount one of increases and decreases, and

from the midpoint towards the third range, the first amount the other one of increases and decreases.

45. The computer readable medium of claim 34, wherein:

the calculating the first amount comprises comparing the first property to first through third ranges to determine the first amount,

the first range including the first reference value and for which the first amount is zero,

the second range being disposed outside of the first range and for which the first amount is non-zero; and

the third range being disposed outside of the first and second ranges and for which the first amount is zero.

the calculating the second amount comprises comparing the second property to fourth through sixth ranges to determine the second amount,

the fourth range including the second reference value and for which the second amount is zero,

the fifth range being disposed outside of the fourth range and for which the second amount is non-zero; and

the sixth range being disposed outside of the fourth and fifth ranges and for which the second amount is zero, and

the calculating the third amount comprises comparing the third property to seventh through ninth ranges to determine the third amount,

the seventh range including the third reference value and for which the third amount is zero,

the eighth range being disposed outside of the seventh range and for which the third amount is non-zero; and

the ninth range being disposed outside of the seventh and eighth ranges and for which the third amount is zero.

46. The computer readable medium of claim 45, wherein:

the second, fifth, and eighth ranges each include a midpoint at which the corresponding one of first, second, and third amount is at one of a maximum and a minimum,

from the midpoint towards the corresponding first, fourth, and seventh ranges, the corresponding first, second, and third amounts one of increases and decreases, and

from the midpoint towards the corresponding third, sixth, and ninth ranges, the corresponding first, second, and third amounts the other one of increases and decreases.