RGB to RGBW color decomposition method and system

• US 8,049,763 B2
• Filed: 01/22/2008
• Issued: 11/01/2011
• Est. Priority Date: 08/13/2007
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Kwak, Young Shin, Park, Du-Sik, Park, Ju Yong
• Primary Examiner(s): Yang; Ryan R
• Application Number:
  US12/017,395
• Publication Number:
  US 20090046307A1
• Time in Patent Office: 1,379 Days
• Field of Search: 345589-603
• US Class Current: 345/589
• CPC Class Codes: G09G 2320/0209 Crosstalk reduction, i.e. to reduce direct or indirect influences of signals directed to a certain pixel of the displayed image on other pixels of said image, inclusive of influences affecting pixels in different frames or fields or sub-images which constitute a same image, e.g. left and right images of a stereoscopic display
• CPC Class Codes: G09G 2340/06 Colour space transformation
• CPC Class Codes: G09G 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• CPC Class Codes: G09G 3/3607 for displaying colours or for displaying grey scales with a specific pixel layout, e.g. using sub-pixels display of colours in flat matrix panels other than liquid crystal displays G09G3/2003; grey scales specific for television H04N3/127
• 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

Abstract

A Red Green Blue-to-Red Green Blue White (RGB-to-RGBW) color decomposition method and system. The RGB-to-RGBW color decomposition method includes: determining an output value of white based on inputted RGB values and a saturation; and outputting the output value when an input color is a pure color.

Claims

1. A Red Green Blue-to-Red Green Blue White (RGB-to-RGBW) color decomposition method, the method comprising:

determining, using a computer, an output value of white corresponding to a RGBW output signal, based on inputted RGB values and a saturation of the inputted RGB values; and

outputting the output value.

2. The method of claim 1, wherein the output value of white increases as a maximum value of the RGB values increases and a saturation of an input color decreases.

3. The method of claim 1, wherein the determining of the output value comprises:

receiving the RGB values and determining a maximum value of the RGB values;

calculating the saturation based on the RGB values; and

calculating the output value of white based on the maximum value and the saturation.

4. The method of claim 3, wherein the calculating of the output value of white calculates the output value of white using Equation 4:

R_out=R_in,

G_out=G_in,

B_out=B_in,

W_out={(1−

S)(1−

α

)+α

}*Max(R_in,G_in,B_in), 

 

[Equation 4]

where Rh denotes an input value of red, G_in denotes an input value of green, B_in denotes an input value of blue, R_out denotes an output value of red, G_out denotes an output value of green, B_out denotes an output value of blue, W_out denotes an output value of white, S denotes a saturation, Max(R_in, G_in, B_in) denotes a maximum value of the RGB values, and a denotes a value between 0 and 1.

5. The method of claim 1, wherein the calculating of the output value of white comprises:

converting the RGB values into color space values including a brightness and a saturation component using a color space conversion;

calculating the output value of the RGB values using the color space values; and

calculating the output value of white using a value S and a value V of the color space values.

6. The method of claim 5, wherein the calculating of the output value of the RGB values comprises:

calculating a value V′

by enhancing a brightness value V of the color space values including the brightness and the saturation component;

calculating R′

G′

B′

values, the R′

G′

B′

values being the RGB values when a value S of the color space values including the brightness and the saturation component is maximum, using the saturation value S and the value V′

; and

calculating the output value of the RGB using the R′

G′

B′

values, the value S, and the value V′

.

7. The method of claim 6, wherein the calculating of the value V′

comprises;

linearly increasing the value V based on an inputted model parameter Vth; and

calculating the value V′

by clipping the value V at a predetermined maximum value when the value V is greater than the predetermined maximum value.

8. The method of claim 6, wherein, when the value S is greater than an inputted model parameter Sth for at least one of a value R, a value G, and a value B of the RGB values, the calculating of the output value of the RGB comprises determining at least one of a value R′

, a value G′

, and a value B′

of the R′

G′

B′

values to be at least one of the value R, the value G, and the value B.

9. The method of claim 6, wherein:

when the value S is less than or equal to an inputted model parameter Sth for at least one of a value R, a value G, and a value B of the RGB values, the calculating of the output value of the RGB comprises increasing the output value linearly proportional to the value S; and

when the value S is 0, the calculating of the output value of the RGB comprises determining the value V′

as at least one of the value R, the value G, and the value B.

10. The method of claim 5, wherein, when the value S of white is greater than 0 and is less than an inputted model parameter Sth, the calculating of the output value of white comprises determining the value V as the output value.

11. The method of claim 5, wherein, when the value S of white is greater than an inputted model parameter Sth and is less than 1, the calculating of the output value of white comprises linearly decreasing the output value from the value V to a minimum value of the value V.

12. The method of claim 11, wherein:

the minimum value is a value determined by the value V; and

when the value V is less than or equal to an inputted model parameter Vth, the minimum value is 0, and when the value V is greater than the inputted model parameter Vth, the minimum value increases to a maximum value of an inputted model parameter value W_add when the value V is 1.

13. The method of claim 5, wherein the calculating of the output value of white further comprises:

performing linearization of the RGB values; and

applying a display gamma to the output value of the RGB values and the output value of white.

14. A Red Green Blue-to-Red Green Blue White (RGB-to-RGBW) color decomposition method, the method comprising:

receiving inputted RGB values and determining a maximum value of the RGB values;

calculating, using a computer, a saturation based on the RGB values; and

calculating an output value of white corresponding to a RGBW output signal, based on the maximum value and the saturation.

15. The method of claim 14, wherein the calculating of the output value of white comprises calculating the output value of white using Equation 5:

R_out=R_in,

G_out=G_in,

B_out=B_in,

W_out={(1−

S)(1−

α

)+α

}*Max(R_in,G_in,B_in), 

 

[Equation 5]

where R_in denotes an input value of red, G_in denotes an input value of green, B_in denotes an input value of blue, R_out denotes an output value of red, G_out denotes an output value of green, B_out denotes an output value of blue, W_out denotes an output value of white, S denotes a saturation, Max(R_in, G_in, B_in) denotes a maximum value of the RGB values, Min(R_in, G_in, B_in) denotes a minimum value of the RGB values, and a denotes a value between 0 and 1.

16. A Red Green Blue-to-Red Green Blue White (RGB-to-RGBW) color decomposition method comprising:

converting RGB values into color space values including a brightness and a saturation component using a color space conversion; and

calculating, using a computer, an output value of white corresponding to a RGBW output signal, using a saturation value S and a brightness value V of the color space values.

17. The method of claim 16, further comprising:

calculating an output value of the RGB values using the color space values.

18. The method of claim 16, wherein the calculating of the output value of the RGB values comprises:

calculating a value V′

by enhancing a value V of the color space values;

calculating R′

G′

B′

values, the R′

G′

B′

values being the RGB values when a value S of the color space values is maximum, by using the value S and the value V′

; and

calculating the output value of the RGB using the R′

G′

B′

values, the value S, and the value V′

.

19. The method of claim 18, wherein the calculating of the value V′

comprises;

linearly increasing the value V based on an inputted model parameter Vth; and

calculating the value V′

by clipping the value V at a predetermined maximum value when the value V is greater than the predetermined maximum value.

20. The method of claim 18, wherein, when the value S is greater than an inputted model parameter Sth for at least one of a value R, a value G, and a value B of the RGB values, the calculating of the output value of the RGB comprises determining at least one of a value R′

, a value G′

, and a value B′

of the R′

G′

B′

values as at least one of the value R, the value G, and the value B.

21. The method of claim 18, wherein:

when the value S is less than or equal to an inputted model parameter Sth for at least one of a value R, a value G, and a value B of the RGB values, the calculating of the output value of the RGB comprises increasing the output value linearly proportional to the value S, and

when the value S is 0, the calculating of the output value of the RGB comprises determining the value V′

as at least one of the value R, the value G, and the value B.

22. The method of claim 16, wherein, when the value S of white is greater than 0 and is less than an inputted model parameter Sth, the calculating of the output value of white comprises determining the value V as the output value, and

when the value S of white is greater than an inputted model parameter Sth and is less than 1, the calculating of the output value of white comprises linearly decreasing the output value from the value V to a minimum value of the value V.

23. The method of claim 22, wherein:

the minimum value is a value determined by the value V; and

when the value V is less than or equal to an inputted model parameter Vth, the minimum value is 0, and when the value V is greater than the inputted model parameter Vth, the minimum value increases to an inputted model parameter value W_add when the value V is 1.

24. The method of claim 16, further comprising:

performing linearization of the RGB values; and

applying a display gamma to the output value of the RGB values and the output value of white.

25. A non-transitory computer-readable recording medium storing a program to implement a Red Green Blue-to-Red Green Blue White (RGB-to-RGBW) color decomposition method, the method comprising:

determining an output value of white corresponding to a RGBW output signal, based on inputted RGB values and a saturation; and

outputting the output value.

26. A Red Green Blue-to-Red Green Blue White (RGB-to-RGBW) color decomposition system comprising:

a white output value determination unit to determine an output value of white based on inputted RGB values and a saturation of the inputted RGB values; and

an output unit to output the output value when an input color is a pure color.

27. The system of claim 26, wherein the output value of white increases as a maximum value of the RGB values increases and a saturation of an input color decreases.

28. The system of claim 26, wherein the white output value determination unit comprises:

an RGB maximum value check unit to receive the RGB values and to check the maximum value;

a saturation calculation unit to calculate the saturation based on the RGB values; and

a white output value calculation unit to calculate the output value of white based on the maximum value and the saturation.

29. The system of claim 26, wherein the white output value determination unit comprises:

an RGB value conversion unit to convert the RGB values into color space values including a brightness and a saturation component using a color space conversion;

an RGB output value calculation unit to calculate the output value of the RGB values using the color space values; and

a white output value calculation unit to calculate the output value of white using a saturation value S and a brightness value V of the color space values.

30. A Red Green Blue-to-Red Green Blue White (RGB-to-RGBW) color decomposition system comprising:

an RGB maximum value check unit to receive inputted RGB values and to check a maximum value;

a saturation calculation unit to calculate a saturation based on the RGB values; and

a white output value calculation unit to calculate an output value of white based on the maximum value and the saturation.

31. The system of claim 30, wherein the white output value calculation unit calculates the output value of white using Equation 6:

R_out=R_in,

G_out=G_in,

B_out=B_in,

W_out={(1−

S)(1−

α

)+α

}*Max(R_in,G_in,B_in), 

 

[Equation 6]

where R_in denotes an input value of red, G_in denotes an input value of green, B_in denotes an input value of blue, R_out denotes an output value of red, G_out denotes an output value of green, B_out denotes an output value of blue, W_out denotes an output value of white, S denotes a saturation, Max(R_in, G_in, B_in) denotes a maximum value of the RGB values, and a denotes a value between 0 and 1.

32. A Red Green Blue-to-Red Green Blue White (RGB-to-RGBW) color decomposition system, the system comprising:

an RGB conversion unit to convert the RGB values into color space values including a brightness and a saturation component using a color space conversion; and

a white output value calculation unit to calculate the output value of white corresponding to a RGBW output signal, using a saturation value S and a brightness value V of the color space values.

33. The system of claim 32, further comprising:

an RGB output value calculation unit to calculate the output value of the RGB values using the color space values including the brightness and the saturation component.

34. The system of claim 33, wherein the RGB output value calculation unit comprises:

a V enhancement unit to calculate a value V′

by enhancing a value V of the color space values including the brightness and the saturation component;

a R′

G′

B′

calculation unit to calculate R′

G′

B′

values, the R′

G′

B′

values being the RGB values when the value S is maximum using the value S and the value V′

; and

an output value calculation unit to calculate the output value of the RGB using the R′

G′

B′

values, the value S, and the value V′

.

35. The system of claim 32, wherein:

when the value S of white is greater than 0 and is less than an inputted model parameter Sth, the white output value calculation unit determines the value V as the output value; and

when the value S of white is greater than an inputted model parameter Sth and is less than 1, the white output value calculation unit linearly decreases the output value from the value V to a minimum value of the value V.

36. The system of claim 32, further comprising:

a linearization unit to perform linearization of the RGB values; and

a gamma application unit to apply a display gamma to the output value of the RGB values and the output value of white.

37. A system to convert from RGB (Red-Green-Blue) to RGBW (Red-Green-Blue-White) without negatively impacting a brightness, the system comprising:

a white value determining unit to determine a white value corresponding to a RGBW output signal and an output RGB value based on an input RGB value such that the white value increases linearly as the output RGB value increases; and

an output unit to output the white value and the RGB value corresponding to a pixel to be displayed on a display.

38. The system of claim 37, wherein the white value determining unit comprises:

a maximum value determination unit to determine a maximum value of the input RGB values;

a saturation calculation unit to calculate a saturation based on the maximum value; and

a white value calculation unit to determine the white value based on the maximum value and the saturation.

39. The system of claim 37, wherein the white value determining unit comprises:

an RGB conversion unit to convert the RGB values into HSB (hue-saturation-brightness) values;

an RGB value calculation unit to determine the output RGB values based on the HSB values; and

a white value calculation unit to determine the white value based on the HSB values.

40. The system of claim 39, wherein the RGB value calculation unit comprises:

a brightness enhancement unit to enhance a brightness value of the HSB values;

an RGB determination unit to determine intermediate RGB values based on the enhanced brightness value and a saturation value of the HSB values; and

an RGB output unit to determine the output RGB values based on the intermediate RGB values, the enhanced brightness value, and the saturation value.

41. The system of claim 39, wherein the white value determining unit further comprises:

a linearization unit to linearize the input RGB values such that the linearized RGB values are linearly proportional to brightness; and

a gamma unit to apply a gamma to the output RGB values and the white values;

wherein the RGB conversion unit converts the linearized RGB values into the HSB values.

42. The system of claim 37, wherein the white determining unit determines the white value such that the white value increases as a maximum value of the input RGB value increases and a saturation of the input RGB value decreases.

43. The system of claim 37, wherein the white determining unit only determines the white value, without adjusting the input RGB values.