IP Library Granted Patent US 6,972,772
Granted Patent B1
US 6,972,772 · App. 10/641,214 · Granted Dec 6, 2005

White point correction without luminance degradation

Assignee: Apple Computer, Inc.
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Quick Facts
Patent No.
US 6,972,772
App. No.
10/641,214
Granted
Dec 6, 2005
Kind
B1
Abstract

White point is corrected without degrading luminance on a display device. A white point manager modifies the balance between red, green and blue according to a target white point up to a threshold gray value. As the gray scale approaches white from the threshold gray value, the white point manager blends the balance between red, green and blue from the target white point substantially towards the native white point for the display device, so as not to degrade luminance as the gray scale approaches white.

Claims (60)

1. A method for correcting white point without degrading luminance on a display device, the display device having a native white point, the method comprising:

for a first range of gray values up to a threshold gray value, modifying a balance between red, green and blue according to a target white point; and

for a second range of gray values exceeding the threshold gray value, blending the balance between red, green and blue from the target white point substantially towards the native white point for the display device.

2. The method of claim 1 wherein blending the balance between red, green and blue further comprises:

interpolating red, green and blue from the threshold gray value to the native white point for the display device.

3. The method of claim 1 wherein blending the balance between red, green and blue further comprises:

interpolating red, green and blue from the threshold gray value to a target value between the threshold gray value and the native white point for the display device.

4. The method of claim 1 wherein the second range extends from the threshold gray value to the native white point for the display device.

5. The method of claim 1 wherein the second range extends from the threshold gray value to a target value between the threshold gray value and the native white point for the display device.

6. The method of claim 1 further comprising:

receiving a control signal indicating the target white point.

7. The method of claim 6 wherein receiving a control signal indicating the target white point further comprises:

receiving the control signal from one of a group of sources consisting of:

a user operated input device;

an optical display calibration device; and

an internal automated display calibration mechanism.

8. The method of claim 7 further comprising:

saving the target white point as a user preference.

9. The method of claim 1 further comprising:

modifying measured gamma for the display device to a desired gamma, thereby correcting gamma for the display device.

10. A computer system for correcting white point without degrading luminance on a display device, the display device having a native white point, the computer system comprising:

a software portion configured to modify a balance between red, green and blue according to a target white point, for a first range of gray values up to a threshold gray value; and

a software portion configured to blend the balance between red, green and blue from the target white point substantially towards the native white point for the display device, for a second range of gray values exceeding the threshold gray value.

11. The system of claim 10 further comprising:

a software portion configured to interpolate red, green and blue from the threshold gray value to the native white point for the display device.

12. The system of claim 10 further comprising:

a software portion configured to interpolate red, green and blue from the threshold gray value to a target value between the threshold gray value and the native white point for the display device.

13. The system of claim 10 further comprising:

a software portion configured to receive a control signal indicating the target white point.

14. The system of claim 13 further comprising:

a software portion configured to save the target white point as a user preference.

15. The system of claim 10 further comprising:

a software portion configured to modify measured gamma for the display device to a desired gamma, thereby correcting gamma for the display device.

16. A computer system for correcting white point without degrading luminance on a display device, the display device having a native white point, the computer system comprising:

means for modifying a balance between red, green and blue according to a target white point, for a first range of gray values up to a threshold gray value; and

means for blending the balance between red, green and blue from the target white point substantially towards the native white point for the display device, for a second range of gray values exceeding the threshold gray value.

17. The system of claim 16 further comprising:

means for interpolating red, green and blue from the threshold gray value to the native white point for the display device.

18. The system of claim 16 further comprising:

means for interpolating red, green and blue from the threshold gray value to a target value between the threshold gray value and the native white point for the display device.

19. The system of claim 16 further comprising:

means for receiving a control signal indicating the target white point.

20. The system of claim 19 further comprising:

means for saving the target white point as a user preference.

21. The system of claim 16 further comprising:

means for modifying measured gamma for the display device to a desired gamma, thereby correcting gamma for the display device.

22. A computer program product for correcting white point without degrading luminance on a display device, the display device having a native white point, the computer program product comprising:

program code for modifying a balance between red, green and blue according to a target white point, for a first range of gray values up to a threshold gray value;

program code for blending the balance between red, green and blue from the target white point substantially towards the native white point for the display device, for a second range of gray values exceeding the threshold gray value; and

a computer readable medium on which the program codes are stored.

23. The computer program product of claim 22 further comprising:

program code for interpolating red, green and blue from the threshold gray value to the native white point for the display device.

24. The computer program product of claim 22 further comprising:

program code for interpolating red, green and blue from the threshold gray value to a target value between the threshold gray value and the native white point for the display device.

25. The computer program product of claim 22 further comprising:

program code for receiving a control signal indicating the target white point.

26. The computer program product of claim 25 further comprising:

program code for saving the target white point as a user preference.

27. The computer program product of claim 22 further comprising:

program code for modifying measured gamma for the display device to a desired gamma, thereby correcting gamma for the display device.

Assignments (2)
CHANGE OF NAME Recorded Mar 7, 2008
From: APPLE COMPUTER, INC.
To: APPLE INC.
Reel/Frame 020638/0127 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Aug 13, 2003
From: CHEN, KOK; MARCU, GABRIEL G.
To: APPLE COMPUTER, INC.
Reel/Frame 014401/0595 →