Method and device for improved display standard conformance

• US 20070067124A1
• Filed: 07/28/2006
• Published: 03/22/2007
• Est. Priority Date: 08/01/2005
• Status: Active Grant

• Current Assignee: Barco NV
• Original Assignee: Barco NV
• Inventors: Kimpe, Tom, Dorval, Etienne
• Granted Patent: US 9,368,057 B2
• Time in Patent Office: Days
• US Class Current: 702/67
• CPC Class Codes: G09G 2320/0242 Compensation of deficiencies in the appearance of colours
• CPC Class Codes: G09G 2320/0285 using tables for spatial correction of display data
• CPC Class Codes: G09G 2320/0693 Calibration of display systems
• CPC Class Codes: G09G 3/006 Electronic inspection or testing of displays and display drivers, e.g. of LED or LCD displays testing individual LED's G01R31/2635; testing lamps G01R31/44; testing of optical features of LCD displays G02F1/1309
• CPC Class Codes: G09G 3/2092 Details of a display terminals using a flat panel, the details relating to the control arrangement of the display terminal and to the interfaces thereto suitable for both CRT and flat panel G09G5/003; specific for a CRT G09G1/165

Abstract

The invention provides a new method to calibrate a display system such that the display system is conforming to an enforced standard for a wider range of parameters, e.g. viewing angles, than compared to traditional calibration methods. This is obtained by calculating an optimised set of calibration parameters for the display to be conform to the enforced standard for the selected range of parameters.

Claims

1. A method for calibrating a matrix display with respect to at least one enforced greyscale or colour display standard, the method comprising

obtaining a characterisation of the non-conformance in greyscale or colour values of the matrix display as a function of its drive signals with respect to a plurality of relevant values of at least a first parameter,

calculating a set of calibration parameters in function of at least the first parameter, based on the at least one enforced greyscale or colour display standard, and the characterised non-conformance in greyscale or colour values of the matrix display,

optimising the set of calibration parameters with respect to a degree of conformance to the at least one enforced greyscale or colour display standard for all values of at least the first parameter within a relevant parameter range, thus obtaining a set of optimal calibration parameters for use with the matrix display.

2. A method according to claim 1, wherein characterising the non-conformance in greyscale or colour values of the matrix display with respect to at least a first parameter comprises creating native transfer curves for the matrix display, and this for every value of the first parameter within the relevant parameter range.

3. A method according to claim 2, wherein creating native transfer curves for every value of the first parameter within the relevant parameter range comprises measuring native transfer curves for some values of the first parameter within the relevant parameter range, and generating native transfer curves for other values of the first parameter by interpolation.

4. A method according to claim 1, wherein the first parameter is viewing angle.

5. A method according to claim 4, wherein the relevant parameter range is a viewing cone of 20°

.

6. A method according to claim 1, furthermore comprising configuring the matrix display with the set of optimal calibration parameters.

7. A method according to claim 6, wherein configuring the matrix display with the set of optimal calibration parameters comprises loading the set of optimal calibration parameters into the display, into a graphical board, into a host operating system or into an application running on the host operating system.

8. A method according to claim 1, wherein the set of optimal calibration parameters are in the form of a look-up table.

9. A method according to claim 1, wherein obtaining a characterisation of the non-conformance in greyscale or colour values of the matrix display with respect to relevant values of at least a first parameter comprises characterising the non-conformance in greyscale or colour values of the matrix display with respect to relevant values of at least the first parameter.

10. A method according to claim 1, wherein obtaining a characterisation of the non-conformance in greyscale or colour values of the matrix display with respect to relevant values of at least a first parameter comprises loading a previously determined characterisation of the non-conformance in greyscale or colour values of the matrix display with respect to relevant values of at least the first parameter.

11. A method according to claim 1, furthermore comprising determining an actual value of the first parameter, and automatically selecting an optimal pre-set so that the display system has optimal conformance to the at least one enforced greyscale or colour display standard with respect to the actual value of the first parameter.

12. A method according to claim 1, there being a plurality of zones of emissive elements in the matrix display, at least two of the zones having a different parameter value for at least the first parameter at a particular moment in time, wherein the method comprises taking into account different relevant parameter ranges of at least a first parameter for at least two of the zones, and separately optimising the set of calibration parameters of these at least two zones with respect to a degree of conformance to the at least one enforced greyscale or colour display standard for all values of at least the first parameter within the parameter range relevant for that zone, thus obtaining a set of optimal calibration parameters for use with the matrix display.

32. A method according to claim 11, wherein said enforced greyscale display standard is the Digital Imaging and Communications in Medecine standard published by National Electrical Manufacturers Association.

13. A calibration device for calibrating a matrix display with respect to at least one enforced greyscale or colour display standard, the calibration device comprising

first storage means for storing a characterisation of the non-conformance in greyscale or colour values of the matrix display as a function of its drive signals with respect to a plurality of relevant values of at least a first parameter,

second storage means for storing a set of calibration parameters in function of at least the first parameter, based on the at least one enforced greyscale or colour display standard, and the characterised non-conformance in greyscale or colour values of the matrix display,

calculation means for optimising the set of calibration parameters with respect to a degree of conformance to the at least one enforced greyscale or colour display standard for all values of at least the first parameter within a relevant parameter range, thus obtaining a set of optimal calibration parameters for use with the matrix display.

14. A device according to claim 13, furthermore comprising means for creating native transfer curves for the matrix display, and this for every value of the first parameter within the relevant parameter range.

15. A device according to claim 14, wherein the means for creating native transfer curves for every value of the first parameter within the relevant parameter range comprises measurement means for measuring native transfer curves for some values of the first parameter within the relevant parameter range, and calculation means for generating native transfer curves for other values of the first parameter by interpolation.

16. A device according to claim 13, wherein the first parameter is viewing angle.

17. A device according to claim 16, wherein the relevant parameter range is a viewing cone of 20°

.

18. A device according to claim 13, furthermore comprising configuration means for configuring the matrix display with the set of optimal calibration parameters.

19. A device according to claim 18, wherein the configuration means comprises means for loading the set of optimal calibration parameters into the display, into a graphical board, into a host operating system or into an application running on the host operating system.

20. A device according to claim 13, furthermore comprising a third storage means for storing pre-sets of optimal calibration parameters for pre-determined first parameter values.

21. A device according to claim 20, furthermore comprising means for determining an actual value of the first parameter, and selection means for automatically selecting an optimal pre-set from the third storage means so that the display system has optimal conformance to the at least one enforced greyscale or colour display standard with respect to the actual value of the first parameter.

22. A method for correcting non-conformance in greyscale or colour values of at least one zone of emissive elements in a matrix display, the correcting being with respect to at least one enforced greyscale or colour display standard, the method comprising

storing characterisation data characterising the non-conformance in greyscale or colour values of the at least one zone of emissive elements as a function of its drive signals for a plurality of relevant values of at least a first parameter of the characterisation data,

pre-correcting, in accordance with the characterisation data, the drive signals of said at least one zone of emissive elements so as to obtain a greyscale or colour level conform said enforced greyscale or colour display standard within a pre-determined deviation range from each of the at least one enforced greyscale or colour display standards, wherein said pre-correcting is performed based on an input value of the greyscale or colour value to be displayed and a selection of a range of at least the first parameter of the characterisation data for which non-conformance with respect to the at least one enforced greyscale or colour display standard is to be corrected within the pre-determined deviation range.

23. The method according to claim 22, wherein the range of at least the first parameter includes at least one of a range of viewing angles under which the at least one zone of emissive elements is or is to be viewed at, a range of at least one display related parameter, or a range of at least one environmental parameter.

24. The method according to claim 23, wherein the display related parameter includes one or more of matrix display temperatures, backlight luminance, backlight colour temperature, display settings, calibration tables, graphical board settings, settings of a host operating system, settings of an application running on a host operating system.

25. The method according to claim 23, wherein the environmental parameter includes any of intensity of ambient light, colour temperature of ambient light, ambient temperature the matrix display is or is to be used at, ambient light values the matrix display is or is to be used at.

26. The method according to claim 22, wherein the pre-determined deviation range comprises a deviation up to 2%, preferably up to 5%, more preferably up to 10%, from the at least one enforced greyscale or colour display standard.

27. A method according to claim 22, there being a plurality of zones of emissive elements, wherein each zone of emissive elements is corrected by a different calibration function.

28. A method according to claim 22, wherein a zone of emissive elements consists of one emissive element.

29. A method according to claim 22, wherein a zone of emissive elements comprises a plurality of emissive elements, each emissive element of a zone being assigned a same characterisation data.

30. A method according to claim 22, wherein said pre-correcting the drive signal is performed based on using a look-up table.

31. A method according to claim 22, wherein said pre-correcting the drive signal is performed at least partially based on using a mathematical function.

33. A method according to claim 22, wherein the pre-correcting is carried out in real-time.

34. A method according to claim 22, wherein the pre-correcting is carried out off-line.

35. A system for correcting non-conformance in greyscale or colour values of at least one zone of emissive elements in a matrix display, the correcting being with respect to at least one enforced greyscale or colour display standard, the system comprising

a memory means for storing characterisation data characterising the non-conformance in greyscale or colour values of the at least one zone of emissive elements as a function of its drive signals for a plurality of relevant values of at least a first parameter of the characterisation data,

a correction device for pre-correcting, based on an input value of the greyscale or colour value to be displayed and a selection of a range of at least the first parameter of the characterisation data for which non-conformance with respect to the at least one enforced greyscale or colour display standard is to be corrected within the pre-determined deviation range, and in accordance with the characterisation data, the drive signals of said at least one zone of emissive elements so as to obtain a greyscale or colour level conform said enforced greyscale or colour display standard within a pre-determined deviation range from each of the at least one enforced greyscale or colour display standards.

36. A system according to claim 35, furthermore comprising a characterising device for generating characterisation data for the at least one zone of emissive elements by establishing a relationship between the greyscale or colour levels of each of said at least one zone of emissive elements and the corresponding drive signal for a plurality of relevant parameter values in the parameter range for at least the first parameter.

37. A system according to claim 36, wherein said characterising device comprises an image capturing device for generating an image of the emissive elements of the matrix display.