Apparatus and method for measurement, encoding and displaying of object color for digital imaging

• US 20020012461A1
• Filed: 05/16/2001
• Published: 01/31/2002
• Est. Priority Date: 05/17/2000
• Status: Active Grant

• Current Assignee: Tidal Photonics Incorporated
• Original Assignee: Tidal Photonics Incorporated
• Inventors: Stange, Ulrich, MacKinnon, Nicholas
• Granted Patent: US 6,961,461 B2
• Time in Patent Office: Days
• US Class Current: 382/164
• CPC Class Codes: H04N 1/60 Colour correction or control H04N1/54 takes precedence
• CPC Class Codes: H04N 1/6088 by viewing conditions, i.e. conditions at picture output
• CPC Class Codes: H04N 1/62 Retouching, i.e. modification of isolated colours only or in isolated picture areas only

Abstract

Methods, systems, devices and the like for measuring, encoding and displaying of object color for digital imaging, to control the apparent color of an item under different lighting or display conditions. The present invention helps provide accurate color for such items, both on the internet and in other situations, and can, if desired, determine whether a display screen is accurately displaying the color and also correct the image on the screen if it is not accurate. Also, probes suitable for taking accurate measurements of the intrinsic color characteristics, or intrinsic wavelength-dependent response, of an object, and software or databases that provide information for a variety of lighting situations and light sources.

Claims

1. A computer-implemented method of adjusting at least one color of at least one object in a digital image comprising:

a) providing the image containing the object and determining the chrominance values of the object in the image;

b) providing a reference data set comprising an illumination-dependent color of the object that represents the color of the object under a desired illumination condition;

c) adjusting the chrominance values of the object in the image using the reference data set to provide a different desired color of the object in the image that represents the color of the object under the desired illumination condition.

2. The method of claim 1 wherein the image includes at least a second object in the image.

3. The method of claim 2 wherein the method further comprises segmenting the object from a remainder of the image.

4. The method of claim 2 wherein the image comprises pixels and the method further comprises adjusting all pixels in the image that have chrominance values similar to the chrominance values of the object substantially the same as pixels corresponding to the object.

5. The method of claim 1 wherein the method further comprises obtaining the illumination-dependent color by:

a) providing an intrinsic-object color of the object to illumination;

b) providing at least one illumination light source reference data set comprising wavelength-dependent intensity characteristics of a desired illumination light source sufficient to define the wavelength-dependent energy distribution of the desired illumination light source;

c) combining a tristimulus function and the intrinsic object-color of the object and the illumination light source reference data set to calculate at least one set of tristimulus values for the object when illuminated by the desired illumination light source, and therefrom determining the illumination-dependent color of the object.

6. The method of claim 1 wherein the method further comprises adjusting the image at a remote terminal of a computer network.

7. The method of claim 6 wherein the computer network comprises an internet network.

8. The method of claim 6 wherein the computer network comprises a fiber optic network.

9. The method of claim 6 wherein the computer network comprises a wireless network as a carrier of the computer signal.

10. The method of claim 6 wherein the method is implemented over the network such that the adjusting is performed at a remote terminal and computer-implemented programming able to perform the method is installed on the remote terminal in combination with the image.

11. The method of claim 1 wherein the adjusting adjusts for different artificial lights.

12. The method of claim 1 wherein the adjusting adjusts for at least one of the group consisting of different latitudes, different altitudes, different times of day and different weather situations.

13. The method of claim 1 wherein the illumination-dependent color of the object is an artificially created illumination-dependent color.

14. The method of claim 5 wherein the intrinsic-object color of the object is obtained using a numerical or graphical representation of the illumination-dependent color of the object in combination with a spectrum of a reference light source illuminating the image.

15. The method of claim 1 wherein the method further comprises adjusting the illumination-dependent color of the object using gamut-mapping wherein the gamut is defined by image rendering capabilities of an image rendering device.

16. The method of claim 1 wherein the image is associated with an identifiable tag that invokes the method of adjusting.

17. The method of claim 1 wherein the image is associated with an identifiable tag such that the adjusting can be initiated by an external actuator.

18. The method of claim 16 wherein the identifiable tag is a file.

19. The method of claim 16 wherein the adjusting is associated with a switch operably linked to be turned on by the identifiable tag.

20. The method of claim 1 wherein the method is performed by a computer program that is combined with the image in a single file.

21. The method of claim 20 wherein the object comprises a depiction of a real item and the intrinsic object-color of the real item is an intrinsic object-color of the real item.

22. The method of claim 20 wherein the object comprises a depiction of an artificially-created object and the intrinsic object-color of the artificially-created object comprises predetermined assigned chrominance values.

23. The method of claim 1 wherein the method further comprises determining the luminance values of the object in the image.

24. The method of claim 23 wherein the method further comprises adjusting the luminance values or using the luminance values to determine pixels to be adjusted.

25. The method of claim 1 wherein the method further comprises limiting the colors to be corrected to chrominance values characteristic of diffuse reflection.

26. A computer comprising computer-implemented programming able to perform the method of claim 1.

27. A computer-readable memory comprising computer-implemented programming able to perform the method of claim 1.

28. A computer-readable memory comprising an object potentially needing adjusting according to the method of claim 1 operably linked to an identifiable tag that invokes the adjusting from a remote location.

29. A system comprising at least one probe able to detect an intrinsic object-color of an object to illumination and a computer comprising computer-implemented programming able to perform the method of claim 5.

30. The system of claim 29 wherein the probe resolves the intrinsic object-color to about 5 nm.

31. The system of claim 29 wherein the probe resolves the intrinsic object-color to about 2 nm.

32. The system of claim 29 wherein the probe comprises a spectroradiometer.

33. The system of claim 29 wherein the system further comprises an illumination light source having a known energy spectrum and the system comprises computer-implemented programming that correlates the response from an object illuminated by illumination light from the illumination light source with the known energy spectrum and therefrom determines the intrinsic object-color of the object.

34. The system of claim 33 wherein the system further comprises at least one light-blocking element surrounding the illumination light and the probe such that substantially no light other than the illumination light contacts the object at a location being detected by the probe.

35. A computer-contained reference data set comprising an illumination-dependent color of an object under at least two different lighting conditions.

36. The reference data set of claim 35 wherein the reference data set comprises the illumination-dependent color of an object for at least three different types of lighting conditions selected from the group consisting of artificial lights, different latitudes, different altitudes, different times of day, different weather situations, and different altitudes.

37. The reference data set of claim 36 wherein the object is an artificially-created object.

38. The reference data set of claim 36 wherein the object is static.

39. The reference data set of claim 36 wherein the object is depicted in a sequence of images that together depict movement or change.