Method for matching color and appearance of a coating containing effect pigments

• US 8,065,314 B2
• Filed: 10/01/2007
• Issued: 11/22/2011
• Est. Priority Date: 10/02/2006
• Status: Active Grant

• Current Assignee: Axalta Coating Systems Ip Co Llc (Axalta Coating Systems Ltd.)
• Original Assignee: E. I. du Pont de Nemours and Company (Corteva, Inc.)
• Inventors: Obetz, Judith Elaine, Rodrigues, Allan Blase Joseph, Kettler, Wilhelm, Gallagher, John Paul, Prakash, Arun
• Primary Examiner(s): WILSON, KIMBERLY LOVEL
• Application Number:
  US11/906,208
• Publication Number:
  US 20090019086A1
• Time in Patent Office: 1,513 Days
• Field of Search: 707/758, 702/32, 345/589, 356/402
• US Class Current: 707/758
• CPC Class Codes: G01J 3/46 Measurement of colour; Colour measuring devices, e.g. colorimeters measuring colour temperature G01J5/60
• CPC Class Codes: G01J 3/463 Colour matching

Abstract

The present invention is directed to a method for identifying one or more matching formulas for matching color and appearance of a target coating containing effect pigments. The present invention is also directed to a system for identifying one or more matching formulas for matching color and appearance of a target coating containing effect pigments.

Claims

1. A method for identifying one or more matching formulas for matching color and appearance of a target coating containing effect pigments, said method comprising the steps of:

a) obtaining color data of the target coating;

b) obtaining appearance data of the target coating;

c) comparing the color data and the appearance data to color characteristics and appearance characteristics stored in a coating database by calculating color difference between said color data and said color characteristics, and feature distances between said appearance data and said appearance characteristics; and

d) selecting from the coating database, one or more said matching formulas, wherein said matching formulas have color characteristics that match the color data and appearance characteristics that match the appearance data;

wherein said matching formulas are selected by selecting and ranking alternate coatings from said coating database based on the color difference, ranking said alternate coatings based on the feature distances to produce an initial appearance ranking list, adjusting said initial appearance ranking list based on said appearance data to generate a refined appearance ranking list, and selecting said matching formulas based on top ranked coatings in said refined appearance ranking list.

2. The method of claim 1, wherein the color data comprise spectral reflectance data.

3. The method of claim 1, wherein the color data comprise a color identification code selected from a color code of a vehicle, a vehicle identification number (VIN) of the vehicle, a part of the VIN, or a combination thereof.

4. The method of claim 1, wherein the effect pigments are gonioapparent flakes.

5. The method of claim 1, wherein the target coating is affixed to surface of an automotive body.

6. A method for identifying one or more matching formulas for matching color and appearance of a target coating containing effect pigments, said method comprising the steps of:

a) obtaining color data of the target coating using a color measurement device;

b) obtaining one or more target images of the target coating at one or more pre-set illumination intensities using an imaging device;

c) measuring characteristics of said target coating from said target images to generate appearance data;

d) comparing the color data and the appearance data to color characteristics and appearance characteristics stored in a coating database by calculating color difference between said color data and said color characteristics, and feature distances between said appearance data and said appearance characteristics; and

e) selecting from the coating database, one or more said matching formulas, wherein said matching formulas have color characteristics that match the color data and appearance characteristics that match the appearance data;

wherein said matching formulas are selected by selecting and ranking alternate coatings from said coatings database based on the color difference, ranking said alternate coatings based on the feature distances to produce an initial appearance ranking list adjusting said initial appearance ranking list based on said appearance data to generate a refined appearance ranking list, and selecting said matching formulas based on top ranked coatings in said refined appearance ranking list.

7. The method of claim 6, wherein the step b) comprises:

i) sequentially providing illuminations to the target coating at at least two said preset illumination intensities;

ii) directing a reflection of each of said illuminations from said target coating to the imaging device to sequentially capture one or more target images of said target coating.

8. The method of claim 6, wherein the step b) comprises:

i) providing illuminations to the target coating at a fixed illumination angle and at said pre-set illumination intensities;

ii) selecting an effective illumination of an effective intensity under which the effect pigments of the target coating exhibit varying brightness;

iii) directing a reflection of said effective illumination from the target coating to the imaging device to capture at least one image of the target coating.

9. The method of claim 6, wherein the step b) comprises:

i) sequentially providing illuminations to the target coating at two or more illumination angles and at said one or more preset intensities;

ii) directing a reflection of each of said illuminations from said target coating to the imaging device to sequentially capture one or more target images of said target coating.

10. The method of any one of claims 6-9, wherein the color measurement device is a colorimeter, spectrophotometer, or a goniospectrophotometer.

11. The method of any one of claims 6-9, wherein the color data comprise spectral reflectance data.

12. The method of any one of claims 6-9, wherein the color data comprise a color identification code selected from a color code of a vehicle, a vehicle identification number (VIN) of the vehicle, a part of the VIN, or a combination thereof.

13. The method of any one of claims 6-9, wherein the imaging device is a digital imager.

14. The method of any one of claims 6-9, wherein the effect pigments are gonioapparent flakes.

15. The method of any one of claims 6-9, wherein the target coating is affixed to surface or an automotive body.

16. The method of any one of claims 6-9, wherein the color measurement device and the imaging device are configured to obtain said color data and said target images from a same portion of the target coating simultaneously or sequentially.

17. The method of any one of claims 6-9, wherein the color measurement device and the imaging device are configured to obtain said color data and said target images from different portions of the target coating simultaneously or sequentially.

18. The method of claim 6, wherein said step c) comprising the step of obtaining a fractional area of each of the target images having image intensities above a first threshold level (Area T1), a fractional area of said each of the target images having sparkle objects expanded at a second threshold level (Area Exp), and a fractional area of said each of the target images having new sparkle objects at said second threshold level (Area New);

and wherein said initial appearance ranking list is produced based on at least ratios of (Area Exp)/(Area T1) and (Area New)/(Area T1).

19. A system for identifying one or more matching formulas for matching color and appearance of a target coating containing effect pigments, said system comprising;

a) a color measurement device for obtaining color data of the target coating;

b) an appearance measurement device for obtaining appearance data of the target coating;

c) a computing device comprising a processor and a memory member;

d) a coating database containing coating formulas associated with color characteristics and appearance characteristics, wherein the coating database is accessible from the computing device; and

e) a computing program product operatively residing in the memory member that causes the computing device to perform a computing process comprising the steps of

i) receiving the color data and the appearance data of said target coating;

ii) comparing said color data and said appearance data to color characteristics and appearance characteristics stored in the coating database by calculating color difference between said color data and said color characteristics, and feature distances between said appearance data and said appearance characteristics; and

iii) selecting from the coating database, one or more said matching formulas, wherein said matching formulas have color characteristics that match the color data and appearance characteristics that match the appearance data;

wherein said matching formulas are selected by selecting and ranking alternate coatings from said coating database based on the color difference, ranking said alternate coatings based on the feature distances to produce an initial appearance ranking list, adjusting said initial appearance ranking list based on said appearance data to generate a refined appearance ranking list, and selecting said matching formulas based on top ranked coatings in said refined appearance ranking list.

20. The system of claim 19, wherein the color measurement device is a colorimeter, spectrophotometer, or a goniospectrophotometer.

21. The system of claim 19, wherein the color data comprise spectral reflectance data.

22. The system of claim 19, wherein the color data comprise a color identification code selected from a color code of a vehicle, a vehicle identification number (VIN) of the vehicle, a part of the VIN, or a combination thereof.

23. The system of claim 19, wherein the appearance measurement device is a digital imager.

24. The system of claim 19, wherein the effect pigments are gonioapparent flakes.

25. The system of claim 19, wherein the target coating is affixed to surface of an automotive body.

26. A system for identifying one or more matching formulas for matching color and appearance of a target coating containing effect pigments, said system comprising:

a) a color measurement device for obtaining color data of the target coating;

b) an imaging device for obtaining target images of the target coating at said pre-set illumination intensities;

c) an illumination device to provide illuminations at one or more pre-set illumination intensities to the target coating and to direct a reflection of said illuminations to the imaging device;

d) a computing device comprising a processor and a memory member;

e) a coating database containing coating formulas associated with color characteristics and appearance characteristics, wherein the coating database is accessible from the computing device; and

f) a computing program product operatively residing in the memory member that causes the computing device to perform a computing process comprising the steps of;

i) receiving the color data and the target images of said target coating;

ii) measuring characteristics of said target coating from said target images to generate appearance data;

iii) comparing said color data and said appearance data to color characteristics and appearance characteristics stored in the coating database by calculating color difference between said color data and said color characteristics, and feature distances between said appearance data and said appearance characteristics; and

iv) selecting from the coating database, one or more said matching formulas, wherein said matching formulas have color characteristics that match the color data and appearance characteristics that match the appearance data;

wherein said matching formulas are selected by selecting and ranking alternate coatings from said coating database based on the color difference, ranking said alternate coatings based on the feature distances to produce an initial appearance ranking list, adjusting said initial appearance ranking list based on said appearance data to generate a refined appearance ranking list, and selecting said matching formulas based on top ranked coatings in said refined appearance ranking list.

27. The system of claim 26, wherein the color measurement device is a colorimeter, spectrophotometer, or a goniospectrophotometer.

28. The system of claim 26, wherein the color data comprise a color identification code selected from a color code of a vehicle, a vehicle identification number (VIN) of the vehicle, a part of the VIN, or a combination thereof.

29. The system of claim 26, wherein the imaging device is a digital imager.

30. The system of claim 26, wherein the effect pigments are gonioapparent flakes.

31. The system of claim 26, wherein the illumination device comprises means for modulating illumination intensity.

32. The system of claim 26 wherein the illumination device comprises means for modulating illumination angle.

33. The system of claim 26, wherein the color measurement device comprises means for modulating illumination angles.

34. The system of claim 26, wherein the color measurement device comprises means for modulating illumination intensity.

35. The system of claim 26 further comprising a second database for storing and retrieving said color data and said appearance data, wherein the second database is accessible from the computing device.

36. The system of claim 26, wherein the color measurement device is operatively coupled to the computing device via wired or wireless connections.

37. The system of claim 26, wherein the imaging device is operatively coupled to the computing device via wired or wireless connections.

38. The system of claim 26, wherein the color measurement device and the imaging device are configured in one housing unit.

39. The system of claim 26, wherein the color measurement device and the imaging device are configured in separate housing units.

40. The system of claim 26, wherein the color measurement device and the imaging device are configured to obtain said color data and said target images from a same portion of the target coating simultaneously or sequentially.

41. The system of claim 26, wherein the color measurement device and the imaging device are configured to obtain said color data and said target images from different portions of the target coating simultaneously or sequentially.

42. The system of claim 26, wherein the computing device is a portable computing device.

43. The system of claim 42, wherein the portable computing device is operatively coupled to the color measurement device or the imaging device via wireless connections.

44. The system of claim 26, wherein the target coating is affixed to surface of an automotive body.

45. The system of claim 26, wherein said step ii) comprising the step of obtaining a fractional area of at least one of the target images having image intensities above a first threshold level (Area T1), a fractional area of said one of the target images having sparkle objects expanded at a second threshold level (Area Exp), and a fractional area of said one of the target images having new sparkle objects at said second threshold level (Area New);

and wherein said initial appearance ranking list is produced based on at least ratios of (Area Exp)/(Area T1) and (Area New)/(Area T1).