Method and apparatus for evaluating color in an image

• US 9,076,068 B2
• Filed: 08/08/2013
• Issued: 07/07/2015
• Est. Priority Date: 10/04/2010
• Status: Active Grant

• Current Assignee: Datacolor AG Europe (Datacolor AG)
• Original Assignee: Datacolor Holding AG
• Inventors: Agarwal, Niraj, Wei, Hong
• Primary Examiner(s): Mehta, Bhavesh
• Assistant Examiner(s): Niu, Feng
• Application Number:
  US13/962,495
• Publication Number:
  US 20130322750A1
• Time in Patent Office: 698 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: G01J 3/462 Computing operations in or between colour spaces; Colour management systems
• CPC Class Codes: G01J 3/463 Colour matching
• CPC Class Codes: G01J 3/50 using electric radiation detectors
• CPC Class Codes: G01J 3/524 Calibration of colorimeters
• CPC Class Codes: H04N 1/6033 using test pattern analysis H04N1/6055 takes precedence

Abstract

A method for evaluating a color of a sample includes acquiring a color calibrated swatch of the sample, the color calibrated swatch comprising a plurality of pixels, and comparing all pixels that are of a first color in a swatch of a standard to all of the plurality of pixels that are of a second color, wherein the second color is a color in the swatch of the sample that is most similar to the first color in the swatch of the standard.

Claims

1. A method for performing a color comparison between a first swatch comprising a first set of pixels and a second swatch comprising a second set of pixels, the method comprising:

computing a first set of weighted mean RGB values for the first swatch;

computing a second set of weighted mean RGB values for the second swatch; and

calculating a color difference between the first swatch and the second swatch, based on the first set of weighted mean RGB values and the second set of weighted mean RGB values, wherein the calculating disregards at least one of;

(1) a color that is present in the second swatch, but outside a threshold distance from any color in the first swatch or (2) a spatial distribution of colors in the first swatch and a spatial distribution of colors in the second swatch.

2. A method for performing a color comparison between a first swatch comprising a first set of pixels and a second swatch comprising a second set of pixels, the method comprising:

computing a first set of weighted mean RGB values for the first swatch;

computing a second set of weighted mean RGB values for the second swatch;

calculating a color difference between the first swatch and the second swatch, based on the first set of weighted mean RGB values and the second set of weighted mean RGB values; and

generating a list, the list comprising a plurality of pairs of colors, each of the plurality of pairs of colors including a color from the first swatch and a color from the second swatch that is closest among all colors in the second swatch to the color from the first swatch.

3. The method of claim 2, further comprising:

calculating a percentage of colors present in the second swatch that are also present in the first swatch.

4. A method for performing a color comparison between a first swatch comprising a first set of pixels and a second swatch comprising a second set of pixels, the method comprising:

computing a first set of weighted mean RGB values for the first swatch;

computing a second set of weighted mean RGB values for the second swatch;

calculating a color difference between the first swatch and the second swatch, based on the first set of weighted mean RGB values and the second set of weighted mean RGB values; and

generating a list, the list comprising a plurality of pairs of colors, each of the plurality of pairs of colors including a color from the second swatch and a color from the first swatch that is closest among all colors in the first swatch to the color from the second swatch.

5. The method of claim 4 further comprising:

calculating a percentage of colors present in the first swatch that are also present in the second swatch.