Color analysis based upon transformation to spherical coordinates

#1. Field of the Invention

#The present invention relates generally to a color analysis and evaluation method based upon a transformation of three primary color measurements from an x,y,z cartesian coordinate system to a spherical coordinate system.

#More particularly, the subject invention pertains to a color analysis and evaluation method based upon a transformation of three primary color measurements from an x,y,z cartesian coordinate system to a rotated spherical coordinate system in which a target color vector in the cartesian coordinate system defines the primary z axis in the rotated spherical coordinate system. In one disclosed embodiment, a computerized color analysis method uses a color camera to take a picture of a finished baked product, and rates its overall appearance by measuring specific features and comparing them to standard measurements for the product.

#The foregoing objects and advantages of the present invention for color analysis based upon transformation to spherical coordinates may be more readily understood by one skilled in the art with reference being had to the following detailed description of several preferred embodiments thereof, taken in conjunction with the accompanying drawings wherein like elements are designated by identical reference numerals throughout the several views, and in which:

#FIG. 1 illustrates an equilateral triangular color map with the three primary colors RGB at its vertices which is used to map red, green and blue chromaticity coordinates, and is useful in understanding color;

#FIG. 2 illustrates a cartesian x,y,z coordinate system for plotting a specific measured color variable according to its measured components of red, blue and green;

#The present invention measures the closeness of a color to a selected target color, and is applicable to color analysis in general over the complete color spectrum.

#Currently cameras and image processing by computers frequently organize color into three primary components such as red, green and blue. In spatial coordinates, the color system is located in the first quadrant, as illustrated in FIG. 2. For example, saturated green has coordinates (0, 200, 0), while saturated yellow (a mixture of red and green) has coordinates (200, 200, 0).

#The present invention is based upon the premise that in a spherical coordinate system as illustrated in FIG. 3, a color analysis can be better understood and more easily diagnosed and analyzed.