Patent ID: 11921051
Assignee: GEMOLOGICAL INSTITUTE OF AMERICA, INC. (GIA)
Field: Measurement (Instruments)
Classification: CPC G | IPC G

Claim 0:
1. A method of analyzing a gemstone, the method comprising:
by a computer with a processor and memory, receiving a plurality of color, digital pixelated images of a gemstone,
wherein the received plurality of color, digital images are in Cyan, Magenta, Yellow, and Key (CMYK) color mode,
wherein each of the images represents a different view angle of the gemstone;

by the computer, receiving an indication of a pre-determined category for the gemstone;
by the computer, quantifying a color component for each pixel in a defined area of one of the plurality of images, thereby converting values for individual color components to at least two parameters representing a color characteristic of each pixel;
wherein converting values for individual color components includes converting pixels to the CMYK color mode images to Red Green Blue (RGB) color mode,
by the computer, converting the first converted RGB color mode for the first received image pixels to Commission Internationale de l′Elcairage (CIE) color space values of L*, a* and b*,
by the computer, converting each pixel in a second area of a second received image of the multiple color images in the CMYK color mode images to RGB color mode,
by the computer, converting the second converted RGB color mode for the second received image pixels to CIE color space values of L*, a* and b*;
by the computer, converting the CIE color space values of lightness L*, a* and b* to chroma (C*) and hue (h*) values, and
by the computer, comparing the L*, C* and h* values to previously determined standard values to determine a color grade for the gemstone;
by the computer, determining an average value for each of the parameters for all pixels in the defined area;
by the computer, calculating a color score of the gemstone based on the determined average value for each of the parameters;
by the computer, assessing a color quality of the gemstone by comparing the color score for each of the parameters values of corresponding color scores of one or more control gemstones in the pre-determined category.