US 12,270,765 B2
Apparatus and method for assessing optical quality of gemstones
Hiroshi Takahashi, Morristown, NJ (US)
Assigned to Gemological Institute of America, Inc., Carlsbad, CA (US)
Filed by Gemological Institute of America, Inc., Carlsbad, CA (US)
Filed on Jan. 24, 2024, as Appl. No. 18/421,823.
Application 15/588,389 is a division of application No. 14/673,776, filed on Mar. 30, 2015, granted, now 9,678,018, issued on Jun. 13, 2017.
Application 18/421,823 is a continuation of application No. 17/670,411, filed on Feb. 11, 2022, granted, now 11,921,051.
Application 17/670,411 is a continuation of application No. 16/697,164, filed on Nov. 26, 2019, granted, now 11,280,743, issued on Mar. 22, 2022.
Application 16/697,164 is a continuation of application No. 15/588,389, filed on May 5, 2017, granted, now 10,533,951, issued on Jan. 14, 2020.
Prior Publication US 2024/0159683 A1, May 16, 2024
This patent is subject to a terminal disclaimer.
Int. Cl. G06T 7/90 (2017.01); G01N 21/25 (2006.01); G01N 21/87 (2006.01); G01N 33/00 (2006.01); G01N 21/88 (2006.01)
CPC G01N 21/87 (2013.01) [G01N 21/255 (2013.01); G01N 33/389 (2024.05); G06T 7/90 (2017.01); G01N 21/88 (2013.01); G01N 2201/061 (2013.01); G01N 2201/0631 (2013.01); G01N 2201/0634 (2013.01); G01N 2201/0638 (2013.01); G01N 2201/065 (2013.01)] 16 Claims
OG exemplary drawing
 
1. An apparatus for assessing a color characteristic of a sample gemstone, comprising:
an optically opaque platform configured for supporting a sample gemstone;
a light source configured to provide uniform diffused illumination to the sample gemstone on the platform;
a camera, wherein the camera and platform are configured to rotate relative to each other and capture color images of the sample gemstone; and
a computer with a processor and memory in communication with the camera, the computer configured to:
(i) determine a proportion or shape characteristic of the sample gemstone based on a plurality of color images captured by the camera, wherein each image of the plurality of color images includes a full image of the sample gemstone, taken at different image angles, and comprises a plurality of pixels;
(ii) convert color component values for individual color components in at least a portion of the plurality of pixels in an area in each image of the plurality of color images to one or more parameters representing a pixel color characteristic of each pixel;
(iii) determine an average parameter value for each of the one or more parameters for the portion of the plurality of pixels in the area in each image of the plurality of color images;
(iv) calculate one or more color scores of the sample gemstone based on average parameter values of the one or more parameters of all the plurality of pixels in the area in the plurality of color images; and
(v) assign a color grade to the sample gemstone by comparing the one or more color scores to control values of corresponding control color scores of one or more control gemstones.