Patent ID: 8705018
Filing Date: 2014-04-22
Classification: G01N

Abstract:
1. An arrangement for determining an optical property of a gemstone, comprising: a holder for holding the gemstone in an upright position in which a table of the gemstone is uncovered; an annular support bounding an interior and having a longitudinal axis, the annular support having an open passage extending along the axis through the annular support between opposite open ends; a plurality of annular frontlights stationarily mounted in the interior of the annular support, the annular frontlights being spaced apart along the axis and being concentric with the axis, the annular frontlights surrounding the open passage at different diameters and being remote from the open passage, the annular frontlights facing the uncovered table of the gemstone for directing light rays at different orientations to the uncovered table of the gemstone for return therefrom as return light; a stationary backlight for directing light toward a culet of the gemstone to illuminate the gemstone; an imager spaced away from the gemstone, and operative for imaging the return light through the open passage as a plurality of frontlit images, and for imaging the illuminated gemstone through the open passage as a backlit image; and a controller for sequentially energizing the annular frontlights along the axis to enable the imager to sequentially image the frontlit images along the axis, and for processing at least one of the frontlit and the backlit images to determine the optical property of the gemstone.