Abstract: An apparatus (10) for assessment, evaluation and grading of gemstones has a stage (11) upon which a gemstone may be supported. The stage is enclosed in a housing (15) that is impervious to light. There is at least one light source (14) located in the housing which is adapted to project incident light onto the gemstone. Means for rotating and tilting the stage so as to vary the orientation of the gemstone to the incident light are also present. A digital camera (16) is located in the housing adjacent the or each light source and is adapted to take images of the gemstone based on reflection and/or refraction of the incident light. The apparatus also includes information processing means for calibrating and analyzing the images. The information processing means is programmed with instruction sets for assessing one or more of color, cut, clarity, scintillation, brilliance, lustre, dispersion and sheen. The gemstone is supported upon the stage by securing means (17) engaging the gemstone at its bottom surface.

Abstract: An apparatus (10) for assessment, evaluation and grading of gemstones has a stage (11) upon which a gemstone may be supported, the stage being enclosed in a housing (15) that is impervious to light. At least one light source (14) located in the housing is adapted to project incident light onto the gemstone. There are means for rotating and tilting the stage so as to vary the orientation of the gemstone to the incident light. A digital camera (16) is located in the housing adjacent the or each light source and is adapted to take images of the gemstone based on reflection and/or refraction of the incident light. There are also information processing means for calibrating and analyzing the images, with the information processing means being programmed with an instruction set for color calibrating the images and then analyzing the color calibrated images by segmentation and histogram measurement.

Abstract: An apparatus (10) for assessment, evaluation and grading of gemstones has a stage (11) upon which a gemstone may be supported. The stage is enclosed in a housing (15) that is impervious to light. There is at least one light source (14) located in the housing which is adapted to project incident light onto the gemstone. Means for rotating and tilting the stage so as to vary the orientation of the gemstone to the incident light are also present. A digital camera (16) is located in the housing adjacent the or each light source and is adapted to take images of the gemstone based on reflection and/or refraction of the incident light. The apparatus also includes information processing means for calibrating and analysing the images. The information processing means is programmed with instruction sets for assessing one or more of colour, cut, clarity, scintillation, brilliance, lustre, dispersion and sheen. The gemstone is supported upon the stage by securing means (17) engaging the gemstone at its bottom surface.

Abstract: An apparatus (10) for assessment, evaluation and grading of gemstones has a stage (11) upon which a gemstone may be supported, the stage being enclosed in a housing (15) that is impervious to light. At least one light source (14) located in the housing is adapted to project incident light onto the gemstone. There are means for rotating and tilting the stage so as to vary the orientation of the gemstone to the incident light. A digital camera (16) is located in the housing adjacent the or each light source and is adapted to take images of the gemstone based on reflection and/or refraction of the incident light. There are also information processing means for calibrating and analysing the images, with the information processing means being programmed with an instruction set for colour calibrating the images and then analysing the colour calibrated images by segmentation and histogram measurement.