Abstract: A method for determining a level of solar radiation at a point of interest (POI). Multiple sky images are captured by a distributed network of digital cameras. Sun location parameters are determined. A three-dimensional (3D) sky model is generated based on the sky images. Generating the 3D sky model includes generating 3D object data based on the sky images to model one or more objects in a region of sky, and generating position data to model a position of the one or more objects in the region of sky. A level of solar radiation at the POI is determined based on the position data and 3D object data of the 3D sky model and the sun location parameters.

Abstract: A method for determining a level of solar radiation at a point of interest (POI). Multiple sky images are captured by a distributed network of digital cameras. Sun location parameters are determined. A three-dimensional (3D) sky model is generated based on the sky images. Generating the 3D sky model includes generating 3D object data based on the sky images to model one or more objects in a region of sky, and generating position data to model a position of the one or more objects in the region of sky. A level of solar radiation at the POI is determined based on the position data and 3D object data of the 3D sky model and the sun location parameters.

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.

Abstract: A method of identifying endmember spectral values from multispectral image data, where each multispectral data value is equal to a sum of mixing proportions of each endmember spectrum. The method comprises the steps of processing the data to obtain a multidimensional simplex having a number of vertices equal to the number of endmembers. The position of each vertex represents a spectrum of one of the endmembers. Processing the data is conducted by providing starting estimates of each endmember spectrum for each image data value. The mixing proportions for each data value is estimated from estimates of the spectra of all the endmembers. The spectrum of each endmember is estimated from estimates of the mixing proportions of the spectra of all the endmembers for each image data value. The estimation steps are repeated until a relative change in the regularised residual sum of squares is sufficiently small. The regularised residual sum of squares includes a term which is a measure of the size of the simplex.

Abstract: A method of identifying endmember spectral values from multispectral image data, where each multispectral data value is equal to a sum of mixing proportions of each endmember spectrum. The method comprises the steps of processing the data to obtain a multidimensional simplex having a number of vertices equal to the number of endmembers. The position of each vertex represents a spectrum of one of the endmembers. Processing the data is conducted by providing starting estimates of each endmember spectrum for each image data value. The mixing proportions for each data value is estimated from estimates of the spectra of all the endmembers. The spectrum of each endmember is estimated from estimates of the mixing proportions of the spectra of all the endmembers for each image data value. The estimation steps are repeated until a relative change in the regularised residual sum of squares is sufficiently small. The regularised residual sum of squares includes a term which is a measure of the size of the simplex.