An important component of camera calibration is to derive a mapping of a camera’s output RGB to a deviceindependent color space such as the CIE XYZ or sRGB6. Commonly, the calibration process is performed by photographing a color chart in a scene under controlled lighting and finding a linear transformation M that maps the chart’s colors from linear camera RGB to XYZ. When the XYZ values corresponding to the color chart’s patches are measured under a reference illumination, it is often assumed that the illumination across the chart is uniform when it is photographed. This simplifying assumption, however, often is violated even in such relatively controlled environments as a light booth, and it can lead to inaccuracies in the calibration. The problem of color calibration under non-uniform lighting was investigated by Funt and Bastani2,3. Their method, however, uses a numerical optimizer, which can be complex to implement on some devices and has a relatively high computational cost. Here, we present an irradiance-independent camera color calibration scheme based on least-squares regression on the unitsphere that can be implemented easily, computed quickly, and performs comparably to the previously suggested technique
Presented at IS&T/SPIE ELECTRONIC IMAGING, 2-6 February 2014, San Francisco, California, United States
Pouya Bastani, Brian Funt, "Simplifying irradiance independent color calibration," Proc. SPIE 9015, Color Imaging XIX: Displaying, Processing, Hardcopy, and Applications, 90150N (3 February 2014) https://doi.org/10.1117/12.2042507
Proceedings of SPIE. Color Imaging XIX: Displaying, Processing, Hardcopy, and Applications
Simplifying Irradiance Independent Color Calibration
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