In satellite images, the true color of a body of water, or anything else they depict, is not precise. Radiometric calibration, which improves the color accuracy of an image and enables it to be used to solve remote sensing problems, has always been a costly endeavor. A cooperative effort between Stennis Space Center and Innovative Imaging and Research Corporation (I2R), a small business located on the center's campus in southern Mississippi, is changing that. I2R has built a better, more efficient, and cheaper integrating sphere, a hollow globe whose internal surface is coated with a highly reflective white coating that diffuses light equally in all directions. The result is a uniform glow with no discernable features that gives a feeling of disorientation looking into it. It's this blank uniformity that allows the operator to know that when a camera looks into the sphere, precisely the same wavelengths of light are hitting every pixel in the camera's focal plane with equal intensity. Then, the sensitivity of each of the individual photodetectors in the camera is adjusted until the resulting image reproduces the constant field of light in the integrating sphere.
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