Radiometry calibration system and method for electro-optical sensors

摘要

A system (100) and method for focal plane array calibration using an internal non-uniform calibration source (30). In the illustrative embodiment, the system (100) includes a first mechanism (16) for calculating a relative gain of each detector element in the focal plane array (20) relative to at least one reference element, a second mechanism (17) for obtaining the absolute gain of the reference element, and a third mechanism (18) for calculating the absolute gains for all other detector elements using the relative gains in conjunction with the absolute gain of the reference element. The relative response of each pixel is calculated from measurements of the response of each pixel using an internal calibration source (30) at two or more different source positions, and two illumination intensities at each position. Measurements using a pair of source positions separated by k pixels establishes the relative response of the i^th pixel with respect to the (i+k)^th pixel. Through this recursive relationship and other pairs of source position with a different shift vector k, the relative response of every pixel in the FPA can be established. Then, the absolute radiometric calibration of at least one reference pixel is accomplished using a known external source (40), such as a star. The absolute response calibration of each pixel can then be obtained using the recursive relationship in combination with the reference pixels.