Path planning for inner-element aniformity test of multi-element infrared detector

An ap proach of path planning for inner -element uniformity auto -test of multi -element infrared detector was proposed based on a single element's response to the infrared spot scanning, which formed the central line of the special distribution formed by the signal intensity. The method could be used to locate the element path. According to the alignment of infrared spot and the center of sensitive surface of multi -element infrared detector, the 2 -dimension distribution of an element output signal intensity was obtained by infrared spot scanning on the sensitive surface which was on the mobile station of high precision 6 -degree -of -freedom. The response signal intensity distribution was analyzed; a conclusion was that both the edge points of a response signal can be obtained through extremum of 3rd order derivative. Projecting the signal intensity distribution on to a 2-dimention image, the gray intensity of which was in accord with the signal intensity. Every order derivative of the projected signal could be easily obtained by convolution with 1st, 2nd, and 3rd order derivative of Gaussian convolution kernel separately, while the edge points of each section was extracted. The center points can be calculated by arithmetic mean of two edge points, and the central line of the 2-dimensional distribution band can be fitted, which was also the scanned inner-element length direction. According to this direction and topology of elements, the auto scanning path for testing the inner-element uniformity was planned. Finally, an experiment was presented. Results show that the proposed approach advances the efficiency and accuracy of inner-element uniformity testing of multi-element infrared detector.