Synthesis Of Infrared Spectral Signatures

A method is presented for synthesis of the spectral dependence of infrared sources. Blackbody sources of different temperatures are used as basis functions in this synthesis. The basis functions are linearly combined with appropriate weighting coefficients to approximate the desired spectral distribution. We demonstrate the method by synthesizing blackbody functions of certain temperatures that are not one of the basis functions. The parameters to be determined in the synthesis are the temperatures of the basis functions and the values of the weighting coefficients. Realistic hardware constraints are imposed, such as quantization of the weighting coefficients and the use of a limited number of basis functions. The error in the synthesis is determined as a function of the number of basis sources. The use of four sources was found to be a good compromise, with approximately a 4% error over the 3 to 5 μm band