The optimization of two color (3∼5um and 8∼12m) sensor fusion

A real time (30 frame) two color sensor fusion method utilizes a dichroic mirror to separate incident radiation into 3-5 and 8-12 mm wavebands. The overlapped thermal images created by the dichroic mirror and optical path difference are shifted and made to coincide together, directly on the focal plane. This is the basis for developing an optical image coincide technology which can replace the conventional circuit of the time delay and integration (TDI). It greatly reduces the deterioration caused by TDI circuits and results in a better image quality. In the experiment, it was found that when several different bandpass filters are inserted into the optical paths, there exists an optimized fusion relationship among the incident power, waveband, detector responsivity and preamplifier gain. if an appropriate adjustment is made the signal to noise ration of the combined thermal can be improved a factor above of 30% or more.