Abstract: Automation temperature calibration system based on meteorological measurement issues
such as big noise, low contrast in the image, homomorphic filtering is proposed for contrast limited
adaptive image preprocessing method on the basis of the image preprocessing technology. Try median
filter for infrared image denoising, and use the principle of homomorphic filtering to enhance image
details based on the premise that the noise would not be enhanced. However feature points and
non-feature points are very confusing when the image is very poor quality in the method of
homomorphic filtering, so the method of equalling limited contrast adaptive histogram is used to adjust
the dynamic range of the image. The simulation results verify the feasibility of the method.

Key words: image preprocessing, median filter, histogram equalization, homomorphic filtering, adaptive