Based on the mechanism of infrared image imaging and the working mode of thermal imager,infrared image is often mixed with a lot of random noise,which is an important reason for deterioration of infrared images and videos.Median filter is a common nonlinear filtering method,it has a good effect on image denoising.The size of the processing window of the median filter needs to be set in advance and cannot be changed during the processing,the larger the processing window of the median filter is,the stronger the ability to remove noise,but the more serious the loss of image details.Considering the influence of window size on noise reduction ability and details processing capacity,the algorithm of median filteris improved.Experiments show that in the process of removing noise with median filter,the window size can be dynamically adjusted along with the noise distribution of window image,so as to remove noiseand keep the details of the image as far as possible andto improve the overall effect of image processing.