To realize the real-time problem of the image enhancement technology in the infrared thermal sight system,a window enhancement method was put forward according to the vision characteristic of human's eye.A proper size sub-image was first taken out of the whole infrared image and the sub-image was then processed with a certain enhancement algorithm,while pixels out of the sub-image were not processed.The hardware processing flow chart was given.It is proved from the analysis that the processing time of backg...