The Research to Pretreatments of Infrared Images

The contrast is low, and the noise is strong in infrared images, in order to resolve these problems, the Gray Adjustment Act and the Butterworth Filter were introduced. At first, characteristics of infrared images were analyzed. The frequency distribution of the defect region, the transition region and the normal region was concluded, and targets of image processing to every area were designed. According to targets, processing steps were devised and implemented. Through steps, high-frequency signals, from the noise, were reduced and the background of the normal regional was cut down. So fuzzy defect signals became clear, and the contrast of picture was also improved. These were beneficial to automatically calculate and extract defect features.