Pseudo-color coding method of infrared images based on human vision system

Infrared images often display in gray scale. The low contrast and the unclear visual effect are the most notable characters of infrared images that make difficult to observe. It is a fact that gray scale is not sensitive to human eyes, and it has only 60 to 90 just noticeable differences (JNDs). In comparison with gray scale, color scale might give up to 500 JNDs. Usually people can distinguish many kinds of colors much more than grays. And in gray images, human don't have the ability to tell apart the nuances about detail. Pseudo-color coding enhancement is the task of applying certain alterations to an input gray-image such as to obtain color-image that is a more visually pleasing. In this paper, we introduced a pseudo-color coding method based on human vision system for infrared images display. The HSI space is especially fit for human vision system and is viewed as an approximation of perceptual color space. So the pseudo-color coding method introduced is based on HSI space. In the first place, the individual functional relationship of Hue, Intensity, and Saturation with gray scale level is established. In the second place, the corresponding RGB values are obtained through transformation from the HSI color space to the RGB space. Lastly, the effect of Infrared images enhancement based on the pseudo-color coding method is displayed. Results indicate that this method is superior to other methods through the comparison.