Design And Implementation Of Infrared Themral Imaging Instrument Based On ARM9

Uncooled focal plane array thermal imaging system is one of the focused researches in the filed of thermal imaging system. Depending on lower cost, higher dependability, smaller bulk and lower dissipation, the uncooled infrared thermal imaging instrument holds important position in infrared fields.Facing the disadvantages of high-noise, low-contrast, blur, bad vision effect, poor resolving power in the infrared image, unfriendly man-machine interface and low real-time at present, this paper designs and finishes the real-time processing system of the infrared thermograph image based on ARM9, in order to improve the quality of image, enhancing the real-time characteristics and friendly man-machine interface, combining with existed real-time processing arithmetic about infrared image system. In the process of infrared image, the infrared images with big dynamic range, high resolution, poor uniformity, and low background noise. The system uses the Windows CE embedded operating system to enable real-time infrared imaging system has a strong, friendly man-machine interface and so on. Its major works are as follows:Firstly, the article introduces the working principle of the infrared image system and uncooled infrared thermal imaging system, and then discusses the infrared image data uses DMA read under the control design, analyzing the noise in the infrared image and low frequency noise has been eliminated by using median filter and enhancing the neighborhood average which making image smoothly. In order to make out the temperature of the objects from images intuitively, pseudo color transformation has been used on the enhancement of gray image to increase resolving power of human eyes. Histogram equalization has been adopted in the paper in order to make Gray-scale transformation of the infrared image and enhance contrast of infrared images. Aiming at disadvantages of infrared image for the existing file formats and as standardization and BMP Image File Format visible shortcomings, a new infrared image file format was designed. The image gray value and the object relationship were analyzed, the temperature - gray conversion model was found by the calibration blackbody. The temperature measurement function of the algorithm was analyzed and the corresponding function was designed. Three methods to observe the temperature was achieved. Point temperature measurements show that the coordinates of points, and the corresponding gray-scale temperature. Surface temperature shows that the whole lot of infrared thermal image of the overall maximum temperature, minimum temperature, average temperature, the region temperature shows the infrared thermal images any rectangular area within the scope of the maximum temperature, minimum temperature, and average temperature. Due to the defects of infrared detector itself and no uniformity existed in the process of images generated; non-uniformity correction of infrared image has been implemented by making use of non-linear correction method. Finally, the system performance tested.