Signal Processing System Design For Scanning Thermal Imager

With the rapid development of science and technology, the infrared thermal imager has been more and more useful, and has shown a large market potential and a bright future. In recent years, the technology has made much progress in advanced countries. However, because of late beginning and technology blockade of foreign countries, the theory research and fabrication process now have much gap compared to the world’s advanced level. So improving the theory and engineering levels of the infrared thermal imager and expanding its application are urgent and essential. As a very important part, the research on the signal processing of scanning IR imager has profound meaning.In this paper, we analyzed the signal processing system in detail on the basis of the feature of 288x4 IR detector and the principle of scanning IR imager. Through the analysis of the thermal imager specification, the technical parameters of the signal processing system are determined and then the specific circuit is designed. In order to design high-performance signal processing system, we analyzed the advantages and disadvantages of various circuits from the points of reliability, electromagnetic compatibility and sensitivity of the product, then the final circuit solution is proposed. The relevant circuits include the low-noise bias voltage supply circuit of the detector, the low-noise preamplifier circuit, the adaptive offset control circuit, the low-noise digital sampling circuit, the non-uniformity correction circuit, the digital signal processing circuit, video conversion circuit and secondary power circuit.The signal processing system is gradually improved by analyzing and solving the problems in the test. The final circuit parameters are determined by a lot of experiments. During the debugging test, we analyzed the existing problems in detail, thus we have a more deep understanding for the design of signal processing system and have a more comprehensive understanding for the design of signal processing system.In the end of this paper, we drew the conclusion. The signal processing system for scanning thermal imager meets the performance requirements, reaching domestic advanced level. The signal processing circuit has certain reference to other infrared imaging system.