Uncooled Infrared Thermal Imaging System Miniaturization

The infrared thermal imaging technique has been widely applied in military and civilian affairs. Relying on its virtues such as small volume and weight, high reliability and performance-cost ratio, uncooled infrared imaging system plays an increasingly important role in the fields of watching and searching targets. On the basis study of present situation in our country, using an infrared focal plane arrays (IRFPA) from France, this paper develops an uncooled infrared thermal imaging system, which satisfied military requirements of our country.According to the general situation of domestic and international infrared thermal imaging technique, this paper analyzes infrared imaging principles, factors affecting imaging systems' performance and working course of microbolometer IRFPA, studies characteristics of infrared image and influencing factors to infrared imaging quality, discusses the contents of nonuniformity correction, blank pixels' replacement and image enhancement, which provides theoretical guide for the uncooled infrared thermal imaging systems' design. This paper adopts the SOPC technology, constructs based on FPGA, proposes the complete miniaturized infrared thermal construct system solution, and expounds function modules design in system, including the IRFPA driving circuit, TEC temperature control circuit, signal processing circuit based on FPGA, A/D data acquisition circuit, D/A video conversion circuit and power circuit. The signal processing circuit is the core of the infrared imaging system, which realizes many functions such as system clock management, real-time signal processing, histogram statistics and video frequency synthesis. The real-time signal processing module is based on the pipeline structure, which integrates nonuniformity correction, blank pixels' replacement and image enhancement in a pipeline. The multi-temperature-point TEC controlling circuit ensures the image's quality and solves the problem of power increasing when the temperature difference between IRFPA and environments increases. Then, this paper finishes the PCB design based on schematic diagram, which has considered system's signal integrity and the power source integrity. The infrared imaging system realizes the image formation after completing software disposition and system software and hardware debugging.