Design Of Uncooled Infrared Imaging System And Evaluation Of Image Quality

Uncooled infrared thermal imaging system has become one of the main research directions of the thermal imaging field because of its small volume, low cost, low power and high reliability. Nowadays the foreign countries take the lead in this area, but with increasing efforts of the domestic research institutions, the technology gap between domestic and overseas is gradually reduced. In this dissertation, an uncooled infrared thermal imaging system has been designed based on the GWIR 02 02 XI AD which is a domestic uncooled infrared focal plane produced by North Guangwei. This uncooled thermal imaging system has completely independent intellectual property rights.Based on the performance characteristics and technical requirements of the focal plane, a high stability and high precision drive circuit for GWIR 02 02 X1AD is designed, including the focal plane power supply circuit, two-way adjustable bias circuit, and temperature control circuit based on TEC module. In addition, the image signal processing and real-time displaying hardware system is designed, which includes the detector output analog signal conditioning circuit, analog-to-digital conversion circuit, the main processing circuit based on FPGA and memory expansion circuit, and video output synthesis circuit. The miniaturization of high speed PCB design has also been completed according to the requirement of system miniaturization. In the end, the system drive software based on FPGA is designed which includes sensor’s configuration and OCC timing, I2C communication and PAL video synthesis timing.To improve the infared image quality the algorithms that aiming at solving the problems of thermal image nonuniformity, blind pixel and low contrast has been researched in this dissertation. Base on this, the two-point nonuniformity correction algorithm, dynamic blind replacement algorithm and double platform histogram equalization algorithm are implemented on FPGA. Video signal successfully displayed on the displayer after been processed and synthesised by FPGA. In the end, the evaluation methods of image quality are researched, and by choosing appropriate image evaluation index the experiments aiming at evaluate the image quality of the system designed in this dissertation has been completed on Matlab.