Ferroelectric Uncooled Irfpa Real-time Imaging Systems And Adaptive Nonuniformity Correction Algorithm Research

Infrared thermal imaging technology is the main stream of night vision technology. It is wildly used in military and civil field as a technology for detecting and distinguishing target. The pyroelectric FPA is the main stream of uncooled ferroelectric focal plane array nowadays.But the imaging quality of the pyroelectric FPA's imaging system has been badly corrupted by the ununiformity. It is hard to meet the requirement of practicality. Improving the manufacture level of the detector is a simple solution, however, the investment is huge and the benefits are not immediate Nonuniformity correction (NUC) techniques in real time have been developed and implemented to solve this problem. These correction techniques can be divided into two primary categories: 1) reference-based correction using calibrated images on startup and 2) scene-based techniques that continually recalibrate the sensor for parameter drifts. Reference-based NUC methods require to halt the normal operation of the system, and they also need a very expensive setup. For these reasons, Scene-Based NUC techniques are actually becoming more popular. The scene-based technique most referred is the one based in the constant statistics constraint. The constant-statistics constraint provides a method for correcting gain and offset errors without using special calibration images and procedures. More important is the constant-statistics constraint algoritym is easy to integrate on IRFPA chip.The subject of my research is: sample an infrared image sequence using infrared imaging system baseded on DSP & FPGA, and verify the theory and application performance of constant-statistics constraint algoritym on MATLAB and Cadence platform in order to lay theories foundation for integratting CS algoritym correction circuit on IRFPA chip.Firstly , the paper start with the fundamental theory , rectifying to fundamental imaging principle of the infrared thermal system, uncooled ferroelectric infrared technique and nonuniformity correction algorityms of pyroelectric FPA. Secondly, the designed real time infrared image system based on DSP & FPGA has been introducted in detail from the hardware structure and software structure. In the system, DSP has realized the image processing and the master control core function of the system processing flow , FPGA has realized data collect, data change and store up, display and the auxiliary control function of the system processing flow. Finally, the principle of constant-statistics constraint algoritym have been studied . Using the collected infrared image sequence , the theory of CS algorithm's correctness and validity have be carried out verification on MATLAB digital simulation platform; the CS algorithm correction circuit has been designed and the feasibility of integratting CS algoritym correction circuit on IRFPA chip has been carried out verification on Cadence simulation platform. Simulated result has been indicated tOhe circuit's function attained the desired effective. The circuit can adopt 0.5μm CMOS handicraft to carry out the hardware circuit realization.