多TDICCD拼接相机成像非均匀性实时校正的硬件实现

Abstract

A real-time imaing nonuniformity correction algorithm on a Field Programming Gate Array(FPGA) platform was proposed to modify the imaging nonuniformity of a multi Time Delay Intration(TDI)CCD mosaic camera.Firstly,the definition of Photo Response Nonuniformity(PRNU) and its generation in the multi-TDICCD mosaic camera were introduced.Then,the synthetical correction algorithm was presented,in which the two-point correction method was used in a single channel,gain averaging correction method among multi-channels and the scene-adaptive correction method among multi-TDICCDs.By considering the reliability and the influence of finite word-length of the FPGA,the synthetical correction algorithm was optimized and implemented on the signal processing FPGA platform.Furthermore,a scheme for modifying correction factors and spaceborne calibration were given.The experimental results indicate that the imaging nonuniformity can be decreased from 4.82% to 0.27% for a single TDICCD,and to 0.41% for a 3-TDICCD mosaic camera with the proposed correction algorithm.It also proves that this correction algorithm has high real time performance,good practicality and efficiency,and satisfies the requirements of target projects.