The Research And Design Of Optical Signal Processing Subsystem In PAT System Of Space Optical Communication Based On DSP

A research and design of optical signal processing subsystem in PAT system of space optical communication is proposed in this dissertation. The subsystem can extract the image position error signal of beacon beam that supplies the input signal of the latter serving system. According to the current high real time peculiarity and high precision demands of beacon beam processing subsystem of space optical communication and the requirements of our project, the method that uses digital signal processor (DSP) to solve the image position error signal extraction of beacon beam is proposed in this dissertation. It have the following advantages: the small system volume, the slight weight, the small power, the high real time peculiarity and the high precision and so on. The combination of hardware and software accelerates the image processing. The part of hardware includes mainly the module of image acquisition, the module of video A/D, the module of image buffer, the module of interface logic control, the module of image processing based on DSP and the module of power management. The hardware modules accomplish the image acquisition, digitization, buffer and processing. In order to improve the real time peculiarity of the subsystem and achieve the synchronization of image acquisition and processing, the subsystem adopts double FIFO buffers of pingpong structure, and devises the fake reading mechanism of DSP to simplify the logic control circuit of double FIFO buffers of pingpong structure. The part of software includes mainly the initialization program for resetting, the interruption table, the core algorithm of image processing and command file. The software modules accomplish the image pre-processing and the high speed and high precision locating of beacon beam. The core algorithms of image processing actively research the algorithms including object searching, threshold partition, object recognition, object locating and object tracking. At last, the testing model of the subsystem is devised, and the result is given, furthermore the real time peculiarity of the subsystem is evaluated in the dissertation.