Study On Image Compensation Technology For Spaceborne Cameras Under Micro-vibration Circumstances

With the developments of the angular resolution of spaceborne cameras, they are getting more and more sensitive to the disturbance of the surrounding environment. The micro-vibration comes from the satellite platform becomes the key factor which affects the imaging quality of these spaceborne cameras. To solve the problem which these micro-vibrations bring, it is necessary to bring in the image compensation system based on optical method, which could compensate the adverse effects directly and effectively.The backgrounds of this paper is briefly introduced, and also the development of modern high resolution spaceborne cameras. A few image compensation methods are compared and the optical compensation method is chosen.The adverse effect which micro-vibrations bring is deeply studied. Starting by analyzing the sources and types of the micro-vibrations, the main source is found which affects the imaging quality of the spaceborne cameras. By mathematical modeling, micro-vibrations effects from different direction, of different type, different frequency and different amplitude are simulated.Movement measurement technology is the front-end technology of image compensation. By comparing a few movement measurement methods, the joint correlation method is chosen to be the appropriate method for spaceborne cameras’ image compensation.A method of electronic joint correlator is introduced, which takes the advantage of volume, weight, power consumption, and also reliability, is a perfect replacement of traditional optical correlators. By reprograming the processor, the calculation process is simplified. The adverse effects are eliminated, and effectively proved by both simulation experiments and semi physical simulation test.To improve the accuracy of the joint correlation algorithm, which could only reach the precision of 1.0 pixel, some improvements have been made and are proved effective by computer simulations and semi physical experiments.The reason of optical compensation can still work under the“Delay Effect”is explained. After series of comparison, it comes to the conclusion of the most appropriate processor for joint correlation algorithm is FPGA chip. The key part of the joint correlation algorithm, 2D FFT is implemented on a FPG chip. The algorithm is simulated as part of a image compensation system, and its effect is proved.