Research On The Image Collection And Processing System Based On The Large Area CCD Camera With Wide Field Of View

When the aerospace camera works for the ground reconnaissance, the target mappingand the other aspect, with the demand for the image information content is more and more great.The large area CCD camera has been gradually applied to the photogrammetry in the aerospace and aviation. Due to the fabrication process restrictions of the large area CCD, multi-chip CCD joint method is the main development direction of the currently advanced aerospace camera. At the same time in many applications, users'demand for the image quality also increasing. At the point of the aerospace camera which is using for the direction of these developments, this paper took the interline CCD KAI-16000 as the study object,in-depth study of the large array CCD high-speed signal processing, the non-uniformity correction of the CCD response, the CCD auto-dimming, and the recovery of the CCD camera image.In the paper, we had the detailed analysis of the interline transfer area CCD KAI-16000's internal structure and working principle.On this foundation we put forward a kind of with high speed image collection scheme including CCD video signal handling and image to postpone store, image transmission and show etc. This scheme supported that the biggest pixel clock of area CCD can reach 27MHz, and the fastest frame frequency can reach 3 frame per second.The reasons, which cause the response non-uniformity of full frame area KAI-16000, were analyzed completely. And a kind of respond non-uniformity detecting system was established. Non-uniformity between the two area CCD and non-uniformity between all pixels had been carried out detection and correction using this system. Two-point correction arithmetic had been put forward for Non-uniformity correction on CCD response degree for linear foundation. After correcting, the standard deviation of response sensitivity reduction arrived original 1/13, and the response non-uniformity of all pixels reduction arrived original 1/10. Non-uniformity of area KAI-16000 had gotten obvious improvement.When the aerospace camera works, we often face to the problem that the image quality has been declined by the too short or too long exposure time. Therefore need to take the camera dimming. Between the lines proposed in this paper we put forward the TDI dimming method which is based on the structure of the interline transfer area CCD,and then we achieve the wide field of large area CCD camera automatically dimming. Experiments proved that: in the dimming mode, the dynamic range of the CCD camera was 20 times larger than the non-dimming mode.At the point of the vignetting phenomenon in the reflection joint,we analysed the vignetting generation mechanism and proposed the model of the vignetting distribution in the middle of the optical field.Using the data from the radialization calibration and the function approximation method to eliminate vignetting phenomenon. We got the optical point spread function by using the Interferometer measurement system.Using the adaptive Wiener filter to eliminate the image quality degradation which is caused by the optical system itself problem.The results of the restoration outfield image indicated that:the PSNR had increased from 26.5dB to 31.6 dB.The definition of the image had promoted obviously.