【作者】 张宇；

【导师】 任建岳；

【作者基本信息】 中国科学院研究生院（长春光学精密机械与物理研究所） ， 光学工程， 2010， 博士

【摘要】 随着航空航天相机在对地侦察、目标测绘等方面对图像信息量的需求越来越大,大面阵CCD相机已经逐步应用到航天和航空摄影测量中,由于目前大面阵CCD制作工艺的限制,多片大面阵拼接的方法成为目前先进航空航天相机的主要发展方向。同时在很多应用中,用户对图像质量的要求也越来越高。针对航空航天相机的这些发展方向,本文以行间转移型面阵CCDKAI-16000作为研究对象,深入研究了大面阵CCD高速信号处理、CCD响应非均匀性校正、CCD自动调光、CCD相机图像恢复等问题。详细分析了行间转移面阵CCDKAI-16000的内部结构和工作原理,设计了满足大面阵行间转移CCD的驱动电路。在此基础上提出了一种高速图像采集方案,包括CCD视频信号处理、图像缓存、图像传输和显示等。该方案支持最大像素时钟可以达到27MHz,最大帧频可达每秒3帧的双面阵CCD拼接成像系统。深入分析了行间转移面阵CCDKAI-16000响应非均匀性产生的原因,并建立了一种响应非均匀性检测系统。利用该系统分别对双面阵片间的非均匀性和每个像元之间的非均匀性进行了检测,在CCD响应度为线性的基础上,提出了两点校正算法并对非均匀性进行了校正。通过校正,片间响应灵敏度的标准偏差降低到校正前的1/13,所有像元之间的响应非均匀性降低到校正前的1/10,双路面阵CCD的非均匀性得到了明显的改善。在航空航天相机拍摄过程中,常常遇到由于曝光时间不足或曝光时间过长而导致图像质量下降的问题。因此需要对拍摄中的相机进行调光。本文提出了基于行间转移面阵CCD结构的TDI调光方法,实现了宽视场大面阵CCD相机自动调光。实验证明:在调光模式下,CCD相机动态范围比无调光模式增大20倍。针对反射镜拼接过程中渐晕现象,分析渐晕产生机理,提出了反射镜拼接结构中视场中心渐晕光场分布数学模型,利用辐射定标数据,采用函数逼近法消除渐晕现象,改善图像质量。利用干涉仪测量光学系统点扩散函数,采用自适应维纳滤波方法,消除光学系统自身降质给图像带来的退化,对外场成像图片进行恢复结果表明,图像PSNR由26.5dB上升到31.6dB。图像清晰图明显提升。更多还原

【Abstract】 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.更多还原