采用卷帘数字域TDI技术的CMOS成像系统设计  

Design of CMOS imaging system based on rolling TDI in digital domain

作　　者：陶淑苹[1,2] 金光[1] 曲宏松[1] 张贵祥[1] 

机构地区：[1]中国科学院长春光学精密机械与物理研究所,吉林长春130033 [2]中国科学院研究生院,北京100049

出　　处：《红外与激光工程》2012年第9期2380-2385,共6页Infrared and Laser Engineering

基　　金：国家自然科学基金青年基金(61008046)

摘　　要：利用FPGA实现面阵CMOS传感器数字域TDI功能,可避免模拟域TDI的复杂电路设计、完善CMOS传感器成像方式、并可改进TDI CCD缺陷,具有重大的研究和应用价值。首先分析了同步快门方式和卷帘快门方式实现TDI的差异,然后根据TDI工作原理,提出了更利于微光成像和推扫成像的卷帘数字域TDI算法,并利用设计的CMOS成像系统进行了成像实验。实验结果表明:卷帘数字域TDI算法正确,不仅可以实现等效于积分时间增加或入射照度增强M倍功能的M级积分,而且可明显改善成像质量,将信噪比为18.37 dB的未积分图像通过10级积分提高至32.65 dB。所提出的卷帘数字域TDI技术使得CMOS相机具备了时间延迟积分功能,改善了成像质量,并改进了TDICCD难以调焦和级数不可连续调整的缺陷。The realization of TDI in digital domain using FPGA for CMOS image sensor can avoid the hard design in simulative domain,consummate the imaging mode for CMOS sensor,and break the limitation of TDI CCD,so it is of great value in researching and application.Firstly,the differences between synchronous and rolling shutter were analyzed.Secondly,a new algorithm called rolling TDI in digital domain was proposed,which was based on the principle of TDI and was better for glimmering and pushbrooming imaging.At last,the algorithm was tested by the designed CMOS imaging system.The experimental result shows that the proposed algorithm is right.Not only the gray level can increase M times after integration,but also the imaging quality can get better.For example,the SNR increases to 32.65 dB when TDI stage is 10,which is 18.37 dB before integration.The research enables CMOS sensor to image in TDI mode,and improves the imaging quality.In addition,it enables CMOS camera to autofocus in real time and change the integration stages continuously,which are the limitations of TDI CCD.

关 键 词：CMOS 卷帘 时间延迟积分 信噪比 推扫 

分 类 号：TP386.5[自动化与计算机技术—计算机系统结构]