摘要
调制传递函数(MTF)是遥感相机的重要评价指标,但是目前对于数字域TDI CMOS相机动态MTF特性研究十分有限,为了深入研究其像质下降机理,结合数字域TDI CMOS成像原理,建立了像元、电子快门、曝光时间、振动引起的数字域TDI成像MTF下降数学模型。结合推导模型开展了预估分析和实验验证。结果表明:传感器的有效像元区域分布会影响图像MTF,且开口率越小影响越大;CMOS传感器的卷帘快门会导致数字域TDI成像MTF下降,卷帘速度越慢影响越严重,其中卷帘速度从6μs变为10μs时,对应的图像MTF从0.191下降为0.177;曝光时间越短则MTF越高,尤其当存在低频像移失配时更为明显,曝光时间从180μs减小为100μs时,图像MTF从0.126提高为0.155,但同时也会影响图像信噪比,因此在实际应用中应合理选择曝光时间。
The modulation Transfer Function(MTF)is an important evaluation index for remote sensing cameras,but at present,the research on the dynamic MTF characteristics of digital domain TDI CMOS cameras is very limited.In order to deeply research its image quality degradation mechanism,combined with the principle of digital domain Time Delay Integration Complementary Metal Oxide Semiconductor(TDI CMOS)imaging,a mathematical model of digital domain TDI imaging MTF degradation caused by pixel,electronic shutters,exposure time and vibration is established.Combined with the derived model,the prediction analysis and experimental verification are carried out.The results show that the regional distribution of effective pixels of the sensor will affect the image MTF with a greater intluence from smaller opening rates,and the rolling shutter of the CMOS sensor will lead to the decrease of the digital domain TDI imaging MTF with a more serious impact for slower rolling shutter speeds.When the rolling shutter speed changes from 6μs to 10μs,the corresponding image MTF decreases from 0.191 to 0.177.As the exposure time shortens,the MTF grows higher,especially when there is low-frequency image shift mismatch.When the exposure time is reduced from 180μs to 100μs,the MTF increases from 0.126 to 0.155 with some influence on the image signal-to-noise ratio.Therefore,the exposure time should be reasonably controlled in practical applications.
作者
陶淑苹
冯钦评
陈晓龙
郑亮亮
张紫玉
高倓
TAO Shu-ping;FENG Qin-ping;CHEN Xiao-long;ZHENG Liang-liang;ZHANG Zi-yu;GAO Tan(Changchun Institute of Optics,Fine Mechanics and Physics,Chinese Academy of Sciences,Changchun 130033,China;University of Chinese Academy of Sciences,Beijing 100049,China)
出处
《中国光学（中英文）》
EI
CAS
CSCD
北大核心
2022年第5期983-991,共9页
Chinese Optics
基金
国家自然科学基金项目(No.62075219)
吉林省重点科技研发计划项目(No.20220201076GX)。
