【作者】 张震；

【导师】 姜宗福； 程湘爱；

【作者基本信息】 国防科学技术大学 ， 光学工程， 2010， 博士

【摘要】 可见光CCD已被广泛应用于科研、生产、生活及国防等各大领域,在探测、识别、鉴定、照相、跟踪、遥感和侦查等方面发挥了重大作用。然而,在可见光CCD受到激光辐照时,它的图像传感性能将会暂时下降或丧失,这就是可见光CCD的激光致眩效应。发掘激光致眩现象并深入剖析其机理有助于正确认识可见光CCD因受强光辐照而输出的失真图像;有助于对可见光CCD进行防护;还有助于对它进行主动干扰。本文基于对可见光CCD基本结构、工作原理和常用技术的理解,主要对其激光致眩现象和机理进行了一系列研究。研究内容如下:1.基于体沟道CCD包含信号电荷状态的一维解析模型,给出了耗尽层尺寸随信号电荷量变化的函数关系。利用该函数给出了沟道电势和表面电势等重要参量随信号电荷量的变化公式。利用这些公式,分析了体沟道CCD电荷处理容量的有限性。2.根据线性工作状态下光强正比于其图像灰度值的设计思想,建立了一种获取精确的CCD图像饱和阈值的方法。在此基础上,给出了测量CCD芯片在强光区间(下限高于图像饱和阈值)内光强响应曲线和利用该曲线确定CCD芯片饱和阈值的方法。分析给出了CCD强光响应曲线中芯片饱和区域仍缓慢上升的原因。3.发现了CCD视频中两个关于串扰的新现象:串扰线缺口和非对称的传统串扰线。利用一种新的串扰机制解释了这两种现象的成因。将这种新的串扰机制和传统串扰机制分别称为第一类和第二类串扰。基于第一类串扰机制,指出了在某些特定条件下,在激光开始或停止照射的场图像中存在光斑单侧串扰线的现象,并通过实验对此进行了验证。实验复现了两种由前人发现但未经解释的串扰现象:均匀串扰线和漂移小光点现象。利用第一类串扰机制对它们进行了解释。文中将这种漂移光点称为次光斑,给出了次光斑距离公式和移动方向判定条件公式,距离公式计算结果与实验结果一致。4.发现了可见光CCD的过饱和效应。实验发现了CCD过饱和效应的特征图像和特征波形。揭示了过饱和效应产生的内在机制。建立了CCD检测电荷的等效电路,并根据所提出的过饱和内在机制,利用等效电路对过饱和波形进行了仿真;给出了过饱和效应光强阈值的量级估算方法。5.发现了三种由CCD常用技术或工作体制所引起的特殊激光致眩现象:光斑振荡现象、线阵CCD旁光斑现象和TDI-CCD视频条纹现象。研究确认了与这三种特殊致眩现象相关的技术和工作体制;给出这些现象产生的具体原因。对于条纹现象,本文还给出了条纹宽度、间距宽度和可见度的计算分析公式,条纹宽度及间距公式的计算结果及可见度公式分析结果与实验结果一致。结合CCD黑体基准技术,给出了面阵CCD基于串扰的一种暂时性全黑屏机制。给出了光斑所在背景图像全部丢失现象的产生原因。更多还原

【Abstract】 Visible light CCD is widely used in many scopes such as scientific research,production,living and national defense etc. It plays an important role in many aspects such as detection, recognition, identification, taking pictures, tracking, remote sensing, and inspection, etc. However, when irradiated by intense light,for example laser, its performances will temporarily decline or loss. This is named as laser dazzling effect. To discover the phenomena of the laser dazzling effect and study its mechanism can help us to understand the distortion picture of CCD, prevent the CCD from being dazzled by intense light, and disturb the enemy CCD.On the basis of knowing enough about the basic structures, work processes and normal technology of CCD camera, this dissertation gives a series of study mainly on its laser dazzling phenomena and mechanisms. The contents of work are introduced briefly as follows:(1)Based on one dimensional analytical model of body-channel CCD containing charge package, relational expression between depletion layer dimension and quantity of signal charge had been given, by which the voltages in channel and surface were expressed. Using them, the thresholds of signal charge that could be manipulated by CCD had been analyzed.(2)According to the proportional relation between the light density and grey value under the linear state, a method to measure light density exact threshold of CCD video saturation was built, on the basis of which, the methods to measure the intense light response curve of CCD chip and to determine the light density saturation threshold of CCD chip using the curve were built. The reason of slow rise in the saturation scope of the response curve was given.(3)In experiment, we two new phenomena about crosstalk: the gap on crosstalk line and nonsymmetric traditional crosstalk line. We used a new crosstalk mechanism to explain the two phenomena. This new mechanism and traditional crosstalk mechanism were separately named as the first and second crosstalk. Based on the first crosstalk, the unilateral crosstalk line in some special situation was predicted and confirmed in experiment. The even crosstalk line and small moving spots phenomena were reproducted in experiment and were explained using the first crosstalk mechanism. These moving spots were named as subordinate sopts. Their distance formula and the moving direction determinant formula were given. The distance formular was confirmed by experiment results.(4)We discovered the excessive saturation effect of visible light CCD. In experiment, the characteristic video and waveform of excessive saturation effect had been discovered. Its intrinsic mechanism had been given. The equivalent circuit of CCD charge measurement was built. Using it, based on the mechanism, the characteristic waveform had been simulated. And based on the intrinsic mechanism, the method to estimste the order of light intensity threhold of excessive saturation effect of CCD had been given.(5)We discovered three special laser dazzling effects that are induced by the usual technology and operation manner used in CCD system: spots vibration of planar CCD, side spots of linear CCD and fringes of TDI-CCD. We cognized the technologies related to the special dazzling phenomena and gave the detailed reasons of the phenomena. About fringes phenomenon, the formulas of their width, space width and visibility have been given.These formulas have been confirmed by experiment results.Combining a black reference technology, we gave the reason of temporary blank screen caused by crosstalk in planar CCD. The reason of background image loss except spots was given.更多还原