【作者】 隋修宝；

【导师】 陈钱；

【作者基本信息】 南京理工大学 ， 光学工程， 2009， 博士

【摘要】 非制冷凝视红外技术是当今发展迅速的、军民两用的高科技技术之一,近年来西方发达国家在该技术的研究上取得了很大的进步,但是仍然存在着以下两方面的问题：一,非制冷凝视焦平面探测器没有完整的(自红外目标温度至焦平面探测器模拟输出)数学模型,因此在工程应用中存在着诸多不便；二,非制冷凝视焦平面探测器因材料、制作工艺以及红外光学系统衍射极限等的限制,输出的红外图像的温度分辨率和空间分辨率都不高。同时,由于国内该领域的研究工作起步较晚,以及国外对技术的长期封锁,我国现阶段的非制冷凝视成像技术的理论研究和制作工艺等与国外发达国家相比还有一定的差距,因此,从非制冷凝视红外焦平面探测器的理论出发,建立完整的数学模型,提出更好的技术和方案并最终研制出高性能的热像仪,对弥补非制冷凝视红外热像仪普遍存在的性能缺陷、提高我国红外成像电子学理论与工程水平、加快非制冷红外成像技术在我国国防建设和国民经济各领域的应用步伐都有着非常重要的意义。本论文从研究非制冷凝视红外焦平面探测器的各种热探测机理以及现有的读出电路出发,对ULIS公司微测辐射热计—320×240非制冷焦平面探测器的原理以及读出电路模型进行分析推导,最终建立了以红外目标温度为自变量、以焦平面探测器模拟输出电压为函数值的非制冷凝视红外焦平面探测器的数学模型。从微扫描技术的原理出发、经过严格的理论推导和实验仿真,验证了微扫描技术在提高红外图像空间分辨率上的重要作用；通过分析国内外主要的微扫描成像的技术方案以及各自的技术难点和优缺点,提出了用圆弧代替阿基米德螺旋线和类离散扫描的改进平板光学元件微扫描方案；根据平板光学元件的微扫描原理,建立了平板光学元件微扫描的锗片倾斜角度模型。从影响信号完整性的因素出发,以非制冷红外焦平面模型的相关结论为指导,提出了低噪声偏置电压以及高精度数字信号处理技术,该技术的理论推导和仿真结果均表明其能够有效抑制偏置电压噪声,保证信号的完整性和稳定性；为解决红外热像仪温度分辨率不高的问题,本论文提出了红外焦平面阵列自适应数字化技术和自适应偏置电压技术,并通过理论计算以及与直方图均衡等软件算法相比较的方法,证明了该技术对提高红外图像的温度分辨率的作用；针对红外图像信噪比不高的特点,提出了红外焦平面阵列多次采样滤波技术,理论分析表明,该技术能够在单帧条件下通过对同一像元点多次采样的方式降低红外图像的随机噪声和红外图像的NETD。在微扫描理论、方案以及锗片倾斜角度模型的指导下,从光学系统对微扫描的性能以及热像仪灵敏度的影响出发,选择了昆明北方光电公司生产的型号为KIR0742的红外镜头；从锗片制作成功率、安装角度不同的锗片与光学系统配合后给微扫描系统带来的总误差出发,确定了锗片厚度和最佳安装角度；为了降低微扫描器的转动惯量、提高其运行的稳定性以及尽量简化锗片的安装、增加其牢固性,对微扫描窗口尺寸以及锗片形状进行了优化；设计了微扫描器的支撑圆盘结构,并利用机械卡槽来保证微扫描器锗片的倾斜角度；为方便、准确地识别微扫描热像仪不同位置的子图像,设计了在微扫描器框架边缘留有不同长度的薄片并配合光藕进行识别的方案；根据微扫描器对驱动电机轴窜动量和扭转力矩的要求,选择了Faulhaber3863H024C无刷直流电机及其相关产品,理论计算出了该电机在进行“加速一减速一匀速”的微扫描运行方式时对微扫描热像仪像旋的降低幅度,并通过实验对微扫描器在驱动电机带动下运行的稳定性进行了测试,证明了微扫描器的设计和驱动电机的选择的合理性。本论文最后对非制冷凝视红外焦平面探测器的数学模型、高性能驱动电路技术、微扫描成像理论、方案、锗片倾斜角度模型和微扫描实现技术进行了效果验证和性能评估,通过对主观图像效果、客观NETD、MRTD、MTF参数的对比得出结论：1)当黑体温度在焦平面探测器衬底温度之上90K范围内时,测试数据和焦平面探测器模型推导出的数据能够较好吻合；当黑体温度高于这个范围并逐渐增大时,测试数据和模型推导出的数据之间的偏差也逐渐增大；2)低噪声偏置电压以及高精度数字信号处理技术、红外焦平面阵列自适应驱动技术、红外焦平面阵列多次采样滤波技术均能提高红外图像的温度分辨率；3)微扫描实现技术能够提高红外图像的空间分辨率。由此证明本论文的理论和关键技术的研究对提高红外图像性能有着重要意义。文章最后结合本论文研究的不足之处给出了今后的研究方向和研究展望。更多还原

【Abstract】 The uncooled staring infrared technology is one of the high-techs which dual used for both military and civilian. Although it has been made great progress in recent years abroad, there are still two main problems left to be resolved:1. Uncooled staring focal plane detectors are inconvenience for using because of the absence of the complete mathematical model; 2.Because of the restrictions of materials, production processes, as well as diffraction limit of the infrared optical system, temperature resolution and spatial resolution of infrared image are not high. Meanwhile, due to the technology blockade and the late-start research in our country, the theoretical research and the production technology are relatively backward; there are still certain gaps between domestic and abroad in the technology of uncooled staring imaging. Therefore, we have to establish a complete mathematical model of the uncooled staring infrared focal plane array detector based on the theory, come up with a better technology and programs and eventually develop a high-performance thermal imager, which effectively resolve the common problems exist in the uncooled infrared detector, and improve the electronic theory of infrared imaging and the engineering level, and it also contains great significances in speeding up the uncooled infrared imaging technology in China’s national defense building and the pace of national economy in various fields of application.In this dissertation, by researching various thermal detection mechanisms of the uncooled staring infrared focal plane array detector and the variety of existing ROIC, I finally established a mathematical model of uncooled staring IRFPA which sets the infrared temperature as the variable, and the FPA analog output voltage of the detector as function value through the derivation of the uncooled FPA theory and the model of ROIC of the ULIS’s 320×240 microbolometer. I also proved that microscanning technology played a crucial role in enhancing the spatial resolution of IR images based on the theory of microscanning technology and the simulation results. By studying the major advantages and disadvantages along with the difficulties in microscanning imaging technology between domestic and international programs, I brought up an idea of taking place of the lieu of Archimedes spiral with circular lines and the discrete scanning mode to improve scanning program of the flat-panel elements. Due to the research on the microscanning principle of flat-panel optical components, I established a model of microscanning tilt angle of flat-panel optical components. Under the guidance of the relevant conclusions of uncooled infrared focal plane model, I put forward a low-noise bias voltage and high-precision digital signal processing technology with the concern of the affections on signal integrity. The theory derivation and the simulation results showed that this technology can inhibit the noise of bias voltage and ensure the integrity as well as the stability of the signal. From the characteristic that IR imager has low temperature resolution and high NETD, I raised the IRFPA adaptive digital technology and the adaptive bias voltage technology and IRFPA multi-sampling filtering technique, and proved that this technology really improved the temperature resolution of infrared image through the method of comparing the theoretical calculations and software algorithms such as histogram equalization, meanwhile, the IRFPA multi-sampling filtering technique can reduce random noise of infrared image and infrared images’NETD through the way of multiple sampling the same pixel points under the single-frame condition. Considering the two aspects of either the affection to the microscanning performance or the sensitivity of IR imager, I chose the KIR0472 IR lens manufactured by Kunming North optic-electric co., ascertained the thickness and the best installation angle of Germanium chip from the success rate of production, installation angle and total error brought by the optical system to the microscanning system under the guidance of microscanning theory, scheme as well as the model. Meanwhile, by optimizing the microscanning window size and the shape of microscanning germanium chip, I studied and optimized the design of disc supporting structure of the micro-scanner, and eventually used the slot machine to determine the structure of installation angle of micro-scanner germanium-chip from the consideration of the reduce of the micro-scanner’s moment of inertia, conveniently and solidly installed the germanium chip, and stably run the micro-scanner. I put forward a recognition method which suggested that there should be different thin slices with different lengths around the framework’s edge of micro-scanners and matched the optical-couple from the convenient and accurate identification of microscanning sub-image starting at different positions. The Faulhaber 3863H024C BLDCM and relevant productions were selected referring to the requirements of the drive motor shaft string momentum and reversing the torque of the micro-scanner. Through the theoretical calculation of the motor’s speed up-slow down-uniform microscanning operation mode of microscanning thermal imager was likely to reduce the degree of image rotation, and through the test of the micro-scanner’s stability under the driving motor, the rationality of the design of micro-scanner and the choose of driving motor has been established.I did specific verification and assessment about the entire mathematical model, high-performance driving technology, microscanning imaging theory and the realization mentioned in this dissertation. Through the compare of the subjective image and the objective NETD, MRTD, MTF parameters, I concluded that:1) When the black body temperature is 90K above the temperature of the substrate’s focal plane, the test figures were anatomized to the theory model; while the temperature went high, the deviation got stronger.2)The low-noise bias voltage and high-precision digital signal processing technology, IRFPA adaptive driving technology, IRFPA multi-sampling filtering technique can increase the temperature resolution of infrared images.3) Microscanning technology can improve the spatial resolution of infrared images. So all the theories and the key techniques will significantly enhance the performance of IR image. At the end of the dissertation, I offered the inadequacies during my research and the prospection of the research in IR imaging.更多还原