红外成像寻的用双色凝视焦平面探测器设计的基本要求

文中讨论了红外成像寻的器用红外焦平面探测器的工作波段、阵列结构、规模、相对孔径等问题,提出双色凝视红外焦平面探测器设计的基本要求: (1)波长组合以相邻波段为宜;(2)双色FPA以叠层结构的凝视型为宜; ( 3)通过限制红外成像传感器的视场,将双色凝视FPA的规模控制在320 ×256以下为宜; (4)在探测元尺寸50μm ×50μm时,中波/长波双色凝视FPA的F数以1～2. 44为宜。     

一种红外引导激光指向双模复合探测技术研究

随着红外光电系统由扫描型发展为凝视型,搜索范围大大增加,但仅得到目标的二维信息,如能与激光主动探测结合,得到角度-角度-距离的三维信息,可实现两者优势互补。提出了一种基于压电倾斜镜(PFSM)的具有指向功能的激光主动探测技术,与凝视型红外相机实现双模复合探测,对目标进行精密跟踪。对其视场、线性度进行了分析和系统测试,所得结果与计算结果相符。     

HgCdTe分子束外延In原子的掺杂特性

报道了用 MBE方法生长掺 In N型 Hg Cd Te材料的研究结果。发现 In作为 N型施主在 Hg Cd Te中的电学激活率接近 1 0 0 % ,其施主电离激活能至少小于 0 .6me V。确认了在制备红外焦平面探测器时有必要将掺杂浓度控制在约 3× 1 0 1 5cm- 3水平。比较了高温退火前后 In在 Hg Cd Te中的扩散行为 ,得出在 40 0°C温度下 In的扩散系数约为 1 0 - 1 4cm2 / sec,确认了 In原子作为 Hg Cd Te材料的 N型掺杂剂的可用性和有效性     

超大视场红外凝视成像技术及其应用浅析

超大视场红外凝视成像技术具有视场大、实时探测、系统体积小等突出优势,广泛应用在空间探测、视频监控、大气环境监测、军事目标预警等重要领域。文章首先主要介绍了大视场红外凝视成像技术的突出优势及研究现状,然后阐述了相关的关键技术及研究方法,并评价和分析了这些方法在实际应用中的效果和不足。针对这些不足,提出了一些改进方法,最后分析了大视场红外凝视成像技术的潜在应用,展望了这项技术的改进和发展方向。     

红外凝视成像几何扭曲效应建模和仿真

为了增加红外凝视焦平面阵列系统成像仿真的置信度,对系统中的成像几何扭曲效应进行了产生机理分析,从二维图像像素角度出发,在空域通过寻求各阵列元对应像素点的径向畸变量建立成像扭曲模型,并利用反演解析的方法对畸变图像中的像素灰度值进行估算,实验仿真结果表明,几何扭曲效应的存在严重影响了系统的成像效果,几何扭曲效应的建模仿真对后续的系统性能评估和算法研究至关重要.     

凝视焦平面探测器的空间采样效应建模仿真

为了增加红外凝视焦平面阵列探测器成像仿真的置信度,对探测器所存在的空间采样效应产生机理进行了分析,并且从空间域角度对其进行了建模,借助于基于图像像素处理的方法进行实验仿真;为了客观地评价空间采样效应对探测器成像质量的影响,定义了图像的负指数型平滑度,实验结果表明,叠加空间采样效应后探测器输出图像的平滑度减小了11.7%,图像局部波动变大,从而验证了红外探测器成像仿真中空间采样效应考虑的必要性。     

超大空域凝视系统中目标检测的特殊问题

超大空域凝视侦测系统使绝大多数军事目标表现为亚像素成像特性.在输出的序列图像中表现出灰度起伏变化,与噪声类似.由于引入了"桶形"畸变,致使目标运动轨表现为曲线特性,现有弱小目标检测方法中目标运动轨迹的直线前提不再成立.同时,天空背景的辐射亮度随仰角不同而变化.通过对超大空域凝视侦测系统中弱小目标检测的诸多特殊问题进行总结分析,有助于后续研究适用于此类系统的、具有针对性的目标检测算法.     

对凝视红外热成像冷反射现象的研究

冷反射现象是在红外热成像系统中制冷的探测器通过前面的光学表面反射而探测到自身的像形成的.控制冷反射是设计红外扫描系统的一个重要指标.在一些光线追迹软件中有对红外扫描系统冷反射的分析工具,却没有优化、分析凝视阵列冷反射的工具.为了控制凝视红外系统的冷反射,一般通过非均匀校正来补偿,但这只对应某一特定的状态校正.当相对于已校正状态的一些条件变化时,冷反射又会重现.通过类比于红外扫描系统,分析了凝视系统的冷反射,并用code v给出了实例.     

Noise characteristics analysis of short wave infrared InGaAs focal plane arrays

The increasing application of InGaAs short wave infrared (SWIR) focal plane arrays (FPAs) in low light level imaging requires ultra-low noise FPAs. This paper presents the theoretical analysis of FPA noise, and point out that both dark current and detector capacitance strongly affect the FPA noise. The impact of dark current and detector capacitance on FPA noise is compared in different situations. In order to obtain low noise performance FPAs, the demand for reducing detector capacitance is higher especially when pixel pitch is smaller, integration time is shorter, and integration capacitance is larger. Several InGaAs FPAs were measured and analyzed, the experiments’ results could be well fitted to the calculated results. The study found that the major contributor of FPA noise is coupled noise with shorter integration time. The influence of detector capacitance on FPA noise is more significant than that of dark current. To investigate the effect of detector performance on FPA noise, two kinds of photodiodes with different concentration of the absorption layer were fabricated. The detectors’ performance and noise characteristics were measured and analyzed, the results are consistent with that of theoretical analysis.     

MBE growth of HgCdTe on silicon substrates for large-area infrared focal plane arrays: A review of recent progress

We review the rapid progress that has been made during the past three years in the heteroepitaxial growth of HgCdTe infrared detector device structures on Si substrates by molecular-beam epitaxy. The evolution of this technology has enabled the fabrication of high performance, large-area HgCdTe infrared focal-plane arrays on Si substrates. A key element of this heteroepitaxial approach has been development of high quality CdTe buffer layers deposited on Si(112) substrates. We review the solutions developed by several groups to address the difficulties associated with the CdTe/Si(112) heteroepitaxial system, including control of crystallographic orientation and minimization of defects such as twins and threading dislocations. The material quality of HgCdTe/Si and the performance of HgCdTe detector structures grown on CdTe/Si(112) composite substrates is reviewed. Finally, we discuss some of the challenges related to composition uniformity and defect generation encountered with scaling the MBE growth process for HgCdTe to large-area Si substrates.