用于三角方向鉴别测量的客观判别模型

为减小人为因素对三角方向鉴别测量的影响,有效提高测量效率,研究了以机器视觉系统替代观察者进行三角方向鉴别测量的途径,建立了一种专门针对三角方向鉴别测量的客观判别模型。该模型以人眼视觉系统对信号的处理过程以及人眼视觉系统的主要效应为基础,利用方向通道滤波器实现图像信号分解,通过计算视觉特征矢量相关度,实现三角形靶标方向的判别。结合凝视型成像系统虚拟样机提供的三角形靶标,进行了客观判别模型与观察者的判别性能对比实验,并给出三组不同靶标尺寸下的对比实验结果。实验结果表明,客观判别模型很好地预测了观察者的判别性能。     

扫描型红外成像系统仿真及TOD曲线预测方法研究

针对实际三角形方向鉴别（TOD）阈值温差测试的数据量大、时间长,以及测试结果常具有不稳定和不确定性等问题,提出一种扫描型红外成像系统效应仿真。建立了红外成像系统性能预测仿真平台,并对靶标效应图进行人眼判定。根据人眼判定结果对神经网络进行了训练。由基于BP神经网络的TOD阈值温差预测方法判定仿真样条的方向,统计正确的判定概率,实现TOD曲线的预测。实验结果表明：该方法预测的TOD曲线与实际测量的TOD曲线具有很好的一致性。     

红外凝视传感器定量仿真及模型验证

针对新一代红外凝视成像传感器,依据红外辐射能量传递和转换的物理过程,完成了对传感器各组成单元的物理效应建模.不同于以往成像模型的定性仿真,该模型实现了对系统各模块成像特性的定量描述,综合考虑了传感器的信号传递特性、空间传递特性、空间采样特性和时空噪音特性,构建了较为完善的高仿真度红外成像仿真模型.为验证仿真模型的有效性,搭建了有效性实验验证平台,获取了真实热像仪的性能曲线和输出图像.通过计算和比较仿真模型和真实热像仪性能曲线和输出图像相似程度,定量化评价了模型的仿真度,验证了仿真模型的有效性.     

光子成像静止点目标的管道滤波探测方法

构建了具有单光子成像能力的光子成像系统,提出应用管道滤波方法实现对光子受限静止点目标的探测。分析了光子图像静止点目标与点状噪声特征,根据静止点目标在序列图像中位置的确定性以及噪声点的不相关性,研究了基于管道滤波的光子成像静止点目标探测方法。为降低目标探测的虚警概率,优化了管道滤波直径。以实验采集得到的多组光子图像序列为样本,获得了探测概率、虚警概率与信号光子数、噪声光子数、管道长度以及检测阈值的关系。检测结果显示,对信号与噪声的平均发生率为0.4和5.215的序列图像,当管道长度为9、检测阈值为2时,探测概率达0.9以上且虚警概率〈0.08。对比多组图像序列的检测结果表明,影响探测概率的主要参数是信号光子数,而影响虚警概率的主要参数是噪声光子数。     

基于图像的飞行器红外辐射特性测量

通过将目标在一定波段内的红外辐射等效为红外成像系统前一定距离下黑体在对应波段内的红外辐射,建立了等效辐射方程。根据黑体辐射定标实验数据,利用非线性回归方法确定了在不同的积分时间条件下红外凝视成像系统输出红外图像的灰度值与在一定距离下的黑体温度之间的定量关系,建立了辐射定标方程。在Visual C++6.0平台下,在对红外目标图像进行SUSAN滤波等预处理后,分析了已知目标距离的红外图像的灰度均值。首先根据辐射定标方程计算出目标等效为黑体的温度,然后利用等效辐射方程反推目标的红外辐射强度,以达到根据跟踪的红外图像确定红外目标辐射特性的目的。此项研究不仅可以为目标识别提供目标分类、识别和辨认所必需的光谱数据库,而且还可以为红外预警提供重要的参考数据。     

红外凝视传感器定量仿真及模型验证

针对新一代红外凝视成像传感器,依据红外辐射能量传递和转换的物理过程,完成了对传感器各组成单元的物理效应建模.不同于以往成像模型的定性仿真,该模型实现了对系统各模块成像特性的定量描述,综合考虑了传感器的信号传递特性、空间传递特性、空间采样特性和时空噪音特性,构建了较为完善的高仿真度红外成像仿真模型.为验证仿真模型的有效性...     

一种用于非制冷红外热成像系统的图像增强方法

在基于微悬臂梁的光学读出红外成像系统中,获得的红外图像有明显噪声,甚至有连续噪点组成孔洞,让目标难以辨识出来,因此提出基于特征模板卷积的红外图像增强方法。利用Hough变换根据微悬臂梁结构的特点,获得特征卷积模板的尺寸信息,根据成像系统特点建立卷积模板。让模板在图像内逐点卷积,建立评价参数阈值消除图像内噪声。进行均值滤波来填补噪声点及FPA单元的间隔,获得增强后的红外图像。实验结果表明,方法不仅能够有效增强光学读出红外成像系统的成像质量,对于普通存在噪声的图像也有良好的噪声消除效果。     

微悬臂梁FPA红外成像系统实时图像去噪算法研究

基于MEMS热传感效应的红外成像有着独特的优势。利用双材料微悬臂梁制作了MEMS IR FPA,并构建了红外成像系统。针对基于双材料微悬臂梁FPA红外成像系统中的图像噪声,提出了离散量和平均灰度的红外图像实时处理算法,解决了灰度阈值分割法在去除噪声的同时滤除掉目标物体像素、使红外图像细节丢失且灰度级减少的问题,在目标物体像素损失较小的情况下,去除了目标物体周围的随机噪声及背景噪声,提高了信噪比。     

对比度阈值函数修正对于NVThermIP模型的影响

NVThermIP模型作为经典的性能模型,在指导红外系统参数的设计优化方面略有不足,因此需要构建更科学合理的综合评估模型.在经典模型基础上,结合人眼噪声的理论和实验研究,利用噪声等效温差修正了系统的对比度阈值函数.并利用现有的红外系统实验数据,对修正后的模型进行图像模糊和不同距离下辨识两方面验证,结果证明该模型具有很高的预测精确度,可为新型系统设计分析提供可靠的依据和理论指导.     

基于FPGA的红外焦平面成像条纹噪声逐帧抑制算法的研究

红外焦平面阵列是当今红外成像技术发展的主要方向,随着器件工艺的进步,红外焦平面阵列探测器有了长足的发展,然而红外图像普遍具有信噪比低的缺点,这大大限制了红外焦平面的应用。与固定图案噪声（FPN）相比,随机噪声的最大特点是每帧均不同,因此去除该类型噪声的算法必须在一帧之内完成。提出了一种新型的单帧去除此类条纹噪声的算法并加以硬件实现,在单帧内设置适合的校正参数和阈值,达到在单帧图像内有效去除条纹噪声的目的。通过算法处理前后的图像对比以及客观的MSE、PSNR测试数据对比,证明了该算法能够有效地改善焦平面器件成像质量。     

TOD Performance Theoretical Model for Staring Thermal Imagers

The TOD (triangle orientation discrimination threshold) metric, as a promising sensor performance measure, is suitable for all types of thermal imaging systems and corresponds to the field performance very well. Since this method was proposed, a great progress has been made in some aspects, such as experimental validation, field performance, and TOD sensor performance model. However, what is still missing is a TOD curve prediction model similar to MRTD (minimum resolvable temperature difference) equation. Here, an equation-based TOD performance model was first developed focusing on staring thermal imagers. Specifically, spatial distribution of the triangle standard test pattern is described quantitatively. Resolution transfer characteristic of the staring infrared imagers is modeled with linear system theory, and system noise is characterized with the introduction of three-dimensional noise model. The modulation effect of overall subsystem of staring thermal imager on the non-periodic triangle standard pattern is analyzed. The matched filter idea is adopted to characterize quantitatively the spatial integration of the eye to signal and various noise components over the triangle pattern area, and the perceived signal-to-noise ratio of the staring thermal imager is derived. Then, the TOD performance theoretical model is established. Comparing with experimental results, this theoretical model gives reasonable prediction of the TOD performance curve of staring thermal imagers. Although more tests and modifications are required, these preliminary results suggest that this model can be developed into a model that predicts the TOD for all kinds of sensors.     

Field Performance Prediction Method Based On Contrast Metric Of Target Sub Regions

The field performance prediction of infrared imaging system is an important subject in infrared imaging field. In this paper, a novel method for predicting TA (target acquisition) performance is proposed, which combines the TOD (triangle orientation discrimination) threshold curve with an improved contrast metric based on the temperature in target sub regions. Specifically, the target is first subdivided into some sub regions with different target/background differential temperatures according to its thermal structure distribution. The number of equivalent triangle patterns across each sub region is calculated utilizing its effective size, the apparent temperature difference line, and the TOD curve. Further, the total number of equivalent triangle patterns over the integral target is achieved. Combining the TOD criteria, the target acquisition ranges for different discrimination (detection, recognition, and identification) levels are obtained by solving a set of equations. Comparisons with the preliminary experimental results show that this new TA approach can provide reasonable prediction of field performance. Foundation Item: The project supported by National Natural Science Foundation of China (No: 60477038).     

Distortion-invariant pattern recognition using synthetic discriminant function based multiple phase-shifted-reference fringe-adjusted joint transform correlation

This paper proposes a novel pattern recognition system for invariance to noise and distortions. The technique first generates a synthetic discriminant function of the target image from its different distorted versions. It then takes four different phase-shifted versions of the reference image, which are individually joint transform correlated with the given input scene. Thus the proposed algorithm produces a single cross-correlation signal corresponding to each potential target. Also a fringe-adjusted filter is designed to generate a delta-like correlation peak with high discrimination between the signal and the noise. The pattern recognition system is also designed for the identification of multiple targets belonging to multiple reference objects simultaneously in a given input scene. The proposed technique is investigated using computer simulation including real-life images in different complex environments.     

基于不同静态性能模型的热成像系统视距估算

 基于NVL75，FLIR92和CFLIR国内外3种不同的热成像系统静态性能模型，采用静态性能参量MRTD建立对面目标的视距估算方程，并通过CFLIR40软件计算，比较不同模型下视距估算结果，得出：凝视型热成像系统在CFLIR模型下计算得到的MRTD值比FLIR92模型计算得到的MRTD值更接近实际测量值；在基本参数相同的条件下，利用MRTD估算的凝视系统的视距远远优于扫描系统的视距；对凝视型系统，从视距估算的结果来看，CFLIR模型略优于FLIR92模型。     

Field Performance Prediction and IR Imaging Simulation Based on Measured System Level Parameters*

Traditionally, the Minimum Resolvable Temperature Difference (MRTD) and the Johnson criteria are used to predict the field performance of IR imaging system. However this method generally leads to far too pessimistic range predictions. For the improvement of the prediction accuracy of the field performance, a novel approach to predict field performance is proposed based on the three-dimensional infrared scene generated by Vega software. Further, this approach utilizes the measured system level parameters to characterize the signal transfer process, noise, and the blur effect of the output image instead of theoretical model. By controlling the target range in the simulated image, a simulation experiment is performed, and the range corresponding to the 75% correct probability of discrimination is achieved by the statistical method. Comparisons with the real experimental result show that this method can give more accurate range prediction than the target acquisition (TA) model based on the MRTD.* Foundation Item: The project supported by The Research Fund for the Doctoral Program of Higher Education(No. 20030701003) and National Natural Science Foundation of China (No: 60277005, 60477038).     

超微弱生物发光图像中的统计检验

应用光电阴极探测灵敏度为０．５ｃｐｓ／ｍｍ＾２的超高灵敏度的光电成像系统，获得了绿豆芽和活体昆明鼠的超微弱生物发光图像，并用统计理论研究了极弱光强条件下光子图像的信号检测和问题，文中在信号和噪声均为泊松分布的条件下，分析了从光子噪声中检验是否有信号的判据以及影响到检验的５个因素对检验结论的影响，以此判据成功地检验到实验获得的昆明鼠发光光子图像中的信号。     

双目遥感凝视系统中运动小目标的快速自动检测

从双目遥感凝视系统的视场重叠区进入系统的信息量大于通过非重叠区的信息量,根据这一特征建立了一种新的运动小目标双目并行快速实时自动检测算法。首先采用差分向量无穷范数算法对原始图像序列做预处理,去掉大量低频噪音和背景,然后采用光流场法对运动小目标进行分割,最后用所提出的空间时间并行快速判定算法对分割的可疑运动小目标进行判定。实验结果表明:由于识别判定算法的空间时间是并行处理的,所以识别判定的平均速度比单目视觉系统提高了50%;在图像信噪比不小于5dB的情况下,准确判定识别的概率为97%。