沙漠背景下红外偏振图像目标检测方法

红外偏振成像探测同时探测目标的强度辐射与反射偏振态,可以获取传统光学无法获取的目标。偏振探测获取的偏振度、偏振角等信息反映不同的物理特性,与强度图像有较强的互补性。针对该特性,提出一种沙漠背景目标红外偏振图像检测方法。使用一种改进的核模糊聚类算法对红外图像和偏振图像进行聚类处理;利用稀疏融合方法将聚类后的红外图像和偏振度图像中的物体信息充分结合,以区分目标与背景,以达到目标检测的目的。实验表明,提出的检测方法相对小波融合和拉普拉斯金字塔融合结果噪声更低、细节更清晰。     

基于核密度估计的红外目标提取方法

提出了有效集成灰度、空间关系和局部标准差信息的新的核密度估计方案,据此设计了一种基于核密度估计的红外目标提取方法,即首先将图像分块,根据块的统计特征获得包含整个目标的约束区域;然后对目标约束区域和相应的背景采样区域进行核密度估计,这里背景采样区域指的是围绕着目标但又不包含目标的图像区域,由目标约束区域向外扩展而形成;最终通过对两种核密度估计对比的阈值判断即能获得所提取的目标.实验验证了所提出的算法简单有效.     

基于空间约束的模糊核聚类红外图像分割

提出了一种基于空间约束的模糊核聚类红外图像分割算法.首先将图像映射到特征空间,在特征空间内进行模糊聚类,针对红外图像中存在的噪声点和野值等干扰问题引入了像素点的八邻域局部空间约束信息,并定义了像素分类可靠性指数修正隶属度函数在整个图像范围内分析像素分类的合理性,其中像素分类可靠性指数包括像素分类灰度可靠性指数和像素分类距离可靠性指数.实验结果表明,这种考虑局部空间约束和整体空间约束的模糊核聚类算法可更有效地对红外图像进行分割.     

基于两时相图像联合分类的SAR图像变化检测

传统分类后比较法(post-classification comparison,PCC)存在分类累积误差问题,且对单幅图像分类精度要求较高,对此,根据不同时相图像的不变信息所具有的相关性,提出了一种基于两时相图像联合分类的SAR图像变化检测方法.该方法以灰度值作为输入信息,通过相似度计算可得两时相图像对应位置像素的灰度相似度,然后求解全局相似度阈值,并用于控制基于K-均值的联合分类器对两时相图像进行联合分类,最后通过类别比较获得变化检测结果.实验结果表明本文方法不但可提高单幅图像的分类精度,而且能够精确地把不同时相图像的不变地物信息划分为同一类别,减少了分类累积误差的影响,提高了变化检测性能.     

结合分类与迁移学习的薄云覆盖遥感图像地物信息恢复

利用多源多时相遥感图像,给出一种结合分类与迁移学习的薄云覆盖遥感图像地物信息恢复算法.首先利用多方向非抽样对偶树复小波变换对多源多时相遥感图像进行多分辨率分解,对分解后的薄云图像的高频系数利用贝叶斯方法进行地物初分类;再对每类地物的低频系数通过迁移最小方差支持向量回归模型进行域自适应学习,获取模型参数;最后利用所获的迁移回归模型,用无云参考图像的低频系数预测薄云覆盖图像的低频系数,去除薄云,恢复薄云覆盖图像的地物信息.实验结果表明,本文算法恢复的地物细节清楚,光谱失真较小.特别对地物季节性变化的薄云覆盖遥感图像,本文算法能有效恢复薄云覆盖区域的地物信息.     

基于改进高斯卷积核的变电站设备红外图像检测方法

在无锚点算法CenterNet模型的基础上,针对基于红外图像的目标检测算法检测精度低、耗时长的问题,给出了一种基于改进高斯卷积核的变电站设备红外图像检测方法,该目标检测方法模型网络结构精简,模型计算量较小。通过现场变电站巡检机器人设备收集数据样本,进行算法模型的训练及验证,实现红外图像变电站设备精准识别及定位。本文以变电站巡检机器人搭配红外热成像仪采集到的红外图像库为基础,用深度学习方法对数据集进行训练和测试,研究变电站红外图像的目标检测技术。通过深度学习技术判断设备中心点位实现目标分类和回归。实验结果表明,该方法提高了变电站目标检测方法的识别定位精度,为变电站设备红外图像智能检测提供了新的思路。     

基于EM的红外扩展目标鲁棒自动跟踪方法

针对红外视频图像的特点,提出了一种基于期望最大化算法的红外扩展目标鲁棒自动跟踪方法.首先利用局部Top-Hat形态学滤波进行背景抑制和去噪,并通过平台直方图技术突出跟踪区域的红外目标灰度信,g-;然后以考虑了像素空间位置信息的高斯加权直方图建立目标的灰度特征模板;最后通过期望最大化迭代计算来估计出各密度分布的最大似然函数的参数集,并由此确定跟踪目标的位置和形状尺寸.实验表明,该方法不仅实现了跟踪窗口随目标尺寸的自适应变化,而且有效克服了红外图像信噪比低的缺点,提高了红外目标实时跟踪的稳健性.     

一种新的基于二型模糊的变核宽模糊核聚类分割算法

针对基于模糊核聚类算法的红外图像分割方法中需要人为调节核宽的局限,提出了一种新的结合二型模糊的变核宽模糊核聚类分割算法.首先由5倍交叉验证初步确定核宽范围;然后根据类与类之间的距离最小值和最大值定义了一种高斯核宽的采样规则,进而分别由这些高斯核宽从模糊核聚类迭代公式中获得隶属度集合和聚类中心集合;最后采用二型模糊融合这个隶属度集合,从而完成聚类分割.实验结果表明,提出的自动模糊核聚类分割方法准确分割出了红外目标区域的轮廓,且抑制了背景对目标区域的干扰,分割效果好,并且具有一定的适应性和自动性,为模糊核聚类算法的研究提供了一种新的思路和方向.     

改进的空间约束加权模糊核聚类红外图像分割

红外图像分割算法对复杂背景下的目标检测跟踪具有重要意义,提出了一种改进的基于空间约束的加权模糊核聚类红外图像分割新算法.在其中引入了红外图像像素间的空间位置约束关系和关于类别的结构信息,并定义了类别权重可靠性指数修正类别权重,不但抑制了红外图像中存在的噪声点和野值等干扰,而且可以保护红外图像中的小目标,防止被背景淹没.通过对实际红外图像的分割结果表明,该算法很大程度上减少了背景像素对目标识别的干扰,适于进行复杂背景下红外目标的准确分割.     

一种基于多分类器融合的双色红外成像目标识别方法

针对双色红外成像系统中的自动目标识别问题,提出了一种基于多分类器融合的红外目标识别方法.该方法首先提取目标的形状特征和面貌特征,并设计多个基于不同特征的分类器对目标进行分类;然后对各个分类器的目标分类结果进行决策级融合处理,并采用所提出的决策规则对多分类器融合分类结果进行处理得到最终的目标识别结果.该方法充分利用了目标在多传感器图像中的多种分类特征信息,提高了系统的目标识别效率和精确性.实验结果证实了该方法的有效性.     

Object detection using transformed signatures in multitemporalhyperspectral imagery

Changes in atmosphere, ground conditions, and sensor response between multitemporal airborne imaging sessions have limited the use of fixed target hyperspectral libraries in helping to identify targets in heterogeneous (cluttered) backgrounds. This hyperspectral target signature instability has resulted in using anomaly detection algorithms to detect targets in real time applications. The anomaly detection algorithms, however, have not detected targets at sufficiently low false alarm rates. This study examines mathematical transforms of target spectral signatures. Specifically this study uses statistical information regarding background clutter taken from one long-wave infrared (LWIR) hyperspectral (8-12 μm) airborne imagery flown on one day, to find the target spectral signature flown on another day (with significantly dissimilar weather conditions). The transforms use overlapping regions in the two data sets but without subpixel level registration. This work analyzes image cubes collected during the November 1998 Hyperspectral Day/Night Radiometry Assessment (HYDRA) data collect. The transformed signatures used in matched filter searches successfully find targets (even targets nearly covered) with low false alarm rates (<1 FA/kilometer²) and remained sensitive to targets using a reduced number of pixels in the overlap region. This work has demonstrated the transformation of target spectral signatures to search for candidate targets using multitemporal hyperspectral images without requiring accurate geo-registration     

An advanced system for the automatic classification of multitemporal SAR images

A novel system for the classification of multitemporal synthetic aperture radar (SAR) images is presented. It has been developed by integrating an analysis of the multitemporal SAR signal physics with a pattern recognition approach. The system is made up of a feature-extraction module and a neural-network classifier, as well as a set of standard preprocessing procedures. The feature-extraction module derives a set of features from a series of multitemporal SAR images. These features are based on the concepts of long-term coherence and backscattering temporal variability and have been defined according to an analysis of the multitemporal SAR signal behavior in the presence of different land-cover classes. The neural-network classifier (which is based on a radial basis function neural architecture) properly exploits the multitemporal features for producing accurate land-cover maps. Thanks to the effectiveness of the extracted features, the number of measures that can be provided as input to the classifier is significantly smaller than the number of available multitemporal images. This reduces the complexity of the neural architecture (and consequently increases the generalization capabilities of the classifier) and relaxes the requirements relating to the number of training patterns to be used for classifier learning. Experimental results (obtained on a multitemporal series of European Remote Sensing 1 satellite SAR images) confirm the effectiveness of the proposed system, which exhibits both high classification accuracy and good stability versus parameter settings. These results also point out that properly integrating a pattern recognition procedure (based on machine learning) with an accurate feature extraction phase (based on the SAR sensor physics understanding) represents an effective approach to SAR data analysis.     

红外图像序列中不均匀背景消除新方法

从红外相机自身特性和使用角度两方面对靶场红外图像序列中不均匀(花纹)背景产生的原因进行了剖析,分析了传统红外图像非均匀校正算法在处理靶场序列红外图像上的优缺点,提出在目标跟踪过程中随着场景变化,基于实时线性标定的非线性红外图像的校正的新方法,克服了传统方法的弊端,实时确定了校正增益系数和校正因子,消除了序列红外图像中不均匀背景。通过对含有弱小目标的靶场实际序列红外图像进行仿真验证表明,新方法去除了图像固定图案噪声,消除了探测器坏元的影响,输出了理想的序列红外图像。     

An adaptive semiparametric and context-based approach tounsupervised change detection in multitemporal remote-sensingimages

A novel automatic approach to the unsupervised identification of changes in multitemporal remote-sensing images is proposed. This approach, unlike classical ones, is based on the formulation of the unsupervised change-detection problem in terms of the Bayesian decision theory. In this context, an adaptive semiparametric technique for the unsupervised estimation of the statistical terms associated with the gray levels of changed and unchanged pixels in a difference image is presented. Such a technique exploits the effectivenesses of two theoretically well-founded estimation procedures: the reduced Parzen estimate (RPE) procedure and the expectation-maximization (EM) algorithm. Then, thanks to the resulting estimates and to a Markov random field (MRF) approach used to model the spatial-contextual information contained in the multitemporal images considered, a change detection map is generated. The adaptive semiparametric nature of the proposed technique allows its application to different kinds of remote-sensing images. Experimental results, obtained on two sets of multitemporal remote-sensing images acquired by two different sensors, confirm the validity of the proposed approach.     

基于模糊聚类的SAR图像变化检测

利用两种模糊聚类算法即模糊C均值聚类(FCM)和Gustafson Kessel聚类(GKC),对SAR图像进行变化检测。差异图是根据不同时相图像的灰度值得到的,为了验证算法的有效性,实验选用两个不同地区的多时相图像,实验结果比较现存的马尔科夫随机场(MRF)和神经网络算法,不但耗用时间短,而且无需变化类和未变化类像素的任何先验分布信息。     

Three-dimensional imaging of objects in accumulated snow usingmultifrequency holography

The three-dimensional (3-D) imaging of objects buried in snow using multifrequency holography is discussed. It is pointed out that the cross-sectional images obtained by radar used for target detection in soils, sand, and snow do not meet expectations in identifying the shapes of targets. A 3-D imaging reconstruction technique using multifrequency holography is proposed that is applied to recognize the shapes of the objects buried in snow. An experimental system using X-band microwaves was constructed and image reconstruction was accomplished mathematically by computer, with the image displayed on a CRT using a specially designed circuit. Field trials are reported in which it was possible to obtain 3-D images of metallic cylinders and a mannequin buried in snow     

Application of log-cumulants to the detection of spatiotemporal discontinuities in multitemporal SAR images

Multitemporal satellite synthetic aperture radar (SAR) images are a useful source of information for geophysicists to monitor changing regions. In this paper, a new approach is proposed to extract from multitemporal SAR images two kinds of information: temporal changes (flooded areas, coastline erosion, etc.) and stable spatial features (roads, rivers, etc.). The novelty of the proposed approach is to detect simultaneously these two kinds of discontinuities. In a first step, the contrast and the heterogeneity information is extracted by a "multitemporal" application of the ratio of local means and by new three-dimensional texture parameters based on the log-cumulants. In a second step, the resulting attributes that measure the time variability or the presence of spatial features are merged. An interactive fuzzy fusion approach is proposed to provide end-users with a simple and easily understandable tool for tuning the change-detection results. The performances of the proposed attributes and fusion technique are presented on a set of seven multitemporal SAR images acquired by the European Remote Sensing (ERS-1) satellite.     

MultiTempGAN: Multitemporal multispectral image compression framework using generative adversarial networks

Multispectral satellites that measure the reflected energy from the different regions on the Earth generate the multispectral (MS) images continuously. The following MS image for the same region can be acquired with respect to the satellite revisit period. The images captured at different times over the same region are called multitemporal images. Traditional compression methods generally benefit from spectral and spatial correlation within the MS image. However, there is also a temporal correlation between multitemporal images. To this end, we propose a novel generative adversarial network (GAN) based prediction method called MultiTempGAN for compression of multitemporal MS images. The proposed method defines a lightweight GAN-based model that learns to transform the reference image to the target image. Here, the generator parameters of MultiTempGAN are saved for the reconstruction purpose in the receiver system. Due to MultiTempGAN has a low number of parameters, it provides efficiency in multitemporal MS image compression. Experiments were carried out on three Sentinel-2 MS image pairs belonging to different geographical regions. We compared the proposed method with JPEG2000-based conventional compression methods and three deep learning methods in terms of signal-to-noise ratio, mean spectral angle, mean spectral correlation, and laplacian mean square error metrics. Additionally, we have also evaluated the change detection performances and visual maps of the methods. Experimental results demonstrate that MultiTempGAN not only achieves the best metric values among the other methods at high compression ratios but also presents convincing performances in change detection applications.     

基于核空间二次相关滤波的红外目标检测

子空间二次综合判别函数(SSQSDF)是一种性能良好的二次相关滤波器,为了更好地对复杂场景中红外目标进行检测,提出了把SSQSDF扩展到高维空间用于红外目标检测的核二次相关检测算法(KSSQSDF).算法主要通过选取适当核函数得到训练样本核矩阵,然后利用核函数性质把SSQSDF转换为以核矩阵表示形式的矩阵方程,最后求解方程获得KSSQSDF算法表达式.KSSQSDF形式简单,能较强抑制目标背景噪声干扰,提高目标检测精度.在真实场景下通过实验验证了KSSQSDF与SSQSDF相比在检测性能上具有优越性.     

地下目标的红外隐身

建立了地下目标的传热模型，数值模拟了不同掩埋深度及其热特性在２４小时以及３６５天外界温度循环中对地表温度的影响。结合红外技术的最新进展，探讨了地下目标红外隐身的途径。