Fusion of Multispectral and Panchromatic Images Using a Restoration-Based Method

Many remote-sensing satellites can obtain images in multispectral and panchromatic bands. By fusing low-resolution multispectral and high-resolution panchromatic images, one can obtain high-resolution multispectral images. In this paper, an image fusion algorithm based on image restoration is proposed to combine multispectral and panchromatic images. For remote-sensing satellites, the wavelength of the panchromatic band usually covers the wavelengths of the multispectral bands. This relationship between the two kinds of images is useful for fusion. In our approach, the low-resolution multispectral images are first resampled to the scale of the high-resolution panchromatic image. The relationship between these two kinds of images is then used to restore the resampled multispectral images. That is, the resampled multispectral images are modeled as the noisy blurred versions of the ideal multispectral images, and the high-resolution panchromatic image is modeled as a linear combination of the ideal multispectral images plus the observation noise. The ideal high-resolution multispectral images are then estimated based on the panchromatic and the resampled multispectral images. A closed-form solution of the fused images is derived here. Experiments show that the proposed fusion algorithm works effectively in integrating multispectral and panchromatic images.     

Multisensor data fusion for surface land-mine detection

Receiver operating characteristic (ROC) curves have been used to examine a novel target recognition system using a number of knowledge-based techniques to automatically detect surface land mines that are present in 30 sets of thermal and multispectral images. A summary of the results, graphed at a probability of detection greater than or equal to 96%, shows the false-alarm rates (FARs) obtained using various combinations of fusing sensors and neural classifiers averaged over the 30 images. The results show that using two neural-network classifiers on the input textural and spectral characteristics of selected multispectral bands, we obtained FARs of approximately 3%. Using polarization-resolved images only, we obtained FARs of 1.15%. Fusing the best classifier output with the polarization-resolved images, we obtained FARs as low as 0.023%. This result has shown the large improvement gained in the sensor fusion. Also, an improvement is shown by comparing these results with those reported in an existing commercial system     

独立成分分析的多光谱图像融合算法

为解决图像空间信息的问题,文章提出了一种独立成分分析的多光谱图像融合算法,将多光谱图像的RGB 3个波段和近红外图像共4个波段进行独立成分分析变化,并对其做加权平均得到主图像信息,将主图像信息与全色图像加权求平均得到一副新的图像,然后将这幅图像还原到4个波段得到融合后的结果图像。     

一种基于假彩色的像素级多传感器图像融合算法

本文给出了一种基于假彩色的像素级多传感器图像融合算法,并将其用于两幅灰度图像的融合中.这种算法将现有的图像融合技术和彩色显示技术相结合,在灰度融合图像的基础上利用色差来表现原图像与灰度融合图像的细节差异.该算法分为三步:首先,用选择与平均相结合的方法得到两幅原图像的灰度融合图像;接着,求出灰度融合图像与两幅原图像的差异图像;最后,将两幅差异图像和灰度融合图像分别送至R、G、B颜色通道进行显示.比起灰度融合图像,最终得到的彩色融合图像在色彩上更丰富,包含更多的细节,直觉上更容易辨认.     

基于Rail-GPSAR实测数据的地雷检测新方法

本文借鉴恒虚警率(CFAR)思想估计图像数据中杂波的统计量,实现图像的预白化处理。在训练图像中选取地雷图像切片的距离向中心切线作为本征向量构造训练数据阵,获取检测器的参数估计,结合主分量分析设计高效的偏差最优线性二次(DOLQ)检测器。验证了DOLQ检测器输出的灰度图像服从Gamma分布,利用其分布参数和实测数据特点确定整体阈值。对得到的二元图像利用形态学操作获取可疑目标块,然后通过整体阈值和局部门限确定的自适应阈值对其进行二次检测,以确保无漏检的情况下尽可能降低虚警。基于图像中目标能量的空间范围,提出了利用能量环对预白化处理后的图像进行目标检测。最后,提出了一种将能量环与DOLQ检测器的检测结果进行决策级融合的新方法,完成对不同土壤环境、埋设深度地雷的检测。对实际图像的检测结果表明,新方法能够显著降低虚警,且具有较好的稳健性。     

基于多级引导滤波器的图像区域融合算法

为了提高多光谱图像与全色图像的融合质量,研究了多种滤波器和融合算法,提出了基于多级引导滤波器的区域融合方法。采用该方法对多光谱图像进行插值,利用改进的分水岭算法对全色图像进行区域划分,并将划分结果映射至每个多光谱图像,然后将多光谱图像与全色图像利用多级引导滤波器分别进行滤波,得到各自的细节信息,最后根据每个区域中全色图像和多光谱图像的关系指标局部相关系数与4阶相关系数的大小,对细节信息进行区域融合,得到融合后的多光谱图像。结果表明,该算法充分保留了多光谱图像的光谱信息,并尽可能多地注入了全色图像的细节信息,成功地提高了多光谱图像的融合效果。     

QuickBird高分辨率影像融合方法比较研究

遥感图像融合的关键就是选择合适的融合方法,恰当的融合方法可在提高图像空间信息的同时,能很好地保持多光谱影像的光谱特性。从应用的角度出发,利用ENVI 4.5、PCI 9.0、ERDAS 9.1和PhotoShop四种软件平台对快鸟卫星(QuickBird)数据进行了融合实验研究,并对相应的融合结果进行了讨论与分析,希望为同类作业者提供借鉴。结果表明,格拉姆-施密特(Gram-schmidt)正交化变换法和彩色合成(PanSharp)方法在提高影像空间分辨率的同时,还较好地保持了多光谱波段的光谱信息,并且色彩信息更符合人的视觉习惯。     

Adaptive polarization image fusion based on regional energy dynamic weighted average

In object trackingandrecognition,thei mage capturedby traditional optical electronic sensors is often corrup-ted by natural background clutters (such as vegetation,terra,cloud, rain, snow and some other nature ob-jects) , which may augment the tracking errors and de-press therecognitionrate.Therefore,howtoreducetheeffects of nature background is an i mportant issue intarget tracking and recognition. Man-made objects in natural clutter can be detectedeasily by measuring the polarization states …     

基于小波变换的红外偏振图像融合算法

为了改善红外图像质量、提高人造目标的可识别率,基于偏振度图像能够较好地凸显人造目标,偏振角较好地描述不同物体表面取向,I图像能反映场景的强度信息的特征,采用对红外图像进行偏振图像融合的算法,即先通过红外热像仪和偏振片拍摄到偏振角度为0°,60°和120°3幅红外图像,再通过计算得到I,Q,U图像,进而得到偏振度图像和偏振角图像,最后对I图像、偏振度和偏振角图像进行红外偏振图像融合,得到高质量的红外偏振图像,由理论分析得到了各个图像的性能指标数据。结果表明,基于小波变换的红外偏振图像融合算法得到的图像数据合理,达到了改善红外图像质量和提高图像中的人造目标的可识别率的目的。     

PCA数值算法在遥感图像处理中的应用

提出一种主分量分析(PCA)的数值算法并介绍了其在遥感图像处理中的应用,主要包括三方面内容:多光谱图像压缩;多光谱图像消噪;多光谱图像与spot全色图像的信息融合.软件实验验证和评价了该算法的有效性和准确性.     

A generalized orthogonal subspace projection approach to unsupervised multispectral image classification

Orthogonal subspace projection (OSP) has been successfully applied in hyperspectral image processing. In order for the OSP to be effective, the number of bands must be no less than that of signatures to be classified. This ensures that there are sufficient dimensions to accommodate orthogonal projections resulting from the individual signatures. Such inherent constraint is not an issue for hyperspectral images since they generally have hundreds of bands, which is more than the number of signatures resident within images. However, this may not be true for multispectral images where the number of signatures to be classified is greater than the number of bands such as three-band pour l'observation de la terra (SPOT) images. This paper presents a generalization of the OSP called generalized OSP (GOSP) that relaxes this constraint in such a manner that the OSP can be extended to multispectral image processing in an unsupervised fashion. The idea of the GOSP is to create a new set of additional bands that are generated nonlinearly from original multispectral bands prior to the OSP classification. It is then followed by an unsupervised OSP classifier called automatic target detection and classification algorithm (ATDCA). The effectiveness of the proposed GOSP is evaluated by SPOT and Landsat TM images. The experimental results show that the GOSP significantly improves the classification performance of the OSP.     

K-L变换在多光谱图像聚类中的应用

遥感图像是通过光谱信息和空间信息表征地物的。选择特定地区不同时相的多光谱图像进行聚类分析,可以实现卫星核查和作物估产等应用目的和要求。多光谱图像的波段间存在大量的冗余数据,文中采用了对多光谱图像先进行K－L变换再进行聚类的解决方法,并对某地区多光谱图像进行了处理分析,取得了理想效果。     

Ship detection optimization method in SAR imagery based on multi-feature weighting

Aiming at the problem that the accuracy of traditional ship detection algorithms is not satisfying in complex scene with many false alarm targets,a ship detection optimization method in SAR imagery based on multi-feature weighting was proposed.Firstly,the marker-based watershed algorithm was employed to remove land from SAR amplitude image.Then,the CFAR algorithm based on log-normal distribution was used to obtain candidate targets from no land image.Furthermore,the length to width ratio,the ship area and the contrast ratio of the candidate targets were extracted.Finally,a variance coefficient method was proposed to distribute the weight of the three features,and the confidence levels were calculated by combining the normalized feature vectors of the candidate targets with the feature weight.By determining the best confidence level,false alarm targets among the candidate targets were removed to optimize ship detection results.In order to verify the proposed method,experiments were carried on with the GF-3 SAR images of different complex scenes.The experimental results show that the proposed method is feasible and effective.     

基于小波变换和分段DPCM混合编码的多光谱遥感图像压缩算法

多光谱遥感图像的压缩要利用图像谱内及谱间的相关特性。该文在分析多光谱图像谱内和谱间相关特性的基础上,提出了对多光谱遥感图像进行压缩的分段 DPCM和 SPIHT相结合的混合压缩算法,即首先利用分段 DPCM算法去除谱间冗余,再利用高效的 SPIHT小波压缩算法对预测误差图像进行编码。实验取得了令人满意的效果,证明了该算法的有效性。     

基于NSCT的多光谱和全色图像的融合

提出了一种基于无下采样Contourlet变换的多光谱和全色图像的融合方法.该方法在对多光谱影像进行IHS变换的基础上,对多光谱的I分量和高分辨率的全色影像分别进行无下采样Contourlet变换(NSCT),然后对分解得到的近似分量以及各层金字塔各方向的细节分量利用本文提出的一定的融合准则分别对近似分量和细节分量进行影像融合,最后通过无下采样Conlourlet逆变换得到新的I分量,与H,S分量一起还原到RGB空间,最终得到融合后的高分辨率多光谱彩色图像.本文采用一组多光谱图像和全色图像数据进行融合实验,其实验融合图像的目视效果和统计指标均优于传统的IHS融合方法、小波融合方法以及Contourlet变换方法.     

基于对比度的多分辨图像融合

本文给出一种基于对比度的多分辨图像融合算法.首先,利用小波变换得到待融合图像的多分辨分析,同时得到图像的多分辨对比度序列;然后以对比度为判据,在图像的多分辨分析的相应各级上进行融合,得到融合图像的多分辨分析;最后,利用小波逆变换重构融合图像.算法使用同一场景可见光图像和红外图像进行了验证,结果表明,融合图像完好地显示了源图像各自的信息.     

基于Curvelet变换的自适应多传感器图像融合

提出了基于Curvelet变换的自适应多传感图像融合新算法。算法将全色图像和多光谱图像进行Curvelet变换分解后,针对不同的频率域特点选择不同的融合规则。对低频系数选取区域能量的加权系数自适应融合规则,对高频系数选用了区域特征自适应的融合规则。最后通过重构得到融合图像。将该算法和其他的融合算法进行对比,结果表明,该算法是一种有效可行的图像融合算法。     

SAR图像人造目标检测研究

在合成孔径雷达(SAR)自动目标识别中,人造目标的检测至关重要。该文根据SAR图像的特点,对图像中的人造目标进行了检测。首先采用自适应小波滤波方法对图像进行滤波,在保留图像细节的前提下有效地去除了图像中的乘性噪声,使后续的检测变得相对容易。然后采用基于自适应遗传算法的C-划分二维模糊熵算法对图像进行分割。实验结果表明,该文方法能够有效地检测出图像中的人造目标。     

Super Resolution of Multispectral Images using ℓ1 Image Models and Interband Correlations

In this paper we propose a novel super-resolution based algorithm for the pansharpening of multispectral images. Within the Bayesian formulation, the proposed methodology incorporates prior knowledge on the expected characteristics of multispectral images; that is, it imposes smoothness within each band by means of the energy associated with the ℓ1 norm of vertical and horizontal first order differences of image pixel values and also takes into account the correlation among the bands of the multispectral image. The observation process is modeled using the sensor characteristics of both panchromatic and multispectral images. The method is tested on real and synthetic images, compared with other pansharpening methods, and the quality of the results assessed both qualitatively and quantitatively.     

An optimization algorithm for separating land surface temperatureand emissivity from multispectral thermal infrared imagery

Land surface temperature (LST) and emissivity are important components of land surface modeling and applications. The only practical means of obtaining LST at spatial and temporal resolutions appropriate for most modeling applications is through remote sensing. While the popular split-window method has been widely used to estimate LST, it requires known emissivity values. Multispectral thermal infrared imagery provides us with an excellent opportunity to estimate both LST and emissivity simultaneously, but the difficulty is that a single multispectral thermal measurement with N bands presents N equations in N+1 unknowns (N spectral emissivities and LST). In this study, we developed a general algorithm that can separate land surface emissivity and LST from any multispectral thermal imagery, such as moderate-resolution imaging spectroradiometer (MODIS) and advanced spaceborne thermal emission and reflection radiometer (ASTER) data. The central idea was to establish empirical constraints, and regularization methods were used to estimate both emissivity and LST through an optimization algorithm. It allows us to incorporate any prior knowledge in a formal way, The numerical experiments showed that this algorithm is very effective (more than 43.4% inversion results differed from the actual LST within 0.5°, 70.2% within 1° and 84% within 1.5°), although improvements are still needed