Effect of spatial resolution on classification errors of pure andmixed pixels in remote sensing

It is observed in remote sensing that a finer spatial resolution does not necessarily improve the classification performance. These observations have been understood by using the conceptual explanation that "boundary effect" and "within-class variability" work against one another. Though easily understood, this conceptual explanation cannot be readily used for a quantitative investigation. The authors design a simulation scheme to evaluate systematically the impacts of various parameters on the classification accuracy. The authors employ a model for the class spectral covariance of pure pixels and a linear mixing model for the spectral responses of mixed pixels. Based on these models, the authors derive the statistical characteristics for mixed pixels and assess the corresponding classification errors. As the ratio of ground sampling distance to field size decreases, the classification error associated with pure pixels tends to increase, whereas the classification error associated with mixed pixels tends to decrease from the smaller area of mixed pixels. The simulation results show that the overall classification error first decreases with decreasing ratio of ground sampling distance to field width, reaches a minimum value, and then may increase with further decreasing ratio. The study on the classification error may help the development of classification schemes for high spatial resolution imagery     

Residential area extraction based on saliency analysis for high spatial resolution remote sensing images

Traditional residential area extraction methods for remote sensing image depend on classification, segmentation and prior knowledge which are time-consuming and difficult to build. In this paper, an efficient, saliency analysis-based residential area extraction method is proposed. In the proposed model, an adaptive directional prediction-based lifting wavelet transform (ADP-LWT) is introduced to obtain the orientation feature. A logarithm co-occurrence histogram is employed to compute the intensity feature. The color opponency and diagram objection based on the information are proposed to extract color feature from the contrast in the red–green opponent channel. The saliency map is obtained through a weighted combination based on the feature competition and the residential area is extracted by saliency map threshold segmentation. The experimental results reveal that the residential area extracted by our model has more demarcated boundaries and better performance in background subtraction.     

Simulation of optical remote sensing systems

Research on understanding the remote-sensing process as a system and investigating the interrelated effects of various parameter is described. A system model for the simulation of remote-sensing systems is presented. The system is divided into three parts: the scene, the sensor, and the processing algorithms. Models are presented and implemented for these component systems. Validation of the system model is considered over a specific test site. Results of the simulation for various scene and sensor configurations are included. Results of applying the model to various system configurations using simulated Landsat sensors are then presented to show how the simulation can be used to investigate the interrelated effects of system parameters.<>     

高分辨率遥感图像融合技术的研究

图像融合已成为图像理解和计算机视觉领域中的一项重要而有用的新技术,多源遥感图像数据融合也成为遥感领域的研究热点,其目的是将来自多信息源的图像数据加以智能化合成,产生比单一传感器数据更精确、更可靠的描述和判决,使融合图像更符合人和机器的视觉特性,更有利于诸如目标检测与识别等进一步的图像理解与分析。     

高分遥感影像中道路信息提取方法综述

阐述了道路信息提取的重要性和一般步骤及基本思路,通过对高分辨率遥感图像中道路信息提取方法利用道路特征的不同进行了分类整理,并对经典方法进行分析,希望能对找到一种具有普适性的道路提取方法起到事半功倍的效果。在此基础上结合当前科技发展的方向,从道路提取的基本思想出发,对道路特征提取研究的前景做出展望。     

空间查询技术在遥感数据编目处理中的应用

采用地理信息系统的空间查询技术,解决了遥感卫星数据编目系统对多元化地理信息的需求问题.描述了空间查询技术和编目系统,同时分析了二者相结合的优点.提出了将编目处理中生成的标准景图像视为几何点对象,经过投影转换在地理信息系统数据集中进行空间查询,获取丰富的地理信息以扩充编目元信息的方法.现的多元地理信息的编目系统丰富了遥感数据的描述信息,使得用户能够更直观、更方便、更有效地查询遥感数据,从而达到高效、便捷地利用遥感图像的目的.     

基于地标空间信息的高光谱遥感图像分类

高光谱遥感图像同时具有光谱与空间特征信息,充分利用空间特征能够有效提高分类结果.高光谱图像上同类像素点的邻域空间信息差异较大会影响分类效果,针对这个问题提出了一种新的空间信息利用方法,记作地标空间信息.将光谱信息与地标空间信息结合使用,通过深度信念网络提取特征.实验表明地标空间信息能够有效提高深度信念网络以及对比方法的分类结果.     

Spectral band selection for visible-near infrared remote sensing:spectral-spatial resolution tradeoffs

Recent technological developments permit improved instrumentation for surveillance and resource monitoring, but tradeoffs of spectral resolution and number of spectral bands versus spatial resolution and measurement precision must be considered. A band selection procedure is applied to high spectral resolution (0.01 μ/m) aircraft sensor imagery representing the visible and near-infrared wavelengths (0.4-2.5 μm). Approximately 30-40 spectral bands characterize virtually all the information (variability) in the data, with the precise number depending on issues of data interpretation. This suggests that lower spectral resolution and higher spatial resolution are preferable to the reverse. Further study is needed to evaluate the significance of spectral bands having very low amplitude variability     

一种高分辨率遥感影像建筑物提取方法

采用了一种基于独特像元的快速自动提取建筑物的方法,如线与线之间的交叉点。首先,在预处理阶段采用边缘保留双边滤波器降低噪声,提高建筑物边缘的对比度;其次采用EDLines线段探测器实时准确地提取建筑物线段;最后,采用图表搜索感知分组的方法分层次组织预判线段为候选矩形建筑物。实验证明,该方法可以实现遥感影像建筑物的准确和快速提取。     

On the application of averaging median filters in remote sensing

The application of averaging median filters to remote sensing has been investigated, and the results are presented with some discussion and recommendations. Averaging median filters can be considered as a subclass of the standard median filters. For image processing purposes, a two-dimensional window is first filtered by a number of average filters, and the final result of the averaging filters is equal to the median of the central pixel value and the averaging filter results. Applications of this averaging median filter to Landsat images are presented, and the results show that the fine details are preserved while attenuating the impulsing noise     

高分辨率光学图像目标打击效果评估系统研究

针对传统的基于像素级变化检测的打击效果评估系统的不足,提出了基于变化目标特征向量分析的打击效果评估系统.该系统首先在图像上识别出目标,然后分别在打击前后图像上提取目标特征向量,并对目标特征向量进行分析比较,根据目标特征向量的变化对目标损伤程度进行评估.试验证明该方法有效可行.     

Optical remote sensing of the earth

Optical remote sensing of the earth from aircraft and from orbit has made unique contributions to understanding the dynamics of the atmosphere, oceans, and the vegetation cover of the land, as well as provided new perspectives in the study of the solid earth. This paper encompasses optical remote sensing of the earth's surface in the region of 0.4 to 15 µm and is divided into four areas: principles, applications to science disciplines, recent sensor history, and new technology developments. The latter developments promise to revolutionize the methods used and the types of problems addressed with remote sensing techniques.     

On the molecular-aerosol scattering coupling in remote sensing of aerosol from space

This work is devoted to studies of the influence of the molecular-aerosol coupling on the scalar approximation-based aerosol satellite remote sensing procedures in the ultraviolet-near-infrared spectral range. It was found that the coupling error must be accounted in the aerosol remote sensing problems based on the analysis of the backscattered ultraviolet light.     

On the capacity of OFDM-based spatial multiplexing systems

This paper deals with the capacity behavior of wireless orthogonal frequency-division multiplexing (OFDM)-based spatial multiplexing systems in broad-band fading environments for the case where the channel is unknown at the transmitter and perfectly known at the receiver. Introducing a physically motivated multiple-input multiple-output (MIMO) broad-band fading channel model, we study the influence of physical parameters such as the amount of delay spread, cluster angle spread, and total angle spread, and system parameters such as the number of antennas and antenna spacing on ergodic capacity and outage capacity. We find that, in the MIMO case, unlike the single-input single-output (SISO) case, delay spread channels may provide advantages over flat fading channels not only in terms of outage capacity but also in terms of ergodic capacity. Therefore, MIMO delay spread channels will in general provide both higher diversity gain and higher multiplexing gain than MIMO flat fading channels     

Integrating GIS's and remote sensing image analysis systems byunifying knowledge representation schemes

The major barriers to the integration of remote sensing image analysis and geographical information system (GIS) technologies include the problems with data format, data accuracy, and system communication. This research explores a new path for achieving the integration. The three problems, which at first may seem to be independent of each other, are considered as different aspects of a problem with knowledge (information) representation and are tackled by unifying the systems on a common knowledge representation framework. Three new techniques-relational-linear quadtree, fuzzy representation method, and communication subschema-have been developed to provide such a framework     

Performance characteristics of a narrow-linewidth distributed-Bragg reflector laser for optical remote sensing systems

The performance of a novel ridge-waveguide, distributed-Bragg-reflector laser was tested for spectroscopic remote sensing applications. The laser exhibits a narrow linewidth, excellent side-mode suppression, and flexible, highly repeatable wavelength tuning. These characteristics are significant improvements over current Fabry-Perot lasers, and indicate that distributed-Bragg-reflector lasers are promising candidates for implementing advanced semiconductor-based optical remote sensing systems.     

Novel spectrum sensing method based on the spatial spectrum for cognitive radio systems

Spectrum sensing is the key problem for Cognitive Radio (CR) systems. A method based on the Peak-to-Average Amplitude-Ratio (PAAR) of the Spatial Spectrum (SS) of the received signals is proposed to sense the available spectrum for the cognitive users with the help of the multiple antennas at the receiver of the cognitive users. The greatest advantage of the new method is that it requires no information of the noise power and is free of the noise power uncertainty. Both the simulation and the analytical results show that the proposed method is robust to noise uncertainty, and greatly outperform the classical Energy Detector (ED) method.     

Microwave remote sensing from space

Spaceborne microwave remote sensors provide perspectives of the earth surface and atmosphere which are of unique value in scientific studies of geomorphology, oceanic waves and topography, atmospheric water vapor and temperatures, vegetation classification and stress, ice types and dynamics, and hydrological characteristics. Microwave radars and radiometers offer enhanced sensitivities to the geometrical characteristics of the earth's surface and its cover, to water in all its forms--soil and vegetation moisture, ice, wetlands, oceans, and atmospheric water vapor, and can provide high-resolution imagery of the earth's surface independent of cloud cover or sun angle. A brief review of the historical development and principles of active and passive microwave remote sensing is presented, with emphasis on the unique characteristics of the information obtainable in the microwave spectrum and the value of this information to global geoscientific studies. Various spaceborne microwave remote sensors are described, with applications to geology, planetology, oceanography, glaciology, land biology, meteorology, and hydrology. A discussion of future microwave remote sensor technological developments and challenges is presented, along with a summary of future missions being planned by several countries.