False topographic perception phenomena observed with the satellite images of Moon's surface

False Topographic Perception Phenomena (FTPP) are commonly observed in images of rugged terrain on the surface of the Earth acquired by polar-orbiting satellites. It is interesting to note that due to the absence of atmosphere, vegetation and presence of numerous craters on its surface, the Moon illustrates very vividly and uniquely FTPP, which is less obvious with images of the Earth. In this article images of the Moon taken during the six missions of the NASA Apollo programme and from the Chandrayan-1 Indian satellite are used to demonstrate FTPP on the surface of the Moon. Numerous craters present on the surface of the Moon are perceived as hillock/plateau and vice versa. Combinations of various interrelated factors, for example topographic relief, observer position, Sun azimuth and elevation angles, are responsible for FTPP. Craters in the northern hemisphere of the Moon exhibit FTPP as the Moon's surface was imaged from southern side under equatorial illumination.     

A simple method to account for topography in the radiometric correction of radar imagery

This article presents a method to study and correct radiometric distortions caused by topography in SAR images. The method is easy to implement and requires neither sophisticated software nor code-level programming. It also considers the case of a flat surface having an elevation different from the one for which calibration parameters were derived. An ortho-image of the slant range distance is used with a Digital Elevation Model to generate images of the local incident angle along the range and azimuth directions. The method compensates for variations in the terrain area of each pixel and for the angular dependence of backscatter, allowing the choice of either an empirical or semi-empirical scattering model. The method is applied to high-resolution C-SAR subsets of an agricultural area in the Central Cordillera of Costa Rica. The removal of topographic features appears excellent for local incident angles up to 80°, but small-scale structures have pronounced effects on the radar return for higher local incident angles and are not adequately corrected.     

基于正交投影校正的算法及其应用

基于正交投影的校正算法是近年来在光谱处理上显得较活跃的一种方法。本文介绍了基于正交投影的校正算法的基本原理，并对S．Wold、Fearn等人的比较成熟的5种基于正交投影的校正算法作了比较详细地介绍。最后对5种算法在谷物和柴油的近红外数据上的应用进行了比较和讨论。     

A refined jacobi-davidson method and its correction equation

A central problem in the Jacobi-Davidson method is to expand a projection subspace by solving a certain correction equation. It has been commonly accepted that the correction equation always has a solution. However, it is proved in this paper that this is not true. Conditions are given to decide when it has a unique solution or many solutions or no solution. A refined Jacobi-Davidson method is proposed to overcome the possible nonconvergence of Ritz vectors by computing certain refined approximation eigenvectors from the subspace. A corresponding correction equation is derived for the refined method. Numerical experiments are conducted and efficiency of the refined method is confirmed.     

传感网络虚假信息避免与过滤方法研究与仿真

研究网络假信息过滤控制问题,由于无线传感网络中的节点分布随机性很强,很容易被捕获造成大量的虚假信息被输入,干扰正常通信.受到节点随机性部署的限制,传统算法中缺少节点布置位置风险检测功能和信息校验功能,一旦虚假信息被注入会大幅影响通信效果.提出一种利用位置约束与虚假信息过滤的无线传感网络虚假信息过滤算法,在节点布局过程中对布局的位置信息进行校验,加入位置校验修复因子对节点位置联系进行合理的风险分析,降低节点捕获风险.运用节点信息聚类关联性的特点,对虚假信息进行校验,判断是否为真实的信息关联,过滤虚假信息.实验结果表明,过滤算法能够分布更合理的位置信息,对虚假信息过滤精度较高,同时也改善了网络的稳定性.     

Ultrasonic sensor data integration and its application to environment perception

To move in an unknown or uncertain environment, a mobile robot must collect information from various sensors and use it to construct a representation of the external world. Ultrasonic sensors can provide range data for this purpose in a simple and cost-effective way. However, most ultrasonic sensors are not sufficient for environment recognition because of their large beam opening angles. In this article the beam-opening-angle problem is solved by fusing data from multiple ultrasonic sensors. We propose two methods for sensor data fusion. One uses an artificial neural network (ANN), and the other is based on a mathematical model. Simulations and experiments show that the mathematical model is more accurate when there is no noise in the sensor readings, but the ANN method is better when the sensors are subject to much noise. To extract line segments from the ultrasonic image, we develop a line extractor that is more efficient than traditional line fitting methods in this application. Experimental results show that this method is effective for environment perception in a robotic system. © 1996 John Wiley & Sons, Inc.     

人眼灰度感知建模及其在图像增强中的应用

原直方图均衡化算法处理结果不理想,主要是图像灰度域上实现的均衡化并不代表人眼感知亮度域上的均衡化,对此提出人眼感知亮度域上的直方图均衡化算法,但由于使用的灰度人眼感知模型不准确,处理效果也没有得到明显的改善。提出一种灰度人眼感知模型的建模方法,利用实验测试的方法得到人眼视觉系统临界可见偏差曲线;再推导得到人眼对不同灰度背景下同等灰度差别的敏感度曲线;接着利用上一步结果再通过积分和归一化方法得到灰度人眼感知模型;根据以上灰度人眼感知模型对直方图均衡化算法进行改进。对比实验结果表明,提出算法相比于原直方图均衡化具有明显的改善效果,相比于CLAHE、BBHE以及HMF等直方图改进算法,也具有无需参数调节,增强效果显著和适应性强等优点。     

MODIS observations of the bottom topography and its inter-annual variability of Poyang Lake

Using MODIS 250-m resolution data, we developed a novel approach to derive the bottom topography of Poyang Lake, the largest freshwater lake of China (> 3000 km² at maximum inundation) for every year between 2000 and 2009. The approach differs from other traditional methods (sonar, Lidar, optical inversion, and Radar) but takes advantage of the fast-changing nature of the lake's inundation area. On every image, the water/land boundary is effectively a topographic isobath after correction for the water level gradient. Thus, the ~ 10/year carefully selected MODIS images provided incremental topographic isobaths, from which bottom topography was derived every year. Such-derived topographic maps were validated using limited historical data and other consistency checks. Most of the lake bottom showed an elevation of 12 m to 17 m (referenced against the elevation reference of the Woosung Horizontal Zero). Significant inter-annual variability of the bottom topography from 2000 to 2009 was found for some of the lake's bottom, with more areas associated with bottom elevation increases than decreases. The changes and inter-annual variability in the bottom topography were attributed to the combined effect of human activities (e.g., sand dredging and levee construction) and weather events. One example was the increased bottom elevation from 2002 to 2003, which was apparently due to the excessive precipitation in 2002 and the impoundment of the Three-Gorges Dam in 2003. The 10-year record of the bottom topography of this highly dynamic lake provides baseline information to monitor the impact of future engineering and management activities, to estimate the lake's water and sediment budgets, and to aid ship navigation.     

控制点误差传播模型及其应用

为了获取遥感影像几何纠正误差空间分布情况,提出一种纠正控制点误差传播模型。该模型首先定义了控制点误差,然后按照控制点误差造成纠正模型参数估计的不确定,通过纠正模型传递至整个区域的建模思路构建了控制点误差传播模型。为将模型推广至更一般的情况,定义了表观控制点误差对误差传播模型进行修正。模拟试验表明,应用该模型可以分析纠正模型的适用性,以及纠正控制点数量、质量及空间分布对纠正精度的影响,为纠正控制点选择和优化提供了一种定量分析方法,对遥感产品应用和成果质量控制具有重要意义。     

Depth perception using blurring and its application in VLSI wafer probing

In this paper, we present a technique for measuring the amount of blur of an edge and using this information to determine the distance of a micromanipulator probe from a wafer surface in very large scale integration (VLSI) wafer probing. In this application, a soft and reliable touch of the probe with a metal pad in the wafer is a sensitive operation. The wafer is focused and several images of the probe while approaching the wafer are analyzed. In our theory, the amount of blur is calculated from the height of the step edge and the slope of the intensity profile at the zero crossing. Hence, our formula is simple and easy to use. We estimate the distance of the probe from the surface of the wafer and obtain a robust measure, i.e., one which is valid even in the presence of significant noise in the images. In order to validate our methods, we have experimented with various VLSI patterns as backgrounds.     

感知矿山物联网愿景与发展趋势

给出了矿山物联网的愿景,即实现矿山物与物相连,减少甚至消除监测盲区,运用云计算和大数据技术提取有用的监测信息,真正实现本质安全矿山;从技术和服务模式2个方面梳理了矿山物联网的发展趋势,阐述了雾计算技术、网络分形结构、矿山物体的本体描述与知识化、云计算与大数据技术等概念及其在矿山物联网中的应用与发展,对协同工作模式和购买服务模式进行了展望。     

True multi-image alignment and its application to mosaicing andlens distortion correction

Multiple images of a scene are related through 2D/3D view transformations and linear and nonlinear camera transformations. We present an algorithm for true multi-image alignment that does not rely on the measurements of a reference image being distortion free. The algorithm is developed to specifically align and mosaic images using parametric transformations in the presence of lens distortion. When lens distortion is present, none of the images can be assumed to be ideal. In our formulation, all the images are modeled as intensity measurements represented in their respective coordinate systems, each of which is related to an ideal coordinate system through an interior camera transformation and an exterior view transformation. The goal of the accompanying algorithm is to compute an image in the ideal coordinate system while solving for the transformations that relate the ideal system with each of the data images. Key advantages of the technique presented in this paper are: (i) no reliance on one distortion free image, (ii) ability to register images and compute coordinate transformations even when the multiple images are of an extended scene with no overlap between the first and last frame of the sequence, and (iii) ability to handle linear and nonlinear transformations within the same framework. Results of applying the algorithm are presented for the correction of lens distortion, and creation of video mosaics     

Evaluation of terrain effect on microwave radiometer measurement and its correction

We develop a new technique for terrain correction of coarse resolution satellite microwave radiometer measurements using the high-resolution digital elevation model (DEM). With the high-resolution DEM and a facet model, we first simulated the terrain influences that resulted from both effects of local incidence and polarization rotation (PR) on the microwave radiometer measurements at the different scales of the radiometer footprints. The emissivity signals of bare surfaces are more sensitive on incidence and PR than vegetated surfaces. So the emissivities at different incidence angles of the bare surface generated by the advanced integral equation model (AIEM) were used to simulate the terrain effects on the satellite measurements. It was found that (1) the PR effect at the satellite footprint can be corrected using the absolute mean PR angle from all facets within the footprint, and (2) the satellite measurements can be described as from a mean incidence angle. Both angles can be obtained from all facets within the footprint with the high-resolution DEM and the satellite viewing geometry. Therefore, a corresponding terrain-correction technique was developed for satellite brightness temperature measurements. We also demonstrate the terrain effects on the satellite measurements from the advanced microwave scanning radiometer–earth observing system (EOS) (AMSR-E).     

Frame rate as a QoS parameter and its influence on speech perception

The preservation of QoS for multimedia traffic through a data network is a difficult problem. We focus our attention on video frame rate and study its influence on speech perception. When sound and picture are discrepant (e.g., acoustic ‘ba’ combined with visual ‘ga’), subjects perceive a different sound (such as ‘da’). This phenomenon is known as the McGurk effect. In this paper, the influence of degraded video frame rate on speech perception is studied. It is shown that, when frame rate decreases, correct hearing is improved for discrepant stimuli and is degraded for congruent (voice and picture are the same) stimuli. Furthermore, we studied the case where lip closure was always captured by the synchronization of sampling time and lip position. In this case, frame rate has little effect on mishearing for congruent stimuli. For discrepant stimuli, mishearing is decreased with degraded frame rate. These results indicate that the stiff motion of lips resulting from low frame rate cannot give enough labial information for speech perception. In addition, the effect of delaying the picture to correct for low frame rate was studied. The results, however, were not as definitive as expected, because of compound effects related to the synchronization of sound and picture. Finally, we inspected the still pictures of normal Japanese speech and determined a lower limit of frame rate from the view point of assisting hearing.     

带权约简及其在汉语词性标注自动校对中的应用

提出带权约简的概念,并研究了带权约简算法．首先指出已有约简算法无法融合人类的先验知识;然后提出使用权值向量表示这类知识,用于属性重要性的计算,获得基于区分能力的带权约简算法,并分析带权约简与经典约简的关系;最后将算法应用于汉语词性标注自动校对,并讨论了权值向量的具体设置．实验结果表明,使用所提出的算法及相应权值向量,可获得更有利于预测的约简．     

Network recognition of an MOS integrated circuit from the topography of its masks

Technological data and geometric dimensions of mask patterns define the properties of integrated circuits. These parameters cannot, however, be used directly to analyse the circuits. The MASOB computer program can be used for recognizing the topology and parameters of a lumped-parameter network matched to the integrated circuits. The network can then be readily analysed. Silicon gate MOS technology is assumed. The paper presents the principles of the basic algorithms of the MASOB computer program, written in FORTRAN, and an example of application.     

传统NIDS漏报和误报起因及改进技术

传统的网络入侵检测系统大都采用模式匹配的方法进行入侵检测,有着非常高的漏报率和误报率。本文通过对模式匹配算法检测过程的描述,对其产生漏报和误报的原因进行了分析。针对模式匹配算法带来的高漏报率和误报率,引入了协议分析的方法。协议分析方法通过辨别数据包的协议类型,然后使用相应的数据分析程序进行检测。这种方法可以大幅度地降低漏报率和误报率,大大地提高了入侵检测系统的效率。