基于高亮特征匹配的双视向SAR图像建筑物高度提取

由于城区场景的复杂性和SAR成像几何畸变的影响,基于单幅SAR图像的建筑物高度提取常常存在很大困难。针对这一问题,利用建筑物目标SAR成像形成的叠掩、二次散射、较强单次散射等散射机制对应的高亮特征非常典型,并且对方向性敏感的特点,提出了一种基于双视向SAR图像高亮特征与几何模型匹配的建筑物高度提取方法。首先分析了建筑物目标的SAR图像散射特征及对雷达视向的敏感性,然后构造了建筑物目标在双视向SAR图像上高亮特征几何模型,然后基于灰度均值、灰度概率分布、边界信息定义匹配函数,并利用多种群遗传算法进行优化求解,最终得到建筑物目标的高度信息。基于模拟和机载SAR图像的试验表明该方法的建筑物高度平均反演误差小于1m,可以有效提高建筑物高度反演的精度。     

基于水平集的SAR图像建筑物区域检测

根据合成孔径雷达(SAR)图像建筑物成像的特点,采用基于水平集的分割方法对SAR图像建筑物区域进行检测。结合基于指数小波提取的SAR图像梯度边缘信息,以及基于变差函数提取的SAR纹理特征,建立能量函数模型,进行曲线演化分割从而提取目标。实验结果表明,与基于灰度信息的模型相比,该模型可以准确、快速地检测出大场景SAR图像中的建筑物区域。     

基于L型结构中心线的SAR图像建筑物提取方法

针对在高分辨率SAR图像上具有明显L型结构高亮特征的建筑物目标,提出了一种提取高分辨率SAR图像建筑物L型结构中心线,并进而提取建筑物几何信息的方法.运用基于Gabor纹理特征和模糊C均值的方法对SAR图像进行分割,再结合骨架提取、骨架跟踪、最小外接矩形提取、最小二乘准则等技术实现了L型结构中心线的提取,最后利用中心线获取了建筑物的长度、宽度和方位角信息.基于机载SAR图像的实验表明,利用提出的方法从SAR图像提取的建筑物几何结构和方位信息具有较高的精度.     

高分辨率SAR图像建筑物三维成像几何结构分析

随着SAR分辨率的不断提高,建筑物在SAR图像上表现出越来越明显的几何结构特征,这些特征为重建建筑物三维模型提供了重要的信息。主要论述了建筑物在SAR图像上的成像几何结构,并给出了利用SAR图像上建筑物L型的叠掩结构反演建筑物三维结构的理论基础和方法,最后通过实验证明了该方法的可行性。     

联合显著性与MRF的SAR建筑物分割算法

针对经典马尔可夫随机场（MRF）在进行高分辨率SAR图像分割时存在容易受到斑点噪声干扰等问题,提出一种基于建筑物指数相似度距离及MRF模型（BISD-MRF）的高分辨率SAR建筑物分割算法。基于较复杂SAR场景下建筑物目标可能呈现多种形态结构的问题,设计一种多尺度显著性建筑物指数（MSBI）方案来提取建筑物目标的显著性特征,并通过强度信息重构、纹理显著性提取、频谱显著性信息统计来分别提取不同类型区域的显著性信息,构建适用于SAR建筑物目标的显著性模型。在此基础上,将MSBI值引入到改进的基于改进余弦函数的势函数模型中,利用余弦函数对邻域像素MSBI值进行相似性度量,同时利用特征空间语义信息对像素及其邻域像素标签信息进行有效约束,以提升势函数模型对高分辨率SAR建筑物目标的表征能力。不同平台下的建筑物分割实验结果表明,与MRF、MBI、FRFCM等算法相比,本文算法分割性能平均提升了4.3~10.7个百分点,更适用于较复杂场景下高分辨率SAR建筑物的分割任务。     

SAR图像建筑物成像特性及重建研究方法

基于SAR图像中平面屋顶建筑物的成像机理,介绍SAR图像中建筑物的信息获取和重建方法,包括成像特性、建筑物平面长条屋顶的提取、建筑物高度计算.通过成像原理,利用建筑物二次散射亮线及叠掩、阴影区域定位建筑物屋顶区域,再结合叠掩、阴影区域反推出建筑物高度的计算公式,实现建筑物三维重建.     

基于线特征和控制点的可见光和SAR图像配准

以具有典型人造目标的可见光和SAR (Synthetic aperture radar)图像为研究对象,提出一种自适应多尺度快速Beamlet变换方法提取人造目标在可见光和SAR图像的共有特征---线特征, 并基于线特征构造控制点,设计了一种基于控制点特征的匹配度函数,采用基于特征一致的粗配准和基于控制点的精确配准方法,对待配准图像实现由粗到精的自动配准. 实验表明,在可见光和SAR图像存在较大灰度差异、旋转和平移的情况下,该算法仍然能够精确配准图像.     

利用多尺度SVM-CRF模型的极化SAR图像建筑物提取

极化SAR图像中建筑物相关特征的不充分利用将影响建筑物提取的有效性或引发错误。为解决该问题,提出了一种利用多尺度SVM-CRF模型的极化SAR图像建筑物提取方法。在图像最优分割的基础上,将基于像素的SVM-CRF模型扩展到面向对象的多尺度SVM-CRF模型,使之能同时有效地描述建筑物突出的"面状"特征及其层次、空间上下文相关性。同时,考虑对建筑物描述特征利用不充分所引起的类别模糊问题,使用随机森林算法实现多特征的选择,形成更有效的特征组合以优化SVM-CRF模型中的特征向量。采用Oberpfaffenhofen地区E-SAR数据进行了实验,定性和定量的结果验证了该方法的有效性和准确性。     

干涉、极化干涉SAR技术森林高度估测算法研究进展

在干涉、极化干涉SAR森林高度估测中,估测算法对结果精度起着决定性作用。通过对现有森林高度干涉、极化干涉SAR研究的系统性分析,总结了现有研究中森林高度估测算法的基本原理、模型假设及其应用局限性,并对这些算法在区域和全球尺度森林高度反演中的潜力进行了分析。总结发现,基于干涉SAR技术的DSM-DEM差分法在森林高度反演中精度较高,与极化干涉SAR算法相比,受到森林类型、结构的影响较小,在区域和全球尺度森林高度反演中具有很大潜力。但是其局限性在于是否能够获取大范围高精度的DEM;极化干涉SAR技术利用了森林的极化散射特点,不受DEM的限制,可以大范围地进行森林高度反演,但是在森林异质性大的区域,仍然需要进一步分析森林特征对不同波长相位及相干幅度的影响,根据森林的微波散射原理拓展微波散射模型,才能进一步提高估测结果和精度。此外,由于单基线干涉SAR、极化干涉SAR对森林垂直结构可见性差,因此,发展多维度、多基线SAR及其相应算法并朝这个方向拓展是未来采用干涉SAR、极化干涉SAR进行森林高度反演的主要方向。     

SAR影像建筑物提取与高度反演研究综述

基于SAR影像进行建筑物提取与高度反演,可行的技术方法种类繁多。以使用的影像数量和分辨率为序,以使用的灰度、相位、极化信息为核心,分别从二维提取、三维高度反演两个方面总结了这一技术主题的研究发展现状;并结合当前SAR影像高分辨率、全极化的数据特点和国际最新研究动向,对这一研究方向进行了展望。     

Only connect: teaching, technology and telesis

Abstract This paper describes an approach to the design of interactive multimedia materials being developed in a European Community project. The developmental process is seen as a dialogue between technologists and teachers. This dialogue is often problematic because of the differences in training, experience and culture between them. Conditions needed for fruitful dialogue are described and the generic model for learning design used in the project is explained.     

European Community policy and the market

Abstract This paper starts with some reflections on the policy considerations and priorities which are shaping European Commission (EC) research programmes. Then it attempts to position the current projects which seek to capitalise on information and communications technologies for learning in relation to these priorities and the apparent realities of the marketplace. It concludes that while there are grounds to be optimistic about the contribution EC programmes can make to the efficiency and standard of education and training, they are still too technology driven.     

一种自适应子融合集成多分类器方法

融合集成方法已经广泛应用在模式识别领域,然而一些基分类器实时性能稳定性较差,导致多分类器融合性能差,针对上述问题本文提出了一种新的基于多分类器的子融合集成分类器系统。该方法考虑在度量层融合层次之上通过对各类基多分类器进行动态选择,票数最多的类别作为融合系统中对特征向量识别的类别,构成一种新的自适应子融合集成分类器方法。实验表明,该方法比传统的分类器以及分类融合方法识别准确率明显更高,具有更好的鲁棒性。     

Avoiding semantic and temporal gaps in developing software intensive systems

Development of software intensive systems (systems) in practice involves a series of self-contained phases for the lifecycle of a system. Semantic and temporal gaps, which occur among phases and among developer disciplines within and across phases, hinder the ongoing development of a system because of the interdependencies among phases and among disciplines. Such gaps are magnified among systems that are developed at different times by different development teams, which may limit reuse of artifacts of systems development and interoperability among the systems. This article discusses such gaps and a systems development process for avoiding them.     

Designing economic np control charts: A programmed simulation approach

This paper presents control charts models and the necessary simulation software for the location of economic values of the control parameters. The simulation program is written in FORTRAN, requires only 10K of main storage, and can run on most mini and micro computers. Two models are presented - one describes the process when it is operating at full capacity and the other when the process is operating under capacity. The models allow the product quality to deteriorate to a further level before an existing out-of-control state is detected, and they can also be used in situations where no prior knowledge exists of the out-of-control causes and the resulting proportion defectives.     

The development of robot art

Going through a few examples of robot artists who are recognized worldwide, we try to analyze the deepest meaning of what is called “robot art” and the related art field definition. We also try to highlight its well-marked borders, such as kinetic sculptures, kinetic art, cyber art, and cyberpunk. A brief excursion into the importance of the context, the message, and its semiotics is also provided, case by case, together with a few hints on the history of this discipline in the light of an artistic perspective. Therefore, the aim of this article is to try to summarize the main characteristics that might classify robot art as a unique and innovative discipline, and to track down some of the principles by which a robotic artifact can or cannot be considered an art piece in terms of social, cultural, and strictly artistic interest. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008     

Explanation and prediction: an architecture for default and abductive reasoning

Although there are many arguments that logic is an appropriate tool for artificial intelligence, there has been a perceived problem with the monotonicity of classical logic. This paper elaborates on the idea that reasoning should be viewed as theory formation where logic tells us the consequences of our assumptions. The two activities of predicting what is expected to be true and explaining observations are considered in a simple theory formation framework. Properties of each activity are discussed, along with a number of proposals as to what should be predicted or accepted as reasonable explanations. An architecture is proposed to combine explanation and prediction into one coherent framework. Algorithms used to implement the system as well as examples from a running implementation are given.     

Three Process Perspectives: Organizations, Teams, and People

This paper provides the author's personal views and perspectives on software process improvement. Starting with his first work on technology assessment in IBM over 20 years ago, Watts Humphrey describes the process improvement work he has been directly involved in. This includes the development of the early process assessment methods, the original design of the CMM, and the introduction of the Personal Software Process (PSP)^SM and Team Software Process (TSP){^SM}. In addition to describing the original motivation for this work, the author also reviews many of the problems he and his associates encountered and why they solved them the way they did. He also comments on the outstanding issues and likely directions for future work. Finally, this work has built on the experiences and contributions of many people. Mr. Humphrey only describes work that he was personally involved in and he names many of the key contributors. However, so many people have been involved in this work that a full list of the important participants would be impractical.     

基于复小波噪声方差显著修正的SAR图像去噪

提出了一种基于复小波域统计建模与噪声方差估计显著性修正相结合的合成孔径雷达(Synthetic Aperture Radar,SAR)图像斑点噪声滤波方法。该方法首先通过对数变换将乘性噪声模型转化为加性噪声模型,然后对变换后的图像进行双树复小波变换(Dualtree Complex Wavelet Transform,DCWT),并对复数小波系数的统计分布进行建模。在此先验分布的基础上,通过运用贝叶斯估计方法从含噪系数中恢复原始系数,达到滤除噪声的目的。实验结果表明该方法在去除噪声的同时保留了图像的细节信息,取得了很好的降噪效果。     

How do children do mathematics with LOGO?

Abstract  This paper considers some results of a study designed to investigate the kinds of mathematical activity undertaken by children (aged between 8 and 11) as they learned to program in LOGO. A model of learning modes is proposed, which attempts to describe the ways in which children used and acquired understanding of the programming/mathematical concepts involved. The remainder of the paper is concerned with discussing the validity and limitations of the model, and its implications for further research and curriculum development.