一种基于小波和区域的图像拼接方法

图像拼接技术在图像处理中应用非常广泛.本文给出了一种基于区域的图像拼接方法,首先对拼接的图像进行二进小波变换,在小波域中对各个小波分量进行基于区域的图像拼接,最后进行小波重构,得到完整图像.该方法计算量不大,同时二进小波的采用也平滑了图像拼接后可能出现的缝隙.     

Sub-Pixel Estimation Error Cancellation on Area-Based Matching

Area-based image matching and sub-pixel displacement estimation using similarity measures are common methods that are used in various fields. Sub-pixel estimation using parabola fitting over three points with their similarity measures is also a common method to increase the matching resolution. However, few investigations or studies have explored the characteristics of this estimation.This study analyzed sub-pixel estimation error using two different types of matching model. Our analysis demonstrates that the estimation contains a systematic error depending on image characteristics, the similarity function, and the fitting function. This error causes some inherently problematic phenomena such as the so-called pixel-locking effect, by which the estimated positions tend to be biased toward integer values. We also show that there are good combinations of the similarity functions and fitting functions.In addition, we propose a new algorithm to greatly reduce sub-pixel estimation error. This method is independent of the similarity measure and the fitting function. Moreover, it is quite simple to implement. The advantage of our novel method is confirmed through experiments using different types of images.     

基于剥夺理论的城市社会空间评价与应用

在社会阶层分化、居住空间分异加剧和新贫困问题涌现的背景下,城市规划的土地利用、公共资源分配和设施布局不能仅建立在物质空间评价基础上,还应考虑社会问题的空间分布和社会需求特征,关注城市社会空间的基础评价.首先综述了西方学界社会指标和空间评价研究,以剥夺理论为基础的社会空间和地域政策评价:再分析了中国规划领域内以物质空间为主的基础评价存在的问题:最后以广州市为例,借鉴西方研究尝试构建城市社会空间评价的指标内容、指标处理、综合和空间分析评价方法,并探讨规划启示.     

基于投影法检测光学元件面形的图形处理算法

基于线结构光扫描测量和立体视觉测量相结合的三维检测方法——投影法,能够快速准确地实现光学元件面形的在线检测,通过对采集图片的图像预处理,区域立体匹配分析,曲线拟合及面形实验等算法还原被测光学元件面形模型。实验结果表明,将这种方法用于检测光学元件可以真实还原光学元件三维外貌特性,具有实际应用价值。     

Integrated urban renewal in The Netherlands: a critical appraisal

Urban renewal policies in The Netherlands already have a long history, which is characterised by varying attention for either smaller-scale (neighbourhood) or larger-scale (city) issues, and for either physical, social or economic questions. These variations run parallel with more general discourses on urban dynamics and perceptions of processes in (urban) society at large. In this paper the recent history of urban renewal policies will be briefly sketched, including their main orientations. Recent Big Citie Policies, currently in the third generation, will receive special attention and the actual policy discourse will be critically evaluated and confronted with some essential empirical findings. In this process, the Dutch policy on integrated urban renewal shows clear parallels with the experience in other Western European countries, demonstrating that a Western European paradigm of urban policies is in the making: integrated, area-based, with involvement of both public and market partners and residents. Nevertheless, the Dutch case is more outspoken than the approaches in other Western European countries, by paying more attention to the issue of social cohesion or integration and to the promotion of social mix as a solution for a lack of social cohesion in neighbourhoods. At the same time it is clear that this new paradigm of urban policies shows the characteristics of a discourse that is not based on research and on empirical facts, but that develops its own momentum from shared beliefs regarding the nature of urban problems and the appropriate policy responses. This new paradigm needs reconsideration.     

一种基于区域立体匹配算法的实现及改进

在立体视觉中,立体匹配是立体视觉中算法中最重要也是最难的部分。如何更快更精确的建立两幅图像的匹配基元之间的对应关系,以及解决区域匹配算法计算量大等缺点,一直是立体匹配中的热点。文中首先将图象进行外极线校正,在此基础上,采用一种隐含约束条件结合唯一性约束条件的单向匹配算法(SMP算法),完成了初次匹配及初次去除伪匹配,再采用一种伪极线约束条件,对得到的匹配对进行二次去除伪匹配,最后,对得到的视差图进行插值运算,提高了匹配精度。另外,在匹配过程中,通过Box滤波加速方法,减少了计算匹配窗口相似性的复杂度,缩短了程序运行时间,可以满足系统对实时性的要求。     

基于NSCT的SMP立体匹配算法研究

针对区域立体匹配算法中匹配窗口自适应选择的难点,提出一种基于多尺度分析Nonsubsampled Contourlet变换(NSCT)的快速区域立体匹配新算法.首先介绍NSCT并对其时移不变性进行讨论.采用由粗到精的匹配策略和快速的SMP匹配代价函数降低运算量.实验结果表明,该算法具有很高准确率.     

基于面积分布的3D模型检索技术

基于内容的3D模型检索技术难以提取形状特征,该文通过提取表面面积分布来表示3D模型的形状特征,采用主分量分析方法确保特征满足平移不变性、旋转不变性、对称不变性。以切分块内三角面片面积和与总面积的比值作为特征,确保缩放不变性。二次型形式的距离公式计算的相似度能够有效地区分特征分量的空间位置。实验表明,基于面积分布的检索技术具有较好的检索效果。     

SIFT特征点引导的区域立体匹配算法

根据SIFT特征对旋转、尺度缩放、亮度变化保持不变性的特点,提出基于SIFT特征和边缘特征点的区域匹配方法。该方法确定符合SIFT特征的边缘为可靠特征点,并确定其视差;根据视差梯度原理确定其他点的视差,最后生成稠密的视差图。实验结果表明,SIFT特征的引入,提高了特征点视差的准确性,一些弱纹理区的匹配也有所改善。     

Context-Orientated Meta-Governance in Danish Urban Regeneration

Public service innovation is common in planning and urban policy, but the long-term sustainability of new policy instruments depends on the development of new administrative practices in local government to maintain continual progress. This article analyses the case of a large-scale experiment on organisational change that was conducted in collaboration between two separate municipal departments of the city of Copenhagen. Experience with emerging new patterns of intra- and inter-organisational interaction documents suggests that service innovation and organisational change in this case mutually reinforce each other in a virtuous circle of innovation.