基于继承PSO算法的动态脑磁共振图像配准

提出了一种用于动态图像配准的混合角点继承PSO算法。该方法采用混合角点检测算子来提取角点,并将继承最优种群的思想引入到PSO优化算法中,即对当前图像配准得到的最优种群进行动态继承与变化后,再用于指导后续图像的配准。实验表明：所提出的算法不仅克服了传统的随机重启方式的脑磁共振图像配准算法中随机设定参数导致配准速度慢的问题,而且提高了图像的配准精度和稳定性。     

尽快熟悉REACH积极应对REACH

扼要介绍了REACH的内容与特点,以及对中国化工出口的影响与对策。     

A new Image Registration technique with free boundary constraints: application to mammography

In this paper, a new image-matching mathematical model is presented with its application to mammogram registration. In a variational framework, an energy minimization problem is formulated and a multigrid resolution algorithm is designed. The model focuses on the matching of regions of interest. It also combines several constraints which are both intensity- and segmentation-based. A new feature of our model is combining region matching and segmentation by formulation of the energy minimization problem with free boundary conditions. Moreover, the energy has a new registration constraint. The performances of the new model and an equivalent model with fixed boundary conditions are compared on simulated mammogram pairs. It is shown that the model with free boundary is more robust to initialization inaccuracies than the one with fixed boundary conditions. Both models are applied to several real bilateral mammogram pairs. The model ability to compensate significantly for some normal differences between mammograms is illustrated. Results suggest that the new model could enable some improvements of mammogram comparisons and tumor detection system performances.     

基于复形法配准工业产品CT切片模型和CAD模型

在对工业产品进行体积CT扫描时．会存在定住偏差问题，所以工业产品CT切片模型与其CAD模型之间的配准是必不可少的。首先从CT切片模型的表面选取n个点，再把这n个点到CAD模型的距离平方和作为目标函数，通过复形法搜索目标函数极小值，就可求出空间变换的位置匹配参数和角度匹配参数。仿真结果表明．利用复形法可得到满意的结果。     

简单城市:现象方法和空间比兴一个西部城镇整体重建中的方法研究

从对城市学科技术体系的质疑开始, 分析技术理性的对象性城市与日常城市的本质差异。从现象直观上明辨城市为关于社会空间的界定、分配和组织的场所体系,沿着地方性、城市生活和与空间现象的义理关系,以丰都规划为例,对其空间现象分为经营、演化和运行三个基本方面进行梳理。总结出空间比兴的现象方法和简单城市的营城理念。     

Architects as Hairdressers

Neil Spiller reactionary? Spiller finds himself recoiling into a ‘grumpy old man’ as he observes the emergence of an alarming new trend in architecture schools that prioritises style over matter. Copyright © 2008 John Wiley & Sons, Ltd.     

涡轮叶片形状检测中的模型配准控制点集选取

叶片模型的配准定位是叶片形状检测与分析的一个核心环节。为解决基于迭代最近点方法的叶片密集测量数据与其CAD模型的可靠配准问题,提出一种基于CAD模型的配准控制点集选取方法。结合模型配准可靠性分析技术,预先在叶片CAD模型规划出配准基准点集;通过测量数据与配准基准点集的配准运算,把配准基准点集映射到叶片测量数据上,获取测量模型上对应的配准控制点集;滤除其中可能降低模型配准精度的坏点,得到最终的叶片模型配准控制点集。进行基于仿真与实测数据的叶片模型配准试验及对比分析,总结出一些可用于指导叶片模型配准控制点集选取的策略。结果表明,所提出的叶片模型配准控制点集选取方法是可行的。     

Augmenting reality by using uncalibrated optical tracking

The paper describes the use of an optical tracking method for superimposing computer-generated images oriented and positioned in 3D to augment a real scene. In a medical scenario, a physician may view the images created by an ultrasound device directly related to the patient. Typically, the position of the images or the position of the physician changes almost always and the mapping of images has to be recalculated. The optical tracking method in combination with artificial landmarks, is used to get the information about how to transform the superimposed images After segmenting and tracking the landmarks the perspective transformation of the ultrasonic image can be determined.     

Improving Feature Tracking with Robust Statistics

This paper addresses robust feature tracking. The aim is to track point features in a sequence of images and to identify unreliable features resulting from occlusions, perspective distortions and strong intensity changes. We extend the well-known Shi–Tomasi–Kanade tracker by introducing an automatic scheme for rejecting spurious features. We employ a simple and efficient outliers rejection rule, called X84, and prove that its theoretical assumptions are satisfied in the feature tracking scenario. Experiments with real and synthetic images confirm that our algorithm consistently discards unreliable features; we show a quantitative example of the benefits introduced by the algorithm for the case of fundamental matrix estimation. The complete code of the robust tracker is available via ftp. Received: 22 January 1999, Received in revised form: 3 May 1999, Accepted: 3 May 1999