利用改进的ICCP算法辅助导航

文中研究了ICCP算法的基本原理,分析了ICCP算法的特点,针对ICCP实时性差的不足,借鉴计算机编程思想中的移位寄存器原理给出了改进ICCP算法,同时,改进ICCP算法中每个采样点都可以有多个匹配结果,通过对这些匹配结果求加权平均可以有效消弱结果中的随机误差,从而提高了匹配的可靠性。并通过一个仿真实例,表明改进ICCP算法可以有效改善ICCP算法的实时性,经度方向精度与ICCP算法相当,纬度方向精度有明显的提高。     

基于特征点的影像匹配方法探讨

基于特征点的图像匹配方法是高精度、快速有效和适用性广的匹配算法,它包括特征提取和特征匹配2个步骤。本文在对这一问题进行研究分析的基础上,对相关文献进行综述,介绍并分析了几种典型特征点提取算子的原理和优缺点,为不同应用目的的特征点提取方法选取提供借鉴;特征匹配方面总结了基于特征点匹配的常用方法,就SIFT这一热点做了详细介绍,并进行了实验;最后对匹配中有待进一步研究的问题给出了意见。     

3D Motion parameters determination based on binocular sequence images

Exactly capturing three dimensional (3D) motion information of an object is an essential and important task in computer vision, and is also one of the most difficult problems. In this paper, a binocular vision system and a method for determining 3D motion parameters of an object from binocular sequence images are introduced. The main steps include camera calibration, the matching of motion and stereo images, 3D feature point correspondences and resolving the motion parameters. Finally, the experimental results of acquiring the motion parameters of the objects with uniform velocity and acceleration in the straight line based on the real binocular sequence images by the mentioned method are presented.     

Image relaxation matching based on feature points for DSM generation

In photogrammetry and remote sensing, image matching is a basic and crucial process for automatic DEM generation. In this paper we presented a image relaxation matching method based on feature points. This method can be considered as an extention of regular grid point based matching. It avoids the shortcome of grid point based matching. For example, with this method, we can avoid low or even no texture area where errors frequently appear in cross correlation matching. In the mean while, it makes full use of some mature techniques such as probability relaxation, image pyramid and the like which have already been successfully used in grid point matching process. Application of the technique to DEM generaton in different regions proved that it is more reasonable and reliable.     

An integrated heterogeneous web service retrieval via combination of instance- and metadata-based schema matching method

Schema matching is a critical step in the integration of heterogeneous web service, which contains various types of web services and multi-version services of the same type. Mapping loss or mismatch usually occurs due to schema differences in structure and content and the variety in concept definition and organization. Current instance schema matching methods are not mature enough for heterogeneous web service because they cannot deal with the instance data in web service domain and capture all the semantics, especially metadata semantics. The metadata-based and the instance-based matching methods, in the case of being employed individually, are not efficient to determine the concept relationships, which are crucial for finding high-quality matches between schema attributes. In this paper, we propose an improved schema matching method, based on the combination of instance and metadata (CIM) matcher. The main method of our approach is to utilize schema structure, element labels, and the corresponding instance data information. The matching process is divided into two phases. In the first phase, the metadata-based matchers are used to compute the element label similarity of multi-version open geospatial consortium web service schema, and the generated matching results are raw mappings, which will be reused in the next instance matching phase. In the second phase, the designed instance matching algorithms are employed to the instance data of the raw mappings and fine mappings are generated. Finally, the raw mappings and the fine mappings are combined, and the final mappings are obtained. Our experiments are executed on different versions of web coverage service and web feature service instance data deployed in Geoserver. The results indicate that, the CIM method can obtain more accurate matching results and is flexible enough to handle the web service instance data.     

Matching authority and VGI road networks using an extended node-based matching algorithm

The amount of volunteered geographic information (VGI) has increased over the past decade, and several studies have been conducted to evaluate the quality of VGI data. In this study, we evaluate the completeness of the road network in the VGI data set OpenStreetMap (OSM). The evaluation is based on an accurate and efficient network-matching algorithm. The study begins with a comparison of the two main strategies for network matching: segment-based and node-based matching. The comparison shows that the result quality is comparable for the two strategies, but the node-based result is considerably more computationally efficient. Therefore, we improve the accuracy of node-based algorithm by handling topological relationships and detecting patterns of complicated network components. Finally, we conduct a case study on the extended node-based algorithm in which we match OSM to the Swedish National Road Database (NVDB) in Scania, Sweden. The case study reveals that OSM has a completeness of 87% in the urban areas and 69% in the rural areas of Scania. The accuracy of the matching process is approximately 95%. The conclusion is that the extended node-based algorithm is sufficiently accurate and efficient for conducting surveys of the quality of OSM and other VGI road data sets in large geographic regions.     

MapGIS地质图到SuperMap格式转换的关键方法的实现

在国土GIS软件产品的开发中,各种专题图的制作是系统构建的重点,也是实现国土资源"矿政一张图"式管理的核心。目前,各级国土资源管理部门现有的图件资料多已MapGIS数据格式为主,其中以地质图的情况尤为突出。由于当前MapGIS数据格式与SuperMap格式无法直接实现转换,这就给产品的开发造成不便,导致人力成本和时间成本的增加。为此,本文提出了一种基于空间数据转换处理系统(FME)进行数据格式批量转换的方法,并通过设置实现对原图件颜色信息的获取。在此基础上,通过程序编写进一步将图件的颜色信息转换为XML格式的专题图文件。经过以上步骤,不仅实现了地质图从MapGIS格式到SuperMap格式的转换,而且还保留了原图件的配色方案。在减少工作量、缩短工作时间的同时,提高了专题图的实用性,为国土GIS软件产品在行业中的广泛应用奠定了扎实的基础。     

基于非二次幂Curvelet变换的最小二乘匹配算法及其应用

本文提出了基于非二次幂Curvelet变换的最小二乘匹配算法.首先,根据输入地震信号的频谱和方向等特征进行非二次幂Curvelet变换,根据其特征不同,最大程度地将有效信号和噪声分开;然后,在噪声能量集中的非二次幂Curvelet子记录上对输入数据和预测的噪声模型进行最小二乘匹配滤波处理.本方法提高了常规最小二乘匹配算法在时间空间域内进行信噪分离的稳定性和准确性.对含有面波的实际地震数据进行测试,其结果表明本方法可以有效地压制面波干扰,特别是当面波和有效信号有交叉或重叠等现象出现时,能较好地保护反射同相轴信息.本方法还可用于对含自由表面多次波和层间多次波等地震数据进行自适应信噪分离.     

Ad hoc matching of vectorial road networks

In integration of road maps modeled as road vector data, the main task is matching pairs of objects that represent, in different maps, the same segment of a real-world road. In an ad hoc integration, the matching is done for a specific need and, thus, is performed in real time, where only a limited preprocessing is possible. Usually, ad hoc integration is performed as part of some interaction with a user and, hence, the matching algorithm is required to complete its task in time that is short enough for human users to provide feedback to the application, that is, in no more than a few seconds. Such interaction is typical of services on the World Wide Web and to applications in car-navigation systems or in handheld devices.

Several algorithms were proposed in the past for matching road vector data; however, these algorithms are not efficient enough for ad hoc integration. This article presents algorithms for ad hoc integration of maps in which roads are represented as polylines. The main novelty of these algorithms is in using only the locations of the endpoints of the polylines rather than trying to match whole lines. The efficiency of the algorithms is shown both analytically and experimentally. In particular, these algorithms do not require the existence of a spatial index, and they are more efficient than an alternative approach based on using a grid index. Extensive experiments using various maps of three different cities show that our approach to matching road networks is efficient and accurate (i.e., it provides high recall and precision).

General Terms:Algorithms, Experimentation