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Range scanning of building interiors generates very large, partially spurious and unstructured point cloud data. Accurate information extraction from such data sets is a complex task due to the presence of multiple objects, diversity of their shapes, large disparity in the feature sizes, and the spatial uncertainty due to occluded regions. A fast segmentation of such data is necessary for quick understanding...
In view of the machine parts examination and the recognition situation to the needs of components image outside feature extraction, this paper introduces the Harris operator's basic theory and the realization process of algorithm, analyzes two factors which influence the corner extraction such as noise sensitivity and threshold value, proposes the technique of extraction straight line and circular...
A novel bounding sphere hierarchy is presented to track the potential intersection area of the subdivision surfaces, so the large number of facets should not humble the intersection computation. The compact local patches, which are regular vertex grids, are very helpful to construct and verify the bounding spheres of different levels. Some illustrative results are given to verify the feasibility of...
Fractal is the theory of studying the geometry and rules behind the nonlinear complex systems with self-similarity structure that widely exists in the nature and IFS is the key technology for constructing fractal images. This paper studies various computer construction algorithms for generating fractal images based on IFS attractor and their application range and limitation are analyzed. The deterministic...
VRML text is commonly used in virtual scene to be description for scene, or further prompting information, or conducting hyperlink in WWW. Same with other general model, VRML text model can have different appearance and material properties, and even the texture. But as a matter of fact, VRML text model is just a flat shape without any thickness. Its 3D feature has no way to reflect in VRML browser...
IC wafer image is composed of basic shape, mainly including lines, rectangles, rounds and ellipses. Firstly, this paper analyzes the shape of IC circuit image by the geometry of basic shape. When the images are moved and rotated, the moment has the same feature. Therefore, we can calculate the moment, the barycentric coordinate points and barycentric moment which are invariant in the same image. Secondly,...
In this paper we present the geometric property of perspective invariant angle ordering; the order of angles between point features. We describe how this can be used to exploit the structure of the appearance of features on planar or near planar surfaces to improve precision for localisation and object recognition. We show test results on real-world images that show marked improvement over straight...
Pursuit strategies (formulated using constant-speed particle models) provide a means for achieving cohesive behavior in systems of multiple mobile agents. In the present paper, we explore an n-agent cyclic pursuit scheme (i.e. agent i pursues agent i+1, modulo n) in which each agent employs a constant bearing pursuit strategy. We demonstrate the existence of an invariant submanifold, and state necessary...
ASM (active shape model) and AAM (active appearance model) model are both parametric model based on statistics. We can locate the key points of a face by AAM model accurately. There is a shape model both in the ASM and AAM. When we build the ASM model and AAM model, we must align the shapes of the training set to a unified framework. In the original alignment process, there are only scale, rotation...
Figure tree is a hierarchical presentation which describes the structure of image space based on the collections of regions from an image. And it is constructed through process of multi-scale image segmentation, in which attributes of each node in the tree are calculated and relationships among the nodes retrieved. As a description of an image layout, the knowledge about shapes, or other geometrical...
Point, line and plane are the three elements constitute the design, visual design in the areas of the important position which is obvious. However, many professional scholars for many years failed to understand the good and the true meaning of its application to real social environment, often such a situation is this: In order to constitute the composition, learned later was completely lost. These...
This paper proposed a biometric identification system through 2D fingers' geometry measurements. The hand image captured from digital camera was first preprocessed to segment hand and its contour out from background. Then the finger tops and valleys were located by tracking out the maximum and minimum radial distances to a wrist reference point. The geometry features of index, middle, ring and little...
Three famous and interesting experiments on primitively visual cognition involve the prior perception of global topological properties supported by the distinct responses on anterior temporal lobe direct proportional to various global form stability properties in apparent motion, and drosophila's visual characteristic of transition invariance. In this paper, an explanation on global properties of...
A new geometric constraints histogram descriptor (GCHD) based on curvature mesh graph for image retrieval is presented in this paper. Through this method, the edge and angle geometric constraints based on the curvature mesh graph are extracted firstly. Then the histogram algorithm is applied on the geometric constraints to obtain the histogram matrix for each curvature point. Finally, the histograms...
Localization is an essential problem in wireless sensor networks (WSNs). Many localization algorithms have been proposed, but few efforts have been paid on theoretical analysis on the accuracy of these algorithms. Because it is naturally to formalize range-based localization problems as deterministic parameter estimation problems, for range-based localization algorithms Crameacuter-Rao lower bound...
Shape discretization through union of weighted points or balls appears as a common representation in different fields of computer graphics and geometric modeling. Among others, it has been very successful for implicit surface reconstruction with radial basis functions, molecular atomic models, fluid simulation from particle systems and deformation tracking with particle filters. These representations...
Snake robots have many degrees of freedom, which makes them both extremely versatile and complex to control. In this paper, we address this complexity by introducing two algorithms. Annealed chain fitting efficiently maps a continuous backbone curve to a set of joint angles for a snake robot. Keyframe wave extraction takes joint angles fit to a sequence of backbone curves, and identifies parameterized...
Clustering is often viewed as a synonym of techniques used to reveal the structure in data. The inherent geometrical diversity of data is a strong motivating factor to search for geometrically flexible clusters design supported by the clustering algorithms. In this study, we introduce a concept of geometrically variable fuzzy clustering (making use of Fuzzy C-Means, FCM), in which the fuzzification...
In this paper, a triangle area based boundary shape representation is proposed. By selecting three evenly spaced elements sequentially from a closed edge chain, the area of triangle is calculated. The Triangle Area Representation (TAR) is calculated by changing the spacing. The Bend direction of the edge determines the sign of the triangle. TARN and TARP are negative and positive extensions of TAR,...
With the large scale deployment of biometrics for access control in private and public places, systems are faced the challenge of processing a diverse range of people. Most systems have been well evaluated for adults, however, their application in schools, or for private door access control, raises the question, whether there exists significant difference in performance between age groups in general...
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