Abstract:In this paper, the authors give a new representation for virtual reality, which is defined as an intensity-range function on a latitude-longitude plane. It supports three-degree-freedom viewing(yaw, pitch and roll), continuous zooming and walk-through in a virtual enclosed environment. On the basis of the representation, a hybrid approach is addressed for constructing virtual indoor environment, which only requires a sparse set of still photographs and has no strait restriction on taking original photographs. Experiment results show that the approach is robust.

Abstract:In this paper, the authors mainly discuss about how to express functions based on {0,1} code. At first, the examples are given to explain a new method in signal processing, in which functions are defined from the viewpoint of multi-scale analysis. Then the authors present “coordinate heft separate” method, discover self-similar structure of points set on plain area; based on this self-similar structure, construct orthogonal complete 2-value function system of high-dimension simplicity; enrich and extend the theory and application of Rademacher function and Walsh function.

Abstract:Based on the research of previous models of CAD systems, the component-based model is presented in this paper, aiming at the openness, integration and efficiency of CAD systems. Functions of components and communication among them are discussed in detail. The model has a double-bus architecture, is better in openness than the previous models, is proved to be a solid base for the modelling and implementation of efficient CAD systems with clear architecture. In addition, components can be used as the base of software reuse.

Abstract:Image mosaics is one of the scene encoding approaches and is very popular among many IBR(image based rendering) systems in creating complex virtual environment based on photogeometrics, for example, 360° sphere or cylindrical panoramas, environment maps as well as high resolution images. In this paper, the authors present a robust panoramic image mosaicing scheme which employs complex wavelet pyramid techniques. It addresses the problems of both image matching and registration automatically and simultaneously. Complex wavelet transform guarantees not only a global optimal solution, but also scale and translation invariance for image alignment. The results can be progressively refined on the multiresolution decomposition. This feature guarantees that the scheme has higher performance than the traditional mosaicing techniques. The simplification of similarity measure decreases the complexity of computing. Additionally, the scheme registers images taken directly from digital camera without knowing camera motion and any intrinsic parameters of camera.

Abstract:In this paper, the authors discuss the algorithms for fast-cutting on 3D surface model. Using a 3D reconstruction algorithm based on MC(marching cubes) method, information about grouping and hierarchical bounding boxes are extracted in the generation of 3D surface model. With a B+ tree data structure recording all information, cutting on 3D surface model can be accomplished without tracking all triangular patches. The key point of the algorithms lies in sufficiently employing the information according bounding boxes and 3D (three-dimensional) coherence inherent in MC. It provides a way to fast locate the intersection points and accomplish dividing. The result of this paper can be applied to simulate cutting operation using plane and sphere knife in coxae orthopedics.

Abstract:A new 3D morphing algorithm for polyhedral objects with the same genus is presented in this paper. The proposed algorithm first interactively partitions the two original polyhedra into the same number of polygonal patches, the patch correspondence is also established during partitioning. Then each pair of corresponding patches is parametrized and resampled by using the harmonic maps. A feature polyhedron is finally constructed for each original polyhedron. The shape transition between the original polyhedral models is accomplished by composing three successive transformations using their feature polyhedra as the bridges. Experimental results demonstrate that the algorithm is robust, and can deal with the general cases.

Abstract:A new available method——procedurally generation method and its animation are given in this paper. Marcov sequence theorem is used to solve the static obstacle avoiding problem in Computer Animation and Robotics, so as to generate the walking route, render the in-door floor texture, as the result, the authors give the abasing procedure animation which is convenient to preview and compare the effects. This method is highly realistic, easy to express continuation and tendency in texture generation, the authors also give the method to deal with the difficulty to adjust the parameter as well as the huge computation.

Abstract:Space deformation is a very important tool in computer animation and shape design. In this paper, the authors propose a new general deformation model containing point, line, surface and volume constraints based on the special distribution of the potential function of a generalized metaball. The user specifies a series of constraints, the effective radius and displacement of each constraint, then the deformation model creates a generalized metaball for each constraint according to each specified constraint and its effective radius. The generalized metaball produces a potential function centered on the constraint, it drops from 1 on the constraint to 0 on the effective radius. This deformation model operates on the whole space and is independent of the underlining representation of the object to be deformed. The deformation can be finely controlled by adjusting the parameters of the generalized metaballs. Experiments show this general deformation model is efficient and can deal with line, surface and volume constrains which are difficult for the traditional deformation models.

Abstract:The commonly used cluster based segmentation method assumes that the sample distribution is hyperspherical, but this kind of assumption is not consistent with the real characteristic of the human brain MR (magnetic resonance) image. In order to surmount this drawback, a new algorithm for segmenting MR image based on hyperellipsoidal fuzzy clustering is presented in this paper. Provided experimental results indicate that the proposed strategy is feasible for classifying the white matter and the gray matter of the brain, and has the merits of both high efficiency and remarkable accuracy.

Abstract:A new image-based rendering technique is presented in this paper. Unlike the linear interpolation scheme, this method can exactly simulate the perspective viewing transformation during the walkthrough. To accelerate the view interpolation, the algorithm employs a binary subdivision scheme to optimize the decomposition of the source image so that the number of the resultant blocks is greatly reduced. Holes on the intermediate image are filled by two steps, namely enlarging the transferred blocks at the side adjacent to holes and retrieving the local image within the holes from the destination images by multiple-directional interpolation. Experimental results demonstrated the algorithm is much more accurate and efficient than the traditional one.

Abstract:In this paper, the authors present a new B-spline surface modelling method which fairly fits 3D data points while at the same time strictly interpolates some of them. By using Lagrange multiplier's conditional extreme method, introducing fairness weights and finding the least squares solutions of position deviation and shape curvature, some B-spline fair quasi-fitting modelling surfaces can be obtained. This method obviously has some practical applications in designing outer shell surfaces of transportation tools with windows and gates, or in manufacturing assembled/joined parts of mechanical productions.

Abstract:When implicit surface is defined by equation f(x,y,z)=0, the object defined by the implicit function is the set of points which satisfy the inequation f(x,y,z)≥0. For the object, it's possible to do union, intersection and subtraction etc using R-function. As a special implicit function, the Metaball function can also be used in blend and deformation for solid modeling except the common properties of implicit function. It is proved that R-function can be used in Boolean operation of solid modeling and Metaball model can be used in the blending of shape.

Abstract:In this paper, the authors propose a new bit allocation algorithm, capable of efficiently allocating a given quota of bit to an arbitrary set of different quantizers. This algorithm produces an optimal or very nearly optimal allocation, while allowing the set of admissible bit allocation values to be constrained to non-negative integers. It is particularly efficiency to image coding based on wavelet for using this algorithm.

Abstract:In this paper, a new method for generating fractal surface of Coons type is given by using Bernsley's fractal interpolation and classical interpolation of nets function.

Abstract:Estimation of software reliability according to random testing is of particular importance in software reliability engineering. The author proposes a method for software reliability estimation in this paper. It reckons the complexity of the computation as an important factor of reliability estimation so that software is not considered as a black-box. It uses the pseudo-dimension of software neighbourhood as a measure of software complexity. Therefore, it can be used to estimate software reliability according to fault-based random testing. The author also proves some relationships between computational complexity and the pseudo-dimension of the set of functions that can be computed within the complexity bound.

Abstract:A secure system consists of many sub——systems, even though every one of those sub-systems satisfies a certain security property, the composed system may not be secure, i.e. the composition maybe not satisfy the security property. It does mean that the security property should be composable. In order to solve such problems, a new multilevel security property based on a new concept of noninterference is introduced and the seurity property is proven to be composable in this paper.