Lianguan Shen

Adaptive detection method of degraded parameters in motion blur image

Image restoration technique is an important method to improve the quality of image in flights photograph and machine vision. On account of blur emerge in relative motion and other condition, the paper analyse its mathematic principle, then for each motion pattern we adopt different deblurring method. Be concrete, we first judge the type of motion, for linear motion blur we take both hough transform and error-parameter to estimate the blur parameters, yet for rotate motion blur we take curve-fitting and polar transformation to estimate parameters. After that we apply Wiener filtering to recover image and improve image quality. We perform experiments with linear motion blur parameter (30,70) and rotate motion blur parameter ((128,128), 20°). The contrast results of the experiments indicate that the algorithm can enhance image quality effectively. Compared with traditional handling, ours have the advantage of being high precision, robustness and speediness‥

Smooth spline surface generation over meshes of irregular topology

An efficient method for generating a smooth spline surface over an irregular mesh is presented in this paper. Similar to the methods proposed by [1, 2, 3, 4], this method generates a generalised bi-quadratic B-spline surface and achieves C1 smoothness. However, the rules to construct the control points for the proposed spline surfaces are much simpler and easier to follow. The construction process consists of two steps: subdividing the initial mesh once using the Catmull–Clark [5] subdivision rules and generating a collection of smoothly connected surface patches using the resultant mesh. As most of the final mesh is quadrilateral apart from the neighbourhood of the extraordinary points, most of the surface patches are regular quadratic B-splines. The neighbourhood of the extraordinary points is covered by quadratic Zheng–Ball patches [6].

Medical image processing by denoising and contour extraction

This paper proposes a new algorithm of medical image denoising and contour extraction that can be used in image processing such as medical image reconstruction, image enhancement, image smoothing, feature extraction and image analysis. The algorithm consists of two parts. First, combining median filtering with wavelet transform to enhance and denoise image. Second, Canny edge detection and contour tracing are repeatedly applied to extract the continuous contour lines of image. The method is validated through experiments on real images. The results show that the algorithm achieves good effects, can deals with low quality or marginal vague images which have high spatial redundancy, low contrast and biggish noise, and has a potential of certain practical use.

Subspace Culling for Continuous Collision Detection

This paper presents a novel efficient culling method for continuous collision detection (CCD) problem performed by dimension reduction in subspace. The basic idea is to use a fast one-dimension (1D) reduced filter and a fast two-dimension (2D) reduced filter that remove large amount of false positives and elementary tests between the primitives. The culling method could be combined with other techniques. The algorithm has been implemented and tested on two benchmarks, including cloth-ball simulations and N-body simulations. The results demonstrate that the algorithm can efficiently reduce the number of elementary tests one order of magnitude, and improve the overall performance of collision query about one half.

A Novel Method of Mesh Simplification Using Hausdoff Distance

This paper describes a novel method for surface mesh simplification. Given an initial surface mesh, the goal is to reduce the number of mesh elements and preserve the geometric approximation as well as the shape quality of the resulting mesh. We present a novel method - triangle contraction to simplify the mesh, and two tolerance areas with respect to the reference mesh have been introduced to preserve the geometry of the surface. The reference mesh is then simplified and optimized in order that the resulting mesh belongs to these tolerance areas.

Magnetic Field Analysis of a New 3-Axis Optical Pickup Actuator Based on ANSYS

The magnetic field and the force distribution of a new 3-axis optical pickup actuator are simulated based on ANSYS.

Method to Interpolate Scattered Rainfall Data Using the Thin Plate Spline, B-Spline and Energy Fairing

This paper aims at constructing a smooth surface using scattered rainfall data to gives us a visual distribution of rainfall. A grid is superimposed on the map within the data boundary, and thin plate spline (TPS) method is used to interpolate rainfall data to obtain the values of the grid points. Due to the irregularity of the data boundary, the grid has to be divided into several small regular grids then B-Spline is used to interpolate these grid points to construct surfaces. Finally an energy method is used to join these surfaces together, and it gives us the smoothest joined surfaces in vision.

A Novel Adaptive Algorithm of Catmull-Clark Subdivision Surfaces

The character of the subdivision surfaces is that the number of facets grows exponentially with the level of subdivision. A novel adaptive subdivision algorithm based on Catmull-Clark scheme is presented in this paper by calculating the distance smoothness value of the vertices. The new method generates preferable rendering results than the traditional adaptive approaches such as computing a vertex’s curvature or distance between the control mesh and their limit surfaces. The new method has obvious geometric meaning, programming simplicity, numerical stability and performs efficiently when applied to the model whose mesh has more sharp features.

3D B-Spline surface reconstruction based on the contour information

This paper introduces a 3D surface reconstruction method from serial parallel slices of cross-sections. Depends on the contour shape we get a series of regular points. The density of the points reflects the change of the contour shape, and then corresponding knot vectors and control points are generated from these points. Define a flexible space to compute the knot vector of the surface. For the multi-connectivity problem, using image division translates it into some single-connectivity problem. The centroid of each slice and each closed contour is generated to get the relationship of the contours. So, the many-to-many question translates into some one-to-one question.

Point-by-Point Generation Algorithm for B-spline Curves in Two-Photon Fabrication

In a two-photon femtosecond laser system of three- dimensional micro-fabrication, a model of micro-device is fabricated layer by layer. For each layer, it is fabricated point by point along its contours of cross-sections. So it is necessary to generate process points one by one along the contours. In this paper, the contours of cross section of a model are supposed to be B-spline curves. An efficient algorithm is presented to generate process points for B spline curve. In the proposed algorithm, the parametric increment is adjusted based on the estimation bounds of second derivative.