Xueli Zhou

Accelerated algorithm for 3D intestine Volume Reconstruction base on VTK

3D Volume Reconstruction of the intestine is a crying need to improve the accuracy of disease detection and treatment. This paper adopts the Visualization Toolkit (VTK) combined with VC++ IDE to reconstruct 3D intestine CT images. Ray-Casting is a traditional algorithm for 3D Volume reconstruction of medical images, but the calculation is very large and the speed of creating images is so slow-footed. To overcome the drawback of large quantity of computation, firstly, in order to effectively reduce the amount of redundant data of reconstruction, segment the intestinal part which we interest in by using Region Growing method, then, at the step of image synthesis, set an appropriate threshold of opacity, when the opacity is greater than the threshold value, that means the sampling points behind will not contribute to the color value of current pixel, so terminate the calculation of synthesis, and finally, quickly rebuild 3D intestine. Compared with the traditional algorithm, the accelerated algorithm achieves great enhancement in efficiency, and without significantly reducing image quality.

A dynamical loading of large scale 3D city based on OSG

To dynamically load the large scaled 3D city model based on OSG (OpenSceneGraph), the model is firstly separated small blocks so as to improve the loading speed and save the memory, here we directly separate the scene along the x-axis and y-axis, then we design the algorithm to control the numbers and the positions of loading blocks, thirdly we optimize the algorithm. In the end we give the experimental result to show the virtues of our methods.

3D visualization for heart model from point clouds

In order to improve the efficiency of the ablation operation, this paper proposes a 3D visualization system. In the system, cloud section is used, looking for outer points and eliminating noise-points effectively. And then we adopt Poisson surface reconstruction to achieve 3D reconstruction for scattered point-cloud, which can obtain more ideal geometry. Then, a further optimization is made for the model. The test shows that this system has good reliability and instantaneity.

Design of test platform for 3D graphics pipeline based on Microblaze

As the importance of 3D graphics increased rapidly in handled device performance, we designed a 3D graphics accelerator to fit the low power consumption. In order to testing the capability of the accelerator, a hardware/software co-processing system for 3D graphics pipeline test platform is proposed in this paper. The system consists of a soft-core microprocessor and a dedicated hardware accelerator for 3D graphics pipeline implemented on an FPGA. Thus, we studied the structure of Microblaze in order to translate the 3D model data to the accelerator. The design is described in Verilog HDL and synthesized on a Xilinx Virtex-5 FPGA. The experimental results from this hardware implementation showed that a cow model with 5800 triangle faces rotated smoothly.

An improved interpolation algorithm using nearest neighbor from VTK

This paper proposes an improved image interpolation algorithm using nearest neighbor. The algorithm uses the mathematical morphology to determine the contours of each region for the two slicing images, obtains the interpolation image boundary based on distance transform, and then gets the gray values of all the corresponding points through the nearest neighbor image interpolation. This algorithm can greatly reduce the errors caused by nearest neighbor. By the means of VTK, the experimental result shows that the robust algorithm can improve the quality of the reconstruction image.

A novel interpolation algorithm for 3D reconstruction of medical images

This paper implements a novel interpolation algorithm for three-dimensional reconstruction of medical images. Image Interpolation is often required in three-dimensional reconstruction. This paper analyzes and compares the limits of the traditional interpolation algorithm: grey-based interpolation, shape-based interpolation. To overcome the disadvantages of these traditional algorithms, a novel interpolation algorithm is proposed, which combines the virtues of the both traditional interpolation algorithms. Extensive experiments show that the efficiency of three-dimensional reconstruction can be improved a lot by using the novel algorithm.

Local subdivision on triangle mesh

Subdivision has been a very popular technology in graphics at home and abroad. It can be splited into global subdivision and local subdivision, and the methods to subdivide are various including butterfly, modified-butterfly, loop, linear, Catmull-Clark, Doo-Sabin and so on. These methods can be divided into interpolation subdivision and approach subdivision. In this paper, it mainly involves approach and interpolation algorithm, and it mainly introduces a local subdivision algorithm based on triangle mesh reconstruction by Poisson. Aiming at the global subdivisions disadvantages, it is not only save memory space and shorten run time. Local subdivision is very popular in various fields In many case, global subdivision is too waste resource and low efficiency, so global subdivision is not a fine method to optimize model. According to the request and experimental verification, linear algorithm is more suitable for the subject in this paper.

An efficient cutting method for 3D endocardial geometric model

In this paper, we present one efficient plane cutting method in the endocardial 3D mapping system. The algorithm cuts 3D endocardial surface model through moving plane freely from matrix transformation and rotating the normal line of plane based on VTK platform. The experimental result shows that this approach has a strong ability for endocardial surface model cutting with no sawtooth effect, which can help doctor to give more accurate judgment in medical diagnosis of Catheter ablation technology.

Reconstructing curve on the surface with extreme learning machines

A novel approach for reconstructing the curve contained on the given surface is presented in this paper. We first project the given curve points restricted on the surface onto the corresponding x-y coordinate plane, then a plane curve is constructed with these projected points by using the extreme learning machines. A cylinder is estanlished with the constructed curve as directrix, The required approximation curve restricted on the surface is achieved via the intersection of surface and cylinder. The experiment results show that the proposed method achieve good effect compared to traditional methods using piecewise function to represent the curve on the surface.

Peripheral nerve enhancement based on multi-scale Hessian matrix

To improve the precision of nerve segmentation in CT images, a new comparability function is proposed in this paper to enhance the contrast between nerve structure and other surrounding tissues. It is based on nerves characteristic, i.e. dark tubular structure, and a thorough analysis of the multi-scale Hessian matrix. By comparability function, the gray range of interested nerve structure can be automatically determined, which combines the multi-scale Hessian matrix eigenvalues with intensity information of original nerve CT images. The experimental results show that the improved algorithm can not only enhance the continuous nerve of tubular structure, but also clearly reflect its bifurcations and crossovers. It is very important and significant to the computer-aided disease diagnosis of peripheral nervous system.