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International Symposium on Computer Science and Computational Technology

作者： Gu, Jing Wei, Song Harbin Univ Sci & Technol Inst Comp Sci & Technol Harbin Peoples R China

ISBN: (纸本)9780769534985

In order to resolve the tremendous computation and the low speed of ray casting volume rendering, this paper presents an octree ray casting algorithm based on Multi-core CPUs, Through the merger of the same properties adjacent nodes, the classic octree structure to be optimized, reduces the storage space and improves the octree traversing speed. Simultaneity it combines the Multi-core CPUs with OpenMP parallel technology to increase volume rendering speed. The experiment shows that this algorithm can accelerate the speed of ray casting and doesn't degrade the image quality.

关键词： volume rendering ray casting algorithm octree multi-core CPUs OpenMP prallel technology

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Application of ray casting algorithm in Medical Image Enhancement and Edge Detection

Application of Ray Casting Algorithm in Medical Image Enhanc...

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2023 International Conference on Evolutionary algorithms and Soft Computing Techniques, EASCT 2023

作者： Zhang, Zhengyang The First Affiliated Hospital of Hebei North University Zhangjiakou China

ISBN: (纸本)9798350313413

The ray casting algorithm plays an important role in improving medical images and edge detection. Medical imaging typically includes a large amount of image data, such as computed tomography, magnetic resonance imaging, etc. These data need to be effectively and accurately processed and analyzed in order for doctors to make correct diagnoses. The ray casting algorithm is a method that allows for effective and accurate processing of medical images. This article mainly used experimental methods and algorithm comparison to analyze the running time and accuracy of medical images using different algorithms. The experimental results showed that the image detection accuracy using the improved ray casting algorithm exceeds 95%, which can achieve the enhancement and edge detection of precise medical images, and the effect is better than traditional image processing algorithms. ray casting algorithms can quickly and accurately render medical images, allowing doctors and researchers to better understand and analyze image information. Through the ray algorithm, the voxel-level enhancement and operation of the medical image are realized to improve the contrast and clarity of the image. To detect and extract edge information in medical images to help assist diagnosis and disease analysis. © 2023 IEEE.

关键词： edge detection image enhancement medical imaging ray casting algorithm

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Large-Scale Finite Difference Grid Generation and Visualization Method Based on ray casting algorithm

Large-Scale Finite Difference Grid Generation and Visualizat...

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作者： Tie-chang MA Tian-bao MA Li HAO State Key Laboratory of Explosion Science and Technology Beijing Institute of Technology School of Science Beijing University of Civil Engineering and Architecture

Finite difference method(FDM) is one of the most popular method for explosion ***-scale,accuracy and automatic grid generation is the essential for numerical *** kinds of grid generation method are wildly used:ray casting method and slicing *** this paper,the ray casting method is optimized and some special cases of algorithm are analyzed,which improved the efficiency and stability for large-scale grid generation.A facet searching method is proposed to improve the performance of ray casting *** efficient data storage method is proposed for storing and visualizing grid data,which makes it possible to display trillions of *** advantages of modified ray casting algorithm are presented through performance comparison between ray casting and slicing method in different ***,examples of grid generation and explosion simulation are *** accuracy and practicability of algorithm is proved.

关键词： Grid generation Numerical simulation ray casting algorithm Slicing algorithm

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SPEEDING-UP RE-SAMPLED algorithm IN ray casting VOLUME RENDERING OF MEDICAL IMAGES

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Transactions of Nanjing University of Aeronautics and Astronautics 2005年第1期22卷 52-58页

作者：陶玲王惠南田芝亮南京航空航天大学自动化学院空军机关医院内科

ray casting algorithm can obtain a better quality image in volume rendering, however, it exists some problems, such as powerful computing capacity and slow rendering speed. How to improve the re-sampled speed is a key to speed up the ray casting algorithm. An algorithm is introduced to reduce matrix computation by matrix transformation characteristics of re-sampling points in a two coordinate system. The projection of 3-D datasets on image plane is adopted to reduce the number of rays. Utilizing boundary box technique avoids the sampling in empty voxel. By extending the Bresenham algorithm to three dimensions, each re-sampling point is calculated. Experimental results show that a two to three-fold improvement in rendering speed using the optimized algorithm, and the similar image quality to traditional algorithm can be achieved. The optimized algorithm can produce the required quality images, thus reducing the total operations and speeding up the volume rendering.

关键词： volume rendering ray casting algorithm acceleration algorithm re-sampled algorithm

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i4Ocean: transfer function-based interactive visualization of ocean temperature and salinity volume data

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International Journal of Digital Earth 2021年第6期14卷 766-788页

作者： Fenglin Tian Qing Mao Yazhen Zhang Ge Chen Department of Marine Technology Ocean University of ChinaQingdaoPeople’s Republic of China Qingdao National Laboratory for Marine Science and Technology QingdaoPeople’s Republic of China

In this paper,we present a novel ocean visualization framework,which focuses on analyzing multidimensional and spatiotemporal ocean ***-based visualization methods are explored to effectively visualize ocean *** improved ray casting algorithm for heterogeneous multisection ocean volume data is presented.A two-layer spherical shell is taken as the ocean data proxy geometry,which enables oceanographers to obtain a real geographic background based on global *** efficient ray sampling technique including an adaptive sampling technique and a preintegrated transfer function is proposed to achieve high-effectiveness and high-efficiency ***,an interactive transfer function is also designed to analyze the 3D structure of ocean temperature and salinity anomaly *** on the framework,an integrated visualization system called i4Ocean is *** visualization of ocean temperature and salinity anomalies extracted interactively by the transfer function is demonstrated.

关键词： Ocean temperature and salinity data ray casting algorithm transfer function spherical volume rendering GPU

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An estimate of the time-varying temperature field of the main reflector and subreflector of the Shanghai 65 m radio telescope under solar illumination

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INTERNATIONAL JOURNAL OF STEEL STRUCTURES 2016年第1期16卷 115-124页

作者： Zhong Jie Qian Hongliang Fan Feng Shen Shizhao Harbin Inst Technol Minist Educ Key Lab Struct Dynam Behav & Control Harbin 150090 Peoples R China Harbin Inst Technol Sch Civil Engn Harbin 150090 Peoples R China Harbin Inst Technol Weihai Dept Civil Engn Weihai 264209 Peoples R China

The time-dependent temperature fields of the reflectors of the Shanghai 65 m radio telescope are investigated numerically, taking account of the non-uniform heating of the reflector surfaces due to solar illumination and the constantly changing ambient air temperature. This paper utilizes a ray casting algorithm to calculate the borderline separating the reflector areas in shadow and in sunshine, aiming to provide an accurate calculation of the solar energy absorbed. Then a ray tracing algorithm is utilized to calculate the total solar energy that is reflected by the main reflector area and received by the subreflector surface area. Finally, the solar energy is used as the main thermal load on the reflector surface to numerically examine the temperature distribution on both the main reflector and the subreflector. The results illustrate that the time-varying temperature fields of the reflectors of a radio telescope due to asymmetric solar illumination can be accurately simulated utilizing the ray casting algorithm and the ray tracing algorithm. The occurring periods and avoidance zones of the overheating of the subreflector are identified, among which the maximum temperature of the subreflector reaches 144.9A degrees C. These dangerous observation zones should be avoided during the operation of the radio telescope.

关键词： radio telescope temperature field solar illumination ray casting algorithm ray tracing algorithm

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RENDERING OF SURFACE AND VOLUME DETAILS IN VOLUME DATA

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COMPUTER GRAPHICS FORUM 1995年第3期14卷 C421-&页

作者： CAI, WL CHEN, TZ SHI, JY State Key Lab of CAD&CG Zhejiang University Hangzhou Zhejiang 3 10027 P. R. China E_mail: cad_wlcai@***

Aiming at the detail rendering in volume data, a new volume illumination model, called Composed Scattering Model (CSM), is presented. In order to enhance different details in volume data, scattering intensity is decomposed into volume scattering intensity and surface scattering intensity with different weight functions. According to the Gauss probability distribution of gray and gradient of data, we propose an accurate method to detect the materials in a voxel, called composed segmentation. In addition, we discuss the principle of constructing these weight functions based on the operators defined in composed segmentation. CSM can generate images containing more details than most popular volume rendering models. This model has been applied to the direct volume rendering of 3D data sets obtained by CT and MRl. The resultant images show not only rich details but also clear boundary surfaces. CSM is demonstrated as an accurate volume rendering model suited for detail enhancement in volume data sets.

关键词： VOLUME RENDERING VOLUME ILLUMINATION MODEL ray casting algorithm

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A simplified visual simulation for GIS in consideration with weather and sunlight

A simplified visual simulation for GIS in consideration with...

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IEEE Region 10 International Conference on Electrical and Electronic Technology

作者： Kato, R Makino, M Chuo Univ Dept Informat & Syst Engn Bunkyo Ku Tokyo 1128551 Japan

ISBN: (纸本)0780371011

In this paper, a simplified visualization method is proposed for geographic information systems (GIS) in consideration of weather and sun moving. In order to decrease computational cost in visualization, the proposed method consists of 2 parts;pre-process for generating textures and main process for rendering. In the main process, buildings and roads with shadows are visualized by the ray tracing algorithm. Also in the process, sky, snow, and rain are visualized by textures, which are a priori generated in the pre-process. In the pre-process, some textures such as snow and rain are generated by the ray casting algorithm. Then we can obtain images with weather condition and shadows of sunlight by buildings along the road. It is seen that the computational cost for the main part becomes relatively low in spite of representing shadows and weather.

关键词： computer graphics GIS ray casting algorithm ray tracing algorithm

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Detail enhancement in volume rendering

Detail enhancement in volume rendering

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4th International Conference on Computer-Aided Design and Computer Graphics

作者： Cai, WL Chen, TZ Shi, JY ZHEJIANG UNIV CAD & CGSTATE KEY LABZHEJIANG 310027PEOPLES R CHINA

ISBN: (纸本)0819420158

Aiming at detail enhancement in volume rendering, a new volume illumination model, called Composed Scattering Model (CSM), is presented. In order to enhance different details in data, scattering intensity is decomposed into volume scattering intensity and surface scattering intensity, and composed with boundary detection operators. CSM can generate images containing more details than current volume rendering models. This model has been applied to the direct volume rendering of 3D data sets obtained by CT and MRI. The resultant images show not only rich details but also clear boundary surfaces. CSM is demonstrated as an accurate volume rendering model suited for detail enhancement in volume data set.

关键词： volume rendering volume illumination model ray casting algorithm

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Multiple-Volume Volumetric Rendering Using Graphic Accelerator 44

Multiple-Volume Volumetric Rendering Using Graphic Accelerat...

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44th Latin American Computing Conference on Informatics (CLEI)

作者： Serapiao, Raphael Leite Ramos, Jeferson Vieira da Rocha Fernandes, Anita Maria UNIVALI Curso Ciencia Comp Campus Kobrasol Sao Jose SC Brazil

ISBN: (纸本)9781728104379

Real-time visualization of volumetric data sets demands high computational performance and large in-memory storage capacity. With the technological advance, the means used to acquire these sets, such as Computed Tomography or Magnetic Resonance Imaging, underwent improvements that resulted in a significant increase of the amount of information collected per sample, making it necessary to develop techniques to generate the visualization of this large quantity of information. The research presents in this paper has the purpose to develop a three-dimensional visualization tool to represent in real time volumetric data with the size of hundreds of megabytes. This tool is based on the ray casting algorithm using graphical acceleration features. To achieve this goal, a methodology was used that involved dividing the volume of data into smaller parts, compatible with the memory limitation of the video hardware. Then the data is used to compose a high quality final image representing the information contained in the volume. In order to evaluate and validate this methodology, comparative tests are performed between the standard rendering procedure and the procedure used in this research.

关键词： Three-dimensional visualization Real time volumetric ray casting algorithm Graphical acceleration features

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