Improved marching cubes by combining case lookup table and adjacency lookup sub-table

The marching cubes (MC) is an effective surface rendering method in three-dimensional visualization for medical image sequence. However, most existing MC algorithms are slow and inefficient because they have to process all the cubes for isosurface extraction. An efficient MC algorithm is proposed by combing the case lookup table and a novel adjacent lookup sub-table to exclude unrelated empty cubes. By explicitly building the fix-length adjacent lookup sub-table that is independent on image sequences, the volumes elements are constrained to those only intersect with the isosurface. Both execution time and temporary storage space are further reduced by incorporating the heap data structure in algorithmic implementation. Experimental results on human head, chest foot CT data sets by using the visualization toolkit package show that the traversal cubes decreases by 95%, and the reconstruction time decreases by 20% without any loss of reconstruction quality. Therefore, the proposed method can remarkably speed up the rendering time and be easily integrated into 3D visualization for clinical application.     

Fast Volume Rendering Technology Based on Programmable GPU

Techniques of programmable vertex shader and pixel shader have been integrated in newly developed graphics hardware armed with powerful Graphics Processing Unit(GPU) in recent years, and as a result, real-time volume rendering can be implement. First, rendering pipeline, hardware architectures on per-pixel shading and fast rendering principium of the modern programmable GPU are explained in detail. Second,technology on how to analyze and solve volume rendering problems is described. Finally, maximum intensity projection (MIP) method rendering medical volume data have been implemented based on programmable Graphics Processing Unit. In a performance test, spent time rendering medical volume data based on programmable pixel shader in GPU is obviously less than spent time rendering it do without programmable pixel shader.     

基于医学CT和工业CT扫描研究土壤大孔隙结构特征的区别

为探究医学CT与工业CT在土壤大孔隙特征扫描研究应用的区别,选取青海地区金露梅灌丛原状土壤样品,分别采用医学和工业2种CT对其进行扫描,通过对扫描图像的分析和处理,对比分析2种CT扫描的断层图像质量、土壤大孔隙三维图像以及孔隙度特征3个方面特征,分析2种CT研究土壤大孔隙特征的差异。研究结果表明:(1)从扫描土壤横断面图像质量来看,工业CT的图像质量要明显高于医学CT图像;(2)2种CT图像经处理堆栈出的三维图像在形态上相似,但是工业CT解析出的三维图能更好地体现出不同深度的土壤孔隙分布;(3)2种CT图像经处理得到的孔隙度,随着土壤深度的变化,其特征在整体趋势上大致相同,但工业CT能更准确地反映较深层次土壤的孔隙度。因此可以根据不同的需求选择适宜的CT。     

隧道照明光源光色对驾驶员视觉功效的影响

目前,各国以及CIE的隧道照明设计规范和标准在隧道照明研究中都只考虑隧道路面的亮度或者照度水平,对于色温、显色性和光谱分布等因素对视觉效果的影响考虑不足,导致对隧道照明质量的评价不够科学。笔者从隧道照明光源光色对于驾驶员视觉功效的影响出发,选择两个隧道进行了小目标识别现场实验和不同色温反应时间测试实验,分析了驾驶员视觉功效受隧道照明光源的显色性和色温的影响情况。结果表明:隧道照明光源显色指数越高,驾驶员的视觉功效越好;对于光谱能量分布相似的光源,背景亮度相同时,含有短波成分多的光源照明效果更好,驾驶员的视觉功效也更好。     

Design method of generatingDICOM Image in the high frequency X ray machine

DICOM3.0 standard is complex and rich in contents. Aiming at the difficulty of software design, a programming method of generating DICOM image file in the high frequency X ray machine is proposed. The data structure of DICOM file is analyzed, and then the programming method of generating DICOM image files is introduced in detail. For the proposed method, a template array of the data structure is constructed to save the eigenvalues, transfer syntax, pixel data and so on of the image. All kinds of the data are stored in the DICOM file successively. The programming method can not only transform a BMP file into a DICOM file, but also transform a JPEG file into a DICOM file. It strictly follows DICOM 3.0 protocol. The generated DICOM files can be displayed with the DICOM file browsing software ezDICOM. The programming design was based on VC++6.0.     

Key Technology of Product Visualization Based on Web

The article analyzes two approaches of product visualization,and brings forward a common approach of product data to achieve Web visualization based on IGES standard. It transforms CAD data to universal and useful 3D data, it don't need special browser, and it is very simple and useful. A technological process is introduced to transform Web formats from IGES data. The article also describes concretely triangle anatomy of entity, and the minutia arithmetic of curve face. The principle that triangle piece realize to transform to VRML format is described. With the verification in the prototype system, this approach is proved with reason and credibility.     

Comparison of X-ray CT and MRI of watercore disorder of different apple cultivars

Watercore is an internal disorder that appears as water-soaked, glassy regions near the core in apples. Fast and non-destructive solutions for sensing watercore would be readily accepted in the postharvest industry. X-ray CT and MRI were compared as potential imaging technologies for detecting this particular disorder. After matching the 3D datasets of X-ray CT and MRI, the images that were obtained on identical fruit were compared quantitatively. Both MRI and CT were able to detect watercore, however the contrast in MRI images was superior. High-resolution micro-CT images showed the microstructural changes in watercore fruit: the intercellular spaces of the affected apple tissue are filled with water. This explained the higher density that is detected here by the X-rays and the higher water content in the MRI. Mean and variance of the frequency distribution of MRI and X-ray CT intensity appeared to be a parameter that allows the identification of healthy apples from affected fruit. Automatic image processing based on thresholding the images resulted in comparable watercore classification accuracy of up to 89% for X-ray CT and 79% for MRI data, despite the better contrast in the MRI images.     

基于数码相机的农田景物三维重建

为提出一种基于图像的农田景物三维重建方法。首先从图像文件中提取包含相机焦距等参数的EXIF信息,用以计算相机内参矩阵。根据两幅对应图像的匹配关系,求解本征矩阵并对其SVD分解获得相机外参矩阵,合并相机内外参数构成投影矩阵。其次,以SIFT匹配点的视差作为搜索范围初始限制条件,按像素邻域的SSD值匹配两幅图像中的像素,获得致密的视差图并以三维点云形式重建田块景观,最后,使用“集束调整”算法对最初三维重建结果求精,并将2维图像像素RGB值映射到三维点云上,获得最终结果。从重建效果看,方法真实再现性好,重建过程简洁,具有较高的自动化程度。     

Postharvest noninvasive assessment of fresh chestnut (Castanea spp.) internal decay using computer tomography images

X-ray computed tomography (CT) is an effective noninvasive tool to visualize fresh agricultural commodities’ internal components and quality attributes, including those of chestnuts (Castanea spp). There is no procedure to automatically, effectively and efficiently classify fresh commodities from a continuous inline flow through a CT system. If the information obtained by CT scanning of fresh agricultural commodities is to be used in an industrial application (e.g. inline sorting), automated interpretation of CT images is essential. For this purpose, an image analysis method (algorithm) for the automatic classification of CT images obtained from 2848 fresh chestnuts (cv. ‘Colossal’ and ‘Chinese seedlings’), during the harvesting years from 2009 to 2012, was developed and tested. Classification accuracy was evaluated by comparing the classes obtained from six CT images per chestnut to their internal quality assessment. An experienced human rater performed internal quality assessment by visually and invasively rating fresh chestnut internal decay severity (quality) into 5-, 3- and 2-classes.After CT image preprocessing, cropping and segmentation, 1194 grayscale intensity and textural features were extracted from six resultant CT images per sample. Relevant features were selected using a sequential forward selection algorithm with the Fisher discriminant objective function. 86, 155 and 126 features were effective in designing a quadratic discriminant classifier with a 4-fold cross-validation with a performance accuracy of 85.9%, 91.2% and 96.1% for 5, 3 and 2 classes, respectively. This method is accurate and objective in determining fresh chestnut internal quality, and the methodology is applicable to automatic noninvasive inline CT sorting system development.     

Relation of computerized tomography Hounsfield unit measurements and internal components of fresh chestnuts (Castanea spp.)

Little is known about Chestnut (Castanea spp.) in vivo cultivar characterization and morphology, the effect of mechanical harvesting, peelability, postharvest mold, physiological kernel decay, and quality. Thus, there is a need to develop a nondestructive technique able to assess fresh chestnut internal components, especially disorders. In this study, a medical grade computed tomography (CT) was used to obtain transversal two-dimensional (2D) images from decayed and healthy fresh chestnuts, from the hybrid cultivar ‘Colossal’ and ‘Chinese seedlings’. Attenuation coefficients, referred to as Hounsfield-units (HU) or CT numbers, were acquired from different 2D CT image regions including air, and several chestnut components containing decayed tissue, healthy tissue, various imperfections such as pellicle invagination into healthy kernel, and void spaces. Results offer an in vivo accurate insight of fresh intact chestnuts, and suggest that CT technology is appropriate for inline sorting. HU measurements can be used as a nondestructive predictor of fresh chestnut internal components with a 90.6% overall accuracy rate.     

基于Quest3D的虚拟园林漫游系统的设计与实现

摘要：目前,虚拟现实技术在园林中的应用尚处于探索时期,但随着计算机软硬件水平的提高和可视化技术的不断发展更新,虚拟现实技术在园林中应用的领域逐渐广阔,对园林设计的影响也越来越大。本文以一个城市广场的园林设计为例,结合Quest3D技术制作开发了一个园林漫游展示系统。介绍了园林漫游展示系统的设计过程,研究了园林场景的建模、植物和水体模型的控制、光照和阴影设置、摄像机设置等问题。探讨了Quest3D技术在园林设计中的应用,研究了园林交互展示的相关技术,总结了构建园林漫游展示系统的方法和过程,为园林设计的展示提供一种有效的方法和途径。     

基于等高线渲染法的克里金插值展示技术

目前,空间数据在Web端的表达方式存在网络传输数据量大、插件依赖性强、交互性较差等问题。为了减轻浏览器承载的压力、快速高效地实现空间数据在Web端的可视化表达,本文设计了一种基于等高线渲染法的克里金插值展示技术：在克里金插值算法和等高线渲染法的支持下,用户在Web端通过“框选”工具选择采样点区域,其中采样点数据被传输到服务端进行处理生成插值结果,并返回到Web端进行快速渲染。此技术成功应用在柑橘信息管理系统中,结果表明克里金插值结果的成图时间有效缩短,且Web端的交互性显著增强。     

Rapid Prototyping:A New Method of Digital-Architecture Design Study

This research explores the enlightenment on the design conceptualization and visualization in digital architecture.This study uses 3D models as the main source of data,taking the process of design development as its object.A rapid prototyping(RP) technology is used for 3D color output of design models.The substantiated digital models are used as an important media in design interaction.It is found from the study that RP models were an important media in connecting the virtual world and the real world.Designers could verify their intentions and thus increase efficiency by switching between both worlds.The surface attributes of components and the characteristics of architectural spaces could be merges with images,as a way to extend the freedom in the declaration of a surface's appearance.The large amount of design information can be simplified by explicit visualizing design data.     

Traditional mineral resource visualized dynamic estimation and its application in 3D geological space

A new method for traditional mineral resource visualized dynamic estimation in 3D geological space is proposed, which is adaptive to the characteristics of resource exploitation and reserve classification in China. The method follows the daily workflow of mine exploitation, improves the traditional method for resource estimation by 3D visualization technologies, and replaces abstract regular geometries with real 3D geological models. Thus, the traditional method for resource estimation realizes visualization in the whole workflow of mine exploitation. The application results to some real mines show the estimation results are mainly affected by the spatial location, shape and thickness of mineral blocks and goaf. If the resource dynamic estimation is carried out by constructing 3D mineral models in consistent with real exploitation project, the accuracy of the traditional method can be effectively improved.     

All-around 3D plant modeling system using multiple images and its composition

In this study, we developed an all-around 3D plant modeling system that operates using images and is capable of measuring plants non-destructively without any contact. During the fabrication of this device, we selected a method capable of performing 3D model reconstruction from multiple images. We then developed an improved SfM-MVS (Structure from Motion / Multi-View-Stereo) method that enables 3D reconstruction by simply capturing images with a camera. The resulting image-based method offers a high degree of freedom because the hardware and software can comprise commercially available products, and it permits the use of one or more cameras according to the shape and size of the plant. The advantages of the image-based method are that 3D reconstruction can be conducted at any time as long as the images are already taken, and that the desired locations can be observed, measured, and analyzed from 2D images and a 3D point cloud. The device we developed is capable of 3D measurements and modeling of plants from a few millimeters to 2.4 m of height using this method. This article explains this device, the principles of its composition, and the accuracy of the models obtained from it.     

Optical coherence tomography visualizes microstructure of apple peel

Optical coherence tomography (OCT) has emerged recently as a non-destructive technique to visualize subsurface structures of materials. The objective of this work was to investigate whether OCT is an appropriate method to non-destructively assess the peel structural properties of apple fruit and to compare OCT to confocal microscopy and micro-CT. Peel structural properties of apples from different cultivars (‘Braeburn’, ‘Arlet’, ‘Royal Gala’ and ‘Ida Red’) were measured. The effects of preharvest fertilization treatments and storage duration on calculated structural properties of apple peel from OCT images were investigated. It was found that OCT is a fast, high resolution and high field of view technique that renders 2D and 3D images of apple peel. En-face OCT allows the visualization of the surface topology including cracks in the wax, surface roughness and lenticels. Depth scans with OCT reveal the cellular structure down to a few hundreds of micrometre into the fruit, superior to confocal imaging. Spectral-domain OCT resulted in higher quality images than time-domain OCT. Cuticle, epidermis and hypodermis cells can be resolved in a superior way compared to micro-CT. It was concluded that OCT can be used to visualize peel structural differences between apples, as well as to measure structural changes that occur during storage. OCT is a fast method and allows for combining a high depth resolution with a wide lateral image size.     

The edge element method in the forward problem of magnetic inductiontomography with homogeneous sinusoidal magnetic excitation

The edge finite element method and the imaging visualization have been studied in the forward problem of magnetic induction tomography MIT with homogeneous sinusoidal magnetic excitation. The definite equations of the forward problem were established using the electric field intensity as the vector variable. The edge FE method for solving the definite equations was introduced in detail and realized as the MATLAB program. In order to realize the visualization of MIT in imaging the intracranial hemorrhage, a real human brain finite element model was created with the human head MRI data. On the basis of this model, we realized the 3D visualization of MIT imaging in MATLAB. The research results demonstrated the validity of the definite equations and the edge FE method in calculating the forward problem. And the 3D visualization of MIT imaging with real human brain model established a foundation for the application study of MIT in imaging intracranial hemorrhage.     

A PACS Scheme Based on High-speed Ethernet

Picture archiving and communication system(PACS) is the key way to realize the medical images modernized management, the main work of which is to ensure the medical image information can be transmited and applied with high efficient. The Ether net is a popular local net. The author has described a PACS scheme based on high speed Ether net, with which, many modular functions (medical image sampling, medical image processing, medical image storage, medical image management, medical image review, medical image transmission, medical image edit, et al) can be realized. Also, the PACS can be fused with HIS.     

A power distributed computing system model based on services-oriented architecture

Process communication based power distributed computing model satisfies the demand on real time monitoring and analysis for the economical operation of power grid based on power distributed computation methods, but there are some problems on complexity in common basic functions development and lack of system extendibility. An extendable services-oriented power distributed computation system model is designed and implemented. Software design patterns are applied to design low coupling and extendable system framework. Windows Communication Foundation (WCF) technology is used to implement the services-oriented distributed data communication functions. Windows Workflow Foundation (WWF) technology is used to design the business logic of power distributed computation visually. Data integration functions are implemented by combining the ADO.NET technology. The services-oriented system architecture enhances the integration ability and extendibility. The use of WCF and WWF technology reduces the complexity of the system development.     

Image Format Conversion Between Static DICOM Medical Images and General Medical Images

To make DICOM devices and non-DICOM devices compatible, we need to convert the file format from one to the other. The characteristics of DICOM image file format and normal image file format are studied. The two kinds of file information are construcated, and the file format conversion is implemented. The authors develop a software to convert the file formats between DICOM files and Non-DICOM files. It has been successfully used in PACS, which are operating at hospitals, such as Hospital of anhui province. It is shown that the file format conversion can be implements and can not lose information, and can meet the basic need.