3D Interactive Topological Modeling using Visible Human Dataset

Availability of Visible Human Dataset (VHD)has provided numerous possibilities for its exploitation in both medical applications and 3D animation. In this paper, we present our interactive tools which enable extraction of surfaces for different organs, including bones, muscles, fascia, and skin, from the VHD. The reconstructed surfaces then are used for defining the inter-relationship of organs, a process we refer to as topological modeling. A data base is constructed, which encapsulates structural, topological, mechanical and other relevant information about organs. A 3D interactive tool enables the building and editing of this data base. Such a data base can later be used for different applications in fields such as medicine, sports, education, and entertainment.     

Confocal imaging of porosity in hardened concrete

We present the results of an exploratory 3D study of fine pore structures in hardened cement paste. A laser scanning confocal microscope was used in reflected (epi) fluorescent imaging mode, allowing for the very high optical resolution of features well below 1 μm in size. Images of pore structures were captured using a ‘reverse imaging contrast’ technique where spaces in the material were impregnated with a fluorescent, dyed epoxy-resin, and scanned in the x-y plane by a laser probe. A vertical ‘stack’ of these optical sections was acquired by imaging sequentially through the z-axis. Using this technique it was possible to observe, partially hydrated cement grains, porous natural quartz aggregate interfaces, micro-cracking in the hydrated cement paste and aggregate particles, as well as fine capillary pores and very small air voids. Operating at the limit of its capability the microscope was able to perform high resolution imaging of the internal areas of partially reacted cement grains, and pore structures approximately 0.17 μm across were measured. 3D models were produced to help visualise the true morphology and distribution of porous features.     

Real-Time Image Thresholding Based on Sample Space Reduction and Interpolation Approach

Real-time thresholding is very essential for real-time processing. In this paper, we use pavement crack detection as an example to explain the principle of the proposed approach. Conventional visual and manual analysis approaches to pavement crack detection are very costly, time-consuming, labor-intensive, and subjective. Real-time automated detection of pavement cracks will be very useful for pavement management. We employ the proposed sample space reduction and interpolation approach for thresholding pavement images. The main idea of the proposed approach is based on the fact that the threshold values of gray-level pavement images are strongly related with the values of the mean and standard deviation of the pixel intensities. The experimental results have demonstrated that the proposed approach can determine the threshold values accurately, reliably, robustly, quickly, and automatically. It can be applied to other real-time processing tasks as well.     

Application of a Virtual Environment System in Building Sciences Education

This paper includes a brief review of the application of virtual environments in building sciences and presents details of the application of virtual structural analysis program (VSAP), a virtual reality based structural analysis system developed at Virginia Polytechnic Institute and State Univ. (Virginia Tech), in education and practice. Different elements and modeling options in addition to the implementation of two major earthquakes within VSAP for the demonstration of the behavior of building structures during seismic activities are presented. Modifications to the VSAP in order to simulate progressive collapse of building structures are discussed. Different versions of this system were used in architectural structures courses at Virginia Tech. Results of feedbacks from students in these classes are presented. From these results it is concluded that the VSAP can be used effectively as an experiential teaching∕learning tool in classroom settings. Possible applications of VSAP as a design and research tool in construction industry are discussed.     

Integrating Laser Scanning and Rapid Prototyping to Enhance Construction Modeling

This paper describes an innovative approach to building modeling by integrating three-dimensional (3D) digital laser scanning and rapid prototyping (RP) technology. The process involves capturing a 3D scan of a building exterior and using the RP process to create a 3D physical model. Traditional methods used for feasibility studies, safety analysis, and planning of the building process can be slow, costly, and often impractical. This technique proved to be advantageous in terms of cost, speed, and reduction of human error. The Construction Systems Department at the Peter Kiewit Institute, University of Nebraska, in Omaha, Neb. teamed with Lamp Rynearson and Associates, a consulting engineering firm from Omaha, Neb., to verify that data collected by the laser scanner could be converted to the proper format to create a physical model using RP technology. Results obtained from this project indicate that the technique was less expensive, quicker, and far more accurate than traditional methods.     

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基于电成像测井解释，结合岩心标定和常规测井约束，建立了塔北隆起下奥陶统溶洞及其充填物的电成像测井识别模式。在电成像测井图像上，未充填溶洞一般呈黑色，而充填溶洞则可呈现出黑、棕、黄、白等各种颜色，这取决于充填物的类型和特征。溶洞充填物主要有角砾岩、砂泥岩和结晶碳酸盐岩三种类型：角砾岩呈斑状，其中浅色斑块解释为从围岩跨塌下来的角砾，斑块间深色部分为砂、泥质填隙物；洞穴砂、泥岩一般呈黑色—棕色高导显示，其中常见图像纹理，解释为各种层理构造；洞穴结晶碳酸盐岩因电阻率最高，图像呈白色，并可见纹层状生长构造。洞穴及其充填物与碳酸盐围岩浅棕—亮黄色中高阻电成像测井特征易于区别。研究表明，利用高分辨率电成像测井图像，结合岩心标定和常规测井资料，能够有效地识别碳酸盐岩地层中的古洞穴，并判断其充填与否及充填物的性质。     

An Optical Approach to Structural Displacement Measurement and Its Application

A number of optical devices are commercially available now for measurement. Some of them, such as laser devices and still and video cameras with high resolution, may be used effectively and efficiently for measuring structural displacement. This paper presents an approach to this type of application using a charge-coupled-device camera. It can acquire digitized images for low cost, to be used to identify structural displacement via digital signal processing. It is shown that this approach’s resolution for point measurement is comparable with traditional sensors such as dial gages. Furthermore, it offers a new capability of displacement measurement for a large number of points on a structure, and it can provide spatially intensive displacement data. This kind of data may be used for structural damage detection and health monitoring, as suggested and demonstrated herein.     

Particle Image Velocimetry System with Self-Organized Feature Map Algorithm

Self-organized feature map algorithm and the classical particle tracking technique have been adopted together to analyze the single-exposure double-frame particle images for flow measurement. Similar to the normal correlation technique in particle image velocimetry, the whole region is divided into many small interrogation spots. Instead of applying the correlation algorithm to each of these spots to obtain their rigid translation, the self-organized feature map algorithm is used to compress the information such that every spot is represented by three coded equivalent particles. After tracking these three particles, a linear distributed velocity function can be obtained at every spot. The spot can contain not only translation, but also rotation, shear, and expansion while there is only rigid translation in the spot assumed in the commonly used correlation method. In addition to the theoretical explanation, the suggested method has been verified by a number of digital flow fields which have randomly distributed synthetic particles.     

Seebeck Effect Detection on Biased Device without OBIRCH Distortion Using FET Readout

Laser Stimulated Seebeck Effect Imaging (SEI) is widely used in Microelectronics Failure Analysis, namely when performed through chip backside. The SEI signal shapes are often not easy to interpret though, mostly because of superposition of additional OBIRCH (Optical Beam Induced Resistivity Change). Here, a SEI detection technique independent of OBIRCH interference is presented. When a thermoelectric voltage is generated on an interconnect that drives FET inputs (gate conductor), the voltage influences the FET channel conductance almost currentless producing drain output shift that can be detected as Thermal Laser Stimulation (TLS) signal. As FET output current is clearly separate from the gate, it cannot interfere with the thermoelectric effects in the gate conductor. A full characterization of the structure for several circuit models is presented. Test structures for SEI may be improved when designed with FET readout. Also on ICs SEI can be done with nominal supply voltage as long as the Seebeck junction is located in a gate conductor circuit.