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Articles 1 - 9 of 9
Full-Text Articles in Mechanical Engineering
High-Speed Three-Dimensional Shape Measurement System Using A Modified Twoplus- One Phase-Shifting Algorithm, Song Zhang, Shing-Tung Yau
High-Speed Three-Dimensional Shape Measurement System Using A Modified Twoplus- One Phase-Shifting Algorithm, Song Zhang, Shing-Tung Yau
Song Zhang
This paper describes a high-resolution, real-time, three-dimensional shape measurement system using the modified two-plus-one phase-shifting algorithm. The data acquisition speed is as high as 60frames∕s with an image resolution of 640×480pixels per frame. Experiments demonstrated that the system was able to acquire the dynamic changing objects such as facial geometric shape changes when the subject is speaking, and the modified two-plus-one phase-shifting algorithm can further alleviate the error due to motion. Applications of this system include manufacturing, online inspection, medical imaging, compute vision, and computer graphics.
3d Data Merging Using Holoimage, Song Zhang, Shing-Tung Yau
3d Data Merging Using Holoimage, Song Zhang, Shing-Tung Yau
Song Zhang
Three-dimensional data merging is critical for full-field 3-D shape measurement. 3-D range data patches, acquired either from different sensors or from the same sensor in different viewing angles, have to be merged into a single piece to facilitate future data analysis. In this research, we propose a novel method for 3-D data merging using Holoimage. Similar to the 3-D shape measurement system using a phase-shifting method, Holoimage is a phase-shifting-based computer synthesized fringe image. The virtual projector projects the phase-shifted fringe pattern onto the object, the reflected fringe images are rendered on the screen, and the Holoimage is generated by …
Reliability Of Concrete Masonry Unit Walls Subjected To Explosive Loads, Christopher D. Eamon
Reliability Of Concrete Masonry Unit Walls Subjected To Explosive Loads, Christopher D. Eamon
Civil and Environmental Engineering Faculty Research Publications
This study discuses the development of a procedure that can be used to assess the reliability of concrete masonry unit infill walls subjected to personnel-delivered blast loads. Consideration is given to maintain reasonable computational effort for both the structural analysis and reliability models. Blast load and wall resistance models are developed based on experimental and analytical data, and resistance is evaluated with a large strain, large displacement transient dynamic finite element analysis. A sensitivity analysis is conducted to identify significant random variables and a reliability analysis conducted with a feasible level of computational effort. Reliability indices are estimated for two …
Phase Error Compensation For A 3-D Shape Measurement System Based On The Phase-Shifting Method, Song Zhang, Peisen S. Huang
Phase Error Compensation For A 3-D Shape Measurement System Based On The Phase-Shifting Method, Song Zhang, Peisen S. Huang
Song Zhang
This paper describes a novel phase error compensation method for reducing the measurement error caused by nonsinusoidal waveforms in phase-shifting methods. For 3-D shape measurement systems using commercial video projectors, the nonsinusoidal waveform of the projected fringe patterns as a result of the nonlinear gamma of projectors causes significant phase measurement error and therefore shape measurement error. The proposed phase error compensation method is based on our finding that the phase error due to the nonsinusoidal waveform depends only on the nonlinearity of the projector’s gamma. Therefore, if the projector’s gamma is calibrated and the phase error due to the …
Using Basic Computer Aided Drafting And Design Courses At The Freshman Level To Improve Technology Students Competitiveness In Obtaining Early Academic Career Internships, Anthony Dean, Mustafa Moustafa, Julie Moustafa
Using Basic Computer Aided Drafting And Design Courses At The Freshman Level To Improve Technology Students Competitiveness In Obtaining Early Academic Career Internships, Anthony Dean, Mustafa Moustafa, Julie Moustafa
Engineering Technology Faculty Publications
Many students have the desire to have internships and part-time employment during their academic careers. Often students in their freshman and sophomore years in four year engineering and technology programs find it difficult to be competitive against more senior students for these positions. This paper discusses how students, in the Mechanical Engineering Technology (MET) program at ________________University, through taking CAD and Solid Modeling courses early in their academic careers are well suited to be competitive in obtaining internships and part time employment. This paper discusses the MET programs first two years’ curriculum and how it prepares the students to enter …
Development And Evaluation Of A Simulation System Based Upon Standard Pedestrian Thoroughfare Methodologies, Charles O. Pringle
Development And Evaluation Of A Simulation System Based Upon Standard Pedestrian Thoroughfare Methodologies, Charles O. Pringle
All Master's Theses
This study was undertaken to determine whether existing simulation and modeling systems could be used to analyze and model pedestrian traffic flows. The study incorporates the Highway Capacity Manual 2000 (HCM) (Transportation Research Board, National Research Council [TRB], 2000a) methodologies into a ProModel simulation and then compares and contrasts the results of the HCM calculations with the ProModel simulation.
Atomic Force Microscope Imaging Of Dna And Multi Walled Carbon Nanotubes, Jacob Hohnbaum
Atomic Force Microscope Imaging Of Dna And Multi Walled Carbon Nanotubes, Jacob Hohnbaum
Mechanical Engineering Undergraduate Honors Theses
The Micro and Nano System Laboratory at the University of Arkansas currently is equipped with an Atomic Force Microscope (AFM). This device can be used to measure objects with resolution on the nanometer scale, but there are a number of technical difficulties in performing scans of carbon nanotubes and DNA. The goal of this research is to successfully perform scans on both carbon nanotubes and DNA and to also establish laboratory processing protocols to re-perform such scans in the future. Previous works performed by other researchers in the laboratory provided basic protocols with which to begin the present research. These …
Generic Nonsinusoidal Phase Error Correction For Three-Dimensional Shape Measurement Using A Digital Video Projector, Song Zhang, Shing-Tung Yau
Generic Nonsinusoidal Phase Error Correction For Three-Dimensional Shape Measurement Using A Digital Video Projector, Song Zhang, Shing-Tung Yau
Song Zhang
A structured light system using a digital video projector is widely used for 3D shape measurement. However, the nonlinear γ of the projector causes the projected fringe patterns to be nonsinusoidal, which results in phase error and therefore measurement error. It has been shown that, by using a small look-up table (LUT), this type of phase error can be reduced significantly for a three-step phase-shifting algorithm. We prove that this algorithm is generic for any phase-shifting algorithm. Moreover, we propose a new LUT generation method by analyzing the captured fringe image of a flat board directly. Experiments show that this …
Multilevel Quality-Guided Phase Unwrapping Algorithm For Real-Time Three-Dimensional Shape Reconstruction, Song Zhang, Xiaolin Li, Shing-Tung Yau
Multilevel Quality-Guided Phase Unwrapping Algorithm For Real-Time Three-Dimensional Shape Reconstruction, Song Zhang, Xiaolin Li, Shing-Tung Yau
Song Zhang
A multilevel quality-guided phase unwrapping algorithm for real-time 3D shape measurement is presented. The quality map is generated from the gradient of the phase map. Multilevel thresholds are used to unwrap the phase level by level. Within the data points in each level, a fast scan-line algorithm is employed. The processing time of this algorithm is approximately 18.3 ms for an image size of 640×480 pixels in an ordinary computer. We demonstrate that this algorithm can be implemented into our real-time 3D shape measurement system for real-time 3D reconstruction. Experiments show that this algorithm improves the previous scan-line phase unwrapping …