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Full-Text Articles in Physical Sciences and Mathematics

Three-Dimensional Data Merging Using Holoimage, Song Zhang, Shing-Tung Yau Mar 2008

Three-Dimensional Data Merging Using Holoimage, Song Zhang, Shing-Tung Yau

Song Zhang

Three-dimensional data merging is vital for full-field three-dimensional (3D) shape measurement. All 3D range data patches, acquired from either different sensors or the same sensor in different viewing angles, have to be merged into a single piece to facilitate future data analysis. A novel method for 3D data merging using Holoimage is proposed. Similar to the 3D shape measurement system using a phase-shifting method, Holoimage is a phase-shifting–based computer synthesized fringe image. The 3D information is retrieved from Holoimage using a phase-shifting method. If two patches of 3D data with overlapping areas are rendered by OpenGL, the overlapping areas are …


Three-Dimensional Shape Measurement Using A Structured Light System With Dual Cameras, Song Zhang, Shing-Tung Yau Jan 2008

Three-Dimensional Shape Measurement Using A Structured Light System With Dual Cameras, Song Zhang, Shing-Tung Yau

Song Zhang

A structured light system for three-dimensional shape measurement with single camera has the shortcoming of camera occlusion. To alleviate this problem, this paper introduces a structured light system with dual cameras for three-dimensional shape measurement. We discuss (1) system description, (2) system calibration, (3) three-dimensional data registration using the iterative closest-point (ICP) algorithm, and (4) three-dimensional data merging using holoimage. The principle of the system is introduced, and experiments are presented to verify its performance.


Automatic Identification Of Discourse Moves In Scientific Article Introductions, Elena Cotos, Nick Pendar Jan 2008

Automatic Identification Of Discourse Moves In Scientific Article Introductions, Elena Cotos, Nick Pendar

Elena Cotos

This paper reports on the first stage of building an educational tool for international graduate students to improve their academic writing skills. Taking a text-categorization approach, we experimented with several models to automatically classify sentences in research article introductions into one of three rhetorical moves. The paper begins by situating the project within the larger framework of intelligent computer-assisted language learning. It then presents the details of the study with very encouraging results. The paper then concludes by commenting on how the system may be improved and how the project is intended to be pursued and evaluated.


Absolute Phase-Assisted Three-Dimensional Data Registration For A Dual-Camera Structured Light System, Song Zhang, Shing-Tung Yau Jan 2008

Absolute Phase-Assisted Three-Dimensional Data Registration For A Dual-Camera Structured Light System, Song Zhang, Shing-Tung Yau

Song Zhang

For a three-dimensional shape measurement system with a single projector and multiple cameras, registering patches from different cameras is crucial. Registration usually involves a complicated and time-consuming procedure. We propose a new method that can robustly match different patches via absolute phase without significantly increasing its cost. For y and z coordinates, the transformations from one camera to the other are approximated as third-order polynomial functions of the absolute phase. The x coordinates involve only translations and scalings. These functions are calibrated and only need to be determined once. Experiments demonstrated that the alignment error is within RMS 0.7 mm …