Huynh Quang Huy Viet

An Algorithm for Cutting 3D Surface Meshes

The cutting operation of 3D surface meshes plays an important role in surgery simulators. One of the important requirements for surgical simulators is the faithful representation of interaction paths of a surgical tool. We propose a new strategy for cutting on surface meshes: refinement and separate strategy consisting of the refinement followed by the separation of the refined mesh element. The proposed strategy gives the faithful representation of interaction paths

Bisection Refinement-Based Real-Time Adaptive Mesh Model For Deformation and Cutting of Soft Objects

The subjects described in this paper are a realtime adaptive modeling method for deformable objects and an adaptive cutting method for 3D surface meshes. In the literature so far, adaptive models with high resolution representations at regions of high deformation have not been investigated. In this paper we propose a new method for real-time modeling of soft objects, of which high resolutions dynamically adapt to the regions of high deformation. In order to reduce the computational cost in comparison with the previous methods we use the bisection refinement algorithm. The experimental results show the effectiveness of the proposed method. The cutting operation of 3D surface meshes plays an important role in surgery simulators. One of the important requirements for surgical simulators is the visual reality. We propose a new strategy for cutting on surface mesh: refinement and separate strategy consisting of the refinement followed by the separation of the refined mesh element. Since the advantage of the low computational cost, the bisection refinement method is utilized for the refinement process. The proposed strategy gives the faithful representation of the interaction path

Image-based rendering of the anisotropic BRDF of woven fabrics

The reflectance of fabric surface is commonly represented by a 4D bidirectional reflectance distribution function (BRDF). To generate the BRDF from measured data by a gonioreflectometer with 2 degrees of freedom of the light source and 2 degrees of freedom of the observing direction, it requires an enormous amount of measurements. In this paper, we propose an efficient image-based method for rendering the anisotropic BRDF of woven fabrics based on the micro facet surface geometry determined by the cross-sectional shape of fibers, twist of yarns, and type of weave. At first, we examine the relationship between the reflectance properties and the micro facet surface geometry of a type of woven fabric such as silk-like synthesized fabric. Next, we develop an image-based method for generating the BRDF of woven fabrics from measurement of the reflectances caused by the incident light only in the direction perpendicular to the fabrics surface. The simulation results on arbitrarily colored dresses show the performance of the proposed approach.

Toward Real-time Volume-based Haptic Communication with Realistic Sensation

A volume-based realistic communication system called Haptic Communication is described. The system allows participants to interact in real time with others at remote locations on the network using haptic perception (sense of touch) of soft objects in virtual environments. We constructed the system so that it provides a sense of touch at remote locations in real time. First, an adaptive volume model represents virtual soft objects in PCs at remote locations. Next, the reflection force of the soft object is calculated rapidly and accurately from the parameters of positions and forces at contacting points transmitted via network at each PC. Eventually, the haptic and visual information are rendered by a haptic device (PHANToM) and a volume graphic software in the PCs. We investigated the efficiency of our system via experiments on a simulation of needle insertion with high force feedback rates at two remote locations on a WAN between Ritsumeikan University, Biwako Kusatsu Campus and Shiga Medical University. The experiment results show that the delay due to network traffic is negligible.

Motion from Focus

Based on the triangulation method, the 3D motion of an object can be completely recognized by a stereo camera. However, the question whether or not the 3D motion of an object can be completely recognized by a motionless/fixed monocular camera is the yet-unanswered question. In this paper we propose a method using a motionless monocular camera of which the focus is changed in cycle to recognize the absolute 3D motion of an object

Analysis of the 3D trajectory of absolute motion of an object using a motionless monocular camera

Based on the triangulation method, the 3D motion of an object can be completely recognized by a stereo camera. However, the question whether or not the 3D motion of an object can be completely recognized by a motionless / fixed monocular camera is the yet-unanswered question. In this paper we propose a method using a motionless monocular camera of which the focus is changed in cycle to recognize the absolute 3D motion of an object. We name the method motion from focus.

Analysis of Three-dimensional motion of an object using a fixed monocular camera

The research on analysis of three-dimensional motion by using a monocular camera instead of a stereo camera has important applications for making the microscopes used in microbiology or constructing the autonomous robots used in various fields of industry. We propose a fixed monocular camera whose focus changed cyclically to recognize three-dimensional absolute motion of a rigid object.