Papers by Keyword: Spherical Harmonics

Abstract: To improve the precision and real-time of the virtual liver surgery simulation system with haptic feedback, a novel deformation modelling based on wave equation and spherical harmonic is proposed. Continuous changed liver models were mapped into a common reference system in which corresponding coefficients of spherical harmonic were compared with method of principal components analysis and force feedback were calculated by simplified deformation wave equation. Moreover, system structure design, fast collision detection and real-time feedback operation are also discussed in detail. Experimental platform of virtual liver surgery was established based on vizard 4.0 and Sensable-phantom® desktopTM. Experiment results show that the system can provide a stable force to the human operator and which satisfy the requirement of real-time performance. Establishing a simple and lifelike physics deformation model and a precise and rapid collision detection algorithm favors the performance improvement of the virtual liver surgery simulation system.

Abstract: Human skin is a highly scattering translucent material and is difficult to be scaled. In this paper, we combine approximation of specular reflection with subsurface scattering in the texture space and introduce the dynamic environment lighting to render the human skin to obtain a much more realistic expression. Considering lower computation and requirement for real-time, we use few spherical harmonics coefficients to represent the environment lighting approximated by the environment map. Further, by rotating the environment map, we obtain dynamic rendering effect of human skin appearance, which has a great practical value for creation of virtual character in real scene.

Abstract: The symmetric implosion of the pellet is very important in an inertial confinement fusion (ICF) system. The evaluation of symmetric distribution on the ICF pellet is time and memory consuming, especially when the elements of cylindrical hohlraums are iteratively subdivided. A novel compressive sensing (CS) based approach is presented in this paper to accurately valuate the distribution symmetry with much less computation. The core idea is that, the thermal radiation distribution is transformed in the spherical harmonic field, and the sparsity of spherical harmonics is accurately evaluated through CS approach. Finally, experiments are demonstrated to show higher efficiency of the proposed approach.

Abstract: A mathematical framework called Microstructure Sensitive Design (MSD) has been developed recently to solve inverse problems of materials design, where the goal is to identify the class of microstructures that are predicted to satisfy a set of designer specified objectives and constraints [1]. This paper demonstrates the application of the MSD framework to a specific case study involving mechanical design. Processing solutions to obtain one of the elements of the desired class of textures are also explored within the same framework.