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Sensor Fusion in Multiscale Inspection Systems
Published in Wolfgang Osten, Optical Inspection of Microsystems, 2019
The visibility of a facet is given if it is located at a given pose in the measurement volume of the sensor and if its gradient or curvature is below specific threshold values. However, the measurability gives an estimate for the local measurement uncertainty if the facet would be sampled by a sensor from the respective pose. Both the visibility and the measurability are indicated by a matrix structure, where the rows correspond to the viewpoint candidates and the columns are the marked surface segments. For the determination of these matrices, an efficient ray-tracing module is used. This simulation has to be completed very fast to allow an online planning, which is required if an iterative multiscale inspection strategy is applied. Therefore, the most compute-intensive steps are solved using the graphics processing unit (GPU) of the computer and NVIDIA’s acceleration engine OptiX [35,36].
Multiphysics Analysis System for Heat Pipe–Cooled Micro Reactors Employing PRAGMA-OpenFOAM-ANLHTP
Published in Nuclear Science and Engineering, 2023
Jaeuk Im, Myung Jin Jeong, Namjae Choi, Kyung Min Kim, Hyoung Kyu Cho, Han Gyu Joo
PRAGMA exploits the NVIDIA ray-tracing engine OptiX for neutron tracking on flexible geometry. OptiX is an application framework for achieving optimal ray-tracing performance on the GPU, which provides a simple, recursive, and flexible pipeline for accelerating ray-tracing algorithms. Figure 3 illustrates the ray-tracing pipeline in OptiX for MC neutron simulation. The Any-Hit program is supposed to be utilized for graphics shadow and transparency computation, thus there is no need to use this program in the MC application. However, PRAGMA adopts the Any-Hit program to resolve the self-intersection problem where a ray intersects the same surface repeatedly and results in an infinitesimally small distance; this issue is a well-known and notorious problem in graphics ray tracing due to round-off errors in the floating-point arithmetic.17
Efficient GPU implementation of the time-domain shooting and bouncing rays method on electrically large complex target
Published in Waves in Random and Complex Media, 2022
Yiwen Wei, Dayong Tian, Juan Li, Jingjing Wang, Shuirong Chai, Lixin Guo
In ray tracing, the incident plane wave is launched and modeled by a set of parallel rays from incident direction. These rays are regularly spaced and ray density of at least 10 per linear wavelength is advised in order to obtain relatively accurate result. Thus, enormous number of rays are needed and this causes a serious bottleneck in computational time. In this piece of work, OptiX is primarily employed to leverage this limitation and speed up the ray-tracing process. The NVIDIA® OptiX™ is a general purpose ray tracing engine designed for NVIDIA GPUs [20]. This engine combines a programmable ray tracing pipeline with lightweight scene representation.