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[ACM Press the 2018 Conference - Honolulu, Hawaii (2018.10.09-2018.10.12)] Proceedings of the 2018 Conference on Research in Adaptive and Convergent Systems - RACS '18 - Efficient synthetic light field generation using adaptive multi-level rendering
摘要： Real-time global illumination rendering is very desirable for emerging applications such as Virtual Reality (VR) and Augmented Reality (AR). However, client devices have difficulties to support photo-realistic rendering, such as Ray-Tracing, due to insufficient computing resources. Many modern frameworks adopted Light Field rendering to support device displaying. A Light Field can be pre-computed and store in cloud. During runtime, the display extracts the colors from the Light Field to generate arbitrary real time viewpoints or re-focusing within a predefined area. To efficiently compute the Light Field, We have combined DIBR (Depth-Image-Based-Rendering) and traditional ray-tracing in an adaptive fashion to synthesize images. By measuring the color errors during runtime, we adaptively determine the right balance between DIBR and Ray Tracing. To further optimize the computation efficiency, we also added a multi-level design to exploit the degree of shareable pixels among images to control the computation for error removal. Experiments show that we achieved up to 3.24X speedup in Light Field generation for relative simple scenes like Cornell Box, and about 2X speed up for complex scenes like Conference Room or Sponza.
关键词： Light Field,Ray-Tracing,Image-Based Rendering,Global Illumination
更新于2025-09-11 14:15:04
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A Proposal to Improve Ray Launching Techniques
摘要： In this study, we demonstrate the implementation of an algorithm to model 3D-ray launching. A fixed-size reception sphere and cylinder is used in conjunction with numerical methods to simulate the multipath propagation in a reduced computational time while retaining accuracy. This approach was implemented in a two office environments that were validated previously by the authors in different simulations. The mathematical feasibility of this method in these applications is demonstrated and the obtained results are discussed. The proposed method has been previously validated by authors in different simulations shown in references.
关键词： Propagation,Ray Tracing,Channel modeling,Ray Launching
更新于2025-09-10 09:29:36
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Fast Modeling Methods for Estimating Imaging Performance of Whole Body Screening
摘要： Simulation of millimeter wave imaging system for whole body screening before a safety inspection manufactured is a challenging work. The conventional physical optics (PO) method is a proper high-frequency approximation method to solve the forward problem of imaging. In this letter, a modi?ed PO method is used to calculate not only metal scatterer but also non-metal dielectric medium. A ray tracing (RT) method and its modi?cation are proposed to further fast estimate the performance of multiple-input-multiple-output (MIMO) imaging system. The radiation pattern of transmitter or receiver is taken into account, then the rough imaging performance of arbitrary MIMO system on arbitrary human posture can be acquired in seconds to make the system design ?exible and convenient. The image reconstruction of the proposed method for a human body model with dielectric skin medium and metal pistol has demonstrated the applicability to real-life applications.
关键词： Millimeter wave imaging,concealed weapon detection (CWD),Image reconstruction,Physical optics (PO),Ray tracing (RT),Multiple-input-multiple-output (MIMO)
更新于2025-09-10 09:29:36
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Investigation on laser plasma instability of the outer ring beams on SGIII laser facility
摘要： In order to study the laser plasma instabilities (LPIs) in the context of some novel six-side laser-driven indirect designs like the six-cylinder-port hohlraum and the three-axis cylindrical hohlraum, where the laser beams inject in hohlraum with a large angle. LPI experiments in cylindrical hohlraum with only outer beams were designed and performed based on the current laser arrangement condition of SGIII laser facility for the first time. Stimulated Brillouin backscatter (SBS) was found to be the dominant instability with high instantaneous reflectivity in experiments. A typical feature was obtained in the time-resolved spectra of SBS, which maintained similar for different laser intensities of the interaction beam. The experimental data are analyzed by the hydrodynamic simulations combined with HLIP code, which is based on the ray-tracing model. By analysis of experimental data, it is argued that the mixture of gas and Au in the region of their interface is important to SBS, which indicates the need for the mixture model between the filled gas and the high Z plasma from hohlraum wall in the hydrodynamic simulations. Nonlinear saturation of SBS as well as the smoothed beam are also discussed here. Our effective considerations of the ions pervasion effect and the smoothed beam provide utilitarian ways for improvement of the current ray-tracing method.
关键词： laser plasma instabilities,hydrodynamic simulations,stimulated Brillouin backscatter,ray-tracing model,SGIII laser facility
更新于2025-09-09 09:28:46
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In?vitro and schematic model eye assessment of glare or positive dysphotopsia-type photic phenomena: Comparison of a new material IOL to other monofocal IOLs
摘要： To compare the glare-type photic phenomena for a new intraocular lens (IOL) to other monofocal IOLs, and to investigate how IOL design features might affect these phenomena. Setting: Alcon Laboratories, Inc., Fort Worth, Texas; John A Moran Eye Center, University of Utah, Salt Lake City, USA. Design: Schematic model eye evaluation and in vitro study. Methods: Five monofocal IOL models (Clareon CNA0T0, Tecnis ZCB00, enVista MX60, Eternity W-60, and Vivinex XY1) were used to evaluate glare or positive dysphotopsia-type phenomena. Optical simulations of incoming light were generated using nonsequential ray-tracing software based on a collimated light source for various off-axis angles of illumination. The simulation analyses were verified using a laboratory in vitro bench-top glare measurement system. Results: The Clareon and Vivinex IOLs produced focused off-axis images with negligible peripheral glare characteristics. The Tecnis and enVista IOLs produced dispersed images with additional glare characteristics at 45 degrees of off-axis illumination and higher. The Eternity IOL showed the highest edge-reflected glare characteristic, likely because of its straight optic edge geometry. The laboratory bench images and glare intensity profiles were consistent with the simulation data. Conclusions: In vitro and nonsequential ray-tracing evaluations showed that straight optic edges and peripheral nonimaging optic geometry might contribute to positive dysphotopsia. The IOL designs with optic edge curvature and full functional optics demonstrated the lowest level of glare-type photic phenomena. Only clinical studies can confirm whether the differences observed between the IOLs in vitro are clinically significant.
关键词： glare,intraocular lens,nonsequential ray-tracing,photic phenomena,positive dysphotopsia
更新于2025-09-09 09:28:46
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[IEEE 2018 IEEE International Conference on Computational Electromagnetics (ICCEM) - Chengdu, China (2018.3.26-2018.3.28)] 2018 IEEE International Conference on Computational Electromagnetics (ICCEM) - Investigation of Corner Singularity in Conformal FDTD Structured Mesh Generation Based on Ray Tracing
摘要： Corner singularity in finite-difference time-domain (FDTD) method indicates the incorrect conformal area computed from the intersection information by tangential situation. Tangential situation ray originates from a mesh line aligning on an aligned plane, which leads to the fuzzification of intersection length along Yee grid edge. The intersection position of two perpendicular aligned planes or an aligned plane with arbitrary plane is the position of possible corner singularity, from which the incorrect computed conformal area may result. A universal scheme to solve the corner singularity problem is proposed. By utilizing the in or out information normal to the tangential plane, as well as cell position relation relative to the tangential plane, we can determine whether or not to modify the length of the tangential side of Yee cell for computing the conformal area. A simple numerical example of a hollow rectangular waveguide shows the necessity for handling corner singularity.
关键词： tangential situation,conformal,structured mesh generation,corner singularity,ray tracing,FDTD
更新于2025-09-09 09:28:46
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DESIGN OF NONUNIFORM METALLIC ANECHOIC CHAMBER FOR RADIATION PATTERN MEASUREMENT
摘要： Antenna pattern measurement is an essential step in antenna quali?cation which should be done in anechoic chambers. The common method for construction of the anechoic chamber is to cover all inside walls by the electromagnetic absorbers. In this paper, a new method is presented to design a fully metallic chamber by controlling the electromagnetic wave propagation inside the chamber and guiding them to a piece of absorber. Therefore, a desirable quiet zone is formed inside the chamber while a great reduction of absorber usage is achieved. The proposed chamber is analyzed using ray tracing method, and its performance is evaluated by simulation which shows the practicality of the proposed chamber.
关键词： anechoic chamber,ray tracing method,antenna pattern measurement,electromagnetic absorbers,quiet zone
更新于2025-09-09 09:28:46
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Optical performance analysis of an innovative linear focus secondary trough solar concentrating system
摘要： The parabolic trough solar concentrating system has been well developed and widely used in commercial solar thermal power plants. However, the conventional system has its drawbacks when connecting receiver tube parts and enhancing the concentration ratio. To overcome those inherent disadvantages, in this paper, an innovative concept of linear focus secondary trough concentrating system was proposed, which consists of a fixed parabolic trough concentrator, one or more heliostats, and a fixed tube receiver. The proposed system not only avoids the end loss and connection problem on the receiver during the tracking process but also opens up the possibility to increase the concentration ratio by enlarging aperture. The design scheme of the proposed system was elaborated in detail in this paper. Besides, the optical performance of the semi and the whole secondary solar trough concentrator was evaluated by using the ray tracing method. This innovative solar concentrating system shows a high application value as a solar energy experimental device.
关键词： secondary parabolic trough solar concentrator,optical performance,concentration ratio,linear focus,ray tracing method
更新于2025-09-09 09:28:46
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AIP Conference Proceedings [Author(s) SolarPACES 2017: International Conference on Concentrating Solar Power and Chemical Energy Systems - Santiago, Chile (26–29 September 2017)] - Particle swarm optimization of the layout of a heliostat field
摘要： We present a new solar field layout optimization method that combines the Particle Swarm Optimization (PSO) algorithm with the parallelization power of the Graphical Processing Units (GPU). This new approach enables central receiver system designers to obtain very quickly an optimized field layout that take accurately into account all the optical losses (cosine effect, shadowing, blocking, atmospheric attenuation, and spillage). This is achieved by using a very fast implementation of a ray-tracing engine to compute the fitness objective (the annual performance of the field) that leverage the power of the parallel architecture of the GPUs. Initial results of the software on a couple of case studies are presented. These results demonstrate that solar field efficiency improvement is attainable with the proposed technique.
关键词： GPU,Heliostat Field,Ray-tracing,Solar Field Layout,Particle Swarm Optimization
更新于2025-09-04 15:30:14
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The Monte Carlo Ray-Trace Method in Radiation Heat Transfer and Applied Optics || Fundamentals of Ray Tracing
摘要： A ray is defined as the collection of straight-line path segments followed by an energy bundle from its point of emission to its point of absorption. The definition includes the possibility of intermediate reflection, scattering, refraction, and even diffraction events. Ray tracing involves the application of basic mathematics to the process of identifying the intersection of ray segments with surfaces. Most engineering and science students acquire the required mathematical tools long before they enter university. The current chapter provides a review of the mathematical principles governing ray tracing and the related issues of meshing and indexing.
关键词： Monte Carlo Method,Radiation Heat Transfer,Applied Optics,Mathematical Principles,Ray Tracing
更新于2025-09-04 15:30:14