Zeitschriftenartikel: „Real-time ray tracing“

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Deng, Yangdong, Yufei Ni, Zonghui Li, Shuai Mu und Wenjun Zhang. „Toward Real-Time Ray Tracing“. ACM Computing Surveys 50, Nr. 4 (08.11.2017): 1–41. http://dx.doi.org/10.1145/3104067.

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Yoon, Hyung-Min, Byoung-Ok Lee, Cheol-Ho Cheong, Jin-Suk Hur, Sang-Gon Kim, Woo-Nam Chung, Yong-Ho Lee und Woo-Chan Park. „Real-time Ray-tracing Chip Architecture“. IEIE Transactions on Smart Processing and Computing 4, Nr. 2 (30.04.2015): 65–70. http://dx.doi.org/10.5573/ieiespc.2015.4.2.065.

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Park, Jeong-soo, Woo-chan Park, Jae-Ho Nah und Tack-don Han. „Node pre-fetching architecture for real-time ray tracing“. IEICE Electronics Express 10, Nr. 14 (2013): 20130468. http://dx.doi.org/10.1587/elex.10.20130468.

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Weier, Martin, Thorsten Roth, Ernst Kruijff, André Hinkenjann, Arsène Pérard-Gayot, Philipp Slusallek und Yongmin Li. „Foveated Real-Time Ray Tracing for Head-Mounted Displays“. Computer Graphics Forum 35, Nr. 7 (Oktober 2016): 289–98. http://dx.doi.org/10.1111/cgf.13026.

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Heinrich, H., P. Ziegenhein, C. P. Kamerling, H. Froening und U. Oelfke. „GPU-accelerated ray-tracing for real-time treatment planning“. Journal of Physics: Conference Series 489 (24.03.2014): 012050. http://dx.doi.org/10.1088/1742-6596/489/1/012050.

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Casalino, Giuseppe, Andrea Caiti, Alessio Turetta und Enrico Simetti. „RT2: real-time ray-tracing for underwater range evaluation“. Intelligent Service Robotics 4, Nr. 4 (25.06.2011): 259–70. http://dx.doi.org/10.1007/s11370-011-0093-8.

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Zeng, Zheng, Shiqiu Liu, Jinglei Yang, Lu Wang und Ling‐Qi Yan. „Temporally Reliable Motion Vectors for Real‐time Ray Tracing“. Computer Graphics Forum 40, Nr. 2 (Mai 2021): 79–90. http://dx.doi.org/10.1111/cgf.142616.

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Schmittler, Jörg, Alexander Leidinger und Philipp Slusallek. „A virtual memory architecture for real-time ray tracing hardware“. Computers & Graphics 27, Nr. 5 (Oktober 2003): 693–99. http://dx.doi.org/10.1016/s0097-8493(03)00142-0.

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Spjut, J., A. Kensler, D. Kopta und E. Brunvand. „TRaX: A Multicore Hardware Architecture for Real-Time Ray Tracing“. IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems 28, Nr. 12 (Dezember 2009): 1802–15. http://dx.doi.org/10.1109/tcad.2009.2028981.

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Singh, J. M., und P. J. Narayanan. „Real-Time Ray Tracing of Implicit Surfaces on the GPU“. IEEE Transactions on Visualization and Computer Graphics 16, Nr. 2 (März 2010): 261–72. http://dx.doi.org/10.1109/tvcg.2009.41.

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Wang, Xin, und Risong Zhang. „Rendering transparent objects with caustics using real-time ray tracing“. Computers & Graphics 96 (Mai 2021): 36–47. http://dx.doi.org/10.1016/j.cag.2021.03.003.

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Andrade, Paulo, Esteban Clua, Thales Sabino und Fabio Forti. „A Heuristic Approach to Render Ray Tracing Effects in Real Time for First-Person Games“. Journal on Interactive Systems 5, Nr. 1 (09.07.2014): 1. http://dx.doi.org/10.5753/jis.2014.640.

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Realistic computer graphics effects as mirror reflections, transparency, caustics and detailed shadows are hard to simulate using real time raster based rendering, since they require global illumination approaches. One option is ray trace these effects using a real-time hybrid renderer, where ray tracing and raster rendering are used together to generate the best visual experience. Unfortunately, the ray tracing stage of a hybrid renderer can be a very demanding stage, making it hard to maintain real time frame rates in virtual environments where many elements must be ray traced. This work present a heurist to select the best subset of elements to ray trace in real time, in a hybrid renderer, in order to improve the visual experience offered by an equivalent raster only render, and still maintain the real time experience. The selection process considers rendering time constraints, spatial information of the environment, previous elements selected for ray tracing and current information about the candidate elements.

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Park, Sukjun, und Nakhoon Baek. „A Shader-Based Ray Tracing Engine“. Applied Sciences 11, Nr. 7 (06.04.2021): 3264. http://dx.doi.org/10.3390/app11073264.

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Recently, ray tracing techniques have been highly adopted to produce high quality images and animations. In this paper, we present our design and implementation of a real-time ray-traced rendering engine. We achieved real-time capability for triangle primitives, based on the ray tracing techniques on GPGPU (general-purpose graphics processing unit) compute shaders. To accelerate the ray tracing engine, we used a set of acceleration techniques, including bounding volume hierarchy, its roped representation, joint up-sampling, and bilateral filtering. Our current implementation shows remarkable speed-ups, with acceptable error values. Experimental results shows 2.5–13.6 times acceleration, and less than 3% error values for the 95% confidence range. Our next step will be enhancing bilateral filter behaviors.

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van Aart, Evert, Neda Sepasian, Andrei Jalba und Anna Vilanova. „CUDA-Accelerated Geodesic Ray-Tracing for Fiber Tracking“. International Journal of Biomedical Imaging 2011 (2011): 1–12. http://dx.doi.org/10.1155/2011/698908.

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Diffusion Tensor Imaging (DTI) allows to noninvasively measure the diffusion of water in fibrous tissue. By reconstructing the fibers from DTI data using a fiber-tracking algorithm, we can deduce the structure of the tissue. In this paper, we outline an approach to accelerating such a fiber-tracking algorithm using a Graphics Processing Unit (GPU). This algorithm, which is based on the calculation of geodesics, has shown promising results for both synthetic and real data, but is limited in its applicability by its high computational requirements. We present a solution which uses the parallelism offered by modern GPUs, in combination with the CUDA platform by NVIDIA, to significantly reduce the execution time of the fiber-tracking algorithm. Compared to a multithreaded CPU implementation of the same algorithm, our GPU mapping achieves a speedup factor of up to 40 times.

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Lee, Jinyoung, Woo-Nam Chung, Tae-Hyoung Lee, Jae-Ho Nah, Youngsik Kim und Woo-Chan Park. „Load Balancing Algorithm for Real-Time Ray Tracing of Dynamic Scenes“. IEEE Access 8 (2020): 165003–9. http://dx.doi.org/10.1109/access.2020.3019075.

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Li, Zhi. „Study on Scene Rendering Using Ray Tracing“. Applied Mechanics and Materials 241-244 (Dezember 2012): 2625–29. http://dx.doi.org/10.4028/www.scientific.net/amm.241-244.2625.

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The paper synoptically discusses the basic technological process of the ray tracing method, analyzes its parallel algorithms. Introduce the recent research focus of the field from study on real-time ray tracing and based ray tracing of graphics hardware. Point out the advantages and disadvantages of the ray tracing algorithms to solve scene rendering as well as future research priorities.

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Walewski, Patryk, Tomasz Gałaj und Dominik Szajerman. „Heuristic based real-time hybrid rendering with the use of rasterization and ray tracing method“. Open Physics 17, Nr. 1 (04.10.2019): 527–44. http://dx.doi.org/10.1515/phys-2019-0055.

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Abstract Nowadays, rasterization is the most common method used to achieve real-time semi-photorealistic effects in games or interactive applications. Some of those effects are not easily achievable, thus require more complicated methods and are difficult to obtain. The appearance of the presented worlds depends to a large extent on the approximation to the physical basis of light behaviour in them. The best effects in this regard are global illumination algorithms. Each of them including ray tracing give the most plausible effects, but at cost of higher computational complexity. Today’s hardware allows usage of ray tracing methods in-real time on Graphics Processing Units (GPU) thanks to its parallel nature. However, using ray tracing as a single rendering method may still result in poor performance, especially when used to create many image effects in complex environments. In this paper we present a hybrid approach for real-time rendering using both rasterization and ray tracing using heuristic, which determines whether to render secondary effects such as shadows, reflections and refractions for individual objects considering their relevancy and cost of rendering those effects for these objects in particular case.

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QIN Zhiqiang, 秦志强, 张文阁 ZHANG Wenge, 蒋晓瑜 JIANG Xiaoyu, 闫兴鹏 YAN Xingpeng und 严志强 YAN Zhiqiang. „Realtime Interactive Computergenerated Integral Imaging Method Based on Ray Tracing“. ACTA PHOTONICA SINICA 48, Nr. 9 (2019): 911002. http://dx.doi.org/10.3788/gzxb20194809.0911002.

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Huo, Weiping, Xinzhu Sang, Shujun Xing, Yanxin Guan und Yuanhang Li. „Backward ray tracing based rectification for real-time integral imaging display system“. Optics Communications 458 (März 2020): 124752. http://dx.doi.org/10.1016/j.optcom.2019.124752.

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Hyuck-Joo Kwon, Woochan Park, Sanghoon Lee und Dukki Hong. „A Soft Shadow Technique for a Real-time Mobile Ray Tracing Hardware“. Journal of the Korea Computer Graphics Society 23, Nr. 3 (Juli 2017): 55–64. http://dx.doi.org/10.15701/kcgs.2017.23.3.55.

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Choi, B., B. Chang und I. Ihm. „Improving Memory Space Efficiency of Kd-tree for Real-time Ray Tracing“. Computer Graphics Forum 32, Nr. 7 (Oktober 2013): 335–44. http://dx.doi.org/10.1111/cgf.12241.

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NI, Dong, Si-ping CHEN und Tian-fu WANG. „A beam width aware curvilinear ray tracing method for real-time ultrasound simulation“. JOURNAL OF SHENZHEN UNIVERSITY SCIENCE AND ENGINEERING 29, Nr. 4 (09.08.2012): 322–27. http://dx.doi.org/10.3724/sp.j.1249.2012.04322.

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Reshidko, Dmitry, Masatsugu Nakanato und José Sasián. „Ray Tracing Methods for Correcting Chromatic Aberrations in Imaging Systems“. International Journal of Optics 2014 (2014): 1–11. http://dx.doi.org/10.1155/2014/351584.

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The correction of chromatic aberrations is typically performed using aberration formulas or by using real ray tracing. While the use of aberration formulas might be effective for some simple optical systems, it has limitations for complex and fast systems. For this reason chromatic aberration correction is usually accomplished with real ray tracing. However, existing optimization tools in lens design software typically mix the correction of monochromatic and chromatic aberrations by construction of an error function that minimizes both aberrations at the same time. This mixing makes the correction of one aberration type dependent on the correction of the other aberration type. We show two methods to separate the chromatic aberrations correction of a lens system. In the first method we use forward and reverse ray tracing and fictitious nondispersive glasses, to cancel the monochromatic aberration content and allow the ray tracing optimization to focus mainly on the color correction. On the second method we provide the algorithm for an error function that separates aberrations. Furthermore, we also demonstrate how these ray tracing methods can be applied to athermalize an optical system. We are unaware that these simple but effective methods have been already discussed in detail by other authors.

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Li, Hui, Xinzhu Sang, Linmin Zhao, Duo Chen, Zhidong Chen, Yuan Wang, Xin Zhao et al. „Optimized layered method for real-time interactive holographic display based on ray-tracing technique“. Optical Engineering 59, Nr. 10 (30.01.2020): 1. http://dx.doi.org/10.1117/1.oe.59.10.102408.

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Mohammadi, Leila, Hamid Behnam, Jahan Tavakkoli und Mohammad Avanaki. „Skull’s Photoacoustic Attenuation and Dispersion Modeling with Deterministic Ray-Tracing: Towards Real-Time Aberration Correction“. Sensors 19, Nr. 2 (16.01.2019): 345. http://dx.doi.org/10.3390/s19020345.

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Although transcranial photoacoustic imaging has been previously investigated by several groups, there are many unknowns about the distorting effects of the skull due to the impedance mismatch between the skull and underlying layers. The current computational methods based on finite-element modeling are slow, especially in the cases where fine grids are defined for a large 3-D volume. We develop a very fast modeling/simulation framework based on deterministic ray-tracing. The framework considers a multilayer model of the medium, taking into account the frequency-dependent attenuation and dispersion effects that occur in wave reflection, refraction, and mode conversion at the skull surface. The speed of the proposed framework is evaluated. We validate the accuracy of the framework using numerical phantoms and compare its results to k-Wave simulation results. Analytical validation is also performed based on the longitudinal and shear wave transmission coefficients. We then simulated, using our method, the major skull-distorting effects including amplitude attenuation, time-domain signal broadening, and time shift, and confirmed the findings by comparing them to several ex vivo experimental results. It is expected that the proposed method speeds up modeling and quantification of skull tissue and allows the development of transcranial photoacoustic brain imaging.

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Wang, Yuan, Xinzhu Sang, Zhidong Chen, Hui Li und Linmin Zhao. „Real-time photorealistic computer-generated holograms based on backward ray tracing and wavefront recording planes“. Optics Communications 429 (Dezember 2018): 12–17. http://dx.doi.org/10.1016/j.optcom.2018.07.068.

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SKALA, TIBOR, KAROLJ SKALA und ENIS AFGAN. „IMPACT OF 3D GRAPHIC STRUCTURE COMPLEXITY TO THE RENDERING TIME“. Journal of Circuits, Systems and Computers 22, Nr. 07 (August 2013): 1350057. http://dx.doi.org/10.1142/s0218126613500576.

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The paper presents new approach to the analysis of the time required for rendering, depending on the complexity of the 3D object. Ray tracing is used to measure program complexity measure parameter based on the rendering time. Parametric analysis using ray tracing program is achieved by correlation between image parameters and rendering time. Electronic imaging and image processing (rendering) are considered in the 3D virtual photorealistic imaging design and electronic imaging creation and optimization. We are attempting to treat the complexity as a measure in the process of creating and rendering a complex image. The work is directed towards defining and optimizing the rendering time in the photorealistic 3D image creation process. The correlation between large numbers of image components obtained by the ray tracing program is used to measure the scene complexity regarding of render time. To discover which space variable to use as complexity measure, we cross-correlated variables output by ray tracing program, keeping track of the maximum values. Based on this method, the highest correlation was observed on variable Bounding box succeeded tests, and that way obtained the complexity measure for the image. That way the original research is performed in creating analytical (data-visual) methods for determining the image rendering parameters. The results based on experimental verification on a large number of performed standard tests on real sets of graphical contents, and established the impact of graphical content complexity to the rendering time at distributed cluster computing systems.

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Bai, Chao-ying, Stewart Greenhalgh und Bing Zhou. „3D ray tracing using a modified shortest-path method“. GEOPHYSICS 72, Nr. 4 (Juli 2007): T27—T36. http://dx.doi.org/10.1190/1.2732549.

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We present an accurate 3D ray-tracing algorithm based on a modified (more flexible and economical) shortest-path method (SPM). Unlike the regular SPM in the 3D case, which uses only primary nodes at the corners of each cell and whose accuracy depends on actual cell size, the new method can work with much larger cell sizes by introducing secondary nodes along all bounding surfaces of the cell. This increases the ray angular coverage and permits detailed specification of the velocity field. The modified SPM simultaneously calculates first-arrival times and gradually locates the related raypaths on all grid nodes as the wave field evolves. Its advantages over the regular SPM are its ability to handle high-contrast velocity models more easily, lower memory requirements and less CPU time, and the capability to calculate a relatively large 3D model without losing accuracy. The maximum relative error bound in the computed traveltimes of the modified SPM is established for a uniform velocity field, which may be considered an upper error bound for the whole model in real problems. The modified method in this study is compared with the regular SPM theoretically and on two specific velocity models. The Marmousi model is used to further test the performance of the new approach for both accuracy and flexibility in a complex velocity field. The study shows that the modified SPM is preferable to regular SPM for real 3D problems.

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Casalino, G., A. Caiti, A. Turetta und E. Simetti. „Real-Time Ray-Tracing for Underwater Distance Evaluation with Application to Distributed Localization of AUV Teams“. IFAC Proceedings Volumes 43, Nr. 16 (2010): 211–16. http://dx.doi.org/10.3182/20100906-3-it-2019.00038.

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Magoulès, Frédéric, Guillaume Gbikpi-Benissan und Patrick Callet. „Ray-tracing domain decomposition methods for real-time simulation on multi-core and multi-processor systems“. Concurrency and Computation: Practice and Experience 28, Nr. 16 (12.10.2015): 4352–64. http://dx.doi.org/10.1002/cpe.3696.

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Lee, Jinyoung, Jae-Ho Nah, Woonam Chung, Tae-Hyoung Lee und Woo-Chan Park. „An Implementation of Multi-Chip Architecture for Real-Time Ray Tracing Based on Parallel Frame Rendering“. IEEE Access 9 (2021): 118968–76. http://dx.doi.org/10.1109/access.2021.3107545.

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Anciferov, S., A. Karachevceva und L. Sivachenko. „DESIGN AND PRODUCT DESIGN IN CAD/CAM/CAE NX SYSTEM MANAGED BY TEAMCENTER PLM SYSTEM“. Technical Aesthetics and Design Research 1, Nr. 2 (24.12.2020): 45–52. http://dx.doi.org/10.34031/2687-0878-2019-1-2-45-52.

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The article discusses a system widely implemented in the designing of equipment for the NX construction industry. Along with this system, a modern automation tool was used. The most common and most used products are Siemens products: PLM-system "Teamcenter". The functionality of this configuration is huge, it includes such applications a "Manager of Structure", "Classifier", "Advanced Studio", "Ray Tracing Studio", etc. For example, it is possible to create a single product structure with various configurations, machine components and assemblies, using the "Structure Manager". This structure allows to simplify the introduction of changes and the development of a digital electronic model. For the final visualization and rendering, the NX system provides a certain set of tools, which includes "Extended Studio" and "Ray Tracing Studio". "Advanced Studio" is an application allowing to get high-quality image, including the effects of materials, textures, lighting, shadows and reflections for the product in the CAD/CAM/CAE NX system. "Ray Tracing Studio" allows to get the rendering of the future product. In the Ray Tracing Studio editor, it is possible to configure such parameters as dynamic tracing setting, real-time ray tracing setting, display static high-quality tracing setting, and general display settings. Creation of a product in this system can be considered by the example of a digital electronic model of a roller support.

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Samadi, Nazanin, Xianbo Shi, Les Dallin und Dean Chapman. „A real-time phase-space beam emittance monitoring system“. Journal of Synchrotron Radiation 26, Nr. 4 (18.06.2019): 1213–19. http://dx.doi.org/10.1107/s1600577519005423.

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An electron beam position and angle monitoring system, ps-BPM, has been shown to be able to measure the electron source position and angle at a single location in a beamline at a synchrotron source. This system uses a monochromator to prepare a photon beam whose energy is at that of the K-edge of an absorber filter. The divergence of the beam from the source gives an energy range that will encompass the K-edge of the filter. A measurement of the centre of the monochromatic beam and the K-edge location through the absorber filter gives the position and angle of the electron source. Here, it is shown that this system is also capable of measuring the source size and divergence at the same time. This capability is validated by measurement as the beam size in the storage ring was changed and by ray-tracing simulations. The system operates by measuring the photon beam spatial distribution as well as a K-edge filtered beam distribution. These additional measurements result in the ability to also determine the electron source size and divergence.

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Baumgart, Marcus, Norbert Druml, Markus Dielacher und Cristina Consani. „Investigating Intense Rainfall Influence on Distance Measurement with a Time-of-Flight Camera Sensor Using Optical Ray-Tracing Simulation Technique“. Proceedings 2, Nr. 13 (20.11.2018): 1056. http://dx.doi.org/10.3390/proceedings2131056.

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Robust, fast and reliable examination of the surroundings is essential for further advancements in autonomous driving and robotics. Time-of-Flight (ToF) camera sensors are a key technology to measure surrounding objects and their distances on a pixel basis in real-time. Environmental effects, like rain in front of the sensor, can influence the distance accuracy of the sensor. Here we use an optical ray-tracing based procedure to examine the rain effect on the ToF image. Simulation results are presented for experimental rain droplet distributions, characteristic of intense rainfall at rates of 25 mm/h and 100 mm/h. The ray-tracing based simulation data and results serve as an input for developing and testing rain signal suppression strategies.

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Lee, Sang Joon, Han Wook Park und Sung Yong Jung. „Usage of CO2microbubbles as flow-tracing contrast media in X-ray dynamic imaging of blood flows“. Journal of Synchrotron Radiation 21, Nr. 5 (31.07.2014): 1160–66. http://dx.doi.org/10.1107/s1600577514013423.

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X-ray imaging techniques have been employed to visualize various biofluid flow phenomena in a non-destructive manner. X-ray particle image velocimetry (PIV) was developed to measure velocity fields of blood flows to obtain hemodynamic information. A time-resolved X-ray PIV technique that is capable of measuring the velocity fields of blood flows under real physiological conditions was recently developed. However, technical limitations still remained in the measurement of blood flows with high image contrast and sufficient biocapability. In this study, CO2microbubbles as flow-tracing contrast media for X-ray PIV measurements of biofluid flows was developed. Human serum albumin and CO2gas were mechanically agitated to fabricate CO2microbubbles. The optimal fabricating conditions of CO2microbubbles were found by comparing the size and amount of microbubbles fabricated under various operating conditions. The average size and quantity of CO2microbubbles were measured by using a synchrotron X-ray imaging technique with a high spatial resolution. The quantity and size of the fabricated microbubbles decrease with increasing speed and operation time of the mechanical agitation. The feasibility of CO2microbubbles as a flow-tracing contrast media was checked for a 40% hematocrit blood flow. Particle images of the blood flow were consecutively captured by the time-resolved X-ray PIV system to obtain velocity field information of the flow. The experimental results were compared with a theoretically amassed velocity profile. Results show that the CO2microbubbles can be used as effective flow-tracing contrast media in X-ray PIV experiments.

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Schäfer, Philipp, und Michael Vorlaender. „Ray tracing for efficient simulation of curved sound propagation paths: Towards real-time auralization of aircraft noise“. Journal of the Acoustical Society of America 148, Nr. 4 (Oktober 2020): 2524. http://dx.doi.org/10.1121/1.5147012.

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N. de Sousa, Marcelo, und Reiner S. Thomä. „Enhancement of Localization Systems in NLOS Urban Scenario with Multipath Ray Tracing Fingerprints and Machine Learning“. Sensors 18, Nr. 11 (21.11.2018): 4073. http://dx.doi.org/10.3390/s18114073.

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A hybrid technique is proposed to enhance the localization performance of a time difference of arrival (TDOA) deployed in non-line-of-sight (NLOS) suburban scenario. The idea was to use Machine Learning framework on the dataset, produced by the ray tracing simulation, and the Channel Impulse Response estimation from the real signal received by each sensor. Conventional localization techniques mitigate errors trying to avoid NLOS measurements in processing emitter position, while the proposed method uses the multipath fingerprint information produced by ray tracing (RT) simulation together with calibration emitters to refine a Machine Learning engine, which gives an extra layer of information to improve the emitter position estimation. The ray-tracing fingerprints perform the target localization embedding all the reflection and diffraction in the propagation scenario. A validation campaign was performed and showed the feasibility of the proposed method, provided that the buildings can be appropriately included in the scenario description.

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Mateos-Canseco, Alejandro, Manuel Peña-Cruz, Arturo Díaz-Ponce, Jean-Luc Battaglia, Christophe Pradère und Luis Patino-Lopez. „Time-Resolved Temperature Map Prediction of Concentration Photovoltaics Systems by Means of Coupled Ray Tracing Flux Analysis and Thermal Quadrupoles Modelling“. Energies 11, Nr. 8 (07.08.2018): 2042. http://dx.doi.org/10.3390/en11082042.

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A transient 3D thermal model based on the thermal quadrupole method, coupled to ray tracing analysis, is presented. This methodology can predict transient temperature maps under any time-fluctuating irradiance flux—either synthetic or experimental—providing a useful tool for the design and parametric optimization of concentration photovoltaics systems. Analytic simulations of a concentration photovoltaics system thermal response and assessment of in-plane thermal gradients induced by fast tracking point perturbations, like those induced by wind, are provided and discussed for the first time. Computation times for time-resolved temperature maps can be as short as 9 s for a full month of system operation, with stimuli inspired by real data. Such information could pave the way for more accurate studies of cell reliability under any set of worldwide irradiance conditions.

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Park, Woo-Chan, Dong-Seok Kim, Jeong-Soo Park, Sang-Duk Kim, Hong-Sik Kim und Tack-Don Han. „The design of a texture mapping unit with effective MIP-map level selection for real-time ray tracing“. IEICE Electronics Express 8, Nr. 13 (2011): 1064–70. http://dx.doi.org/10.1587/elex.8.1064.

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Kim, Daeyong, Junick Ahn, Jun Shin und Hojung Cha. „Ray Tracing-based Light Energy Prediction for Indoor Batteryless Sensors“. Proceedings of the ACM on Interactive, Mobile, Wearable and Ubiquitous Technologies 5, Nr. 1 (19.03.2021): 1–27. http://dx.doi.org/10.1145/3448086.

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Light energy harvesting is a valuable technique for batteryless sensors located indoors. A key challenge is finding the right locations to deploy sensors to provide sufficient harvesting capability. A trial-and-error approach or energy prediction method is used as the solution, but existing schemes are either time-consuming or employing a naïve prediction mechanism primarily developed for outdoor environments. In this paper, we propose a light energy prediction technique, called Solacle, which accounts for various factors in indoor light harvesting to provide accuracy at any given location. Exploiting the ray tracing technique, Solacle estimates the illuminance and the luminous efficacy of light sources to predict the harvesting capability, by considering the spatiotemporal characteristics of the surrounding environment. To this end, we defined the optical properties of a space, and devised an optimization approach, specifically a gradient-free-based scheme, to acquire adequate values for the combination of optical properties. We implemented the system and evaluated its efficacy in controlled and real environments. The experiment results show that the proposed approach delivers a significant improvement over previous work in light energy prediction of indoor space.

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Boumsellek, S., und R. Ferran. „Miniature Quadrupole Arrays for Residual and Process Gas Analysis“. Journal of the IEST 42, Nr. 1 (14.01.1999): 27–31. http://dx.doi.org/10.17764/jiet.42.1.p57381407j7677u0.

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This paper includes computer simulations based on ray tracing to aid in the design of miniature quadrupoles. These quadrupoles are then assembled in a matrix-like pattern to operate in parallel. The tradeoffs between sensitivity and resolution for different mechanical and electrical configurations are examined using real-time trajectories of ions. The dependence of resolution versus sensitivity is computed and compared with experimental results. The pressure dependence of the sensitivity is simulated near the upper limit (mtorr range) of the operating pressure. Space charge effects at the inlet of the mass filter are evaluated to properly design electrode apertures and spacing. Using the results of ray tracing, miniature quadrupole arrays were designed and constructed. Performance parameters were derived from recorded spectra and compared with the computations. Since they are able to operate at higher pressures, these sensor-type devices are used as residual gas analyzers (RGAs) and as process gas analyzers (PGAs) in many semiconductor applications. Networking multiple sensors to monitor the state of the semiconductor manufacturing tool and the wafers at different stages of the process enables real-time, wafer-to-wafer control using preset fault detection schemes.

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Mi, Bao, und Charles Ume. „Real-Time Weld Penetration Depth Monitoring With Laser Ultrasonic Sensing System“. Journal of Manufacturing Science and Engineering 128, Nr. 1 (08.08.2005): 280–86. http://dx.doi.org/10.1115/1.2137747.

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A real-time ultrasound-based system for controlling robotic weld quality by monitoring the weld pool is presented. The weld penetration depth is one of the most important geometric parameters that define weld quality, hence, remains a key control quantity. The sensing system is based on using a laser phased array technique to generate focused and steered ultrasound, and an electromagnetic acoustic transducer (EMAT) as a receiver. When a pulsed laser beam is incident on the surface of a condensed matter, either the thermoelastic expansion or ablation induces mechanical vibrations that propagate as ultrasound within the specimen. Both the ultrasound generation by the laser phased array and the reception by the EMAT are noncontact, which eliminates the need for a couplant medium. They are capable of operating at high temperatures involved in the welding process. The ultrasound generated by the laser phased array propagates through the weld pool and is picked up by the EMAT receiver. A signal-processing algorithm based on a cross-correlation technique has been developed to estimate the time-of-flight (TOF) of the ultrasound. The relationship between the TOF and the penetration depth of the weld has been established experimentally and analytically. The analytical relationship between the TOF and the penetration depth, which is obtained by the ray-tracing algorithm and geometric analysis, agrees well with the experimental measurements.

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Thierry, Philippe, Gilles Lambaré, Pascal Podvin und Mark S. Noble. „3-D preserved amplitude prestack depth migration on a workstation“. GEOPHYSICS 64, Nr. 1 (Januar 1999): 222–29. http://dx.doi.org/10.1190/1.1444518.

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We present an algorithm based on the ray+Born approximation for 3-D preserved amplitude prestack depth migration (PAPsDM) of seismic reflection data. This ray+Born inversion scheme allows the quantitative recovery of model perturbations. The Green’s functions are estimated by dynamic ray tracing in 3-D heterogeneous smooth velocity fields with a wavefront construction (WFC) method. The PAPsDM algorithm was implemented on a single‐processor Sun Sparc 20 workstation. Special attention was paid to CPU efficiency and memory requirements. We present an application on a 3-D real marine data set (13 Gbytes). About one week of CPU time is needed to obtain a migrated image of 7 × 1 × 1 km.

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Lai, Zhihua, Nik Bessis, Guillaume De La Roche, Pierre Kuonen, Jie Zhang und Gordon J. Clapworthy. „The Development of a Parallel Ray Launching Algorithm for Wireless Network Planning“. International Journal of Distributed Systems and Technologies 2, Nr. 2 (April 2011): 1–19. http://dx.doi.org/10.4018/jdst.2011040101.

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Propagation modeling has attracted much interest because it plays an important role in wireless network planning and optimization. Deterministic approaches such as ray tracing and ray launching have been investigated, however, due to the running time constraint, these approaches are still not widely used. In previous work, an intelligent ray launching algorithm, namely IRLA, has been proposed. The IRLA has proven to be a fast and accurate algorithm and adapts to wireless network planning well. This article focuses on the development of a parallel ray launching algorithm based on the IRLA. Simulations are implemented, and evaluated performance shows that the parallelization greatly shortens the running time. The COST231 Munich scenario is adopted to verify algorithm behavior in real world environments, and observed results show a 5 times increased speedup upon a 16-processor cluster. In addition, the parallelization algorithm can be easily extended to larger scenarios with sufficient physical resources.

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Schäfer, Philipp, und Michael Vorländer. „Atmospheric Ray Tracing: An efficient, open-source framework for finding eigenrays in a stratified, moving medium“. Acta Acustica 5 (2021): 26. http://dx.doi.org/10.1051/aacus/2021018.

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In this paper, an open-source framework for ray tracing in a stratified moving medium is introduced. This framework provides an efficient method to find eigen-rays connecting a source with a receiver and is designed for the purpose of aircraft noise auralization. The method is tested with respect to accuracy and run-time in an aircraft flyover scenario and compared to a state of the art method. The investigation showed that this method provides eigenrays with preset accuracy for source positions most relevant for flyover scenarios and that it is significantly faster than the state of the art method. According to the performance analysis, the presented approach has great potential for integration into future real-time auralizations of aircraft noise.

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Möller, Gregor, und Daniel Landskron. „Atmospheric bending effects in GNSS tomography“. Atmospheric Measurement Techniques 12, Nr. 1 (03.01.2019): 23–34. http://dx.doi.org/10.5194/amt-12-23-2019.

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Abstract. In Global Navigation Satellite System (GNSS) tomography, precise information about the tropospheric water vapor distribution is derived from integral measurements like ground-based GNSS slant wet delays (SWDs). Therefore, the functional relation between observations and unknowns, i.e., the signal paths through the atmosphere, have to be accurately known for each station–satellite pair involved. For GNSS signals observed above a 15∘ elevation angle, the signal path is well approximated by a straight line. However, since electromagnetic waves are prone to atmospheric bending effects, this assumption is not sufficient anymore for lower elevation angles. Thus, in the following, a mixed 2-D piecewise linear ray-tracing approach is introduced and possible error sources in the reconstruction of the bended signal paths are analyzed in more detail. Especially if low elevation observations are considered, unmodeled bending effects can introduce a systematic error of up to 10–20 ppm, on average 1–2 ppm, into the tomography solution. Thereby, not only the ray-tracing method but also the quality of the a priori field can have a significant impact on the reconstructed signal paths, if not reduced by iterative processing. In order to keep the processing time within acceptable limits, a bending model is applied for the upper part of the neutral atmosphere. It helps to reduce the number of processing steps by up to 85 % without significant degradation in accuracy. Therefore, the developed mixed ray-tracing approach allows not only for the correct treatment of low elevation observations but is also fast and applicable for near-real-time applications.

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Pramitha, M., M. Venkat Ratnam, A. Taori, B. V. Krishna Murthy, D. Pallamraju und S. Vijaya Bhaskar Rao. „Identification of gravity wave sources using reverse ray tracing over Indian region“. Atmospheric Chemistry and Physics Discussions 14, Nr. 13 (29.07.2014): 19587–623. http://dx.doi.org/10.5194/acpd-14-19587-2014.

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Abstract. Reverse ray tracing method is successfully implemented for the first time in the Indian region for identification of the sources and propagation characteristics of the gravity waves observed using airglow emissions from Gadanki (13.5° N, 79.2° E) and Hyderabad (17.5° N, 78.5° E). Wave amplitudes are also traced back for these wave events by including both radiative and diffusive damping. Background temperature and wind data obtained from MSISE-90 and HWM-07 models, respectively, are used for the ray tracing. For Gadanki region suitability of these models is tested. Further, a climatological model of background atmosphere for Gadanki region has been developed using a long-term of nearly 30 years of observations available from a variety of ground-based (MST radar, radiosonde, MF radar), rocket-, and satellite-borne measurements. For considering real-time atmospheric inputs, ERA-Interim products are utilized. By this reverse ray method, the source locations for nine wave events could be identified to be in the upper troposphere, whereas, for five other events the waves seem to have been ducted in the mesosphere itself. Uncertainty in locating the terminal points in the horizontal direction is estimated to be within 50–100 and 150–300 km for Gadanki and Hyderabad wave events, respectively. This uncertainty arises mainly due to non-consideration of the day-to-day variability in tidal amplitudes. As no convection in-and-around the terminal points are noticed, it is unlikely to be the source. Interestingly, large (~9 m s−1 km−1) vertical shear in the horizontal wind is noted near the ray terminal points (at 10–12 km altitude) and is identified to be the source for generating the nine wave events. Conditions prevailing at the terminal points for each of the 14 events are also provided. These events provide leads to a greater understanding of the tropical lower and upper atmospheric coupling through gravity waves.

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Chen, Yingying, Xinzhu Sang, Shujun Xing, Yuanhang Li, Yanxin Guan, Li Liu, Chao Gao, Jingyan Du, Kuiru Wang und Binbin Yan. „Real-time pre-rectification of aberrations for 3D light-field display based on a constructed virtual lens and ray path tracing“. Optics Communications 499 (November 2021): 127292. http://dx.doi.org/10.1016/j.optcom.2021.127292.

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Amador, Gonçalo N. P., und Abel J. P. Gomes. „A Simple Physically-Based 3D Liquids Surface Tracking Algorithm“. International Journal of Creative Interfaces and Computer Graphics 2, Nr. 2 (Juli 2011): 37–48. http://dx.doi.org/10.4018/ijcicg.2011070103.

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Navier-Stokes-based methods have been used in computer graphics to simulate liquids, especially water. These physically based methods are computationally intensive, and require rendering the water surface at each step of the simulation process. The rendering of water surfaces requires knowing which 3D grid cells are crossed by the water’s surface, that is, tracking the surface across the cells is necessary. Solutions to water surface tracking and rendering problems exist in literature, but they are either too computationally intensive to be appropriate for real-time scenarios, as is the case of deformable implicit surfaces and ray-tracing, or too application-specific, as is the case of height-fields to simulate and render water mantles (e.g., lakes and oceans). This paper proposes a novel solution to water surface tracking that does not compromise the overall simulation performance. This approach differs from previous solutions in that it directly classifies and annotates the density of each 3D grid cell as either water, air, or water-air (i.e., water surface), opening the opportunity for easily reconstructing the water surface at an interactive frame rate.

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Liu, Sixin, Xintong Liu, Xu Meng, Lei Fu, Qi Lu und Li Deng. „Application of Time-Domain Full Waveform Inversion to Cross-Hole Radar Data Measured at Xiuyan Jade Mine, China“. Sensors 18, Nr. 9 (15.09.2018): 3114. http://dx.doi.org/10.3390/s18093114.

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Xiuyan Jade, produced in Xiuyan County, Liaoning Province, China is one of the four famous jade in China. King Jade, which is deemed the largest jade body of the world, was broken out from a hill. The local government planned to build a tourism site based on the jade culture there. The purpose of the investigation was to evaluate the stability of subsurface foundation, and the possible positions of mined-out zones to prevent the further rolling of the jade body. Cross-hole radar tomography is the key technique in the investigation. Conventional travel time and attenuation tomography based on ray tracing theory cannot provide high-resolution images because only a fraction of the measured information is used in the inversion. Full-waveform inversion (FWI) can provide high-resolution permittivity and conductivity images because it utilizes all the information provided by the radar signals. We deduce the gradient expression of the time-domain FWI with respect to the permittivity and conductivity using a method that is different from that of the previous work and realize the FWI algorithm that can simultaneously update the permittivity and conductivity by using the conjugate gradient method. Inverted results from synthetic data show that time-domain FWI can significantly improve the resolution compared with the ray-based tomogram methods. FWI can distinguish targets that are as small as one-half to one-third wavelength and the inverted physical values are closer to the real ones than those provided by the ray tracing method. We use the FWI algorithm to the field data measured at Xiuyan jade mine. Both the inverted permittivity and conductivity can comparably delineate four mined-out zones, which exhibit low-permittivity and low-conductivity characteristics. Furthermore, the locations of the interpreted mined-out zones are in good agreement with the existing mining channels recorded by geological data.

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