The Experts below are selected from a list of 1767 Experts worldwide ranked by ideXlab platform
Alexander Keller - One of the best experts on this subject based on the ideXlab platform.
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fast high precision ray Fiber Intersection using tight disjoint bounding volumes
arXiv: Graphics, 2018Co-Authors: Nikolaus Binder, Alexander KellerAbstract:Analyzing and identifying the shortcomings of current subdivision methods for finding Intersections of rays with Fibers defined by the surface of a circular contour swept along a B\'ezier curve, we present a new algorithm that improves precision and performance. Instead of the inefficient pruning using overlapping axis aligned bounding boxes and determining the closest point of approach of the ray and the curve, we prune using disjoint bounding volumes defined by cylinders and calculate the Intersections on the limit surface. This in turn allows for computing accurate parametric position and normal in the point of Intersection. The iteration requires only one bit per subdivision to avoid costly stack memory operations. At a low number of subdivisions, the performance of the high precision algorithm is competitive, while for a high number of subdivisions it dramatically outperforms the state-of-the-art. Besides an extensive mathematical analysis, source code is provided.
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fast high precision ray Fiber Intersection using tight disjoint bounding volumes
International Conference on Computer Graphics and Interactive Techniques, 2018Co-Authors: Nikolaus Binder, Alexander KellerAbstract:We improve the performance of subdivision-based ray/Fiber Intersection for Fibers along Bezier curves by pruning with tight, disjoint bounding volumes in ray-centric coordinate systems. The resulting method calculates precise Intersections on the surface of a Fiber with accurate normals, and performs significantly faster for a high number of subdivisions than state-of-the-art methods pruning sub-regions with axis-aligned bounding boxes.
Nikolaus Binder - One of the best experts on this subject based on the ideXlab platform.
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fast high precision ray Fiber Intersection using tight disjoint bounding volumes
arXiv: Graphics, 2018Co-Authors: Nikolaus Binder, Alexander KellerAbstract:Analyzing and identifying the shortcomings of current subdivision methods for finding Intersections of rays with Fibers defined by the surface of a circular contour swept along a B\'ezier curve, we present a new algorithm that improves precision and performance. Instead of the inefficient pruning using overlapping axis aligned bounding boxes and determining the closest point of approach of the ray and the curve, we prune using disjoint bounding volumes defined by cylinders and calculate the Intersections on the limit surface. This in turn allows for computing accurate parametric position and normal in the point of Intersection. The iteration requires only one bit per subdivision to avoid costly stack memory operations. At a low number of subdivisions, the performance of the high precision algorithm is competitive, while for a high number of subdivisions it dramatically outperforms the state-of-the-art. Besides an extensive mathematical analysis, source code is provided.
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fast high precision ray Fiber Intersection using tight disjoint bounding volumes
International Conference on Computer Graphics and Interactive Techniques, 2018Co-Authors: Nikolaus Binder, Alexander KellerAbstract:We improve the performance of subdivision-based ray/Fiber Intersection for Fibers along Bezier curves by pruning with tight, disjoint bounding volumes in ray-centric coordinate systems. The resulting method calculates precise Intersections on the surface of a Fiber with accurate normals, and performs significantly faster for a high number of subdivisions than state-of-the-art methods pruning sub-regions with axis-aligned bounding boxes.
Muhammad H Zaman - One of the best experts on this subject based on the ideXlab platform.
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rapid quantification of 3d collagen Fiber alignment and Fiber Intersection correlations with high sensitivity
PLOS ONE, 2015Co-Authors: Meng Sun, Alexander Bloom, Muhammad H ZamanAbstract:Metastatic cancers aggressively reorganize collagen in their microenvironment. For example, radially orientated collagen Fibers have been observed surrounding tumor cell clusters in vivo. The degree of Fiber alignment, as a consequence of this remodeling, has often been difficult to quantify. In this paper, we present an easy to implement algorithm for accurate detection of collagen Fiber orientation in a rapid pixel-wise manner. This algorithm quantifies the alignment of both computer generated and actual collagen Fiber networks of varying degrees of alignment within 5°°. We also present an alternative easy method to calculate the alignment index directly from the standard deviation of Fiber orientation. Using this quantitative method for determining collagen alignment, we demonstrate that the number of collagen Fiber Intersections has a negative correlation with the degree of Fiber alignment. This decrease in Intersections of aligned Fibers could explain why cells move more rapidly along aligned Fibers than unaligned Fibers, as previously reported. Overall, our paper provides an easier, more quantitative and quicker way to quantify Fiber orientation and alignment, and presents a platform in studying effects of matrix and cellular properties on Fiber alignment in complex 3D environments.
Shinichi Yoda - One of the best experts on this subject based on the ideXlab platform.
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microgravity experiments on flame spread along fuel droplet arrays using a new droplet generation technique
Combustion and Flame, 2005Co-Authors: Masato Mikami, Hiroshi Oyagi, Naoya Kojima, Masao Kikuchi, Yuichiro Wakashima, Shinichi YodaAbstract:Abstract A new droplet-array generation technique achieved high quality and high reliability in microgravity experiments on multiple-droplet combustion. Each fuel droplet formed at the Intersection of fine, X-shaped SiC Fibers when liquid fuel was supplied through a fine glass tube. We aligned several sets of these X-shaped Fibers and their corresponding fine glass tubes to form a droplet array. All the droplets in the array were simultaneously generated in a short time. In flame-spread experiments, a hot-wire igniter ignited an end droplet to initiate the flame spread along the array. We demonstrated microgravity experiments of droplet array combustion using the new droplet-array generation technique at a drop-experiment facility, MGLAB, in Japan. We successfully generated large droplets, which often fell off the Fiber Intersection in normal gravity, by using this method in microgravity. This technique is also effective in droplet-array combustion experiments using high-volatility fuel, where prevaporization is substantial. We compared the flame-spread rate and the flame-spread limit of these linear droplet arrays with results of an existing experiment, and discussed the effects of the suspending Fiber on the flame spread.
Meng Sun - One of the best experts on this subject based on the ideXlab platform.
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rapid quantification of 3d collagen Fiber alignment and Fiber Intersection correlations with high sensitivity
PLOS ONE, 2015Co-Authors: Meng Sun, Alexander Bloom, Muhammad H ZamanAbstract:Metastatic cancers aggressively reorganize collagen in their microenvironment. For example, radially orientated collagen Fibers have been observed surrounding tumor cell clusters in vivo. The degree of Fiber alignment, as a consequence of this remodeling, has often been difficult to quantify. In this paper, we present an easy to implement algorithm for accurate detection of collagen Fiber orientation in a rapid pixel-wise manner. This algorithm quantifies the alignment of both computer generated and actual collagen Fiber networks of varying degrees of alignment within 5°°. We also present an alternative easy method to calculate the alignment index directly from the standard deviation of Fiber orientation. Using this quantitative method for determining collagen alignment, we demonstrate that the number of collagen Fiber Intersections has a negative correlation with the degree of Fiber alignment. This decrease in Intersections of aligned Fibers could explain why cells move more rapidly along aligned Fibers than unaligned Fibers, as previously reported. Overall, our paper provides an easier, more quantitative and quicker way to quantify Fiber orientation and alignment, and presents a platform in studying effects of matrix and cellular properties on Fiber alignment in complex 3D environments.