Virtual Flythrough Over a Voxel-Based Terrain 1. Introduction
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The Application of Voxel Size Correction in X-Ray Computed Tomography for Dimensional Metrology
SINCE2013 Singapore International NDT Conference & Exhibition 2013, 19-20 July 2013 The Application of Voxel Size Correction in X-ray Computed Tomography for Dimensional Metrology Joseph J. LIFTON1,2, Andrew A. MALCOLM2, John W. MCBRIDE1,3, Kevin J. CROSS1 1The University of Southampton, United Kingdom; Email: [email protected]. 2Singapore Institute of Manufacturing Technology, Singapore; Email: [email protected]. 3The University of Southampton Malaysia Campus (USMC), Malaysia; Email: [email protected]. Abstract X-ray computed tomography (CT) is a non-destructive, radiographic scanning technique that enables the visualisation and dimensional evaluation of both internal and external features of a workpiece; it is therefore an attractive alternative for measurement tasks that prove problematic for conventional tactile and optical instruments. The data output of a CT measurement is a volume of grey value integers that describe the material distribution of the scanned workpiece; the relative spacing of volume-elements (voxels) is termed voxel size and influences all dimensional information evaluated from a CT data-set. Voxel size is defined by the position of a workpiece relative to the X-ray source and detector, and is therefore prone to axis position errors, errors in the geometric alignment of the CT system’s hardware, and the positional drift of the X-ray focal spot. In this work a method is presented for calculating a voxel scaling factor that corrects for voxel size errors, and this method is then applied to a general X-ray CT measurement task and demonstrated to reduce measurement errors. Keywords: X-ray computed tomography, dimensional metrology, calibration, uncertainty, voxel size. -
Temporal Voxel Cone Tracing with Interleaved Sample Patterns by Sanghyeok Hong
c 2015, SangHyeok Hong. All Rights Reserved. The material presented within this document does not necessarily reflect the opinion of the Committee, the Graduate Study Program, or DigiPen Institute of Technology. TEMPORAL VOXEL CONE TRACING WITH INTERLEAVED SAMPLE PATTERNS BY SangHyeok Hong THESIS Submitted in partial fulfillment of the requirements for the degree of Master of Science in Computer Science awarded by DigiPen Institute of Technology Redmond, Washington United States of America March 2015 Thesis Advisor: Gary Herron DIGIPEN INSTITUTE OF TECHNOLOGY GRADUATE STUDIES PROGRAM DEFENSE OF THESIS THE UNDERSIGNED VERIFY THAT THE FINAL ORAL DEFENSE OF THE MASTER OF SCIENCE THESIS TITLED Temporal Voxel Cone Tracing with Interleaved Sample Patterns BY SangHyeok Hong HAS BEEN SUCCESSFULLY COMPLETED ON March 12th, 2015. MAJOR FIELD OF STUDY: COMPUTER SCIENCE. APPROVED: Dmitri Volper date Xin Li date Graduate Program Director Dean of Faculty Dmitri Volper date Claude Comair date Department Chair, Computer Science President DIGIPEN INSTITUTE OF TECHNOLOGY GRADUATE STUDIES PROGRAM THESIS APPROVAL DATE: March 12th, 2015 BASED ON THE CANDIDATE'S SUCCESSFUL ORAL DEFENSE, IT IS RECOMMENDED THAT THE THESIS PREPARED BY SangHyeok Hong ENTITLED Temporal Voxel Cone Tracing with Interleaved Sample Patterns BE ACCEPTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE IN COMPUTER SCIENCE AT DIGIPEN INSTITUTE OF TECHNOLOGY. Gary Herron date Xin Li date Thesis Committee Chair Thesis Committee Member Pushpak Karnick date Matt -
Human Body Model Acquisition and Tracking Using Voxel Data
Submitted to the International Journal of Computer Vision Human Body Model Acquisition and Tracking using Voxel Data Ivana Mikić2, Mohan Trivedi1, Edward Hunter2, Pamela Cosman1 1Department of Electrical and Computer Engineering University of California, San Diego 2Q3DM, Inc. Abstract We present an integrated system for automatic acquisition of the human body model and motion tracking using input from multiple synchronized video streams. The video frames are segmented and the 3D voxel reconstructions of the human body shape in each frame are computed from the foreground silhouettes. These reconstructions are then used as input to the model acquisition and tracking algorithms. The human body model consists of ellipsoids and cylinders and is described using the twists framework resulting in a non-redundant set of model parameters. Model acquisition starts with a simple body part localization procedure based on template fitting and growing, which uses prior knowledge of average body part shapes and dimensions. The initial model is then refined using a Bayesian network that imposes human body proportions onto the body part size estimates. The tracker is an extended Kalman filter that estimates model parameters based on the measurements made on the labeled voxel data. A voxel labeling procedure that handles large frame-to-frame displacements was designed resulting in the very robust tracking performance. Extensive evaluation shows that the system performs very reliably on sequences that include different types of motion such as walking, sitting, dancing, running and jumping and people of very different body sizes, from a nine year old girl to a tall adult male. 1. Introduction Tracking of the human body, also called motion capture or posture estimation, is a problem of estimating the parameters of the human body model (such as joint angles) from the video data as the position and configuration of the tracked body change over time. -
Rendering of Feature-Rich Dynamically Changing Volumetric Datasets on GPU
Procedia Computer Science Volume 29, 2014, Pages 648–658 ICCS 2014. 14th International Conference on Computational Science Rendering of Feature-Rich Dynamically Changing Volumetric Datasets on GPU Martin Schreiber, Atanas Atanasov, Philipp Neumann, and Hans-Joachim Bungartz Technische Universit¨at M¨unchen, Munich, Germany [email protected],[email protected],[email protected],[email protected] Abstract Interactive photo-realistic representation of dynamic liquid volumes is a challenging task for today’s GPUs and state-of-the-art visualization algorithms. Methods of the last two decades consider either static volumetric datasets applying several optimizations for volume casting, or dynamic volumetric datasets with rough approximations to realistic rendering. Nevertheless, accurate real-time visualization of dynamic datasets is crucial in areas of scientific visualization as well as areas demanding for accurate rendering of feature-rich datasets. An accurate and thus realistic visualization of such datasets leads to new challenges: due to restrictions given by computational performance, the datasets may be relatively small compared to the screen resolution, and thus each voxel has to be rendered highly oversampled. With our volumetric datasets based on a real-time lattice Boltzmann fluid simulation creating dynamic cavities and small droplets, existing real-time implementations are not applicable for a realistic surface extraction. This work presents a volume tracing algorithm capable of producing multiple refractions which is also robust to small droplets and cavities. Furthermore we show advantages of our volume tracing algorithm compared to other implementations. Keywords: 1 Introduction The photo-realistic real-time rendering of dynamic liquids, represented by free surface flows and volumetric datasets, has been studied in numerous works [13, 9, 10, 14, 18]. -
Ray Casting Architectures for Volume Visualization
Ray Casting Architectures for Volume Visualization The Harvard community has made this article openly available. Please share how this access benefits you. Your story matters Citation Ray, Harvey, Hanspeter Pfister, Deborah Silver, and Todd A. Cook. 1999. Ray casting architectures for volume visualization. IEEE Transactions on Visualization and Computer Graphics 5(3): 210-223. Published Version doi:10.1109/2945.795213 Citable link http://nrs.harvard.edu/urn-3:HUL.InstRepos:4138553 Terms of Use This article was downloaded from Harvard University’s DASH repository, and is made available under the terms and conditions applicable to Other Posted Material, as set forth at http:// nrs.harvard.edu/urn-3:HUL.InstRepos:dash.current.terms-of- use#LAA Ray Casting Architectures for Volume Visualization Harvey Ray, Hansp eter P ster , Deb orah Silver , Todd A. Co ok Abstract | Real-time visualization of large volume datasets demands high p erformance computation, pushing the stor- age, pro cessing, and data communication requirements to the limits of current technology. General purp ose paral- lel pro cessors have b een used to visualize mo derate size datasets at interactive frame rates; however, the cost and size of these sup ercomputers inhibits the widespread use for real-time visualization. This pap er surveys several sp e- cial purp ose architectures that seek to render volumes at interactive rates. These sp ecialized visualization accelera- tors have cost, p erformance, and size advantages over par- allel pro cessors. All architectures implement ray casting using parallel and pip elined hardware. Weintro duce a new metric that normalizes p erformance to compare these ar- Fig. -
Photorealistic Scene Reconstruction by Voxel Coloring
In Proc. Computer Vision and Pattern Recognition Conf., pp. 1067-1073, 1997. Photorealistic Scene Reconstruction by Voxel Coloring Steven M. Seitz Charles R. Dyer Department of Computer Sciences University of Wisconsin, Madison, WI 53706 g E-mail: fseitz,dyer @cs.wisc.edu WWW: http://www.cs.wisc.edu/computer-vision Broad Viewpoint Coverage: Reprojections should be Abstract accurate over a large range of target viewpoints. This A novel scene reconstruction technique is presented, requires that the input images are widely distributed different from previous approaches in its ability to cope about the environment with large changes in visibility and its modeling of in- trinsic scene color and texture information. The method The photorealistic scene reconstruction problem, as avoids image correspondence problems by working in a presently formulated, raises a number of unique challenges discretized scene space whose voxels are traversed in a that push the limits of existing reconstruction techniques. fixed visibility ordering. This strategy takes full account Photo integrity requires that the reconstruction be dense of occlusions and allows the input cameras to be far apart and sufficiently accurate to reproduce the original images. and widely distributed about the environment. The algo- This criterion poses a problem for existing feature- and rithm identifies a special set of invariant voxels which to- contour-based techniques that do not provide dense shape gether form a spatial and photometric reconstruction of the estimates. While these techniques can produce texture- scene, fully consistent with the input images. The approach mapped models [1, 3, 4], accuracy is ensured only in places is evaluated with images from both inward- and outward- where features have been detected. -
Online Detector Response Calculations for High-Resolution PET Image Reconstruction
Home Search Collections Journals About Contact us My IOPscience Online detector response calculations for high-resolution PET image reconstruction This article has been downloaded from IOPscience. Please scroll down to see the full text article. 2011 Phys. Med. Biol. 56 4023 (http://iopscience.iop.org/0031-9155/56/13/018) View the table of contents for this issue, or go to the journal homepage for more Download details: IP Address: 171.65.80.217 The article was downloaded on 15/06/2011 at 20:11 Please note that terms and conditions apply. IOP PUBLISHING PHYSICS IN MEDICINE AND BIOLOGY Phys. Med. Biol. 56 (2011) 4023–4040 doi:10.1088/0031-9155/56/13/018 Online detector response calculations for high-resolution PET image reconstruction Guillem Pratx1 and Craig Levin2 1 Department of Radiation Oncology, Stanford University, Stanford, CA 94305, USA 2 Departments of Radiology, Physics and Electrical Engineering, and Molecular Imaging Program at Stanford, Stanford University, Stanford, CA 94305, USA E-mail: [email protected] Received 3 January 2011, in final form 19 May 2011 Published 15 June 2011 Online at stacks.iop.org/PMB/56/4023 Abstract Positron emission tomography systems are best described by a linear shift- varying model. However, image reconstruction often assumes simplified shift- invariant models to the detriment of image quality and quantitative accuracy. We investigated a shift-varying model of the geometrical system response based on an analytical formulation. The model was incorporated within a list- mode, fully 3D iterative reconstruction process in which the system response coefficients are calculated online on a graphics processing unit (GPU). -
Voxel Game Engine Using Blender Game Engine
TALLINN UNIVERSITY OF TECHNOLOGY Faculty of Information Technology Department of Computer Science ITV40LT Fred-Eric Kirsi 135216 IAPB VOXEL GAME ENGINE USING BLENDER GAME ENGINE Bachelor's thesis Supervisor: Jaagup Irve Master of Sciences Software Engineer Tallinn 2016 TALLINNA TEHNIKAÜLIKOOL Infotehnoloogia teaduskond Arvutiteaduse instituut ITV40LT Fred-Eric Kirsi 135216 IAPB VOXEL-MÄNGUMOOTOR BLENDER GAME ENGINE ABIL Bakalaureusetöö Juhendaja: Jaagup Irve Magister Tarkvarainsener Tallinn 2016 Author’s declaration of originality I hereby certify that I am the sole author of this thesis. All the used materials, references to the literature and the work of others have been referred to. This thesis has not been presented for examination anywhere else. Author: Fred-Eric Kirsi 23.05.2016 3 Abstract The objective of this thesis is to study various aspects of developing a voxel style game and in the process create a prototype engine to evaluate the possibilities and performance of the algorithms. The algorithms evaluated are Greedy Meshing, A* search, Goal Oriented Action Planning (GOAP), Finite state machine (FSM), and Perlin noise. The used 3d engine is the Bender game engine. The scripting is done in the Python coding language. The result of this work is a working voxel game prototype, where the agents are able to navigate, manipulate, and make decisions in real time. The aim of the prototype is to quantize the performance and feature experience on for the user. The work is divided into four main stages. Firstly evaluation of the work environment and its limitations. Secondly the development and optimization of the voxel implementation. Thirdly the creation and comparison of different pathing implementations. -
Ray Tracing Height Fields
Ray Tracing Height Fields £ £ £ Huamin Qu£ Feng Qiu Nan Zhang Arie Kaufman Ming Wan † £ Center for Visual Computing (CVC) and Department of Computer Science State University of New York at Stony Brook, Stony Brook, NY 11794-4400 †The Boeing Company, P.O. Box 3707, M/C 7L-40, Seattle, WA 98124-2207 Abstract bility, make the ray tracing approach a promising alterna- tive for rasterization approach when the size of the terrain We present a novel surface reconstruction algorithm is very large [13]. More importantly, ray tracing provides which can directly reconstruct surfaces with different levels more flexibility than hardware rendering. For example, ray of smoothness in one framework from height fields using 3D tracing allows us to operate directly on the image/Z-buffer discrete grid ray tracing. Our algorithm exploits the 2.5D to render special effects such as terrain with underground nature of the elevation data and the regularity of the rect- bunkers, terrain with shadows, and flythrough with a fish- angular grid from which the height field surface is sampled. eye view. In addition, it is easy to incorporate clouds, haze, Based on this reconstruction method, we also develop a hy- flames, and other amorphous phenomena into the scene by brid rendering method which has the features of both ras- ray tracing. Ray tracing can also be used to fill in holes in terization and ray tracing. This hybrid method is designed image-based rendering. to take advantage of GPUs newly available flexibility and processing power. Most ray tracing height field papers [2, 4, 8, 10] focused on fast ray traversal algorithms and antialiasing methods. -
Voxel Map for Visual SLAM
This paper has been accepted for publication at the IEEE International Conference on Robotics and Automation (ICRA), Paris, 2020. c IEEE Voxel Map for Visual SLAM Manasi Muglikar, Zichao Zhang and Davide Scaramuzza Abstract— In modern visual SLAM systems, it is a stan- Geometry-awareness dard practice to retrieve potential candidate map points from [Newcombe11] overlapping keyframes for further feature matching or direct [Whelan15] Optimal tracking. In this work, we argue that keyframes are not the [Engel14] optimal choice for this task, due to several inherent limitations, Dense representation such as weak geometric reasoning and poor scalability. We propose a voxel-map representation to efficiently retrieve map [Kaess15] This paper points for visual SLAM. In particular, we organize the map [Nardi19] [Rosinol19] points in a regular voxel grid. Visible points from a camera pose Geometric primitives are queried by sampling the camera frustum in a raycasting [Forster17] manner, which can be done in constant time using an efficient [Klein07] [Mur-Artal15] voxel hashing method. Compared with keyframes, the retrieved Sparse keyframes points using our method are geometrically guaranteed to Efficiency fall in the camera field-of-view, and occluded points can be identified and removed to a certain extend. This method also Fig. 1: The optimal SLAM systems should be efficient and have geometrical naturally scales up to large scenes and complicated multi- understanding of the map (denoted by the golden star). Direct methods (red camera configurations. Experimental results show that our dots) associate each keyframe with a semi-dense depth map. They have voxel map representation is as efficient as a keyframe map more scene information but are not efficient. -
Future Graphics in Games
Future graphics in games Anton Kaplanyan Lead researcher Cevat Yerli Crytek CEO Agenda • The history: Crytek GmbH • Current graphics technologies • Stereoscopic rendering • Current graphics challenges • Graphics of the future • Graphics technologies of the future • Server-side rendering • Hardware challenges • Perception-driven graphics The Past - Part 1 • March 2001 till March 2004 • Development of Far Cry • Development of CryEngine 1 • Approach: A naïve, but successful push for contrasts, by insisting on opposites to industry. size, quality, detail, brightness • First right investment into tools - WYSIWYPlay Past - Part 1: CryEngine 1 • Polybump (2001) • NormalMap extraction from High-Res Geometry • First „Per Pixel Shading“ & HDR Engine • For Lights, Shadows & Materials • High Dynamic Range • Long view distances & detailed vistas • Terrain featured unique base-texturing • High quality close ranges • High fidelity physics & AI • It took 3 years, avg 20 R&D Engineers CryENGINE 2 The Past – Part 2 – CryENGINE 2 • April 2004 till November 2007 • Development of Crysis • Development of CryEngine 2 • Approach: Photorealism meets interactivity! • Typically mutual exclusive directions • Realtime productivity with WYSIWYPlay • Extremely challenging, but successful CryEngine 2 - Way to Photorealism The image cannot be displayed. Your computer may not have enough memory to open the image, or the image may have been corrupted. Restart your computer, and then open the file again. If the red x still appears, you may have to delete the image and then insert it again. The Past - Part 2: CryEngine 2 • CGI Quality Lighting & Shading • Life-like characters • Scaleable architecture in • Both content and pipeline • Technologies and assets allow various configurations to be maxed out! • Crysis shipped Nov 2007, works on PCs of 2004 till today and for future.. -
GPU Volume Voxelization Exploration of the Performance Characteristics of Different GPU-Based Implementations
EXAMENSARBETE INOM TEKNIK, GRUNDNIVÅ, 15 HP STOCKHOLM, SVERIGE 2019 GPU Volume Voxelization Exploration of the performance characteristics of different GPU-based implementations GRIGORY GLUKHOV ALEKSANDRA SOLTAN KTH SKOLAN FÖR ELEKTROTEKNIK OCH DATAVETENSKAP GPU Volume Voxelization Exploration of the performance characteris- tics of different GPU-based implementations Aleksandra Soltan Grigory Glukhov Examiner Johan Montelius Supervisor Thomas Sjöland A thesis presented for the degree of Bachelor of Information and Communication Technology KTH Royal Institute of Technology School of Electrical Engineering and Computer Science SE-100 44 Stockholm, Sweden June 2019 page intentionally left blank 1 Abstract In recent years, voxel-based modelling has seen a reintroduction to computer game development through massive graphics hardware improvements. Never- theless, polygons continue to be the default building block of 3D objects, intro- ducing a need for the transformation of polygon meshes into voxel-based models; this process is known as voxelization. Efficient voxelization algorithms take ad- vantage of the flexibility and control offered by modern, programmable GPU pipelines. However, the variability in possible approaches poses the question of how different GPU-based implementations affect voxelization performance. This thesis explores the impact of GPU-based improvements by comparing four different implementations of a solid voxelization algorithm. The implemen- tations include a naive transition from the CPU to the GPU, a non-branching execution path approach, data pre-processing, and a combination of the two previous approaches. Benchmarking experiments run on four, standard polygo- nal models and three graphics cards (NVIDIA and AMD) provide runtime and memory usage data for each implementation. A comparative analysis is per- formed on the basis of this data to determine the performance impact of the GPU-based adjustments to the voxelization algorithm implementation.