generation of planar radiographs from 3d anatomical models using the gpu
DESCRIPTION
Second PDIS presentation at FEUP. Master's Thesis presentation.TRANSCRIPT
Generation of planar radiographs from 3Danatomical models using the GPU
André dos Santos CardosoSupervisor: Jorge M. G. Barbosa
University of PortoFaculty of Engineering of University of Porto
[email protected], [email protected]
July 14, 2010
André dos Santos Cardoso DRR Generation 1 / 19
Contents1 Introduction
Context OverviewProject’s Objective
2 Why is it Important?3 Our Specific Case4 What Has Been Done?
Wrap-Up5 Current Solution6 What’s expected?7 Involved Technologies
GLSLCUDA
8 Work Plan9 Bibliography
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Context Overview
Digitally Reconstructed Radiographs(DRRs)
Taking a radiography from 3D digitalanatomical models of vertebraeForm of depth peeling, usingray-casting
Key component in 2D/3D registrationprocess
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Context Overview
DRRs are built from vertebrae models represented by 3Dmeshes
DRR generation as mean to validate and/or refine 3Dreconstructions of the spine from multi-planar radiography
Vertebrae Shape Recovery Using 2D/3D Non-RigidRegistration
Important techniques for Scoliosis therapy and follow-ups
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Project’s Objective
Build Fast DRR AlgorithmsDRR calculation is a bottleneck
3D reconstruction usage in aroutine clinical environmentrequires high performances
Take advantage of processingpower of new GPUs and APIs
Common workstations could dothe job!
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Why is it Important?
DRR generation key componentin many 2D/3D registrationproblems
Allows to compare/use datafrom different sources and timestogetherThe CAS model versus real-timeimagery from the patientNonrigid registration
Many applications in medical area
CAS, Radiotherapy, VolumeRecovery
Known to be a common bottleneck
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Why is it Important?
Speed!
Daily work on the field demandson-the-fly results, and highaccuracyAdvantages on using GPUsversus Hardware solutions
CheaperMore accessible
General Purpose Computing onGPUs gaining increasing interestfrom researchers
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Our Specific Case
Where will the OptimizedAlgorithms fit?
Shape Recovery of humanspine – attaining a 3D model ofthe spineBi-planar Radiography
Scoliosis evaluationViable alternative to MRIs andCTs – why?
Expensive, Amount ofRadiation, ProlongedProcedures, Require lyingdown
Not the scope of this project!!
Moura, D. et al [6]
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What has been done in this area?Attenuation Law – monochromatic x-ray radiation
Nout (E ) = Nin(E )× e−∫µ(E ,ρ(x ),Z (x ))dx (1)
Focus on GPU Implementations!
Monte Carlo VolumeRendering
Volumetric integral foreach pixel
Fourier Volume RenderingInverse 2D Fouriertransform of a slice
Shear-WarpingViewing transformations
SplattingThrow voxels into theviewing pane
Ray CastingShoot rays to each pixel
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Wrap-Up
Attenuation law for bone materialFew Applications of DRR to 3D Meshes (most work on CTdata – voxels)Using OpenGL Shading Language (GLSL)
Multi Pass Algorithm is availableSingle Pass Algorithm is considered the state of the art, butno applied implementation exists
Compute Unified Device Architecture (CUDA) peelingapplications exist (but not for computing DRRs)
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Current Solution
InputsCAD model of vertebraeCamera position, object positions, object orientation, …
Outputssimulated Radiograph!
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Current Solution
Ray CastingMultipass AlgorithmRay Casting and DepthPeelingGLSL
Why use CAD models?Problem context requiresdeformations to the 3DmodelFaster to deform CADmodelsGenerally, decreasesamount of computation
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What’s expected?
Enhance the current solution1 Modify code to implement the reported single-pass approach2 Port solution to CUDA3 Test and compare solutions
Significant speed-ups are expected
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Technologies – GLSL
OpenGL ShadingLanguage
Allows the modificationof fixed functionality ofthe GPU pipelineSimilar syntax to C/C++Modules called Shaders
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Technologies – CUDA
Compute Unified DeviceArchitecture
Parallel Computing ArchitectureAllows direct access to parallelprocessors and memoryKernel function executed onGPU device
Allows hierarchicalconfiguration of threads uponkernel launch
Massive data parallelismAllows versatile and morecontrolled programming
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Work Plan
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Thank You for Listening!Ask Away!
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Bibliography
I The opengl shading language.I Lisa Gottesfeld Brown.
A survey of image registration techniques.ACM Comput. Surv., 24(4):325–376, 1992.
I David B. Kirk and Wen mei W. Hwu.Programming Massively Parallel Processors - A Hands-on Approach.Morgan Kaufmann, 2010.
I A. Mitulescu, W. Skalli, D. Mitton, and J. A. De Guise.Three-dimensional surface rendering reconstruction of scoliotic vertebrae using a non stereo-correspondingpoints technique.European Spine Journal, 2002.
I Shinichiro Mori, Masanao Kobayashi, Motoki Kumagai, and Shinichi Minohara.Development of a gpu-based multithreaded software application to calculate digitally reconstructed radiographsfor radiotherapy.Radiological Physics and Technology, 2009.
I Daniel C. Moura, Jonathan Boisvert, Jorge G. Barbosa, and João Manuel Tavares.Fast 3d reconstruction of the spine using user-defined splines and a statistical articulated model.In ISVC ’09: Proceedings of the 5th International Symposium on Advances in Visual Computing, pages586–595, Berlin, Heidelberg, 2009. Springer-Verlag.
I Scott D. Roth.Ray casting for modeling solids.j-CGIP, 18(2), 1982.
I F. P. Vidal, M.Garnier, N. Freud, J. M. Létang, and N.W. John.Simulation of x-ray attenuation on the gpu.In Proceeding of TCPG’09 - Theory and Practice of Computer Graphics, pages 25–32. Eurographics, 2009.
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Bibliography
Full Bibliography Listed in:
https://dev.andrecardoso.eu/bibtexbrowser.php?bib=thesisbib.bib
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