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Efficient Rendering of Anatomical Tree Structures Using Geometry Proxy. Hang Dou*, Christian Bauer**, C hris Wyman*, Reinhard R. Beichel** *Dept. of Computer Science, The University of Iowa **Dept. of Electrical and Computer Engineering, The University of Iowa. Introduction. Motivation.
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Efficient Rendering of Anatomical Tree Structures Using Geometry Proxy Hang Dou*, Christian Bauer**, Chris Wyman*, Reinhard R. Beichel** *Dept. of Computer Science, The University of Iowa **Dept. of Electrical and Computer Engineering, The University of Iowa
Introduction • Motivation Vessel tree structures
Introduction • Motivation • 1. Volume based method. • 2. Tree skeleton (center line) based method.
Introduction • Motivation Isosurface Volume rendering
Introduction • Motivation Limits of volume based method
Introduction • Motivation Standard truncated cone mesh (SCM) Surface convolution [Oeltze 2003]
Introduction • Our Method: rendering tubular tree through geometry proxy. • Does not involve pre-computation for surface reconstruction. • Smooth result with low mesh complexity. • Runs faster than rendering meshes generated from surface reconstruction methods.
Quad Generation • Observation: The projection of a truncated cone can be covered by the projection of a quad.
Quad Generation • Gap filling
Further Optimization • When handle dense data in which the center line points are very close to each other, we only draw the sphere. • We get about 10% speed up.
Further Optimization • We use CG compiler to monitor the number of instructions in OpenGL shaders. • Number of instructions: Before optimization: • Vertex shader: 21 Geometry shader: 240 Fragment shader: 306 After optimization: Vertex shader: 13 Geometry shader: 132 Fragment shader: 186
Results • Test environment: • Linux (C++/OpenGL/GLSL) • Intel Xeon X5450 CPU@3.0GHz • NVIDIA GTX 550 Ti
Results Isosurface Isosurface with QSlim Our Method SCM with 8 points SCM with 8 points SCM with 8 points Airway tree of rat lung with 35,603 center line points
Results Isosurface Isosurface with QSlim Our Method SCM with 8 points SCM with 8 points SCM with 8 points Vascular structure from human lung CT scan with 353,875 center line points
Future Work • Ray primitive intersection is computational intense. • When handle data with high depth complexity, we implement 2 pass rendering. • Get depth information. • Shade the tubular structure.