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TERARECON, INC. Ray-casting in VolumePro™ 1000 Yin Wu, Vishal Bhatia, Hugh Lauer, Larry Seiler.

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Presentation on theme: "TERARECON, INC. Ray-casting in VolumePro™ 1000 Yin Wu, Vishal Bhatia, Hugh Lauer, Larry Seiler."— Presentation transcript:

1 TERARECON, INC. Ray-casting in VolumePro™ 1000 Yin Wu, Vishal Bhatia, Hugh Lauer, Larry Seiler

2 T ERA R ECON, I NC. 2 VolumePro™ 1000 Summary Second generation real-time volume rendering accelerator Ray-casting at 10 9 samples per second Ray-per-pixel image quality Translucent & opaque embedded polygons 8-, 16-, & 32-bit voxels (up to four fields) Geometry-based space leaping, early ray termination …

3 T ERA R ECON, I NC. 3 The Challenge in Ray-casting Performance vs. Image Quality Shear-Warp  Traverse & resample data in memory order.  Warp needed for final image.  Fast  Efficient memory access  VolumePro 500  Image Quality  2 nd resampling  No embedded geometry Full Image order  Traverse & resample data in pixel order  Image Quality  No 2 nd resampling  Embedded geometry  Performance  Memory accesses similar to random access.

4 T ERA R ECON, I NC. 4 VolumePro 1000 Ray-casting Rays through pixels on image plane  Image quality equiv. to full image order  No 2 nd resampling

5 T ERA R ECON, I NC. 5 VolumePro 1000 Ray-casting Rays through pixels on image plane  … Samples organized in planes parallel to faces of the volume  Traverse & process data in memory order  Maximize memory performance

6 T ERA R ECON, I NC. 6 Voxel processing part Traverse data slice-by-slice in memory order Read voxels for each slice of samples Voxel-oriented processing (e.g., gradient estimation) Store in on-chip buffers Sample processing part Define sample points where rays intersect slices Traverse & interpolate on-chip buffer in pixel order Sample-oriented processing  e.g., illumination, filtering, depth testing, compositing Output to image xy-image order — 2 parts (aka shear-image order)

7 T ERA R ECON, I NC. 7 VolumePro 1000 ray-casting (Additional optimizations) Section: rays assoc. with tile of image plane Minimize on-chip buffer space All slices of a section processed before next section Enables early ray termination Mini-block and stamp organized memory Burst accesses to 2  2  2 voxels or 2  2 pixels  From VolumePro 500 Skewed across eight memory channels Parallel access to 8 adjacent mini-blocks or stamps in any dimension  From VolumePro 500, Cube-4 (SUNY Stony Brook)

8 T ERA R ECON, I NC. 8 Block Diagram On-chip Slice buffers Sample processing Voxel processing Sequencer 16-node SIMD processor Voxels (organized as mini-blocks) Pixels (organized as stamps) control Memory Interface eight channels 16-bit DDR SDRAM ( MHz) PCI bus Interface MHz Pipelines 250 MHz

9 T ERA R ECON, I NC. 9 Technical summary Four 250 MHz pipelines, 10 9 samples per second Trilinear interpolations on seven channels  Four colors or voxel fields  Three gradient components Classification of (up to) four voxel fields Phong illumination calculation individual visibility tests Alpha correction, gradient magnitude modulation Perspective rendering (in Shear-Warp)

10 T ERA R ECON, I NC. 10 What next? Is 10 9 samples/second enough? 1 megapixel at 15 fps  ~66 samples/ray (average) Not very many, even with aggressive space leaping Major items yet to be done Content-based space-leaping Faster memory, pipelines, and Sequencer Perspective volume rendering More programmability

11 T ERA R ECON, I NC. 11 Pretty Pictures

12 T ERA R ECON, I NC. 12

13 T ERA R ECON, I NC. 13

14 T ERA R ECON, I NC. 14 Supplementary Slides

15 T ERA R ECON, I NC. 15 Embedding Surfaces in Volumes Allows inserting pointers, medical prostheses, or geological data markers into the volume Also supports arbitrary clipping regions, all in real time Each ray is cast in multiple segments, between surfaces specified by depth buffers Surface rendering performed in 3D graphics chip using OpenGL Front clip bounds Opaque background Trans- lucent surface

16 T ERA R ECON, I NC. 16 Embedding Surfaces in Volumes Allows inserting pointers, medical prostheses, or geological data markers into the volume Also supports arbitrary clipping regions, all in real time Each ray is cast in multiple segments, between surfaces specified by depth buffers Surface rendering performed in 3D graphics chip using OpenGL

17 T ERA R ECON, I NC. 17 Embedding Surfaces in Volumes Allows inserting pointers, medical prostheses, or geological data markers into the volume Also supports arbitrary clipping regions, all in real time Each ray is cast in multiple segments, between surfaces specified by depth buffers Surface rendering performed in 3D graphics chip using OpenGL

18 T ERA R ECON, I NC. 18 Embedding Surfaces in Volumes Allows inserting pointers, medical prostheses, or geological data markers into the volume Also supports arbitrary clipping regions, all in real time Each ray is cast in multiple segments, between surfaces specified by depth buffers Surface rendering performed in 3D graphics chip using OpenGL


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