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| − | == Overview ==
| + | <big>'''Note:''' We are migrating this content to the slicer.org domain - <font color="orange">The newer page is [https://www.slicer.org/wiki/Slicer3:Volume_Rendering here]</font></big> |
| − | The topic of the new Volume Rendering Module is the integration of hardware accelerated volume rendering. There is a special focus of achieving interactive update rates, easy user interaction (e.g. by offering several presets) and the use of label maps. Goals also include incremental updates (if module is used with Editor module), saving and loading of the configuration etc.
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| − | ==Archtecture/Design==
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| − | [[Image:UseCaseVolumeRendering.jpg|thumb|800px|center|Use Case Diagram]]
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| − | | |
| − | ==Test the module==
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| − | *Turn VolumeRenderingModule on (in cmake)
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| − | *Compile
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| − | | |
| − | ==Latest results and limitations==
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| − | ===Description===
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| − | *Loading changing of MRML-Nodes is possible during runtime
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| − | *At the moment no removing of MRML-Nodes possible
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| − | *Change properties (Shading, Interpolation, mapping)
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| − | *Calculate transfer functions automatically
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| − | *Performance:
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| − | **Interrupting is possible in render window.
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| − | **Interrupting somewhere else requires platform dependent coding (q.v. problems)
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| − | *Cropping is possible
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| − | | |
| − | ===Screenshots===
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| − | [[Image:VolumeRendering.jpg|thumb|500px|center|volume rendered label map of the tutorial dataset]]
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| − | [[Image:VolumeRenderingWithShading.jpg|thumb|500px|center|volume rendered label map of the tutorial dataset, shading enabled]]
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| − | [[Image:VolumeRenderingBoneDetection.png|thumb|800px|center|shading enabled, linear interpolation, automatich mapping for bones]]
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| − | | |
| − | ==next Tasks==
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| − | ===ideas implemented in prototyp===
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| − | *Develop different algorithms for labelmap and grayscale volumes -----algorithm for grayscale is missing => new task: presets
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| − | *Find Presets, see also at goals
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| − | *Try to reduce artefacts in labelmaps by using several RGB points in the mapping function -----done, artefacts still there?
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| − | *Implement a possibility to change between different volumes during runtime -----done
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| − | *Have a closer look on the final calculation of the renderer-----Problems, when interrupting outside renderWindow
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| − | *Detect if video card can use 3d Texture Mapping or not, if not use MIP, -----done, there are two new Buttons to simulate having openGl support or not. standard preset is now MIP (performance issue)
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| − | *Add possiblity to change opacity (for labelmaps) -----done, slider
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| − | *Include code to make all models invisible(Good for testing) -----done, new button
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| − | ===not yet implemented in prototyp===
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| − | *Have a closer look on the gradient opacity mapper, when using label maps
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| − | *Try clipping
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| − | *Add progress functionality
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| − | | |
| − | ==Problems==
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| − | *Cannot load the following data
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| − | **spgr (grayscale): tutorial data set (freezes)-----fixed: problems with automatic mapping
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| − | **grayscale (greyscale): brain atlas (freezes)-----fixed:problems with automatic mapping
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| − | **seg (LabelMap): abdomen data set (not freezing, seems to render, but unvisible)-----fixed, use char as datatype, but maybe experimenting with tresholds.
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| − | | |
| − | *How can rendering be interrupted outside renderWindow
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| − | **Do something like [http://www.vtk.org/doc/nightly/html/classvtkRenderWindow.html#007038cc2f7b875bb56a4bcd97937077 vtkRenderWindow::GetEventPending]
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| − | **Problem, may require platform depending code----->Could propably be fixed with tcl-wrapping
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| − | **Experiment with vtkOpenGLVolumeTextureMapper3D, check status more often, debug. add more timers.
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| − | | |
| − | == Goals ==
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| − | | |
| − | Volume rendering presets :
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| − | * MIP (Maximum Intensity Projection)
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| − | **[http://en.wikipedia.org/wiki/Maximum_intensity_projection Wikipedia]
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| − | **[http://www.vtk.org/doc/release/5.0/html/a01399.html vtkFixedPointVolumeRayCastMapper Class Reference]
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| − | * CT Bone and vessel
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| − | **Use Hounsfield units
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| − | ***Bone +400->+1000
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| − | ***Soft tissue +40->+80
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| − | ***Water 0
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| − | ***Fat -60->-100
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| − | ***Lung -400->-600
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| − | ***Air -1000
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| − | **Problem with Vessels: Different contrast mediums?!
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| − | * T1 MR Air/skin interface
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| − | * Label map per-label object rendering
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| − | | |
| − | Slicer3 module interface:
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| − | * Select from loaded volumes
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| − | * Specify preset transfer functions or use KWWidgets tools
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| − | | |
| − | Slicer3 internals:
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| − | * Correct coordinates including transforms
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| − | * Level of detail rendering
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| − | * Proper integration with surface rendering
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| − | Different Volume Rendering Algorithms
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| − | *RayCast
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| − | *2D Texture Mapping
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| − | *3D Texture Mapping
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| − | *...
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| − | | |
| − | == Wish List ==
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| − | * 2D Transfer functions - may require specialized opengl code integrated with VTK. Talk with Gordon about latest work from Utah.
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| − | | |
| − | * use glTexSubImage3D so that incremental changes to the volume can be quickly reflected
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| − | | |
| − | * use distance maps (inlcude several components) in rendering
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