A Framework for Dynamic Volume Rendering Ptolemy II EECS 290N – Final Project T. Crawford 12/04

Outline  Motivation  Overview  Existing Framework in Ptolemy II  Extending the Framework

Motivation  Integrate two existing Ptolemy II libraries  Medical Imaging Systems –MRI Scans 3D Image from 2D slices

Existing Framework  Graphics Library –GRDirector –GRViewScreen –GRShadedShape –GRSceneGraphToken –GRTransform  Image Library –Performs basic image processing functions  FilePortParameter –Allows an actor to receive a file parameter via an input port

Java 3D Geometry Appearance Shape 3D Virtual Universe Locale BG TG From J3D Technical Overview Sun Microsystems VP ViewPlatform View Branch Group Transform Group

GRDirector  All actors that use the Java 3D API must use this director  Forms a topological sort of the actor graph –Directed Acyclic Graphs  All GR models must contain a ViewScreen –Defines the Virtual Universe, Locale, and Branch Graph (BG) elements needed to form a Java 3D scene graph

GRShadedShape  Creates a node to be added to the Scene Graph  createmodel() –creates Appearance of Shape3D  fire() –Sends a reference to a node to output port to be connected to the SceneGraph  Extended by other actors which creates the geometry –Box3D, Sphere3D

More About GR  GRTransform –Base class for Transform Groups –Translate, Scale, etc.  GRSceneGraphToken –Token type for all non-parameter inputs and outputs in GR Domain

Considerations  Dynamically updateable View  Allow parameters to be updated during session  Domain Hierarchy –GR CompositeActors within other domains

Changes to Existing Framework  GRDirector – To allow view screen to be updated dynamically  GRShadedShape – To allow parameters to be updated during rendering session  ImageReader –To read in.dcm file format

New Actors (GR Domain)  Will extend GRShadedShape  Axis2DRenderer –Volume rendering using a stack of 2D images –Image can be updated, but will be redrawn  Axis3DRenderer (optional) –Volume rendering using a 3D texture –Image can be updated without being redrawn –3D textures require

New Actors  ImageStack –Places and stores images in a dynamical array to be referenced by Axis2DRenderer  Other data handling actors as needed –How Axis2DRenderer will read in images is still being explored

Conclusion  Java 3D does perform volume rendering using textures  GRDirector provides the model of computation needed to work with scene graphs  Changes need to be made to existing MoC to allow dynamical viewing