Transcript PowerPoint Presentation - Tele

Tele-immersive Cranial Implant Design
Chris Scharver
September 12, 2001
[email protected]
In collaboration with
Ray Evenhouse, Virtual Reality
Medicine Laboratory
Electronic Visualization Laboratory
University of Illinois at Chicago
Cranial Prosthetics
• Images from the current process
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Before image
Magnetic resonance imaging-based model
Stereo lithography model,
After image
Electronic Visualization Laboratory
University of Illinois at Chicago
Problem Statement
Tele-immersive tools will allow cheaper
and more rapid prototyping and
evaluation of cranial prosthetic implants
than clay and polymer modeling
techniques.
Electronic Visualization Laboratory
University of Illinois at Chicago
Current Surgical Method
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Magnetic resonance scan of patient
Stereo lithography model of defect
Defect sculpted with clay
Defect cast
Implant modeled with dental wax
Implant cast
Surgery and implantation
• Very expensive!
Electronic Visualization Laboratory
University of Illinois at Chicago
Jim Foley’s Top Ten (2000)
• Top ten problems in computer graphics
• Updated list at Vision 2000
• #9 User interfaces for creativity
Electronic Visualization Laboratory
University of Illinois at Chicago
Immersive Modeling
• CHIMP: Chapel Hill
Immersive Modeling
Program (UNC)
– Architecture
– http://www.cs.unc.edu/~
mine/chimp.html
• Samuel (FraunhoferGesellschaft)
– General use
– http://vr.iao.fhg.de/imod
eling/samuel.en.html
Electronic Visualization Laboratory
University of Illinois at Chicago
Skull Model
• Theoretically obtained
from MRI data, then
converted into
geometry for loading
into scene graph
• Manually made from
the Visible Human data
set
Electronic Visualization Laboratory
University of Illinois at Chicago
Hardware Setup
• PHANToM haptic device
– 6DOF position and
rotation
– 3DOF force feedback
• Tracking system
• Display device
– Immersive display?
– Would a monitor suffice?
Electronic Visualization Laboratory
University of Illinois at Chicago
PARIS
• Prototyped using the CAVE
• Hands are visible
through the display
screen through
the use of a
half-silvered
mirror screen
• Tracking is
similar to an
ImmersaDesk
Electronic Visualization Laboratory
University of Illinois at Chicago
Software
• PHANToM
– GHOST API, NT driver only
– Interface with trackd SDK?
• Display and scene graph
– GHOST provides geometry and properties
– OpenSG, Open Inventor, TGS Inventor 3.0,
Performer?
• Additional libraries
– VTK, geolib, NURBS++, CAVERNsoft
Electronic Visualization Laboratory
University of Illinois at Chicago
e-Touch 3D
• Open module API and
building tool
– NT and Solaris
– OpenGL
– GHOST SDK support
• CAVELib, trackd, and
support for other
platforms?
Electronic Visualization Laboratory
University of Illinois at Chicago
Defect Specification
• Outline with “connect
the dots”
• Intersection testing
• Performer provides the
ray casting
• Draping algorithms
• Volumetric collision
detection
Electronic Visualization Laboratory
University of Illinois at Chicago
Modeling Method?
• Parametric surfaces
– Non-Uniform Rational B-Splines (NURBS)
– These are surfaces, not volumes
• Constructive solid geometry
– Most algorithm implement only primitives
– Implementation with polygons more difficult
• Metaballs
– Blobby modeling
– Already used for haptic clay applications
Electronic Visualization Laboratory
University of Illinois at Chicago
Input from Artists
• Constraints
– Implant must be separate piece
– Cannot simply copy and paste the other side
– Minute refinement is required
• What kinds of tools would you use?
• How would you apply 2D modeling tools to a
tele-immersive environment?
Electronic Visualization Laboratory
University of Illinois at Chicago
Collaborative Modeling?
• Mutual exclusions in interaction
• Communication between the participants
– Likely only one haptic user
– Audio conferencing
• Evaluation methods
– Photographs of patient
– Side by side comparisons
– Overlays
• “Teacher-student” paradigm
Electronic Visualization Laboratory
University of Illinois at Chicago
Thesis Concentration
• Not trying to create the ultimate modeling
package!
• What aspects of tele-immersion are
important to this usage?
• Is it worth using these technologies in this
manner?
• What are the benefits and pitfalls?
Electronic Visualization Laboratory
University of Illinois at Chicago
General Time Frame
• September-October
– Install libraries, hook up hardware
– Determine incompatibilities
• October-February
– Interaction and modeling programming
• February-May
– Testing, evaluation, refinement
– Retesting
Electronic Visualization Laboratory
University of Illinois at Chicago
Possible Consequences
• Patient is not required to travel hundreds of
miles until the surgury is planned
• Cost of production is significantly lower than
the current process
• Tangible and quantifiable
contribution of virtual reality
technology to medicine.
Electronic Visualization Laboratory
University of Illinois at Chicago
Credits
• http://www.bvis.uic.edu/VRML/Research/CranialImplants/Cr
anialImplants01.htm
• http://www.evl.uic.edu/images/research/PARIS2.jpg
• http://www.sensable.com/
• http://www.etouch3d.org/etouch.htm
Electronic Visualization Laboratory
University of Illinois at Chicago