SURGICAL SIMULATIONS: IT’S ALL IN A GAME !
Gaming techniques for medical applications.
V. Kotamraju, S. Payandeh, J. Dill
Experimental Robotics Laboratory, Simon Fraser University.
ABSTRACT
THE GRAPHICS PIPELINE
Computer games have come a long way since A.S. Douglas' Tic-Tac-Toe in 1952,
evolving into a well-understood set of methods, including recent developments in realism
and immersiveness for game scenarios.
Surgical Simulation, on the other hand, has barely a decade of technological
development. Surgical techniques have evolved from direct hands-on maneuvers to
indirect minimal-access procedures like Laparoscopy, involving video cameras to show
the surgeon the instruments and operating site. Learning these techniques is difficult, but
recent advances in computer technology have allowed development of virtual training
environments to help the surgeon-to-be.
Visibility determination
clipping, culling,
occlusion testing.
SURGICAL SIMULATION FRAMEWORK
Deformable modeling.
Collision detection and response.
Visual and haptic feedback.
pipeline
parallels
Resolution determination
LOD analysis.
The common component of virtual reality provides an opportunity to apply game
Abstract
programming ideas to such training environments. This poster outlines key techniques in
3D game applications that can enhance current surgical simulation technology.
Transformation
and lighting
Rasterization
PERFORMANCE TUNING
*
Analysis: Profiling, bottlenecks (time, memory).
Uniprocessor: Hierarchical structures.
Multiprocessors: Parallel processing.
Communication bottleneck.
Graphics Processing Unit, Parallel Processing Unit.
*
GEOMETRICAL TECHNIQUES
Collision detection.
Point-inclusion, ray intersection,
convex hull.
Sweep and prune: Variants for
multiple-object collisions.
Triangle reduction: Vertex or edge collapse.
Progressive mesh.
Selection of LOD.
Load-time tuning of hardware.
USER INPUT
function-parallel
data-parallel
Hardware dependency.
Keyboard, mouse.
Haptics: 6 DOF, force and torque feedback.
Organ-force response to users.
*
PARTICLE SYSTEMS
DESIGN PATTERNS
update
real-time data
Abstract systems of interaction.
Between classes, objects, and communication flow.
Use object-oriented programming.
Provide model reusability.
Programming patterns: Spatial index, factory, singleton.
Usability patterns: State, focus, progress.
render
control
interaction
computation and display
GAME
SURGICAL
PROGRAMMING
SIMULATIONS
Dynamic, time-dependent, unconnected mass points.
Particles originate, move and die.
Stochastic modeling used to control particles.
Velocity based on blood-vessel properties.
Particle motion influenced by force-field.
Simulation of blood-flow and blood-clot.
*
TEXTURE MAPPING
Wraps image on surface model.
Provides data or patient-specific view.
Adds realism.
ARTIFICIAL INTELLIGENCE
Finite State Machines: Analyze surgical motions.
Path Planning: Guide trajectory of tool.
Fuzzy logic: Measure surgical competence.
*
3D texture arrays contain original data.
Dynamic local 2D arrays contain visible
surface data.
*
NETWORK PROGRAMMING
Client-server and multi-player systems.
Remote surgical training.
High performance computing systems.
High-speed networks, Grids.
*
LEVEL OF DETAIL
SHADING
Scene described at multiple resolutions.
Discrete (pre-computed) or continuous (on-the-fly).
Fast and realistic rendering.
Efficient GPU utilization.
‘Popping’ may occur, unsuitable for single, large models.
* Images reproduced from existing publications.
References provided as handout.
[email protected] [email protected] [email protected]
Illumination (light and shadows).
Adds visual details.
Components: Ambient, diffuse, specular.
Per-vertex or per-pixel.
Phong model: Vertex-normal interpolation for face.
For curved surfaces.
Light mapping: Light effects on base texture.
SUMMARY
Several computer game development techniques can
be adapted for surgical simulation. The choice and
implementation of a technique must be based on
application requirements.