Transcript Interactive Chesapeake Bay Simulation

Creating and Simulating Skeletal Muscle
from the Visible Human Data Set
Authors:
•Joseph Teran
• Eftychios Sifakis
• Silvia S. Blemker
•Victor Ng-Thow-Hing
•Cynthia Lau
• Ronald Fedkiw
Presented By: Federico Bermudez
21 Mar 2007
MSIM 842 VISUALIZATION II
INSTRUCTOR: JESSICA R. CROUCH
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PROBLEM
• Create anatomically realistic simulations of
the human musculoskeletal system.
• Create visually accurate simulations of the
interactions between muscles and bones.
• This paper present a method for creating such
simulations using the visible human data set.
21 Mar 2007
MSIM 842 VISUALIZATION II
INSTRUCTOR: JESSICA R. CROUCH
2
MOTIVATION
• Anatomically and visually accurate simulations
of the musculoskeletal system are critical in:
• biomechanics
• biomedical engineering
• surgery simulation
• computer graphics
21 Mar 2007
MSIM 842 VISUALIZATION II
INSTRUCTOR: JESSICA R. CROUCH
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APPROACH
PRIOR & RELATED WORK
• Prior work
– Simple less accurate models encompassing many muscles.
– Complex models that only simulate a few number of muscles.
– These models are less visually accurate.
• Related work
– Seems to be concentrated on the use of the Finite Element Method
(FEM), the Finite Volume Method (FVM), and tetrahedral meshes
21 Mar 2007
MSIM 842 VISUALIZATION II
INSTRUCTOR: JESSICA R. CROUCH
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APPROACH
MODEL CREATION
The Visible Human Data Set
Run by the U.S. National Library Of Medicine
Consists of MRI, CT, and anatomical Images
Male data set released in Nov 1994
– Joseph Paul Jernigan (38-year-old Texas murderer executed 5 Aug 1993)
– cadaver was frozen and cut (1871 axial slices at 1 millimeter intervals)
– Photographed and digitized – 15 GB
Female data set released in Nov 1995
– 59-year-old Maryland housewife who died from a heart attack
– cadaver was frozen and cut (5189 axial slices at 0.33 millimeter intervals)
– Photographed and digitized – 40 GB
21 Mar 2007
MSIM 842 VISUALIZATION II
INSTRUCTOR: JESSICA R. CROUCH
5
APPROACH
MODEL CREATION
The Visible Human Data Set
Problems with the data set
– Male brain slightly swollen by the freezing process
– Small blood vessels were collapsed by the freezing process
– His inner ear ossicles were lost during preparation
Site: http://www.nlm.nih.gov/research/visible/
21 Mar 2007
MSIM 842 VISUALIZATION II
INSTRUCTOR: JESSICA R. CROUCH
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APPROACH
MODEL CREATION
The Visible Human Data Set
CT Scan
Color Cryosections
Thorax subset
21 Mar 2007
MSIM 842 VISUALIZATION II
INSTRUCTOR: JESSICA R. CROUCH
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APPROACH
MODEL CREATION
The Visible Human Data Set
21 Mar 2007
MSIM 842 VISUALIZATION II
INSTRUCTOR: JESSICA R. CROUCH
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APPROACH
MODEL CREATION
Repairing Errors
21 Mar 2007
MSIM 842 VISUALIZATION II
INSTRUCTOR: JESSICA R. CROUCH
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APPROACH
MODEL CREATION
Meshing Bone and Muscle
21 Mar 2007
MSIM 842 VISUALIZATION II
INSTRUCTOR: JESSICA R. CROUCH
10
APPROACH
MODEL CREATION
Meshing Bone and Muscle
21 Mar 2007
MSIM 842 VISUALIZATION II
INSTRUCTOR: JESSICA R. CROUCH
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APPROACH
MODEL CREATION
Tendon and Bone Attachment Designation
assign tendon, bone attachments, and muscle properties to sections of the mesh
21 Mar 2007
MSIM 842 VISUALIZATION II
INSTRUCTOR: JESSICA R. CROUCH
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APPROACH
MODEL CREATION
B-Spline Fiber Representation
Use B-spline solids to assign fiber directions to individual tetrahedrons.
21 Mar 2007
MSIM 842 VISUALIZATION II
INSTRUCTOR: JESSICA R. CROUCH
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APPROACH
MODEL CREATION
Skeletal Motion
– Contraction of the muscles drives the motion of bones.
– In this model, the skeleton drives the motion and contraction of muscles, tendons, and
surrounding tissue.
– A realistic model involves intricate knowledge of bones and joints interaction , often
requiring multiple degrees of freedom to describe their movements.
– The Obstacle-set Method was used to modeled the paths of the muscles.
– Cylinders and spheres were used to compute muscles and bones collisions.
21 Mar 2007
MSIM 842 VISUALIZATION II
INSTRUCTOR: JESSICA R. CROUCH
14
APPROACH
MODEL CREATION
Skeletal Motion
21 Mar 2007
MSIM 842 VISUALIZATION II
INSTRUCTOR: JESSICA R. CROUCH
15
APPROACH
MODEL CREATION
Skeletal Motion
21 Mar 2007
MSIM 842 VISUALIZATION II
INSTRUCTOR: JESSICA R. CROUCH
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APPROACH
FINITE VOLUME METHOD
• FVM more intuitive than the finite element method (FEM)
• FVM reduces the stress inside a tetrahedron to a simple multidimensional
force pushing on each face.
• The inverting FVM algorithm developed from the FVM facilitates the
simulation of objects that must undergo deformation and return to their
original or partial shape.
• Video – 01 & 02 show simulations using the inverting FVM.
21 Mar 2007
MSIM 842 VISUALIZATION II
INSTRUCTOR: JESSICA R. CROUCH
17
APPROACH
CONSTITUTIVE MODEL FOR MUSCLE
• An strain energy function is used to model the
contracting of the muscles.
• Model includes only what is necessary to produce
bulk length-based contraction along the muscle fiber
direction.
• As we will see on the video, the bulk deformations of
the muscles are very subtle.
21 Mar 2007
MSIM 842 VISUALIZATION II
INSTRUCTOR: JESSICA R. CROUCH
18
APPROACH
EMBEDDING FRAMEWORK
• The complete model of the upper limb consist of over 30 muscles
constructed with over 10 million tetrahedra.
• A dynamic Free Form Deformation embedding scheme was used to reduce
the computational cost.
• The BCC grid size used resulted in a tenfold reduction in the size of the
simulation mesh.
• Time step restriction for stability was relaxed by a factor of 25.
• These factors enabled the full finite element simulation at rates of 4
minutes per frame on a Xeon 3.06 GHz CPU.
• A nonmanifold simulation mesh is obtained by collapsing equivalent
vertices.
21 Mar 2007
MSIM 842 VISUALIZATION II
INSTRUCTOR: JESSICA R. CROUCH
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APPROACH
FASCIA AND CONNECTIVE TISSUES
• Muscles are enclosed in a network of connective tissue that keep them in
close contact during motion.
• Model enforces a state of frictionless contact between the muscles.
• In essence the intersection between different muscles is determined and
recalculated each time during motion in order to maintain the muscle
tissues in close contact.
• Video – 03 shows the simulation without fascia.
21 Mar 2007
MSIM 842 VISUALIZATION II
INSTRUCTOR: JESSICA R. CROUCH
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APPROACH
SIMULATING SKELETAL MUSCLE
Run videos
1. Video – 04 - Frontal View
2. Video – 05 - Side View
21 Mar 2007
MSIM 842 VISUALIZATION II
INSTRUCTOR: JESSICA R. CROUCH
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Evaluation
• The construction of the muscles, tendons,
and bones seems to be correct.
• I think the simulation shows the compression
and relaxation if the muscles visually
accurate.
21 Mar 2007
MSIM 842 VISUALIZATION II
INSTRUCTOR: JESSICA R. CROUCH
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Conclusion & Future Work
• The authors successfully created a visually accurate simulation of the
interaction of the bones, muscle, and underlying tissue of the human right
upper limb.
• Current hardware and algorithm technology still too complex to achieve
whole body simulations.
• Create subject-specific models with MRI and CT data.
• Morph VHP data set to match specific subject or body type using
anatomical landmarks.
21 Mar 2007
MSIM 842 VISUALIZATION II
INSTRUCTOR: JESSICA R. CROUCH
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Questions
• How much more complex would be to simulate the
whole body.
• Can this technique be use to simulate the
involuntary muscles such the hear heart?
• Can this technique be applied to the design of
artificial limbs.
21 Mar 2007
MSIM 842 VISUALIZATION II
INSTRUCTOR: JESSICA R. CROUCH
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