CS53000 - Spring 2020
Introduction to Scientific Visualization
Lecture
Tensor Field Techniques
March 5, 2020
Tensor Field Techniques Lecture 11 March 5, 2020 Outline Basics - - PowerPoint PPT Presentation
CS53000 - Spring 2020 Introduction to Scientific Visualization Tensor Field Techniques Lecture 11 March 5, 2020 Outline Basics of tensor algebra Tensor glyphs Hyperstreamlines DTI visualization CS53000 / Spring 2020 : Introduction to
CS53000 - Spring 2020
Introduction to Scientific Visualization
March 5, 2020
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
2
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
p-order tensor in n-space: linear transformation between vector spaces Special cases:
0th order: scalars 1st order: vectors 2nd order: matrices
In Visualization “tensors” are mostly 2nd order tensors
3
Ti1,..,ip, ∀j ∈ 1, .., p, 1 ≤ ij ≤ n
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
2nd order tensors map vectors to vectors Symmetric / antisymmetric with Represented* by matrices in cartesian basis
(*) tensors exist independently of any matrix representation
4
Tt = ±T
∀~ u, ~ v ∈ I Rn, T~ u · ~ v = ~ u · Tt~ v
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
Eigenvalues, eigenvectors Real symmetric tensors: eigenvalues are real and eigenvectors are orthogonal Sorted eigenvalues Invariants: quantities (function of the tensor value) independent of reference frame:
eigenvalues and functions thereof (e.g., trace, determinant)
5
⇤ I R, ⇤⌥ u ⇥= ⌥ 0, T⌥ u = ⌥ u
λ1 ≥ λ2 ≥ ... ≥ λn
~ ei · ~ ej = ij
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
Forces
stress: cause of deformation strain: deformation description
Derivative
Jacobian: 1st-order derivative of a vector field Hessian: 2nd-order derivative of a scalar field
Diffusion tensor field
6
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
Forces
stress: cause of deformation strain: deformation description
Derivative
Jacobian: 1st-order derivative of a vector field Hessian: 2nd-order derivative of a scalar field
Diffusion tensor field
6
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
Forces
stress: cause of deformation strain: deformation description
Derivative
Jacobian: 1st-order derivative of a vector field Hessian: 2nd-order derivative of a scalar field
Diffusion tensor field
6
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
Anisotropy characterizes tensor shape Example: ink diffusion
7
Kleenex Newspaper
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
Eigenvalues: Deviatoric: Partial anisotropy: linear: planar: spherical:
8
cl = λ1 − λ2 λ1 + λ2 + λ3 λ1 ≥ λ2 ≥ λ3 cp = 2(λ2 − λ3) λ1 + λ2 + λ3 ¯ λ = 1 3 X
i
λi
T = ¯ λI + D
cs = 3λ3 λ1 + λ2 + λ3
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
Eigenvectors: non-oriented directional info.
Have no intrinsic norm Have no intrinsic orientation
Eigenvectors ≠ vectors! Tensor visualization requires combined visualization of eigenvectors and eigenvalues
9
T⇧ u = ⇧ u ⇒ T(µ⇧ u) = (µ⇧ u) T⌅ u = ⌅ u ⇒ T(−⌅ u) = (−⌅ u)
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
A 2nd order symmetric 3D tensor is fully characterized by its 3 real eigenvalues (shape) and associated orthogonal eigenvectors (orientation)
10
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
11
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
12
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
13
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
14
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
14
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
15
Superquadrics and angle- preserving transformations, IEEE Computer Graphics and Applications 18(1), 1981
qz(θ,φ) = B @ cosα θsinβ φ sinα θsinβ φ cosβ φ 1 C A , 0 ≤ φ ≤ π 0 ≤ θ ≤ 2π
qz(x,y,z) = ⇣ x2/α +y2/α⌘α/β +z2/β −1 = 0.
qx(θ,φ) = B @ cosβ φ −sinα θsinβ φ cosα θsinβ φ 1 C A , 0 ≤ φ ≤ π 0 ≤ θ ≤ 2π
qx(x,y,z) = ⇣ y2/α +z2/α⌘α/β +x2/β −1 = 0.
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
Parameters 𝛽 and 𝛾 are a function of the tensor’s anisotropy measures:
16
cl ≥ cp = ⇒ α = (1−cp)γ β = (1−cl)γ q(θ,φ) = qx(θ,φ) q(x,y,z) = qx(x,y,z) cl < cp = ⇒ α = (1−cl)γ β = (1−cp)γ q(θ,φ) = qz(θ,φ) q(x,y,z) = qx(x,y,z)
cl = λ1 −λ2 λ1 +λ2 +λ3 cp = 2(λ2 −λ3) λ1 +λ2 +λ3 cs = 3λ3 λ1 +λ2 +λ3
Joint Eurographics/IEEE VGTC Symposium on Visualization 2004
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
Superquadric glyphs
17
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
18
Joint Eurographics/IEEE VGTC Symposium on Visualization 2004
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
18
Joint Eurographics/IEEE VGTC Symposium on Visualization 2004
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
19
Joint Eurographics/IEEE VGTC Symposium on Visualization 2004
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
19
Joint Eurographics/IEEE VGTC Symposium on Visualization 2004
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
20
Joint Eurographics/IEEE VGTC Symposium on Visualization 2004
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
20
Joint Eurographics/IEEE VGTC Symposium on Visualization 2004
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
Color-coding can be used to facilitate the interpretation of the orientation e.g., emax mapped to R=|x|, G=|y|, B=|z|
21
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
22
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
23
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
+λ3 +λ1 +λ1 +λ2 −λ3
λ2 = 0 λ1 =
λ
2= − λ
3λ
1= − λ
2λ
1= − λ
3λ1 = λ2 λ2 = λ3 λ1 = λ2 λ2 = λ3
λ2 > 0 λ2 < 0
λ3 < λ1 > 0
>
Glyphs for general symmetric tensors? Eigenvalues can be positive or negative
24
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
25
(α, β)
β
u
IEEE TVCG 16 (6) (IEEE Visualization 2010)
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
26 (a) Glyphs on vertical cutting plane (b) Superquadric tensor glyphs; s(D) ∝ D (c) Superquadric tensor glyphs; s(D) ∝ D1/2
IEEE TVCG 16 (6) (IEEE Visualization 2010)
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
Distribute (discrete) glyphs over continuous domain in data-driven way Reveal underlying continuous structures Remove artifacts caused by sampling bias
27
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
28
Regular grid Glyph packing
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
29
Regular grid Glyph packing
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
Method for symmetric 2nd order tensor fields in 3D Identify eigenvector fields w.r.t. associated eigenvalues
30
and
x ⇥ I R3 ⇤ T(x) x ⇤⇥ λ1(x) λ2(x) λ3(x) x ⇥ ⇧ ei(x), T(x) = i(x)⇧ ei(x)
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
Tensor field lines (2D/3D): curve everywhere tangential to a given eigenvector field
31
A Unified Approach to the Design of Visualization Software for the Analysis of Field Problems, SPIE Proceedings, Vol. 1083, 1989
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
Remark: numerical integration using e.g. Runge- Kutta is faced with the problem of maintaining
32
A Unified Approach to the Design of Visualization Software for the Analysis of Field Problems, SPIE Proceedings, Vol. 1083, 1989
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
Compute tensor field line along major eigenvector Sweep geometric primitive representing two other eigenvalues and eigenvectors
Ellipse stretched along eigenvectors by eigenvalues Cross depicting eigenvectors + eigenvalues
Color coding on geometric primitive determined by
33
Visualization of Second Order Tensor Fields and Matrix Data, IEEE Visualization 1992
⇥ e1
λ1
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
Eigenvectors are orthogonal: cross section always orthogonal to tensor field line Eigenvalues mapped to length of edges in cross section: problems with negative eigenvalues
34
Visualization of Second Order Tensor Fields and Matrix Data, IEEE Visualization 1992
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
35
Visualization of Second Order Tensor Fields and Matrix Data, IEEE Visualization 1992
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
36 CS530 / Spring 2019 : Introduction to Visualization. Tensor Fields 03/25
37
Hotz, I.; Feng, L.; Hamann, B.; Joy, K. Tensor-fields Visualization using a Fabric like Texture on Arbitrary two-dimensional Surfaces. Mathematical Foundations of Scientific Visualization, Computer Graphics Springer , 2006
CS53000 / Spring 2020 : Introduction to Scientific Visualization .
March 5, 2020
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
37 CS53000 / Spring 2020 : Introduction to Scientific Visualization .
March 5, 2020
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
38
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
39
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
40
Extension of Hultquist’s stream surfaces to eigenvector fields
Visualization of Second Order Tensor Fields and Matrix Data, IEEE Visualization 1992
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
Diffusion Tensor (DT)-MRI measures anisotropic (directional) diffusion properties of biological tissue (e.g., brain) Diffusion tensor is symmetric positive definite (positive eigenvalues) Objective: use tensor information to reconstruct the path of tissue fibers Problems: (very) noisy data + isotropy
41
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
42
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
43
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
44
Park, Westin, and Kikinis, BWH, Harvard Medical School, 2003
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
Motion of water through tissue Faster in some directions than others
45
isotropic anisotropic Newspaper Kleenex
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
46
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
46
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
47
Anisotropy high along white matter fiber tracts
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
47
Anisotropy high along white matter fiber tracts
1.7 0.1 -0.1 0.1 2.3 -0.3
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
47
Anisotropy high along white matter fiber tracts
3.7 0.3 -0.8 0.3 0.6 -0.1
1.7 0.1 -0.1 0.1 2.3 -0.3
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
47
Anisotropy high along white matter fiber tracts
2.1 -0.1 -0.2
3.7 0.3 -0.8 0.3 0.6 -0.1
1.7 0.1 -0.1 0.1 2.3 -0.3
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
Moving Least Squares: Apply Gauss filter mask whose support is determined by current path orientation and local anisotropy Trace fiber path along filtered eigenvector
48
Oriented Tensor Reconstruction: Tracing Neural Pathways from Diffusion Tensor MRI, IEEE Visualization 2002
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
49
Oriented Tensor Reconstruction: Tracing Neural Pathways from Diffusion Tensor MRI, IEEE Visualization 2002
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
50
Oriented Tensor Reconstruction: Tracing Neural Pathways from Diffusion Tensor MRI, IEEE Visualization 2002
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
51
Heart Fiber Reconstruction from Diffusion Tensor MRI, IEEE Visualization 2003
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
52
linear
mode = 1
mode = 0
planar
mode = -1
λ2 λ3 λ1
mode = -1 mode = 0 mode = +1
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
52
linear
mode = 1
mode = 0
planar
mode = -1
λ2 λ3 λ1
mode = -1 mode = 0 mode = +1
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
52
linear
mode = 1
mode = 0
planar
mode = -1
λ2 λ3 λ1
mode = -1 mode = 0 mode = +1
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
52
linear
mode = 1
mode = 0
planar
mode = -1
λ2 λ3 λ1
mode = -1 mode = 0 mode = +1
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
Slice Inspection: RGB(e1) (original data)
53
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
Slice Inspection: RGB(e1)
54
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
Slice Inspection: FA
55
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
Slice Inspection: | FA|
56
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
Slice Inspection: ridge strength: max(0, λ3)
57
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
Slice Inspection: g.e3 (modulated by strength)
58
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
Slice Inspection: sqrt((g.e3)2 + (g.e2)2)
59
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
3-D Results: coronal fibers
60
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
3-D Results: ridge surfaces
61
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
3-D Results: valley surfaces
62
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
3-D Results: valley surfaces with
63
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
3-D Results: brainstem fibers
64
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
3-D Results: brainstem ridge surfaces
65
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
3-D Results: brainstem valley surfaces
66
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
3-D Results: combined results
67
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
68
425 lines with length > 15mm Sort based on average ridge strength
1.5 x 1.5 x 1.5 mm
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
69
1.5 x 1.5 x 1.5 mm
FOR = Fornix, CB = Cingulum Bundles Sort based on average ridge strength
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020
Line Creases of White Matter Anisotropy
70
CBL CBR FOR ILF ICP ML CST
CS53000 / Spring 2020 : Introduction to Scientific Visualization.
March 5, 2020 71
Visualization 2009
DTI CT