Avanessia Mitchell
Image processing
Robotics
Image Processing is a process used to convert an
image signal into a physical image.
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Diagonalization of
Symmetric Matrices
The process of finding a corresponding
diagonal matrix D.
D=
λ1 ⋯ 0
⋮ ⋱ ⋮
0 ⋯ λ 𝑛
∋ A=PDP−1
𝑃 = 𝐯1 ⋯ 𝐯 𝑛 𝐯 𝑇
𝑖 𝐯𝑗 = 0 , i ≠ 𝑗
An nxn matrix A is a 𝐑𝐞𝐚𝐥 𝐒𝐲𝐦𝐦𝐞𝐭𝐫𝐢𝐜 𝐦𝐚𝐭𝐫𝐢𝐱 if A = AT.
Real Symmetric Matrices are always diagonalizable!
𝐮𝑖=
𝐯 𝑖
∥𝐯 𝑖∥
Now P = 𝐮1 𝐮2 …… 𝐮n where D =
λ1 ⋯ 0
⋮ ⋱ ⋮
0 ⋯ λn
∴ 𝐴 = 𝑃𝐷𝑃−1
and P is an orthogonal matrix
where 𝑃−1
= 𝑃 𝑇
𝐮𝑖
𝑇
𝐮𝑗 =
0 , 𝑖 ≠ 𝑗
1 , 𝑖 = 𝑗
The Spectral decomposition of A is the representation
of A that breaks up A by the spectrum of A.
𝐴 = 𝑃𝐷𝑃 𝑇= 𝐮1 ⋯ 𝐮 𝑛
λ1 ⋯ 0
⋮ ⋱ ⋮
0 ⋯ λ 𝑛
𝐮1
⋮
𝐮 𝑛
𝐴 = λ1 𝐮1 𝐮1
𝑇
+λ2 𝐮2 𝐮2
𝑇
+ ⋯ + λ 𝑛 𝐮 𝑛 𝐮 𝑛
𝑇
𝐴 = λ𝑖 𝐮𝑖 𝐮𝑖
𝑇
𝑛
𝑖=1
Quadratic Forms
A quadratic form on Rn
is Q 𝐱 on Rn
whose
value at a vector 𝐱 can be expressed as
Q 𝐱 = 𝐱T
A𝐱
A Quadratic form Q 𝐱 = 𝐱 𝑇
A x
Q(x)=𝐱 𝑇
𝐼𝐱 =∥ 𝐱 ∥2
𝑎𝑖𝑗 = 𝑎𝑗𝑖 non diagonal
𝑎𝑖𝑖 diagonal
𝐱 𝑇
Ax= 𝐱 𝑖 𝐱𝑗
𝑎𝑖𝑖 𝑎𝑖𝑗
𝑎𝑖𝑗 𝑎𝑗𝑗
𝐱 𝑖
𝐱𝑗
=
𝑎𝑖𝑖 𝐱 𝑖
2
+ 2𝑎𝑖𝑗 𝐱 𝑖 𝐱𝑗+𝑎𝑗𝑗 𝐱𝑗
𝟐
Constrained
Optimization
m = min *𝐱TA𝐱: ∥ 𝐱 ∥ + = 1
M = max {𝐱TA𝐱: ∥ x ∥ } = 1
Q 𝐱 = a𝐱1
2
+ b𝐱2
2
+ c𝐱3
2
, a ≧ b ≧ c
a𝐱1
2
+ b𝐱2
2
+ c𝐱3
2
≦ a𝐱1
2
+ a𝐱2
2
+ a𝐱3
2
Q(x) ≦ a(𝐱1
2
+ 𝐱2
2
+ 𝐱3
2
)
Q(x) ≦ a
Q(x) ≦ 𝑐
where 𝐱 𝑇
𝐱 = 1
𝑚 ≤ λ𝑖 ≤ 𝑀
a ≤ 𝑄 𝑥 ≤ 𝑐
The Singular Value
Decomposition
∥ 𝐴𝐱 𝑖 ∥2= 𝐱 𝑖(𝐴 𝑇 𝐴)𝐱 𝑖 = λ𝑖
λ𝑖 ≥ λ𝑖+1≥ ⋯ ≥ λ 𝑛 ≥ 0
∑=
D 0
0 0
where the D=
σ1 ⋯ 0
⋮ ⋱ ⋮
0 ⋯ σr
σi are the singular values of A.
𝜎𝑖 = λ𝑖
If A is an m × n matrix with rank r. ∃ an m × n
matrix ∑ for which the diagonal entries in
D are the first singular values of A,
σ1 ≧ σ2 ≧ ⋯ ≧ σr > 0
∃ an m × m orthogonal matrix U and nxn
orthogonal matrix V ∋ A = U∑VT
𝐬𝑖 =
1
𝜎𝑖
𝐴𝐯𝑖 , 1 ≤ 𝑖 ≤ 𝑟
U = 𝐬1 ⋯ 𝐬 𝑟
V = 𝐮1 … 𝐮 𝑛
unit eigenvectors 𝐴 𝑇 𝐴
Applications to Image
Processing & Statistics
In image processing an 𝐢𝐦𝐚𝐠𝐞 is a function Q 𝒙
Q 𝐱1, 𝐱2 = 𝐱 𝑇
A𝐱
A pixel in an image is a square matrix within
the mxn neighborhood of an image.
Lay, C. David.3ed.Linear Algebra and its applications. (chapters
5,6,7)
http://www.wisegeek.org/what-is-image-processing.htm
www.wisegeek.com
Lipschaum’s ,Seymour, PhD. Lipson, Marc ,PhD.5ed.Linear
Algebra(Schuam’s outlines)
Vuthy, Teav. Pineda, R. Dr. Angel. Using the singular value
decomposition (SVD) image compression. Royal University of
Phnom Penh.
𝑄𝑢𝑒𝑠𝑡𝑖𝑜𝑛𝑠?

Avanessia Mitchell , final research presentation

  • 1.
  • 2.
  • 3.
    Image Processing isa process used to convert an image signal into a physical image.
  • 4.
  • 5.
  • 6.
    The process offinding a corresponding diagonal matrix D. D= λ1 ⋯ 0 ⋮ ⋱ ⋮ 0 ⋯ λ 𝑛 ∋ A=PDP−1 𝑃 = 𝐯1 ⋯ 𝐯 𝑛 𝐯 𝑇 𝑖 𝐯𝑗 = 0 , i ≠ 𝑗
  • 7.
    An nxn matrixA is a 𝐑𝐞𝐚𝐥 𝐒𝐲𝐦𝐦𝐞𝐭𝐫𝐢𝐜 𝐦𝐚𝐭𝐫𝐢𝐱 if A = AT. Real Symmetric Matrices are always diagonalizable!
  • 8.
  • 9.
    Now P =𝐮1 𝐮2 …… 𝐮n where D = λ1 ⋯ 0 ⋮ ⋱ ⋮ 0 ⋯ λn ∴ 𝐴 = 𝑃𝐷𝑃−1 and P is an orthogonal matrix where 𝑃−1 = 𝑃 𝑇 𝐮𝑖 𝑇 𝐮𝑗 = 0 , 𝑖 ≠ 𝑗 1 , 𝑖 = 𝑗
  • 10.
    The Spectral decompositionof A is the representation of A that breaks up A by the spectrum of A. 𝐴 = 𝑃𝐷𝑃 𝑇= 𝐮1 ⋯ 𝐮 𝑛 λ1 ⋯ 0 ⋮ ⋱ ⋮ 0 ⋯ λ 𝑛 𝐮1 ⋮ 𝐮 𝑛 𝐴 = λ1 𝐮1 𝐮1 𝑇 +λ2 𝐮2 𝐮2 𝑇 + ⋯ + λ 𝑛 𝐮 𝑛 𝐮 𝑛 𝑇 𝐴 = λ𝑖 𝐮𝑖 𝐮𝑖 𝑇 𝑛 𝑖=1
  • 11.
  • 12.
    A quadratic formon Rn is Q 𝐱 on Rn whose value at a vector 𝐱 can be expressed as Q 𝐱 = 𝐱T A𝐱
  • 13.
    A Quadratic formQ 𝐱 = 𝐱 𝑇 A x Q(x)=𝐱 𝑇 𝐼𝐱 =∥ 𝐱 ∥2 𝑎𝑖𝑗 = 𝑎𝑗𝑖 non diagonal 𝑎𝑖𝑖 diagonal 𝐱 𝑇 Ax= 𝐱 𝑖 𝐱𝑗 𝑎𝑖𝑖 𝑎𝑖𝑗 𝑎𝑖𝑗 𝑎𝑗𝑗 𝐱 𝑖 𝐱𝑗 = 𝑎𝑖𝑖 𝐱 𝑖 2 + 2𝑎𝑖𝑗 𝐱 𝑖 𝐱𝑗+𝑎𝑗𝑗 𝐱𝑗 𝟐
  • 14.
  • 15.
    m = min*𝐱TA𝐱: ∥ 𝐱 ∥ + = 1 M = max {𝐱TA𝐱: ∥ x ∥ } = 1
  • 16.
    Q 𝐱 =a𝐱1 2 + b𝐱2 2 + c𝐱3 2 , a ≧ b ≧ c a𝐱1 2 + b𝐱2 2 + c𝐱3 2 ≦ a𝐱1 2 + a𝐱2 2 + a𝐱3 2 Q(x) ≦ a(𝐱1 2 + 𝐱2 2 + 𝐱3 2 ) Q(x) ≦ a Q(x) ≦ 𝑐 where 𝐱 𝑇 𝐱 = 1
  • 17.
    𝑚 ≤ λ𝑖≤ 𝑀 a ≤ 𝑄 𝑥 ≤ 𝑐
  • 18.
  • 19.
    ∥ 𝐴𝐱 𝑖∥2= 𝐱 𝑖(𝐴 𝑇 𝐴)𝐱 𝑖 = λ𝑖 λ𝑖 ≥ λ𝑖+1≥ ⋯ ≥ λ 𝑛 ≥ 0
  • 20.
    ∑= D 0 0 0 wherethe D= σ1 ⋯ 0 ⋮ ⋱ ⋮ 0 ⋯ σr σi are the singular values of A. 𝜎𝑖 = λ𝑖
  • 21.
    If A isan m × n matrix with rank r. ∃ an m × n matrix ∑ for which the diagonal entries in D are the first singular values of A, σ1 ≧ σ2 ≧ ⋯ ≧ σr > 0 ∃ an m × m orthogonal matrix U and nxn orthogonal matrix V ∋ A = U∑VT
  • 22.
    𝐬𝑖 = 1 𝜎𝑖 𝐴𝐯𝑖 ,1 ≤ 𝑖 ≤ 𝑟 U = 𝐬1 ⋯ 𝐬 𝑟 V = 𝐮1 … 𝐮 𝑛 unit eigenvectors 𝐴 𝑇 𝐴
  • 23.
  • 24.
    In image processingan 𝐢𝐦𝐚𝐠𝐞 is a function Q 𝒙 Q 𝐱1, 𝐱2 = 𝐱 𝑇 A𝐱 A pixel in an image is a square matrix within the mxn neighborhood of an image.
  • 25.
    Lay, C. David.3ed.LinearAlgebra and its applications. (chapters 5,6,7) http://www.wisegeek.org/what-is-image-processing.htm www.wisegeek.com Lipschaum’s ,Seymour, PhD. Lipson, Marc ,PhD.5ed.Linear Algebra(Schuam’s outlines) Vuthy, Teav. Pineda, R. Dr. Angel. Using the singular value decomposition (SVD) image compression. Royal University of Phnom Penh.
  • 26.