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* Define the counter-clockwise rotation matrix
 
* Define the counter-clockwise rotation matrix
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the matrix rotates vector <math>v_0</math> in a 2-D real space by angle <math>\theta</math> in a fixed coordinate system.
  
 
<math>\begin{bmatrix}
 
<math>\begin{bmatrix}
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* C. A. Bouman. ECE 637. Class Lecture. Digital Image Processing I. Faculty of Electrical Engineering, Purdue University. Spring 2013.
 
* C. A. Bouman. ECE 637. Class Lecture. Digital Image Processing I. Faculty of Electrical Engineering, Purdue University. Spring 2013.
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* E. W. Weisstein, "Rotation Matrix." From MathWorld--A Wolfram Web Resource. http://mathworld.wolfram.com/RotationMatrix.html. May 8th, 2013 [May 21st, 2013]
  
  

Revision as of 12:02, 21 May 2013

sLecture

Topic 2: Tomographic Reconstruction
Intro
CT
PET
Co-ordinate Rotation


The Bouman Lectures on Image Processing

A sLecture by Maliha Hossain

Subtopic 3: Co-ordinate Rotation

© 2013




Excerpt from Prof. Bouman's Lecture


Accompanying Lecture Notes


  • Define the counter-clockwise rotation matrix

the matrix rotates vector $ v_0 $ in a 2-D real space by angle $ \theta $ in a fixed coordinate system.

$ \begin{bmatrix} \cos(\theta) & -\sin(\theta) \\ \sin(\theta) & \cos(\theta) \end{bmatrix} $

  • Define the new coordinate system $ (r,z) $

$ \begin{bmatrix} x \\ y \end{bmatrix} = A_{\theta}\begin{bmatrix} r \\ z \end{bmatrix} $


Fig 1: Geometric Interpretation


  • Inverse Transformation

$ \begin{bmatrix} r \\ z \end{bmatrix} = A_{-\theta}\begin{bmatrix} x \\ y \end{bmatrix} $


References

  • C. A. Bouman. ECE 637. Class Lecture. Digital Image Processing I. Faculty of Electrical Engineering, Purdue University. Spring 2013.



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