Line 36: Line 36:
 
=Accompanying Lecture Notes=
 
=Accompanying Lecture Notes=
  
 +
----
 +
 +
* Define the counter-clockwise rotation matrix
 +
 +
<math>\begin{bmatrix}
 +
\cos(\theta) & -\sin(\theta) \\
 +
\sin(\theta) & \cos(\theta)
 +
\end{bmatrix}</math>
 +
 +
* Define the new coordinate system <math>(r,z)</math>
 +
<math>\begin{bmatrix}
 +
x \\
 +
y
 +
\end{bmatrix} = A_{\theta}\begin{bmatrix}
 +
r \\
 +
z
 +
\end{bmatrix}
 +
</math>
 +
 +
 +
 +
[[Image:CR_fig1.png|400px|thumb|left|Fig 1: Geometric Interpretation]]
 +
 +
 +
* Inverse Transformation
 +
<math>\begin{bmatrix}
 +
r \\
 +
z
 +
\end{bmatrix} = A_{-\theta}\begin{bmatrix}
 +
x \\
 +
y
 +
\end{bmatrix}
 +
</math>
  
 
----
 
----

Revision as of 16:49, 9 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

$ \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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