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Inhaltsverzeichnis

Image Preprocessing

  • Briefly explain the two types of image distortion
  • Given U=AX, what is A called?
  • Write the above in matrix notation (no coordinates given, just (x_k, \y_k)).
  • Name one interpolation method and describe briefly.

Defect pixel interpolation

  • Write down the Band limitation algorithm/steps.
  • State 2 disadvantages of bandlimitation
  • Defect pixel interpolation in frequency domain (equation derivation)

Sinograms (Fan Beam), 3D Reconstruction

  • What is above image called (sinogram)
  • Label the x- and y- axis of the diagram, briefly explain how we get sinogram from measured CT values.
  • Map sinogram on to X-Y plane by describing or drawing
  • State Orlov’s condition
  • Draw on the unit sphere one example that satisfies Orlov’s condition and one example that doesn’t.

Iterative Reconstruction

  • Kaczmarz Method given, what's another name for this method (Algebraic Reconstruction Technique)
  • Given x_(i+1)= x_i +λn, derive for x_i.
  • What is the main drawback of this method? (Slow convergence is the main drawback of ART.)
  • Give alternate options. (Simultaneous ART (SART) and Simultaneous Iterative Reconstruction Technique (SIRT))

Rigid Registration

  • Properties of Rotation Matrix
  • Fill in the blanks for optimization problem for 2-D rigid registration (pk, qk, Rotation and Translation Equation).

SVD

  • Applications of SVD (MCQ)
  • Are the singular values randomly arranged or in decreasing order diagonally and are they non-negative or negative values? (MCQ)