pruefungen:nebenfach:mipda2023

Inhaltsverzeichnis

Image Preprocessing
Defect pixel interpolation
Sinograms (Fan Beam), 3D Reconstruction
Iterative Reconstruction
Rigid Registration
SVD

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)