Sampling model — formula?
Discrete sampled function: $f_d(m,n)=f(m riangle x,n riangle y)$.
Aliasing — cause?
Under-sampling causes high frequencies to appear as low ones.
Discrete sampled function
Sampled at regular grid points in space.
Aliasing
Falsely low frequency artefacts from under-sampling.
Nyquist theorem
Prevents aliasing with proper sampling rate.
Nyquist frequency
Half the maximum original frequency.
Anti-aliasing filters
Low-pass filters before sampling.
Image quality measures
Assess image fidelity and diagnostic utility.
Contrast in imaging
Difference in signal intensity between features.
Answer 11 questions on Medical Imaging Fundamentals.
1. What is aliasing in a sampled image?
2. In two-dimensional rectangular sampling, which expression gives the sampled image values?
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