Frequency domain Flashcards
1
Q
Discrete 2D Fourier transform (DFT).
A
2
Q
Sampling theorem in 2D.
A
𝐹𝑋 = 1/𝛥𝑋 > 2𝑢𝑚𝑎𝑥 and 𝐹𝑌 = 1/𝛥𝑌 > 2𝑣𝑚𝑎𝑥
Where 𝑢𝑚𝑎𝑥 and 𝑣𝑚𝑎𝑥 are the maximum spatial frequencies of the signal along X and Y, respectively
3
Q
What is aliasing.
A
- Undersampling
- Can be compensated by means of a LPF
4
Q
Spectrum and phase of the DFT.
A
…
5
Q
How to apply a filter in the frequency domain.
A
DFT -> G=FH -> IDFT
6
Q
Low pass filters + functions.
A
Used for smoothing.
Types:
- Ideal
- Butterworth
- Gaussian
7
Q
High pass filters + functions.
A
Used for sharpening.
Types:
- 1 - H(Ideal)
- 1 - H(Butterworth)
- 1 - H(Gaussian)
