Laboratory ofImage Processing

Pier Luigi Mazzeopierluigi.mazzeo@cnr.it

July 24, 2014

The Fourier Transform with images

Display the obtained fft image

Download from my website the fftshow function, put it in your work directory

The fft examples

The fft examples

fftshow(cf, ‘log’)

Try with this circle (its edge appears burred). What does happen?

Filtering in the frequency domain (LP)

• Try to use different cut off (i.e. 5 and 30).• Try to use a circle with a gentle cutoff (i.e. b).

Filtering in the frequency domain (HP)

• Try to use different cut off (i.e. 5 and 30).• Try to use a circle with a gentle cutoff (i.e. b).

Gaussian filtering

Gaussian filtering HP(cont.)

Butterworth filtering

Butterworth filtering (cont.)

Butterworth filtering (cont.)

Butterworth filtering (cont.)