I have to calculate the "Low Band Power" for a region (not always rectangular) inside an Image. I have to do this because I have to implement the algorithm explained in this paper (see page 2 in the paragraph "Fire Detection Algorithms") using Matlab. So my questions are:
How can I calculate the Low Band Power?
The idea is to follow this three steps:
- FI = Calculation of the 2D Fourier Transform with fft2
- LBFI = Make 0 all value outside a circle (low band pass)
- PSD = Calculation of the Power
In code
FI = fftshift(fft2(img));
LBFI = % not yet done
PSD = sum(sum(abs(LBFI).^2))
Is there a way to adapt this algoritm for a not rectangular region?
I think that there's no way to make something similar but I hope to be wrong