Pit Pattern Classification in Colonoscopy using Wavelets - WaveLab
Pit Pattern Classification in Colonoscopy using Wavelets - WaveLab
Pit Pattern Classification in Colonoscopy using Wavelets - WaveLab
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2 <strong>Wavelets</strong><br />
Logarithm of energy (LogEnergy)<br />
cost(I) =<br />
N∑<br />
log ∗ (s) with s = I(i) 2<br />
i=1<br />
Entropy<br />
N∑<br />
cost(I) = − s log ∗ (s) with s = I(i) 2<br />
i=1<br />
L p -Norm<br />
cost(I) =<br />
N∑<br />
|I(i)| p<br />
i=1<br />
Threshold<br />
cost(I) =<br />
N∑<br />
{ 1 if I(i) > t<br />
a with a =<br />
0 else<br />
i=1<br />
where I is the <strong>in</strong>put sequence (the subband), N is the length of the <strong>in</strong>put, log ∗ is the logfunction<br />
with the convention log(0) = 0 and t is some threshold value.<br />
(a) Source image<br />
(b) LogEnergy (c) Entropy (d) L-Norm (e) Threshold<br />
Figure 2.3: Different decomposition trees result<strong>in</strong>g from different cost functions us<strong>in</strong>g the<br />
Haar wavelet.<br />
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