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Pit Pattern Classification in Colonoscopy using Wavelets - WaveLab

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5 Results<br />

Feature Feature vector length s k-value for k-NN<br />

BEST-BASIS METHOD (BB)<br />

k-NN (2 classes) Subband energy 1 14<br />

k-NN (6 classes) Subband energy 1 50<br />

SVM (2 classes) Subband energy 8 N/A<br />

SVM (6 classes) Subband energy 41 N/A<br />

BEST-BASIS METHOD (STRUCTURAL FEATURES) (BBS)<br />

k-NN (2 classes) KNNTD N/A 50<br />

k-NN (6 classes) KNNTD N/A 43<br />

SVM (2 classes) FEUNV 14 N/A<br />

SVM (6 classes) FEUNV 30 N/A<br />

BEST-BASIS CENTOIDS (BBCB)<br />

k-NN (2 classes) Subband energy 32 3<br />

k-NN (6 classes) Subband energy 23 33<br />

SVM (2 classes) Subband variance 45 N/A<br />

SVM (6 classes) Subband variance 29 N/A<br />

PYRAMIDAL WAVELET TRANSFORM (WT)<br />

k-NN (2 classes) Subband energy 9 22<br />

k-NN (6 classes) Subband energy 9 25<br />

SVM (2 classes) Subband variance 50 N/A<br />

SVM (6 classes) Subband energy 15 N/A<br />

LOCAL DISCRIMINANT BASES (LDB)<br />

k-NN (2 classes) Subband variance 7 13<br />

k-NN (6 classes) Subband energy 21 14<br />

SVM (2 classes) Subband energy 19 N/A<br />

SVM (6 classes) Subband variance 69 N/A<br />

Table 5.6: Test configuration details for the best results obta<strong>in</strong>ed (<strong>Pit</strong> pattern images)<br />

result of 36%. However, <strong>in</strong> the six classes case the k-NN classifier shows only poor classification<br />

results for the pit pattern types II, III-S and V. For the latter two types this is possibly<br />

due to the limited number of images available for these classes. The SVM classifier however<br />

shows a clearly better classification performance for the pit pattern type II.<br />

The tables 5.8 and 5.9 show the result distribution matrices for the two classes case and<br />

the six classes case, respectively, us<strong>in</strong>g pit pattern images. An entry a i,j <strong>in</strong> such a result<br />

distribution matrix located at row i and column j means, that a i,j percent of the images<br />

belong<strong>in</strong>g to class i have been classified as class-j images. Therefore, a result distribution<br />

matrix for a perfect classification result would be a matrix hav<strong>in</strong>g only values of 100 on the<br />

ma<strong>in</strong> diagonal - thus a diagonal matrix.<br />

Look<strong>in</strong>g at the tables 5.8 and 5.9, we can clearly see that these matrices are far from be-<br />

68

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