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Master Thesis - Department of Computer Science

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(1) (2) (3) (4)<br />

(1) (2) (3)<br />

Figure 3.9: Training samples for three databases: first, second and third row shows<br />

the training set for Yale, PIE, and ORL databases, respectively.<br />

The performance <strong>of</strong> subject-specific subband face on ORL database, which has<br />

a considerable amount <strong>of</strong> pose variation is given in Table 3.5. The maximum PRA<br />

obtained on this database is 91.67% for 2D-LDA using the first criterion. The same<br />

method also gives the minimum EER <strong>of</strong> 1.67%. LDA is observed to provide a maxi-<br />

mum PRA gain <strong>of</strong> 10.00% with fourth criterion on this database.<br />

3.4.3 Comparison with Ekenel’s Multiresolution Face Recognition [36]<br />

We have also compared the performance <strong>of</strong> our approach with a recent wavelet-based<br />

method denoted as Ekenel’s multiresolution face recognition [36]. They used 2D<br />

DWT to decompose the original image upto level-III and obtained A1, H1, V1, D1 in<br />

the first level, A2, H2, V2, D2 in second level, and at the third level they generated<br />

16 subband images by decomposing A2, H2, V2 and D2 further and thus obtained a<br />

total <strong>of</strong> 24 subsampled images. Daubechies 4-tap wavelet was used for wavelet tree<br />

decomposition. For each subband they extracted features using PCA and ICA, and<br />

nearest neighborhood criterion was used for classification. They used three different<br />

64

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