Tutorial 7

Tutorial 7 of COMP435p: Biometrics Authentication

by Qu Xiaofeng, csxfqu@comp.polyu.edu.hk

1. Answer the following questions

2. Understand the eigenfaces algorithm (P8: 26-29) and eigenfaces recognition algorithm (P8: 30-31).

3. Eigenface is PCA-based method which is introduced in Lecture 5. At the fifth step of PCA method (P5:23-24) the k most principal components are selected based on the ratio (γλ) of the eigenvalue sum of selected components to the total sum. Please decide the value of k when the threshold of γλ is 95%. (<font color=darkred>7</font>)

In P8:31 there is a training set including 27 facial images to get eigenfaces. Can you give the value of k according to the training result (eigenfaces)? (<font color=darkred>9</font>)

4. P8:34 shows some examples of local features. Please try to define the geometry features based on the woman’s face image (refer to P8:34 ) and give the number of features. (<font color=darkred>21</font>)