The face images

The image data can be found in /staff/sushil/classes/ml/code/book/nn/faces. This directory contains 20 subdirectories, one for each person, named by userid. Each of these directories contains several different face images of the same person.

You will be interested in the images with the following naming convention:

<userid>_<pose>_<expression>_<eyes>_<scale>.pgm

• <userid> is the user id of the person in the image, and this field has 20 values: an2i, at33, boland, bpm, ch4f, cheyer, choon, danieln, glickman, karyadi, kawamura, kk49, megak, mitchell, night, phoebe, saavik, steffi, sz24, and tammo.

• <pose> is the head position of the person, and this field has 4 values: straight, left, right, up.

• <expression> is the facial expression of the person, and this field has 4 values: neutral, happy, sad, angry.

• <eyes> is the eye state of the person, and this field has 2 values: open, sunglasses.

• <scale> is the scale of the image, and this field has 3 values: 1, 2, and 4. 1 indicates a full-resolution image (128 columns $\times$ 120 rows); 2 indicates a half-resolution image ( $64 \times 60$); 4 indicates a quarter-resolution image ( $32 \times 30$). For this assignment, you will be using the quarter-resolution images for experiments, to keep training time to a manageable level.

If you've been looking closely in the image directories, you may notice that some images have a .bad suffix rather than the .pgm suffix. As it turns out, 16 of the 640 images taken have glitches due to problems with the camera setup; these are the .bad images. Some people had more glitches than others, but everyone who got ``faced'' should have at least 28 good face images (out of the 32 variations possible, discounting scale).