This page is to exclude audience (like students and other people on the background) which can be needed for privacy reasons but also, and especially in some specific cases, for the software to follow only the teacher (the only one out of the audience exclusion zone)

If you open this page in the CamDirector web GUI (Teacher Tracker > Audience), you will see the preview of the CamDirector 

Click on the blue line at the bottom of the preview. You can drag the audience exclusion line up (2 below) or down to exclude the people you want to exclude, as in that example below:

Make sure not to set this too high, it should never be above the waist of the teacher.