Algorithm 1: Edge-Level Evaluation of a PIDS

1 Initialize variables n, $n_{\mathrm{pre}}$ and $n_{\mathrm{post}}$.

2 Calculate IN for all $\mathcal{II}$s of the video.

3 If two or more INs intersect, merge them into a single expanded IN.

4 Calculate intrusion beginning neighbourhood IBN for each $\mathcal{II}$.

5 Obtain alarms $\mathcal{A}\left(\mathcal{P}\right)$ from the PIDS.

6 Calculate TP, FN and FP.

7 Calculate precision, recall and other metrics.