Perspective deformations on the image plane make the analysis of object behaviors difficult in surveillance video. In this paper, we improve the results of trajectory-based scene analysis by using single camera calibration for perspective rectification. First, the ground-plane view is estimated from perspective images captured from a single camera. Next, unsupervised fuzzy clustering is applied on the transformed trajectories to group similar behaviors and to isolate outliers. We evaluate the proposed approach on real outdoor surveillance scenarios with standard datasets and show that perspective rectification improves the accuracy of the trajectory clustering results.