Video-based nonphotorealistic and expressive illustration of motion

We present a semi-automatic approach for adding expressive renderings to images and videos that highlight motions and movement. Our technique relies on motion analysis of video where the motion information from the image sequence is used to add expressive information. The first step in our approach is to extract a moving region of the video by segmenting and then grouping regions of compatible motions. In the second step, a user can interactively choose or refine a grouping region that represents the moving object of interest. In the third and final stage, the user can apply various visual effects such as a temporal-flare, time-lapse, and particle-effects. We have implemented a prototype system that can be used to illustrate and expressively render motions in videos and images, with simple user interaction. Our system can deal with most translational and rotational motions without a need for a fixed background.