7. Camera Motion Analysis

7. Camera Motion Analysis

As noted in section 5, camera parameters are strongly related to ball movement. Pan, tilt and zoom values are calculated for each shot, using techniques shown in section 3. The curves of these values are filtered and quantized, using 5 levels for pan, 3 for tilt and zoom. Analysis of the videos has shown that conditions such as a flying ball rather than a change of direction can be observed from camera motion parameters. Through heuristic analysis of these values, three descriptors of low, medium and high ball motion have been derived. Figure 5.19 shows a typical shot action: at time t_start a player kicks the ball toward the goal post. Acceleration and deceleration (at time t_OK) can be identified. Often zoom on the goal post can be observed.

Figure 5.19: Typical shot action— at time t_start the ball is kicked toward the goal post. Symbols on the right identify low, medium and high motion.