Abstract:
We evaluate and compare video visualization techniques based on fast-forward.
A controlled laboratory user study (n = 24) was conducted to determine the
trade-off between support of object identification and motion perception, two
properties that have to be considered when choosing a particular fast-forward
visualization. We compare four different visualizations: two representing the
state-of-the-art and two new variants of visualization introduced in this
paper. The two state-of-the-art methods we consider are frame-skipping and
temporal blending of successive frames. Our object trail visualization
leverages a combination of frame-skipping and temporal blending, whereas
predictive trajectory visualization supports motion perception by augmenting
the video frames with an arrow that indicates the future object trajectory.
Our hypothesis was that each of the state-of-the-art methods satisfies just
one of the goals: support of object identification or motion perception.
Thus, they represent both ends of the visualization design. The key findings
of the evaluation are that object trail visualization supports object
identification, whereas predictive trajectory visualization is most useful
for motion perception. However, frame-skipping surprisingly exhibits
reasonable performance for both tasks. Furthermore, we evaluate the
subjective performance of three different playback speed visualizations for
adaptive fast-forward, a subdomain of video fast-forward.