Effects of Object Density on Speed Perception of First-Person Perspective Navigation Videos

The perception of moving speed in navigation video images differs from that in real-world environments due to the reduced availability of sensory cues. Previous studies have indicated that speed perception in first-person perspective videos is more linear in spaces filled with objects than in sparse environments. However, the impact of object density on the linearity of speed perception remains unclear. This study investigates the effect of object density on the perception of moving speed in first-person perspective videos. A user study involving 44 participants was conducted, where they viewed a movie navigating through a hallway, and their speed perception was assessed across six levels of object density using the psychophysical method of magnitude estimation. An analysis based on Stevens’ power law revealed a positive correlation between the object density and perceived speed. In particular, the perceived speeds increased with the object density up to a moderate density level. The highest linearity of speed perception was observed at moderate densities. In contrast, overly dense environments exhibited diminished linearity, similar to conditions with sparse or no objects. These findings suggest the existence of a critical density threshold for maintaining linear speed perception in moving images, providing insights for the design of videos, such as navigation information.