The Use of Depth in Change Detection and Multiple Object Tracking

Users require to quickly and reliably process information in visually complex scenarios. Detecting changes in visual displays and tracking multiple moving targets are important in tasks ranging from surveillance, air traffic control and process management to gaming. By integrating depth information into visual displays we may alleviate some of the difficulties users face in these tasks. In this paper, we report on a study investigating the allocation of attention in three-dimensional space and on the use of depth in the detection of visual changes and multiple object tracking. For this we developed a task combining change detection with multiple object tracking. Stimuli were presented on a Multi Layer Display that allows displaying information on different depth layers. We found that participants detected colour changes faster than changes in depth and there was no additional benefit in combining colour and depth change. They could track more simultaneously moving objects correctly when they were equally distributed across two depth layers. Increasing the complexity of the tracking task had less effect on performance in a concurrent change detection task when the tracking objects were distributed across two depth layers.