Foreground Occlusions

  

Figure 2.1: Foreground Occlusion

The foreground occlusion blocks the view of the boundary of the display. In general, foreground occlusions can be binocular.

A ``foreground occlusion'' can be thought of as a ``peephole'' through which to view a display, possibly a peephole for each eye (see Figure 2.1). More formally, a ``foreground occlusion'' is defined here to be ``an obstruction mounted in front of a display in such a way that only the display (and not its boundary) is visible through the obstruction, and such that the display is at a greater visual distance than all other available visual cues.''

Because a foreground occlusion places the display at a greater distance than other visual cues, it encourages the observer to interpret the display as the visual background. The importance of this is discussed below.