Figure 6.7 shows several other monocular cues. As shown in Figure 6.7(a), shadows that are cast by a light source encountering an object provide an important cue. Figure 6.7(b) shows a simple drawing that provides an ordinal depth cue called interposition by indicating which objects are in front of others. Figure 6.7(c) illustrates the image blur cue, where levels are depth are inferred from the varying sharpness of focus. Figure 6.7(d) shows an atmospheric cue in which air humidity causes far away scenery to have lower contrast, thereby appearing to be further away.
Steven M LaValle 2020-01-06