Skip to main content
. Author manuscript; available in PMC: 2016 Jan 31.
Published in final edited form as: J Exp Psychol Hum Percept Perform. 2014 Nov 10;41(1):111–126. doi: 10.1037/a0038287

Figure 2.

Figure 2

Locating a target suspended in midair above the ground surface. (a) The image of the target overlaps with the optic contact on the ground surface. To determine the location of the suspended target, the visual system needs to determine the target’s relative position to the ground surface. For example, knowing its vertical height with respect to the ground, i.e., its distance to the physical contact, can help determine its distance. The horizontal distance of the physical contact on the ground is the same as the horizontal distance of the target. (b) The visual system can use the relative binocular disparity (η) between the suspended near target and a far target on the ground to derive the location of the suspended target. Specifically, if the distance of the far target on the ground surface (Df) is known, the visual system can derive the relative distance, dr, based on the relative binocular disparity (η) between the near and far targets and the observer’s inter-pupil distance (p). Knowing Df and dr,, the visual system can obtain the distance of the near target (Dn= Df − dr). The equation above the figure depicts the relationship between Dn and dr.