Stereopsis is the component of depth perception retrieved by means of binocular disparity through binocular vision. It is not the only contributor to depth perception, but it is a major one. Binocular vision occurs because each eye receives a different image due to their slightly different positions in one's head. These positional differences are referred to as "horizontal disparities" or, more generally, "binocular disparities". Disparities are processed in the visual cortex of the brain to yield depth perception. While binocular disparities are naturally present when viewing a real three-dimensional scene with two eyes, they can also be simulated by artificially presenting two different images separately to each eye using a method called stereoscopy. The perception of depth in such cases is also referred to as "stereoscopic depth".
Wheatstone's mirror stereoscope
Depth perception is the ability to perceive distance to objects in the world using the visual system and visual perception. It is a major factor in perceiving the world in three dimensions. Depth perception happens primarily due to stereopsis and accommodation of the eye.
Shots at different distances
The horizon line is at the height of the armrests.
View from a window on the 2nd floor of a house
Earth curvature