Depth Perception Chapter 7

I.  Depth perception – refers to the ability to perceive 3 dimensions using only 2-dimensional cues

1. Cues to depth perception

1. Binocular cuing sources

1. Convergence refers to the degree to which the eyes come together.

• As objects get closer, pupils angle inward more (greater convergence).

• The brain tracks eye position to gauge distance.

2. Binocular disparity  

Demonstration: The Pulfrich pendulum Illusion

Corresponding and Non-corresponding Points

• Fovea: The region on the retina where visual acuity is highest.

  • Objects focused on the fovea fall onto corresponding retinal points in both eyes.

• Haptopper: The line that marks corresponding retinal points.

• Crossed and Uncrossed Disparity:

  • Crossed: Objects closer than the fixation point fall on non-corresponding points.

  • Uncrossed: Objects further than the fixation point.

2. Monocular cuing sources

 - refers to the cues that can be used to perceive depth using only ONE eye. 

1. Pictorial Monocular cues - refers to cues that can be used in a STATIC 2-DIMENSTIONAL PICTURE or image to produce a sense of depth

1. Linear Perspective - refers to the idea that parallel lines appear to converge at some distant point

2. Apparent Size: The further away an object is, the smaller it appears to be.

3. Texture Gradient: Texture appears less distinct as distance increases, contributing to depth perception.

4. Interposition: When one object overlaps another, the overlapped object is perceived as further away.

5. Shadow Cue: The brain used Shadows to perceive depth

6. Height in the Visual Field: Objects closer to the bottom of the scene (near the horizon line) usually look farther away. Objects farther from the horizon line usually look closer

7. Atmospheric Perspective: This is when things far away look blurrier, lighter, or less detailed than things up close. 

B. Non-pictorial Monocular Cues- 

Refers to cues that can be used with one eye to produce a sense of depth, but can not be represented in a static 2- dimensional image or picture.

1. Accommodation - How the lens change shape i order to clearly focus objects on the fovea. The closer, the lens get rounder. The further, the lens get flatter. 

2. Motion Parallax - When we move, nearby objects appear to move more quickly than object further away. The further away it is the slower it goes through the visual field

Deletion: When part of an object gets covered or “disappears” as another object moves in front of it.

Accretion (Revealing): It occurs when a previously hidden part of an object becomes visible again as something moves away from it.