Depth and size perception

the retina of each eye can only encode two dimensions

depth perception seems automatic and unavoidable

Most sources about depth are monocular

Pictorial cues, static cues

1. interposition, overlap

partly covered objects appear further away

primary source of depth information

2. size cues

familiar size

3. Texture gradients

refers to the fact that the texture of a surface becomes denser as the distance increases

J. J. Gibson (1950) was among the first to emphasize texture gradients

4. Linear perspective

parallel lines appear to meet in the distance

1435 Alberti's De Pictura described the principle of linear perspective

5. Atmospheric perspective, aerial perspective

at a distance objects look blurry and bluish

we acquire a scale that is appropriate to the region in which we live

6. Height cues, elevation cues

objects near the horizon appear further away

first describe by Euclid in 300 B.C.

Most of our visual experience involves moving objects or moving retinas

7. Motion Parallax

when you move your head sideways objects at different distances appear to move at different speeds

focus on the window frame, hold your hand in front of your eyes, move your head to the left

* hand moves right, things in the background move left

* movement is related to the fixation point

Binocular factors

8. convergence

only good for object within 5 to 10 feet

9. binocular disparity

eyes are about 7 cm apart, enough to guarantee different views of objects

the different images fuse together into a single image containing depth