Notes

3-D depth and shape perception

3-D depth and shape
-we see objects in three-dimensions.
-
-visual system transforms 2-D representation into a 3-D representation
-the "cue" approach: the 2-D array od light contains info. or cues to 3-D depth
-A 3-D representation is constructed by the brain from info. in the 2-D image

cues
A. monocular - cues that work with one eye:
-oculomotor:accommodation(-focus achieved by changing lens curvature - amount of muscle contraction is correlated with object distance)
---pictorial: shape/depth from contour, shading, linear perspective and texture gradients, relative image size, elevation, atmospheric perspective
shading/lightening:
-surface that are facing a light source are the brightest.
-as a surface faces away from the light, it appears less bright and more shaded
- the pattern of lightness and darkness across an object/surface suggests sth about its shape
-usually assume light source is coming from above
linear persecutive and texture gradients: systematic decrease in size and spacing of more distant elements
linear perspective: apparent convergence at a distance of physically parallel lines
texture gradients: refinement of size and spacing of surface elements with distance
(-focus achieved by moving distance of "receptor" surface relative to the lens or vice versa)
B. binocular -cues that require 2 eyes to work
-oculomotor: convergence
-binocular disparity

motion parallax: the relative motion of elements in a display specifies depth and structure
when you moves your head,
-close elements move fast in a opposite direction
-element at the fixation point doesn't move
-elements far behind the fixation point move fast in the same direction