exam 1 grade distribution

Exam 1 Grade Distribution

Mean = ~77

Exam 1 Grade Distribution

Mean = ~77

Note the “ceiling effect”: these grades would have gone here if the max score was more than 100

Upcoming:

Read article by Gregory for ThursdayRead chapter by Pinker for February 28th

Seeing Depth

• The world is 3D, the retina is 2D !

Depth Cues

• Four categories:1.Pictorial2.Physiological3.Motion4.Stereoscopic

Pictorial Depth Cues

– Shadows and Shading

Pictorial Depth Cues

– Retinal image size– far objects smaller than near objects

• Retinal image size– problem: big far things same as close

small things– “solved” by size constancy: Perceived size

is adjusted according to perceived distance (based on other cues)

– forms the basis for several visual illusions

Pictorial Depth Cues

• Retinal image size

Pictorial Depth Cues

• Retinal image size

Pictorial Depth Cues

• Linear perspective

Pictorial Depth Cues

• Texture gradient

Pictorial Depth Cues

• Height in the plane

Pictorial Depth Cues

More Depth Cues

• Pictorial Depth Cues• Physiological Depth Cues• Motion Parallax• Stereoscopic Depth Cues

Physiological Depth Cues

– Two Physiological Depth Cues1. accommodation2. convergence

Physiological Depth Cues

– Accommodation

Physiological Depth Cues

– Convergence

Physiological Depth Cues

– Convergence– small angle of convergence = far away– large angle of convergence = near

– What two sensory systems is the brain integrating?

– What happens to images closer or farther away from fixation point?

Physiological Depth Cues

– Convergence and accommodation are reflexively linked

Under what circumstances might this be a problem?

Motion Depth Cues

– Motion1. Parallax

Motion Depth Cues

– Parallax

Motion Depth Cues

– Parallax– points at different locations in the visual

field move at different speeds depending on their distance from fixation

Muller - Lyer Illusion

Muller - Lyer Illusion