Visual does both bottomup and top down processing

Spatial Frequencies: Resolutions

• We use contrast and spacial frequency to prcess visual info
• Look at characteristics in grid
• Frquency refers to # of bars, high is many bars, low freq is little bars

Contrast Sensitivity Functions

We see more fine detail than cats
they can see low frequency and low consast thngs

Monocular Depth Cues

• Perspective
  • Parrallel lines converging at the horizon
• Relative size
• Texture and shading

Retinal Disparity

Right of center processed by left hemisohere, ivice phersa

• Disparity between left and retina varries
• Average gives us depth and stuff
• They have overlapping veiews
• 3d films use horizontal and verticle filters

Color Vision

3 Cone Pigments RGB

Opponent Process Theory

• No more receptive fields
• Red center, green surround, cant see reddishgreen
• yellow is red and green

Color Deficient

• Delietion of Red Cone gene
• or green one
• around x chromosome, sex linked, affecting males
• blue can some times be taken away
  • on chromosome 7, not sex linked
• Color Contrast
  • Perception of color shift based on surroundings
  • Midevil tapestry artists put certain colors next to echother for rich perseption
• Color contancy: perceptual adjustments based on lighting
  • red sweater produces different perception in flourescents, dark, and sunshine, tho you stillp ercieve it as the same color

Infant Vision

• same approach to measuring cats vision
• infants stare at pattern lpnger than plain grey stimulus
• when staring time diverges from 50/50, they see pattern
• see a fairly blurly world
• midlife, peole bc more farsight
• healthy adults expect changes in vision
• poorly treated vision loss can lead to dementia

Amblyopia

• Lazy eye
• muscles of eye dont cordinate movement
• treated by patching dom eye or by surgeyr
• happen quickly cus of critical periods in development

Cataracts

• clouding of lends, treated by removal of lens
• age related

Visual Acuity

Many need correction

• Eyeball shorten, hyperopia, farsighted
• Elongated, Mypoia, nearsighted
• astigmatism uneven surface of cornea, not reccomended in physiclaly active adults

Scotoma

Blind spot, results from damage in retina.

Visual Agnosia

Cant recognize objects but can describe them