CS781 - Colour for Computer Graphics - Winter 2009

Lecture 8

Visual Response to Light

Colour matching functions depends on something done by humans,

Light enters eye

1. The Eye

Cornea

Iris

Lens

Acqueous & Vitreous Humours

Sclera

Macular Pigment

Optical Quality

Aging

Colour Quality

Aging

2. The Retina

Overall Layout

Blood vessels

Fovea

Periphery

Generic Photoreception

Bacterial purple: ion pump

Rods and cones: G-coupled

Ganglion cells:

Rods

Cones

Ganglion Cells and Others

Quality of Photodetection

Absolute Thresholds

Dynamic Range

  1. Of individual photoreceptors
  2. Of the entire system. Numbers are log_10 (lux = lumens /m^2)
    Light level Natural conditions Photodetectors Greek name
    -5 to -2 Moonless night Rods Scotopic
    -2 to -1 Night with moon Rods & cones Mesopic
    -1 to +2 Between night & day Cones Photopic
    +2 to +4 Dawn, overcast Cones Photoopic
    +4 to +6 Sunny Cones, bleaching Photopic

For comparison

Or another set of categories (minima)

3. Neural Processing

Amacrine Cells

Bipolar Cells

Ganglion Cells

Inter-cell Communication

Synapses


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