Result of converting physical energy into meaningful signals that are consistent and stable (constancy across different situations [but not always])
Low-level (meaning-less, bottom up), Unconscious
High-level (meaningful, top-down), Unconscious and Conscious
Photon gets absorbed by media of different surface
Photon angle changed one time as it passes through media
Photon angle changed multiple times before going through media
Photon gets reflected away from media
Ambient Optic Array (AOA)
the optical information available to the eye at a given point in time, consists of light coming from direct sources as well as from reflections, refractions, etc.
Cells that are sensitive to light
Process that turns light into electrical information (neural impulses)
Allow only one light ray through from any given direction, Upside-down, left-right Reversed
One lens, many receptors. What humans have.
Allow only one light ray per tube, right-side up, left-right maintained, low resolution, inefficient use of space
Individual lens/receptor units (ommatidia), wide angle of view, low resolution
Two lenses, 130,000,000 receptors, light gets focused twice: first by cornea (most focusing power), then by lens (fine tuning). Finally, image is projected onto the retina
Why are photoreceptors at the back of the eye?
The cells that replenish the pigment epithelia are not transparent. They also need to be adjacent to the photoreceptors, so the photoreceptors must be turned around.
Only one kind, gray-scale vision, more sensitive to light, less sensitive to detail, operate in low light, located everywhere but the fovea
Three kinds of cones, color vision, less sensitive to light, more sensitive to detail, operate in high light, located predominately in the fovea
Densely packed receptors, only cones present, blood vessels and nerves pushed away
Periphery (everywhere but fovea)
Both rods and cones, but mostly rods. Blood vessels block some light
Only cones are active in fairly bright settings
Only rods are acitve in fairly dim settings
Both rods and cones are active in intermediate settings
Unit of measurement representing the light emitted from a single candle, human eye can see one candela at a distance of one mile away in perfect darkness
Eyes adapt to darkness and after about 10 minutes rods take over vision
To stare directly at something
The apparent bluish shift under low illumination. Application in media: reduce brightness, contrast, and saturation, and increase blueness
The passing through any homogenous medium (happens in a straight line)
The area you can see in the world
The image projected onto your retina
Area within which a cell is responsive to stimulation (the plus and minus analogy)
Ganglion Receptive Fields
Cover a two dimensional swatch of the retina, rather than a single spot, this is a region on the retina covering many photoreceptors. (anatomy: optic nerve --> Ganglion cell --> bipolar cell --> rod --> pigment epithelium --> receptive field)
Lateral Geniculate Nucleus (LGN)
Center-surround receptive fields very similar to receptive field of a ganglion cell.
Simple Cells (Simple Cortical)
An orientation-sensitive cell located in primary visual cortex (V1), edge detectors or bar detectors, excitatory and inhibitory areas arranged side-by-side. Responds best to bars of a particular orientation.
Compex Cells (Complex Cortical)
In visual cortex, oriented RFs, cannot detect spots or stationary bars of light, orientation and motion sensitive, no longer dark/light sensitive, RF is large and unbounded
Hypercomplex Cells (End-Stopped Cells)
Identical to Complex Cells but also length-specific. Respond to corners, angles, or bars of a particular length moving in a particular direction.
Ganglion Cell (Optic Nerve Fiber)
Center-surround receptive field. Responds best to small spots, but will respond to other stimuli.