Sensation and Perception

Blue color, short wavelength

Green color, medium wavelength

Red color, long wavelength

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

Normal Vision

Farsightedness

Nearsightedness

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

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

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

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)

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)

Center-surround receptive fields very similar to receptive field of a ganglion cell.

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.

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

Identical to Complex Cells but also length-specific. Respond to corners, angles, or bars of a particular length moving in a particular direction.

Center-surround receptive field. Responds best to small spots, but will respond to other stimuli.