Sensation & Perception - Lecture 3 Flashcards
Contrast
The difference in luminance between an object and the background, or between lighter and darker parts of the same object.
Acuity
The smallers spatial detail that can be resolved at 100% contrast.
Cycle
For a grating, a pair consisting of one dar bar and one bright bar.
Visual angle
The angle subtended by an object at the retina.
Sine wave grating
A grating with sinusoidal luminance profile.
Amblyopia
A developmental disorder characterized by reduced spatial vision in an otherwise healthy eye, even with proper correction for refractive error. Also known as lazy eye.
Spatial frequency
The number of grating cycles per unit of visual angle in a given unit of space.
Cycles per degree
The number of grating cycles per degree of visual angle.
Contrast sensitivity function (CSF)
A function describing how the sensitivity to contrast depends on the spatial frequency of the stimulus.
Contrast threshold
The smallest amount of contrast required to detect a pattern.
Fourier analysis
A mathematical procedure by which any signal can be separated into component sine waves at different frequencies. Combining the sine waves will reproduce the original signal.
Phase
The position of a grating relative to a fixed position measured in degrees, where one complete cycle is 360 degrees.
Filer
An acoustic, electrical, electronic, or optical device, instrument, computer program, or neuron that allows the passage of some range of parameters and blocks the passage of others.
Lateral geniculate nucleus (LGN)
A structure in the thalamus, part of the midbrain, that receives input form the retinal ganglion cells and has input and outputs connections to the visual cortex.
Magnocellular layer
Either of the bottom two neuron-containing layers of the lateral geniculate nucleus, the cells of which are physically larger than those in the top four layers.