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One phase is a continuous call that can last for several minutes; during this period the frequency varies between 5.5 and 6.2 kHz and 6.0–7.5 kHz 4–6 times a second. In the other phase, the song is interrupted by breaks of increasing frequency resulting in a staccato sound. These breaks can be mistaken for silence as the difference in ...
Trace of saccades of the human eye on a face while scanning Saccades during observation of a picture on a computer screen. A saccade (/ s ə ˈ k ɑː d / sə-KAHD; French:; French for 'jerk') is a quick, simultaneous movement of both eyes between two or more phases of focal points in the same direction. [1]
Ocular drift is the fixational eye movement characterized by a smoother, slower, roaming motion of the eye when fixed on an object. The exact movement of ocular drift is often compared to Brownian motion, which is the random motion of a particle suspended in fluid as a result of its collision with the atoms and molecules that comprise that fluid.
An example of eye movement over a photograph over the span of just two seconds. Eye movement includes the voluntary or involuntary movement of the eyes. Eye movements are used by a number of organisms (e.g. primates, rodents, flies, birds, fish, cats, crabs, octopus) to fixate, inspect and track visual objects of interests.
The flicker fusion threshold, also known as critical flicker frequency or flicker fusion rate, is the frequency at which a flickering light appears steady to the average human observer. It is a concept studied in vision science , more specifically in the psychophysics of visual perception .
The term echolocation was coined by 1944 by the American zoologist Donald Griffin, who, with Robert Galambos, first demonstrated the phenomenon in bats. [1] [2] As Griffin described in his book, [3] the 18th century Italian scientist Lazzaro Spallanzani had, by means of a series of elaborate experiments, concluded that when bats fly at night, they rely on some sense besides vision, but he did ...
Human echolocation is the ability of humans to detect objects in their environment by sensing echoes from those objects, by actively creating sounds: for example, by tapping their canes, lightly stomping their foot, snapping their fingers, or making clicking noises with their mouths.
When using a circular form, the pupil will constrict under bright light, increasing the f-number, and will dilate when dark in order to decrease the depth of focus. [49] Note that a focusing method is not a requirement. As photographers know, focal errors increase as aperture increases. Thus, countless organisms with small eyes are active in ...