Day Systems Flashcards
What are the two binocular factors to consider?
Convergence and stereopsis
What is convergence, and how is it used to measure distance?
Convergence is the angle difference between the eyes. A steeper angle means the object is closer to the viewer.
What is stereopsis?
Differences in retinal images, with overlap providing distance information.
How does binocular depth perception impact the aviator?
Close distances yield low resolution and make it difficult for aviators to determine hover height.
What are the different monocular cues?
Geometric perception, retinal image size, aerial perspective, & motion parallax
GRAMS
Define is geometric perspective?
An object appears to have a different shape when it is viewed at varying distances and altitudes.
Includes: linear perspective, apparent foreshortening and vertical position in field
A subcategory of geometric perspective, define linear perspective.
Parallel lines appear to converge as distance from the observer increases.
Ex: railroad tracks, runways, rectangular landing areas
A subcategory of geometric perspective, define apparent foreshortening.
Distortion of shape of an object or terrain feature when viewed from a distance at both higher and lower altitudes.
Ex: Round objects appear elliptical (oval and narrow), while square objects take the shape of a trapezoid
A subcategory of geometric perspective, define vertical position in the field.
Objects or terrain features at greater distances from the observer appear higher in the field of view than those closer to the observer.
Area recon and cross check will compensate for this
Define retinal image size
An image focused on the retina is perceived by the brain to be of a given size.
Factors that aid in determining distance using retinal image size are increasing/decreasing size of objects, terrain association, known size of objects, and overlapping contours (I.T.K.O.)
A tool in using retinal image size to determine distance, what is known size of objects
The nearer an object is to the observer, the larger its retinal image.
Must be familiar with the object to use this tool
A tool in using retinal image size to determine distance, what is Increasing or decreasing size of objects
If the retinal image of an object increases in size, the object is moving closer to the observer
A tool in using retinal image size to determine distance, what is terrestrial association
Comparison of one object with another object of known size helps in determining the relative size and apparent distance of the object from the observer
Ex: A helicopter observed near an airport is judged to be in the traffic pattern and, therefore, at about the same distance as the airfield.
A tool in using retinal image size to determine distance, what is overlapping contours
An object partially concealed by another object is behind the object concealing it
CAUTION: Lights disappearing or flickering in the landing area should be treated as barriers and the flight path adjusted accordingly
In the context of monocular cues, what is aerial perspective
An object’s clarity and its shadow are perceived by the brain and cues for estimating distance
Factors to determine distance using aerial perspective are fading colors or shades, loss of detail or texture, position of light source and direction of shadow (F.L.P)
