Monocular Cues Flashcards
Geometric Perspective
An object’s shape changes as it is viewed from different angles and distances.
Types:
Linear perspective
Apparent Foreshortening
Vertical Position in Field
Linear Perspective
Parallel lines converge at distance towards the horizon.
Apparent Foreshortening
Objects and terrain features become more narrow or oval as distance increases and altitude decreases.
Vertical Position in the Field
Objects farther away appear higher towards the horizon.
Retinal Image Size
Used in distance estimation. Images on the retina are perceived as a certain size.
Factors that help:
Known size of objects.
Increasing and decreasing size of objects.
Terrestrial Association.
Overlapping contours or interposition of objects.
Known Size of Objects
The brain learns to accurately estimate the distance of objects of known size by their retinal image size.
Increasing and Decreasing Object size
If the retinal image of an object is growing it is getting closer, and the opposite if it is shrinking.
Terrestrial Association
Comparison of one object with another of known size aids in size and distance determination.
Overlapping Contours and Interposition of Objects
When objects overlap, the obstructed object is further away. The unobstructed is closer.
Aerial Perspective
An object’s color and clarity and its shadow are perceived to estimate distance.
Fading of Colors and Shades
An Object viewed through haze, fog, or smoke appears to be farther than it actually is.
Loss of Detail or Texture
The further an object is away, the less detail is visible.
Position of light and shadow
If an object’s shadow is closer to the observer, then the object is closer to the observer than the light source.
Motion Paralax
The closer a stationary object is to a moving observer, the faster it will appear to move as the observer moves.
