Distance estimation and depth perception

Question 1

Geometric Perspective:
(LAV)

Answer 1

An object appears to have a different shape when it is viewed at varying distances and from different angles

○ Linear Perspective: Parallel lines such as railroad tracks tend to converge as distance from the observer increases

○ Apparent Foreshortening: The shape of an object or terrain feature appears elliptical (oval and narrow) when viewed from a distance at both higher and
lower altitudes

○ Vertical Position in the field: Objects or terrain features at greater distances from the observer appear higher on the horizon than those closer to the observer

Question 2

Monocular Cues:

Answer 2

● Geometric Perspective
○ Linear Perspective
○ Apparent Foreshortening:
○ Vertical Position in the field

● Retinal Image Size
○ Known Size of Objects
○ Increasing or Decreasing Size of Objects
○ Terrestrial Association
○ Overlapping Contours

● Aerial Perspective:
○ Fading of Colors or Shades
○ Loss of Detail or Texture
○ Position of Light Source and Direction of Shadow

● Motion Parallax

Question 3

● Retinal Image Size
(KITO)

Answer 3

● Retinal Image Size: An image focused on the retina is perceived by the brain to be of a given size

○ Known Size of Objects: The nearer an object is to the observer, the larger its retinal image. By experience, the brain learns to estimate the distance of familiar
objects by the size of their retinal image

○ Increasing or Decreasing Size of Objects: If the retinal image of an object increases in size, the object is moving closer to the observer (and vice versa)

○ Terrestrial Association: Comparison of one object such as an airfield with another object of known size such as a helicopter helps in determining the
relative size and apparent distance of the object from the observer.

○ Overlapping Contours: When objects overlap, overlapped object is further away

Question 4

● Aerial Perspective
(FLP)

Answer 4

● Aerial Perspective: An object’s clarity and its shadow are perceived by the brain and cues for estimating distance

○ Fading of Colors or Shades: An object viewed through haze, fog, or smoke appears less distinct and at a greater distance than it actually is.

○ Loss of Detail or Texture: The further an observer is from an object, the less apparent discrete details become

○ Position of Light Source and Direction of Shadow: The direction in which the shadow is cast depends on the position of the light source

Question 5

Motion Parallax:

Answer 5

Often considered the most important depth perception cue. Refers to the apparent relative motion of stationary objects as viewed by an observer moving
across the landscape. Near objects appear to move past or opposite the path of motion; far objects appear to move in the direction of motion or remain fixed.

Question 6

Reference:

Answer 6

Reference: TC 3-04.93 Ch. 8