Depth Perception –Monocular and Binocular Depth

cues

Unit 1 Psychology

Depth Perception• Depth perception involves interpretation

of visual cues that indicate how near or far away objects are.

• To make judgements of distance people rely on quite a variety of clues which can be classified into two types:

binocular and monocular cues.

Types of Depth CluesBinocular Monocular

Retinal Disparity Accommodation

Convergence Pictorial Depth Cues

Binocular Cues• Binocular Depth cues are clues about distance

based on the differing views of two eyes• Example: Viewmaster/Stereomaster toy

Monocular Cues

• Monocular depth cues are clues about distance based on the image in either eye

alone

When do we use these cues?

• When something is far from us, we rely on monocular cues, those that require the use of only one eye. For closer objects, we use both

monocular cues and binocular cues, those that necessitate both eyes.

Pictorial Depth Cues Include:

Linear Perspective

Interposition

Height in the visual field

Texture Gradient

Relative Size

Binocular Monocular

Retinal Disparity Accommodation

Convergence Pictorial Depth Cues

Monocular cues include: Accommodation and Pictorial Cues

• Accommodation occurs when the curvature of the lens adjusts to alter visual focus. When you focus on a close object, the lens of your

eye gets fatter (rounder) in order to give you a clear image. When you focus on distant

objects, the lens flattens out to give you a better image of them

WATCH THE VIDEO (available on Wikispace)

Pictorial Depth Cues

• It is a monocular depth cue• Pictorial cues are so named because artists

use them to create depth and distance on two-dimensional surfaces such as paper and

canvas. There is 5 pictorial depth cues - they include:

1. Linear Perspective

• Parallel lines that run away from the viewer seem to get closer together

• Linear perspective is the apparent convergence of parallel lines as they recede

(‘go back’) in distance

2. Interposition

• Also called overlap, occurs when one object partially blocked object is perceived as further

away than the objects that obscures it (and vice versa)

• The shapes of near objects overlap or mask those of more distant ones

Because of interposition you can see that this little character is

in front of his parents

3. Texture Gradient

• As distance increases, a texture gradually becomes denser and less distinct

• Texture gradient refers to the gradual reduction of detail that occurs in a surface as it recedes into the distance, compared with a

surface that is close and perceived in fine detail

Example of Texture GradientLook at the tiles and buildings

4. Relative Size

• If separate objects are supposed to be of the same size, the larger ones are seen as closer

• Refers to the tendency to visually perceive the object that produces the largest image on the

retina as being closer, and the object that produces the smallest image to be further away. The objects being perceived must be

expected to be about the same size in real life.

Because of Height in the visual field, you will recognise that the people closer to the horizon are further away, and things further from the horizon are closer to you (i.e. the hand and arm)

As a class point out where the pictorial depth cues are for the pictures on the following slides

Write in Textbook:Linear Perspective

Interposition

Height in the visual field

Texture Gradient

Relative Size

http://www.facebook.com/photo.php?pid=4153439&id=539272480

Use the 5 pictorial cues you have just learned to discuss a photo

Do one or more and please

Your Task