Transcript Depth Perception * Pictorial depth cues

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 Clues
Binocular
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.
Binocular
Monocular
Retinal Disparity
Accommodation
Convergence
Pictorial Depth Cues
Pictorial Depth Cues Include:
Linear Perspective
Interposition
Height in the visual field
Texture Gradient
Relative Size
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 Gradient
Look 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
Use the 5 pictorial cues you have just learned to
discuss a photo
Do one or more and please