Brightness Constancy

Brightness constancy is our ability to see objects as continuing to have the same brightness even though light may change their immediate sensory properties.

This is the same rubric paper. The top one has only the fan light on it whereas the bottom picture has both the fan light and the desk lamp. This is an example of brightness constancy because the paper's color and background remained the same but the lighting changed giving the illusion that it is a different colored paper.

Size Constancy

Size constancy is one type of visual subjective constancy. Within a certain range, people's perception of one particular objects' size will not change, regardless of changes in distance or the video size change on the retina.

This man in the front appears to be the same size as the man behind when viewed at different distances from the viewer. However, when the man from behind is brought forward to the same location, he looks considerably smaller (assuming the image the image did not change). Clearly, our perception of size constancy is based on the ability to take depth information into consideration. In reality they are the same size, but our perception deceives us.

Shape Constancy

Shape constancy refers to the phenomenon in which the perception of the shape of a given object remains constant despite changes in the shape of the object's retinal image.

No matter how you look at the clock, you see a circular clock. It does not change because of a different view point. It is simply a circular clock.

Monocular Cues

Monocular cues are any depth cues that are available to either eye separately. Examples include relative size (smaller objects seem farther away), interposition (if one object blocks another it seems closer), and relative clarity (hazy objects seem farther away then sharp/clear ones).

The first image is an example of relative size. The book in the back seems smaller than the other one, but they are actually the exact same size. The change in depth has skewed the brain's perception of size.

The second image is an example of linear perspective. The parallel lines of the road appear to come together due to their distance. The distance is perceived as very far when this illusion occurs.

Motion Perception

Motion perception is how your brain infers the speed and direction of any objects in your visual field. In terms of depth, your brain assumes that shrinking objects are retreating and enlarging objects are approaching. The brain is also tricked by movies and television, which are really a lot of images played in rapid succession. When we see it, however, the images appear to continuously move.

       
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This optical illusion is an example of motion perception. Although the sequence is really just oval like shapes of varying lengths, we perceive motion when we move our eyes from one side of it to the other.

Rules of perceptual orginization - Binocular Cue

Depth cues, such as retinal disparity and convergence, that depend on the use of two eyes

EX:

Rules of Perceptual Organization - Figure-ground Perception

The orginization of the visual field into objects (the figures) that stand out from their surroundings (the ground).

EX:

Batman and the background vs. Bird man and the background

Proximity

Nearness in place, time, order, occurrence or relation. 

Grouping nearby figured together.

EX: 

Instead of seeing 15 dots, you see 3 rows of 5 and 5 columns of 3.

Rules of Perceptual Organization - Closure

Law of Closure - Objects grouped together are seen as whole.

Example: I created a pattern using dominoes. As you can see, it resembles a star. It is, however, somewhat discontinuous, having gaps between each domino. Our eyes perceive the pattern as an image, like this pattern and the image of a star, despite the gaps within the pattern.

Rules of Perceptual Organization - Continuity

Law of Continuity - Lines are seen as following the smoothest path.

Example - With the branches of many trees and bushes, multiple branches stem from another. Our eyes perceive some branches as being continuous, while others seem to jut outward awkwardly. In this picture of a rose bush branch, our eyes tend to follow Path A rather than Path B due to the continuous nature of Path A.

Rules of Perceptual Organization - Similarity

Law of Similarity - Items that are similar tend to be grouped together.

Example - In the toolbar of any internet browser, the different headings each contain a variety of command options. The options are broken into different subcategories based off of function, separated by lines. This shows similarity through the visual perception of grouping to separate the functions into groups.