Sunday, November 2, 2014

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