Size Constancy

We perceive objects as having a constant size, even while our distance from them varies.

When we view the NYC sky line from a distance, we know the buildings are enormous, even though they would seem tiny if we held our hand out next to the view.  Our brains know the buildings in the background are tall, because of they are deep in our visual field.

Convergence (Binocular Cue)

Convergence is a neuromuscular cue caused by the eyes' greater inward turn when they view a near object.

http://www.blelb.ch/oldblelbsite/english/blelbspots/spot11/images/lena.jpg

Because her finger is close to her face, the girls eyes' turn inward to look at it. This is an example of convergence. 

Retinal Disparity (Binocular Cue)

Human eyes receive slightly different images because of the distance apart they are. The brain compares the two images, and the difference is called Retinal Disparity. It's an important cue to the relative distance of different objects.

http://allfortheboys.com/storage/AftbOptical2.jpg?__SQUARESPACE_CACHEVERSION=1343877637942

When you hold your two index fingers in front of your eyes, like the boy, you should see a floating "finger sausage". This is called the retinal disparity. It comes from your two retinas seeing different things.

Visual Illusions

Visual illusions involve visual deception. Due to the arrangement of images, effect of colors, impact of light source or other variable, a wide range of misleading visual effects can be seen.

Example 1:

This insect uses visual deception to evade its predators.  When first looking at this insect, many animals (and humans too!) would think he was a leaf.

Example 2:

Believe it or not, this building is simply made out of parallel lines and staggering blocks.  Because of visual deception though, our eyes view the lines as sloping and the building as crooked.  The contrast of the black and white colors come into affect as well, because if other colors were used the effect would go away.

Example 3:

This faucet with running water appears to our eyes as though it is floating.  Our eyes deceive us and make us wander how there is enough water pressure to be holding a faucet that high up in the sky. In reality, there is a very big tube down the middle of it that holds the structure up.

Texture Gradient (Monocular Cue Cont.)

Texture gradient is when a gradual change from a coarse or distinct texture to a fine, indistinct texture signals increasing distance.
Objects far away appear smaller and more densely packed.


https://s-media-cache-ak0.pinimg.com/736x/94/7e/a3/947ea340e46d882c193f50d297e2d26c.jpg

The flowers' texture in this photograph grows more and more indistinct until all you can really pick out is the color red. This indicates distance.

Interposition (Monocular Cue Cont.)

Interposition is when one object partially blocks our view of another, we perceive the blocked object as farther away and the object blocking to be closer.

https://farm5.staticflickr.com/4031/4402290092_db8967c8bc_m.jpg

In this photograph of some baby penguins, there are three that are blocking the others partially, making them seem closer to the camera than the ones that are behind them.

Perceptual Constancies: Shape Constancy

Sometimes an object whose actual shape cannot change seems to change with the angle of our view. We perceive the form of familiar objects as constant even while our retinal images of them change.













Even though our view of the cereal box changes in these images, we still maintain that the cereal box has a box-like shape. The different angles of the cereal boxes causes a change of shape on our retinas, but our brains are still able to retain its box-like configuration.

Relative Size (Monocular Cue)

A monocular cue of distance that states if two objects are similar in size, we perceive the one that casts the smaller retinal image to be farther away.

http://psych.hanover.edu/Krantz/art/scolls.jpg

The two men in the boats are assumed to be the same size when next to each other, so the one that is smaller in the painting seems farther away.

Relative Height (Monocular Cue)

A monocular cue in which we perceive objects higher in our field of vision as farther away.
Relative height also contributes to the illusion that vertical dimensions are longer than identical horizontal dimensions.

https://s-media-cache-ak0.pinimg.com/originals/1b/fc/ca/1bfccaccd787e07b225fa16ba38b8294.gif

In the picture, the horizon is indicated by the straight line that goes across the picture. The man located all the way to the left, closest to the top, seems farther away because he's higher in the field of vision. Meanwhile the one in the bottom right corner seems closer.

Perceptual Constancies: Brightness Constancy

We perceive an object as having constant lightness even while its illumination varies. Perceived lightness depends on the amount of light an object reflects relative to its surroundings.


Snow will reflect more light during the day than the middle of the night, but you can still the snow is white during the night. Even though the brightness varies during the two times of the day, our eyes and brains recognize the snow as the same color.

Relative Clarity (Monocular Cue)

A monocular cue which states that hazy objects are often perceived as farther away than clear objects.

http://www.brianmicklethwait.com/culture/monparl.jpg

In this painting, the slight haziness of the boats make them seem far away from the clearly painted dock, and the very faint buildings and bridge even farther away in the distance.

Perception of Movement: Stroboscopic Motion

The brain will perceive continuous movement in a rapid series of slightly varied images.  The motion between each image is constructed in our minds.

When a flip book is flipped, the previous image is replaced by another image that is a slightly altered version of the first.  In our minds this creates a "motion picture".  The brain sees these images as one rather than separate entities.

Figure-Ground Perception

A type of perceptual grouping which is a vital necessity for recognizing objects through vision. You see the foreground of an image and everything else that forms around it is just the background. 

At first you just see pillars, and then with a closer look, you see the people in it

Proximity

Objects near each other are grouped together.

In this picture the girls are grouped together and the boys are grouped together because of their proximity to one another.

Similarity

Items that are similar tend to be grouped together by our mind.

In this picture, you'll view vertical columns of colors(because they are similar) rather than horizontal columns.

Continuity

We like perceive fluid and continuous figures rather than disconnected ones.

You'll see this as a smooth path of dominoes, rather than seeing different lines and angles.

Closure

Rule of perceptual that states that we tend to fill in the blanks and missing pieces and see things as complete
.
In this picture, you'll see a triangle even though it is just cut up kiwi.