Tag Archives: middle vision

Link

In a recent trip to San Francisco over spring break I was confronted with a common psychological problem, a problem of perception. While roaming the rolling hills of the iconic California city, it was hard to establish my bearings. Once reaching the summit of one hill, I looked to find a ridge to follow only to find a series of other large hills and troughs extended before me. The illusion of a horizon was all around me. This experience of an illusionary horizon can be explained through the use of the psychological perception principle of middle vision.

Endless hills of San Francisco.

Middle vision is a proposed theory for visual processing following basic feature extraction and object recognition and contextual understanding. A large roll in middle vision is the perception of edges to determine objects. This leads right into another perceptual theory of figure and ground. Terminology indicative of Gestalt psychology, in which “the whole is greater than the sum of the parts”, a figure is the object which is distinguished from the surrounding ground. However, the two can be competing creating dual images depending upon the recognized figure versus ground.

Changes in horizon perception.

Changes in horizon perception.Steep hills of San Francisco.

Along with object recognition, the Gestalt grouping rule of good continuation in which two elements will tend to group together if they lie on the same contour helps explain my difficulty distinguishing my horizon. Additionally, the city’s architecture and landmark structures created occlusion to the real contour of the city’s hills. When dealing with occlusion that disrupts perception like this the relatability, also known as the degree to which two line segments appear to be part of the same, is used to distinguish curvature.

Further examples of this perceptual problem can be discovered on the Internet through popular anti-gravity videos. These videos “show” a car that defies gravity and rolls up hill while in neutral without any source of energy or operation by a driver. Pop-culture frenzy circulated around these videos as they provide “evidence” against the Newtonian physics that our modern world is built on.  Investigation into these videos by trained scientists however revealed the fundamental perception issue. The bottom of the hill that represented the ground was actually the top of the hill and the true horizon of the landscape providing the gravitational force. As stated in a recent Forbes article, “ the position of trees and slopes of nearby scenery, or a curvy horizon line, can blend to trick the eye so that what looks uphill is actually downhill,” thus creating an optical illusion by the landscape (1).

1. Berezow, Alex. "European Journalist Blame "Anti-Gravity" Spot on Magic, Not Physics." Forbes. 11 Nov 201311 Nov 2013: n. page. Web. <http://www.forbes.com/sites/alexberezow/2013/11/19/european-journalists-blame-anti-gravity-spot-on-magic-not-physics/>.

 

Photo Sources:

http://www.woohome.com/photograph/steep-hills-of-san-francisco

http://boingboing.net/2010/11/30/san-franciscos-steep.html

http://boingboing.net/2010/11/30/san-franciscos-steep.html

“Eye” Spy Storage Wars

Leave a reply

Where’s Waldo? and I Spy are two book series that provide hours of entertainment to children as they attempt to find the hidden objects and people. To adults, however, these books do not have enough action or excitement. Several years ago, I began watching a television show that interested me because it contained components similar to I Spy, yet with the excitement and drama of a reality TV show. It appears that the adult equivalent to Where’s Waldo? and I Spy is the show, Storage Wars, in which people view storage units from an outside viewpoint, then bid on the actual contents. The bidders must identify hidden objects that are blocked by other items in order to most accurately assess the value of the unit before waging a bid. It is important to understand the role of middle vision and how it allows the principle of Storage Wars to be physically possible for the human brain.

Middle vision is responsible for processing and perceiving an object as a unique and entire item. Understanding the broader concept of object recognition helps in clarifying the function of middle vision because middle vision is a fundamental aspect in perceiving an “unknown” item. Object recognition allows people to identify something that has personally never been seen before, recognize partially occluded items, and distinguish an object from any visual perspective, called viewpoint invariance. Using the tools of middle vision and basic feature extraction, object recognition becomes an automatic and rapid process.

Some of the main components of middle vision include detection of edges, contour, and grouping. When factored together, these characteristics exemplify Gestalt psychology- “the whole is greater than the sum of its parts.” For example, the image below is a unit from Storage Wars and contains various items that are not positioned in normal context. By utilizing the Gestalt grouping rules of similarity and parallelism, it is apparent that the five oblong pieces of wood protruding forward on the right side of the picture are all legs connected to a desk. Even though the sixth leg is cut off in the picture and this is an unconventional viewpoint of a desk, a person should still be able to identify it with the help of middle vision and personal experience. This is just one of the many instances that middle vision allows people to differentiate items from one another even if the whole object is not in view.

www.aetv.com

www.aetv.com

After spending several minutes studying this picture, you will be surprised at the number of objects you are able to identify without previously seeing this image or any of the exact items. Although many of the show’s treasures are hidden deep within the vast pile of junk, there are occasions when a bidder’s middle vision manages to identify the “wow factor” from a six-by-six inch exposure of the object. However, that really makes you wonder whether the object was truly spotted or if that is just reality TV at its finest.

Middle Vision and the Panda

Leave a reply

            The example of perception that I have witnessed is the World Wildlife Foundation symbol. To many people, it simply looks like a panda. When I first saw this image on the television, I also immediately perceived this as a panda. However, many people do not realize that this is an example of an illusion that they are seeing in their everyday lives. Since the panda is mostly black, the other lines are not necessary to complete the outline of the panda. The human eye automatically fills out the rest of the panda, even though there is not a black line at the top of the panda, and it is actually just blank space.

            This is an example of middle vision, which is a stage of visual processing that comes after basic feature extraction and before object recognition and scene understanding. With the panda, the main features of the panda that are black have already been recognized. However, it requires middle vision in order to determine what the object is completely, since the panda is not completely drawn. Middle vision also involves the perception of edges and surfaces. This is what is happening with the panda. The panda is seen as a whole object because we are perceiving its edges.

            Middle vision also helps to determine which regions of an image should be grouped together into objects. For example, the black parts of the panda are immediately grouped together at first. These black parts of the panda then help to determine the parts that should be grouped together to make the entire symbol. The white parts of the panda is actually just blank space, not part of the panda. Middle vision plays a part in the perception that the blank space actually being a part of the panda, even though it technically is not.