Visual ambiguity presentation team assignment


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This was a team assignment. The other team members are listed on the title slide. I have had a few people inquire about this assignment, so I decided to post it online to help fellow UOP students out.

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  • The visual system operates on a set of assumptions or visual cues from the environment that help bring meaning and organization to the images that we perceive visually. In order to better understand the ambiguity between the physical object in the environment and the visual representation of the object in our brain, psychology has proposed several theories. Template theory, feature-matching theories, object-centered theory, and multiple view theory seek to explain the aforementioned discrepancy and how our visual system resolves this problem.
  • All three of these pictures exploit the ambiguity of visual perception. From one perspective these pictures are an old woman with long hair. From another perspective these pictures are a young woman with a choker necklace. The way in which our visual system represents the pixels on this screen to the brain is mediated by memory, cortical processing, and visual cues (Willingham, 2007). Whether our brain stores templates, several or only one, for an old woman and a young woman or we construct the image mentally from basic shapes (geons), it is clear that there is some top-down, cortical processing involved in our perception of this picture. A few psychologists have theorized that a rough sketch of the image is projected straight to the pre-frontal cortex (PFC), which allows the PFC input into the processing in the visual cortex (Bar, 2003). Furthermore, the multiple view theory aspires to incorporate viewer-centered representations and object-centered representations into a coherent theory of visual perception, which incorporates stored templates and top-down, cortical processing. In all, the resolution of visual ambiguity by the visual system is a complex process that includes bottom-up processing, such as visual cues and object-centered representations and top-down processing, such as templates, feature matching, and geons.
  • The template theory works by comparing what we are seeing to images that we have stored in our memories on ‘templates’. If the image that we see matches the template then we know what the object is. The problem with this theory is that it would require a large amount of templates stored in memory and the image that is being seen would have to be identical to an image on the memory templates.
  • Feature matching theories use parts of an image or pattern (such as lines) to recognize the image by comparing it with features already stored in memory. This process begins with basic features that we will continue to put together to make more and more complex features until we are able to identify what it is that we are seeing. The theory states that we recognize the letters of the alphabet through the pattern of lines, curves, and circles, or in other words features, that the letters possess.
  • -In object centered theories, the locations of the various parts comprising that object are defined in relation to the object as a whole. Object centered theories assume that object recognition is independent of the position of the viewer. -One such theory is Biederman’s geon theory that proposes objects can be identified by any combination of 36 simple geometric shapes called geons. He likens the geons to the letters of the alphabet but combining to make objects instead of words. -There are three basic properties of geons. 1. They are readily identifiable from various angles 2. They can be recognized amidst busy visual surroundings 3. Each geon can potentially be distinguished from each other from nearly any view point -A conclusion of these theories is that because of recognizable combinations of parts, whole objects can be brought to our cognition even if part of the whole is obscured through darkness or other obstructions.
  • -We started the presentation with three pictures. There are ambiguities in the introductory set of three faces if indeed any or all of them are faces. There are varying degrees of ambiguity within each picture and from one to another. Are these parts of nature scenes? Is it an old woman, or a young woman or girl? Now turn the picture sideways or upside down. What do you see? -Both families of theories have their strengths and weaknesses. A weakness of the viewer centered theory is if the viewer has seen an object from only one point of view, what happens when the same object is seen differently? A weakness of the object centered theory is that some objects such as faces are not composed of geon figures and so the individual face would not be recognized. -Are there are ambiguities in this concluding set of pictures. This last slide has the same set of objects from two viewpoints. Is the picture on the left from the first person’s viewpoint a board resting atop two boxes? What are those 2 things on top of the board? From the second person’s viewpoint it is likely a desk, but what is that light doing hanging from the ceiling or is it attached to the wall or is it even a light? -What is the solution? Neither family of theories is totally accurate nor does one appear superior. Brain imaging and scientific studies show that for optimal cognition the brain uses both viewer and object centered representations in cognitive perception (Visual Perception, n.d.). So it appears a compromise is in order. Let’s be grateful for both!
  • Visual ambiguity presentation team assignment

    1. 1. UNIVERSITY OF PHOENIX KEVIN CONNELL KRISTINA NELSON COY STOKER Visual Ambiguity Presentation Visual Ambiguity 1
    2. 2. Table of Contents Visual Ambiguity 2 <ul><li>Introduction </li></ul><ul><li>Template Theory </li></ul><ul><li>Feature-matching Theories </li></ul><ul><li>Object-Centered Theory </li></ul><ul><li>Conclusion </li></ul>
    3. 3. Introduction <ul><li>zxcvz </li></ul>Visual Ambiguity 3
    4. 4. Template Theory <ul><li>Viewer-Centered Theory </li></ul><ul><li>Recognition by comparing retinal images to images on memory templates </li></ul><ul><li>Would require large number of templates in memory </li></ul>Visual Ambiguity 4
    5. 5. Feature-matching Theories <ul><li>Uses parts of patterns such as horizontal, vertical, or slanted lines for recognition </li></ul><ul><li>Patterns or images are recognized by comparing their features with ones stored in memory </li></ul><ul><li>Features start out basic and become more and more complex until an image or pattern is recognized </li></ul>Visual Ambiguity 5
    6. 6. <ul><li>Object-Centered Theories </li></ul><ul><li>Biederman’s Geon Theory </li></ul><ul><li>What is a geon? </li></ul><ul><li>Properties of geons. </li></ul><ul><ul><li>1.View Invariance </li></ul></ul><ul><ul><li>2.Stability to visual noise </li></ul></ul><ul><ul><li>3.Discriminability </li></ul></ul><ul><li>Cognition </li></ul>Object-Centered Theory Visual Ambiguity 6
    7. 7. Conclusion Visual Ambiguity 7 <ul><li>Conclusion </li></ul><ul><ul><li>Introductory pictures </li></ul></ul><ul><ul><li>Viewer or object centered theories </li></ul></ul><ul><ul><li>Concluding pictures </li></ul></ul><ul><ul><li>Solution </li></ul></ul>
    8. 8. References Visual Ambiguity 8 Moshe, B. (2003) A cortical mechanism for triggering top-down facilitation in visual object recognition. Journal of Cognitive Neuroscience, 15 (4), 600-609. Retrieved August 2, 2009, from EBSCOHost Database. Visual perception. (n.d.) Psychology: An International Perspective. Retrieved August 3, 2009, from Psypress Web site: Willingham, D. T. (2007). Cognition: The thinking animal. New York, NY: Pearson Prentice Hall.