VSP Motion Perception

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EleanorN1130
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147740
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VSP Motion Perception
Updated:
2012-04-15 18:32:19
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VSP Motion Perception
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  1. What is the illusion of motion of one's entire self, as a result of motion in one's peripheral visual field?
    • Vection
    • ex: sitting in stationary care and feel like you are moving
  2. What does info about an object motion involve?
    muscular, oculomotor control, vestibular systems
  3. What does the retina use to percieve motion?
    Visual pathway only
  4. What two ways can retinal motion occur?
    • 1. stationary eye and moving target
    • 2. stationary target and moving eye
  5. What is the perceptual disappearance of a stabilized retinal image called?
    "Troxler effect"
  6. Will high or low spatial frequncies fade easier?
    LOW
  7. The human visual system is sensitive to ? in light simulation
    CHANGES
  8. The minimum amplitude of perceivable motion varies with what?
    retinal eccentricity
  9. How small of a movement does stimulus need to make for a person to detect it?
    • Foveal: approx 20 arc seconds or less
    • (20deg = ~3 arc minutes)
  10. How slowly can the stimulus move for a person to barely detect that it is moving? what is this called?
    • Without reference 10-20 arc min/sec
    • With reference much better: 1-2 arc min/sec
    • Velocity

    *10x better if you have nearby stationary reference stimulus to compare to the stimulus that is moving
  11. Does percievable velocity incr or decr with increasing luminance?
    Decreases
  12. 5 ways by which an object might appear to move
    • 1. real motion
    • 2. illusionary motion
    • a. autokinetic effect
    • b. induced motion (motion contrast)
    • c. motion aftereffects
    • d. stroboscopic motion
  13. What is it called when a small, stationary object viewed against an otherwise completely featureless VF will appear to move about randomly w/in a small area even though it's not really moving?
    Autokinetic effect (type of illusory motion)

    ex: small pt of light in dark room appears to randomly move
  14. What is it called when a stationary object appears to move due to the motion of surrounding objects or contours?
    Induced motion (an illusory motion)

    • ex. motion of clouds makes moon like its moving
    • or Reverse Spoke illusion
  15. Induced motion is always percieved to be in what direction compared to that of the inducing objects and contours?
    opposite
  16. Special case of induced motion that only operates accross very short distances.
    Motion contrast
  17. Illusory changes in the perception of motion that occur during prolonged viewing of moving objects or contours.
    motion adaptation
  18. Illusory perception of motion of stationary objects or changes in the perception of motion of moving objects after prolonged viewing of moving objects of contours.
    Motion After-effects
  19. Prolonged viewing of an object moving at constant velocity may cause a decrease in the percieved speed of motion
    velocity adaptation

    ex. when driving going 70 mph and slow to 35mph now you feel like you are going extreeeemely slow
  20. Motion detection and contrast detection thresholds increase during prolonged vieweing of moving objects or contours but only for objects or contours moving in the same or similar direction
    Direction-specific adaptation
  21. Motion after effect (MAE) demonstrates...
    binocular transfer (but weaker after effect in unadapted eye)
  22. If the field viewed after adaptation contains contours moving in a direction w/in 30 degr of that of the adaptingmotion, the percieved direction of their motion may be altered by the adaptation.
    2D directional afterefect

    • ex: if you adapt to motion in 180 degr meridian, you may not be able to detect that objects are moving w/in 30degr of that motion
    • *objects must move faster for you to detect they are moving
  23. Examples of the motion after effect
    • 1. waterfall illusion
    • 2. spiral illusion
    • 3. buddha example
  24. Illusory motion resulting from the successive presentation of a stimulus at different locations along a continuous path. Also called>
    Stroboscopic motion or "apparent motion"
  25. example of stroboscopic motion
    phi motion: lights on billboard turned on and off successively with optimal durations and intervals, appear to be a single light moving around perimeter of sign
  26. 4 types of stroboscopic motion
    • 1. alpha motion
    • 2. beta (phi)motion
    • 3. gamma motion
    • 4. delta motion
  27. illusory motion of 2 stimuli in reverse direction when the luminance of one is signif higher than other
    delta motion

    ex. in notes
  28. illusory expansion and contraction of an object as its luminance is incr or decr on successive presentations
    Gamma motion

    ex: as luminance incr in the square, it appears to expand
  29. illusory motion of an object due to successive presenations at optimally spaced positions along a continuous path
    Beta (phi)motion

    ex: lights on billboard/marquee
  30. illusory expansion or contraction of and object d/t successive presentations of difference sizes of the object
    alpha motion


    If you show incr sizes of same object in succession it looks like the object is moving closer to you
  31. Laws that describe the relationships among various stimulus parameters necessry to maintain optimum phi motion when andy one parameter is changed.
    Korte's Laws
  32. Korte's laws; if you incr luminance you have to:
    • increase spatial separation (space bw lights)
    • decr interstimulus interval (time bw flashes)
  33. Korte's laws; if you increase ISI (interstimulus interval) you have to:
    • increase duration (amount of time the light is turned on)
    • increase spatial separation (space bw the lights)
  34. Which order of motion stimuli is the movement of areas or contours that is defined by their luminance.
    Changing luminance over time
    First order motion

    most "real" moving objects, phi motion
  35. Which order of motion stimuli is defined by mvnt of areas whose contours or shapes are defined by texture; and NOT by luminance. Example?
    second-order motion

    randot stereo test; motion defined form, coherent motion
  36. Which order of motion stimuli is defined by mvnt of areas defined as "figure" with neither luminance nor texture boundaries. Example?
    third-order motion

    ex: isoluminant displays
  37. Motion of elements that all share the same velocity (direction and speed) of motion. and what order of motion perception is this?
    Coherent motion (2nd order motion)

    ex dalmation in texture disappears when moved in a uniform direction and speed.
  38. The object that we see is moving, using both eyes.
    Cyclopean motion
  39. Cyclopean motion; Coherent motion against a static random element background.
    Random element kinematogram (cinematogram)
  40. Cyclopean motion; Coherent motion against a dynamic random element background (background in which each background element undergoes spatial displacements of random direction and/or magnitude)
    random element correlograms (dynamic random element kinematograms)

    ex: background moves in diff direction of shape
  41. LIke random element stereograms , random element motion displays req solution of a...
    "correspondance problem"(match image seen with either eye)
  42. Minimum proportion of elements in a dynamic random element disply that must undergo the same velocity of motion for this to be detected.
    Coherent motion.

    ex in notes
  43. Describe a clinical application of coherent motion threshold.
    • randomly present different proportions of dots undergoing coherent motion on consecutive presentations in an n-alternative choice paradigm
    • Forced choice: on each presentation, the subject guesses the direction of coherent motion
  44. Minimum spatial displacemtn of elements necessary for the perception of stroboscopic motion
    the minimum displacement threshold (Dmin
  45. Clinical Example of the minimum displacement threshold (Dmin
    displacement acuity

    typically 6-10 arc seconds (tell when lines on top of each other are 2 lines and not one)
  46. What is the maximum spatial displacement of elements that supports the perception of 2nd order motion? example
    the maximumm displacement threshold (Dmax


    max amount you could move the target/texture for them to still percieve it as a fluid motion, rather than it just jumping
  47. Typical the maximum displacement threshold (Dmax) is
    15 arc minutes
  48. 2 parts of Braddicks 2 process model of motion perception
    • 1. short-range motion
    • 2. long-range motion
  49. Which part of Braddick's model supports 1st order motion (eg: continuous and phi motion)
    Long range motion
  50. Which part of Braddick's model supports 2nd order stroboscopic motion ?
    Short-range motion
  51. Which motion perception of Braddicks model has spatial displacemnts within the Dmin to Dmax range?
    short-range, 2nd order
  52. Which motion perception of Braddicks model that operates with displacement larger than Dmax
    Long range motion (1st order)
  53. What does Braddicks model rely heavily upon?
    Magnocellular pathway
  54. In this Order of motion the perception of motion for stimuli whose contours are defined only by differences in color without any luminance or texture differences is very weak when compared with motion of stimuli definced by luminance or texture
    3rd order (isoluminant) motion
  55. Remaining 3rd order motion is thought most likely to depend on which pathway?
    parvocellular
  56. Sometimes a motion of a stimulus is...
    ambiguous
  57. This may influence perception of the direction of motion within
    Example?
    Apeture problem

    ex: barber pole illusion and figure ground segregation
  58. Averaging of component motion vectors. The brain must average the direction of all stimuni it sees to decide which way things are moving.
    Resolution of motion ambiguity
  59. Correlations of motion velocity from different portions of a display. If sufficiently consistent witha a rigid transformation of size and shape in 3D space, may elicit the perception of depth from a 2D display.
    Kinetic Depth Effect ("Depth" from Motion)

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