P.135 - CH. 10

• cue approach to depth perception


  focuses on identifying information in the retinal image that is correlated with depth in the scene
• oculomotor cues

  monocular cues

  binocular

  3 different cues
• Cues based on the visual information available within one eye
• Oculomotor


  Cues based on our ability to sense the position of our eyes and the tension in our eye muscles
• Binocular


  Cues that depend on visual information within both eyes
• convergence and accommodation


  oculomotor cues are created by 2 things:
• convergence


  the inward movement of the eyes that occurs when we look at nearby objects
• accommodation


  the change in the shape of the lens that occurs when we focus on objects at various distances
• pictorial cues

  motion-based cues

  monocular cues involve 2 cues:
• pictorial cues


  are sources of depth information that can be depicted in a picture
• Occlusion


  occurs when one object hides or partially hides another from view
• relative height


  this cue proposes that objects with their bases closer to the horizon are usually seen as being more distant
• familiar size


  we use this when we judge distance based on our prior knowledge of the sizes of objects
• familiar size cue


  this cue is most effective when other information about depth is minimized
• relative size


  proposes that when two objects are known to be of equal physical size, the one that is farther away will take up less of your field of view than the one that is closer
• Perspective Convergence


  parallel lines appear to come together in the distance
• perspective convergence


  you experience this when parallel railroad tracks that appear to converge in the distance
• Atmospheric perspective


  this occurs because the farther away an object is, the more air and particles, thus, distant objects appear less sharp than nearer objects
• Sunlight contains a distribution of all of the wavelengths in the spectrum, but the atmosphere preferentially scatters short-wavelength light, which appears blue

  why is the sky blue?
• texture gradient


  this creates perception of depth because elements seen as being spaced more closely are perceived as farther
• Shadows


  decreases in light intensity caused by the blockage of light
• polarized light


  light waves that vibrate in only one orientation
• Binocular disparity


  the difference in the retinal images of the two eyes that provides information about depth
• motion parallax

  deletion & accretion


  2 types of motion-induced cues
• Motion parallax


  occurs when nearby objects appear to glide rapidly past us, but more distant objects appear to move more slowly
• Deletion and Accretion


  occurs when some things become covered, and others become uncovered
• deletion


  occurs when objects become covered
• accretion


  occurs when objects become uncovered
• best guess


  each monocular cues can only give their
• covergence, occlusion, relative size information


  for nearby objects we rely on 3 things:
• stereoscopic vision


  different viewpoints for the two eyes are the basis of _______
• stereoscopic depth perception


  depth perception created by input from both eyes
• strabismus

  misalignment of the eyes
• suppress vision in one eye


  what does the visual system do to avoid double vision in strabismus?
• polarized light


  image separation used in 3D movies
• corresponding retinal points


  points on the retina that would overlap if the eyes were superimposed on each other
• horopter


  any other objects that fall on corresponding points are located on a surface
• horopter


  The location of objects whose images lie on corresponding points
• noncorresponding points


  images of objects that are not on the horopter fall on ______
• absolute disparity


  the degree to which these objects deviate from falling on corresponding points