Weekly Reading

• What is the main topic of Week 5 in the study material?

  Perceiving size and distance
• How are the perception of size and distance connected?

  They depend upon one another
• What are the three dimensions of size mentioned in the study material?

  Height, width, and depth
• Why do retinal images lack the third dimension?

  Because they are flat and only have two dimensions
• What is the challenge in perceiving size and distance from two-dimensional images?

  We need to extract three-dimensional information from two-dimensional images
• What is the missing component in both size and distance perception and surface color perception?

  In size and distance perception, it is the third dimension; in color perception, it is the spectrum of illumination
• What are depth cues?

  Sources of information about depth and distance in retinal images
• What are binocular depth cues?

  Depth cues that arise from differences in retinal images in both eyes
• What are monocular depth cues?

  Depth cues present in a single image
• What are pictorial depth cues?

  Depth cues present in static images like photographs and paintings
• What are non-pictorial depth cues?

  Depth cues present in moving images and when you move your head
• What is size constancy?

  Perceived size of an object remains constant despite changes in distance
• How does size constancy relate to retinal images?

  It means we see properties of the world rather than properties of the retinal images
• What is the relationship between image size and distance?

  The size of the image depends on the distance of the object
• How can you determine the distance of an object using familiar size?

  By knowing the actual physical size of the object and measuring its image size
• What is the equation relating object size, distance, image size, and eye diameter?

  Object size (S) / distance (D) = image size (s) / eye diameter (E)
• If a tennis ball has a diameter of 6.7 cm and its image size is 0.5 mm, how far away is it?

  Approximately 3.35 meters away
• What is Emmert's Law?

  Perceived size of an after-image increases as the perceived distance of the background increases
• How does Emmert's Law relate to perceived size and distance?

  It shows that perceived size depends on perceived distance
• What is the size-distance invariance hypothesis (SDIH)?

  The ratio of perceived size to perceived distance equals the ratio of measured image size to eye diameter
• How does the size-distance invariance hypothesis help in understanding visual perception?

  It provides a mathematical relationship between perceived size and distance
• What are the key concepts related to size and distance perception?

  • Depth cues: sources of information about depth and distance
  • Binocular depth cues: require both eyes
  • Monocular depth cues: present in a single image
  • Size constancy: perceived size remains constant despite distance changes
  • Emmert's Law: perceived size increases with perceived distance
  • Size-distance invariance hypothesis: ratio of perceived size to distance equals ratio of image size to eye diameter
• Why is it important to distinguish between perceived and actual properties of objects?

  Because perceived properties can differ from physical properties based on visual experience
• How does trigonometry relate to familiar size as a cue for distance?

  It helps to establish the relationship between object size, distance, and image size
• What is the significance of the fovea in relation to retinal images?

  The fovea is where the retinal images of objects fall, affecting perception
• What are the implications of the size-distance invariance hypothesis in visual perception?

  It suggests a consistent relationship between perceived size and distance across different contexts
• What is the title of the paper by Lou, L. (2007) mentioned in the study material?

  Apparent afterimage size, Emmert’s law, and oculomotor adjustment
• What does Emmert’s law state about perceived size and distance?

  • Emmert’s law does not specify how big something appears based on image size and perceived distance.
  • It relates perceived size to perceived distance but is less precise than the SIZE-DISTANCE INVARIANCE HYPOTHESIS (SDIH).
• What is the SIZE-DISTANCE INVARIANCE HYPOTHESIS (SDIH)?

  The SDIH states that the ratio of perceived size to perceived distance equals the ratio of measured image size to eye diameter.
• How can the SIZE-DISTANCE INVARIANCE HYPOTHESIS be expressed mathematically?

  $\frac{\text{Perceived size}}{\text{Perceived distance}} =$$\frac{\text{Measured image size}}{E}$
• What does the rearranged SDIH formula tell us about perceived size?

  Perceived size depends on perceived distance and measured image size.
• What is size constancy?

  • Size constancy is the perception that an object's size remains constant despite changes in image size due to distance.
  • It relies on accurate distance perception to maintain perceived size.
• How does size constancy relate to the SIZE-DISTANCE INVARIANCE HYPOTHESIS?

  If distance perception is accurate, size constancy is maintained according to the SDIH.
• What is the image size of a tennis ball located 3.35 meters away?

  About 0.5 millimeters.
• What perceived size does the tennis ball have if its image size is 0.5 millimeters?

  It is perceived to be about 6.7 centimeters.
• If the tennis ball's image size increases to 1.2 millimeters, what is its perceived distance?

  It should be seen as 55.8 eye diameters or 1.4 meters away.
• What does the SDIH imply about perceived size when distance perception is accurate?

  Perceived size remains approximately constant despite changes in image size.
• What are size illusions and how are they constructed?

  • Size illusions occur when perceived size depends on perceived distance.
  • They can be illustrated using examples like the two monsters in a tunnel.
• Why do the two monsters in Figure 3 appear to be different sizes?

  They appear different due to perceived distance, despite being the same size.
• What is the main depth cue mentioned in the context of the two monsters in the tunnel?

  Linear perspective.