Use of “constant physical size” and “familiar physical size”

Imagine that you are standing on a soccer field. There are three soccer balls on the field, each like
the depiction below. The three soccer balls are at different distances from you, but are the same
physical size.
a) (3 marks) Produce an illustration in which you use at least three of the following monocular
cues to convey the depth relationship among the three soccer balls. That is, draw a picture
that depicts, from your vantage point in the scene described above, that the soccer balls are
at different distances.
• Occlusion
• Retinal size
• Retinal position
• Aerial perspective
• Linear perspective
You are free to create this picture either by hand and scanned (e.g., by taking a photograph
of the hand-drawn picture with a phone) or with the assistance of a computer. However, it
cannot be a photograph of a real scene.
There is no association between the marks awarded and the “quality” of the illustration
(provided the information in your drawing is properly communicated).
b) (3 marks; AEL: 1 or 2 sentences per cue) Explain how each of the three cues that you chose
from the list above conveys that the soccer balls are at different distances in your drawing.
c) (3 marks; AEL: a few sentences) Imagine that there is a soccer ball, a tennis ball, and a golf
ball (instead of the three soccer balls) and that you are trying to determine the relative
depth relationships among the three balls. Explain how having the three different types of
ball affects your potential use of “constant physical size” and “familiar physical size”
information to disambiguate the retinal size cue to depth.
d) (3 marks; AEL: a few sentences) Imagine a hypothetical scenario in which there was one
depth cue that provided a much more reliable estimate of a soccer ball’s depth than other
cues, and that this increased reliability was evident through repeated instances of feedback
obtained from the act of kicking the ball. With reference to the Ernst, Banks, & Bülthoff
(2000) study that was considered in tutorials, explain the potential effect of such feedback
within the process of depth cue combination.
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