Assignment #3 - Stereopsis and motion

Due Tuesday 2/19

1. Shown below is a one-dimensional cross-section of a random-dot pattern:

a) If you were to make a strereogram pair from this pattern, using this pattern as the stimulus for the right eye, show what a one-dimensional cross-section from the complentary pattern (for the left eye) would need to look like in order for you to perceive a square in the center floating above the background.

b) Now show a one-dimensional cross-section of the complementary pattern needed to create the percept of a square behind the surrounding region.

Draw a diagram illustrating the viewing geometry and the reasoning you used to create your stereogram. You should also draw your patterns for (a) and (b) directly beneath the one shown above. You will need to consult the handout showing the viewing geometry for foreground and background objects.

2. Explain the waterfall illusion in terms of distributed coding principles. That is, show what the population of activity on a number of motion-tuned neurons would look like before and after adaptation to a particular moving stimulus. (You must state what the adaptation and test stimuli look like, as well as the preferred directions of the neurons in your bar plots.)