Visual structure & Blind spot

Question 1 What do these devices have in common?

These devices make use of electromagnetic waves Capture electromagnetic waves and transform them into various forms.

What does the eye do?  Transducing light energy into electrical energy

Transduction  Light enters the eye  A photon hits the receptor  changes the shape of pigment molecules in the receptor  triggers massive chemical reactions  generate electrical signals in the receptor

Reflection of light What we see is a reflection of light. Different objects reflect different wavelengths, –  different objects show different colors

Photo receptors in the eye are geared to capture different wavelengths

Eye Photo receptors Two types of photo receptors – rod & cone

Photo receptors are facing away from the light source. The optic nerve carries neural information to this spot. What happens? –No receptors, no vision  blind spot

The distribution of cones and rods on the retina Cones are concentrated mainly on the fovea. There are no rods on the fovea. We move eyes to capture images on the fovea.

Question We don’t see an unseen gap. What we see is a continuous scene. How come?

Main Point by Durgin et al. The blind spot filling-in phenomenon is functionally similar to the perception of amodally occluded areas. (p. 137)

Zero-crossing Surface segmentation Mapping the 2D retinal data to the 3D environment.

1308 x 952. (0, 255)

Gaussian filtering Zero-crossing edge detection