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Sensing and the Imaging Process (II) Introduction to Computational and Biological Vision CS 202-1-5261 Computer Science Department, BGU Ohad Ben-Shahar

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Page 1: Sensing and the Imaging Process (II)ben-shahar/Teaching/Computational-Vision… · Sensing and the Imaging Process (II) Introduction to Computational and Biological Vision CS 202-1-5261

Sensing and the Imaging Process

(II)

Introduction to Computational and Biological Vision

CS 202-1-5261

Computer Science Department, BGU

Ohad Ben-Shahar

Page 2: Sensing and the Imaging Process (II)ben-shahar/Teaching/Computational-Vision… · Sensing and the Imaging Process (II) Introduction to Computational and Biological Vision CS 202-1-5261

The human eye

Page 3: Sensing and the Imaging Process (II)ben-shahar/Teaching/Computational-Vision… · Sensing and the Imaging Process (II) Introduction to Computational and Biological Vision CS 202-1-5261

The human eye

Page 4: Sensing and the Imaging Process (II)ben-shahar/Teaching/Computational-Vision… · Sensing and the Imaging Process (II) Introduction to Computational and Biological Vision CS 202-1-5261

The human eye

Pinhole camera model

Page 5: Sensing and the Imaging Process (II)ben-shahar/Teaching/Computational-Vision… · Sensing and the Imaging Process (II) Introduction to Computational and Biological Vision CS 202-1-5261

The human eye

Pinhole camera model

wP

hP

iP

Page 6: Sensing and the Imaging Process (II)ben-shahar/Teaching/Computational-Vision… · Sensing and the Imaging Process (II) Introduction to Computational and Biological Vision CS 202-1-5261

The human eye

The retina:

The biological image plane

Page 7: Sensing and the Imaging Process (II)ben-shahar/Teaching/Computational-Vision… · Sensing and the Imaging Process (II) Introduction to Computational and Biological Vision CS 202-1-5261

The human eye

Aside – Neural signaling and communication

Retinal bipolar cell Cerebellar

pyramidal cell

Cerebellar

Purkinje cell

Page 8: Sensing and the Imaging Process (II)ben-shahar/Teaching/Computational-Vision… · Sensing and the Imaging Process (II) Introduction to Computational and Biological Vision CS 202-1-5261

The human eye

Aside – Neural signaling and communication

Page 9: Sensing and the Imaging Process (II)ben-shahar/Teaching/Computational-Vision… · Sensing and the Imaging Process (II) Introduction to Computational and Biological Vision CS 202-1-5261

The human eye

Aside – Neural signaling and communication

Page 10: Sensing and the Imaging Process (II)ben-shahar/Teaching/Computational-Vision… · Sensing and the Imaging Process (II) Introduction to Computational and Biological Vision CS 202-1-5261

The human eye

The retina

Variety of cells:

Photoreceptors: ~100 million (95% rods,5% cones)

Bipolar cells

Ganglion cells

Amacrine cells

Horizontal cells

Optic nerve:

Made of axons of secondary (ganglion) neurons

~1 million axons

Page 11: Sensing and the Imaging Process (II)ben-shahar/Teaching/Computational-Vision… · Sensing and the Imaging Process (II) Introduction to Computational and Biological Vision CS 202-1-5261

The human eye

A defective design?

Light

Page 12: Sensing and the Imaging Process (II)ben-shahar/Teaching/Computational-Vision… · Sensing and the Imaging Process (II) Introduction to Computational and Biological Vision CS 202-1-5261

The human eye

The optic disk and the blind spot

Page 13: Sensing and the Imaging Process (II)ben-shahar/Teaching/Computational-Vision… · Sensing and the Imaging Process (II) Introduction to Computational and Biological Vision CS 202-1-5261

The human eye

The optic disk and the blind spot

Page 14: Sensing and the Imaging Process (II)ben-shahar/Teaching/Computational-Vision… · Sensing and the Imaging Process (II) Introduction to Computational and Biological Vision CS 202-1-5261

The human eye

Rods and cones

Rods:

•Extremely sensitivity to light

•Single photon response

•Low spatial resolution

•Single response profile

•B&W night vision (scotopic)

Cones:

•Relatively insensitive to light

•100 photos for response comparable with rods

•High spatial resolution

•Different (3 types of) response profiles

•Color daylight vision (photopic)

Page 15: Sensing and the Imaging Process (II)ben-shahar/Teaching/Computational-Vision… · Sensing and the Imaging Process (II) Introduction to Computational and Biological Vision CS 202-1-5261

The human eye

Rods and cones

Page 16: Sensing and the Imaging Process (II)ben-shahar/Teaching/Computational-Vision… · Sensing and the Imaging Process (II) Introduction to Computational and Biological Vision CS 202-1-5261

The human eye

Rods and cones

Page 17: Sensing and the Imaging Process (II)ben-shahar/Teaching/Computational-Vision… · Sensing and the Imaging Process (II) Introduction to Computational and Biological Vision CS 202-1-5261

The human eye

Rods and cones: distribution across the retina

Page 18: Sensing and the Imaging Process (II)ben-shahar/Teaching/Computational-Vision… · Sensing and the Imaging Process (II) Introduction to Computational and Biological Vision CS 202-1-5261

The human eye

The fovea (“pit”)

•Extremely high density of cone receptors

•Few rods. None in the foveola.

•Displaced neural layers

•No blood vessels

•1-1 relationship with bipolar and ganglion cells

1.2 mm

Page 19: Sensing and the Imaging Process (II)ben-shahar/Teaching/Computational-Vision… · Sensing and the Imaging Process (II) Introduction to Computational and Biological Vision CS 202-1-5261

The human eye

The fovea: distribution of optic fibers