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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: Powerpoint on the eye

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: Powerpoint on the eye

The human eye

Page 3: Powerpoint on the eye

The human eye

Page 4: Powerpoint on the eye

The human eye

Pinhole camera model

Page 5: Powerpoint on the eye

The human eye

Pinhole camera model: Basic geometry

Image plane

VirtualImageplanePinhole

(center of projection)

Optical axis

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The human eye

f

),,( zyxP

),,( fyxP iii

Pinhole camera model: Perspective projection

),,( fyxP iii

OPOPi

O

zf

yy

xx ii

zyfyzxfx

i

i

Page 7: Powerpoint on the eye

The human eye

Durer (c. 1500)

Pinhole camera model: Perspective projection

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The human eye

Pinhole camera model: Basic geometry

Recovery of structure is ill defined

Page 9: Powerpoint on the eye

The human eye

The retina:

The biological image plane

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The human eye

Aside – Neural signaling and communication

Retinal bipolar cell Cerebellar pyramidal cell

Cerebellar Purkinje cell

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The human eye

Aside – Neural signaling and communication

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The human eye

Aside – Neural signaling and communication

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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

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The human eye

A defective design?

Light

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The human eye

The optic disk and the blind spot

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The human eye

The optic disk and the blind spot

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The human eye

Rods and conesRods:

•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)

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The human eye

Rods and cones

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The human eye

Rods and cones

Shor

t (S)

Med

ium

(M)

Long (L)

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The human eye

Rods and cones: distribution across the retina

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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 22: Powerpoint on the eye

The human eye

The fovea: distribution of optic fibers