Video Processing

In: Science

Submitted By amrishsoni
Words 4501
Pages 19
Basics of Video

Yao Wang
Polytechnic University, Brooklyn, NY11201
yao@vision.poly.edu

Outline






Color perception and specification
Video capture and display
Analog raster video
Analog TV systems
Digital video

© Yao Wang, 2004

Video Basics

Color Perception and Specification






Light -> color perception
Human perception of color
Type of light sources
Trichromatic color mixing theory
Specification of color
– Tristimulus representation
– Luminance/Chrominance representation

• Color coordinate conversion

© Yao Wang, 2004

Video Basics

3

Light is part of the EM wave

from [Gonzalez02]

© Yao Wang, 2004

Video Basics

4

Illuminating and Reflecting Light
• Illuminating sources:
– emit light (e.g. the sun, light bulb, TV monitors)
– perceived color depends on the emitted freq.
– follows additive rule
• R+G+B=White

• Reflecting sources:
– reflect an incoming light (e.g. the color dye, matte surface,
cloth)
– perceived color depends on reflected freq (=emitted freqabsorbed freq.)
– follows subtractive rule
• R+G+B=Black
© Yao Wang, 2004

Video Basics

5

Eye Anatomy

From http://www.stlukeseye.com/Anatomy.asp
© Yao Wang, 2004

Video Basics

6

Eye vs. Camera

Camera components

Eye components

Lens

Lens, cornea

Shutter

Iris, pupil

Film

Retina

Cable to transfer images

Optic nerve send the info to the brain

© Yao Wang, 2004

Video Basics

7

Human Perception of Color


Retina contains photo receptors
– Cones: day vision, can perceive color
tone
• Red, green, and blue cones
• Different cones have different frequency
responses
• Tri-receptor theory of color vision
[Young1802]

– Rods: night vision, perceive brightness
only



Color sensation is characterized…...