Image - BRIGHTNESS AND COLOR Motivation ! ! ! ! Use images...

Info iconThis preview shows pages 1–13. Sign up to view the full content.

View Full Document Right Arrow Icon
BRIGHTNESS AND C O L O R
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Motivation ! Use images to recover information about the world ! We need to understand image formation ! We need to understand the physics of light reflection ! In some cases we can INVERT image formation process ! We can extract invariant properties of surfaces of imaged objects ! Geometric properties: shape reconstruction ! Material properties: reflective properties, intrinsic color
Background image of page 2
Example ! Shape from shading Moon surface Synthetic image Computed elevation map
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Overview ! What is Light ! Elements of Photometry ! Related to brightness of light, not colors ! Definitions of radiance, irradiance, radiosity, reflectance ! Color Perception ! Effect of light spectrum ! Color reflectance ! Eye sensitivity ! Color Models
Background image of page 4
Electromagnetic Spectrum ! Light is just one part of electromagnetic spectrum ! X rays 0.1 nanometer ! Radio waves 1 meter or more ! Light 380 to 770 nanometers (1000 nm = 1/100 paper sheet)
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Waves
Background image of page 6
Spectral Description of Light ! A light source can be described by its spectral power distribution ! relative power emitted at each wavelength
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Photons and Waves ! EM radiations are both particles and waves ! At short wavelengths, particle effects ! At long wavelengths, wave behavior ! Photon energy Q = h f = h c / λ ! Plank’s constant h = 6.623 10 -34 J s ! c = 2.998 10 8 m/s speed of light ! f = c /
Background image of page 8
Photons ! Electron-hole pairs are separated by the built-in field and are collected in the external circuit ! Quantum efficiency q ( λ ), ratio of electron flux to photon flux for each wave length ! Weak photons go through, energetic photons are stopped too early n p d
Background image of page 9

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
How Light Behaves ! Light interacts with materials ! Reflection ! Diffraction ! Refraction ! Transmission ! Light waves interact ! Interference
Background image of page 10
Brightness of a Surface Related to ! power emitted by source ( across all wavelengths ) ! power received by surface ! power reflected by surface ! power refracted by lens and received by eye or camera sensors n ( θ i , φ i ) ( θ e , φ e )
Background image of page 11

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Solid angles ! Measure the proportion of space contained between a point to a surface. ! Unit is steradian (
Background image of page 12
Image of page 13
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 39

Image - BRIGHTNESS AND COLOR Motivation ! ! ! ! Use images...

This preview shows document pages 1 - 13. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online