Lecture 20 – review

Labs: questions

Next Wed – Final: 18 March 10:30-12:20

Thursday, 12 March

- physical basis of remote sensing- spectra- radiative transfer- image processing- radar/lidar-thermal infrared- applications

What is remote sensing?

Measurement from a distance

Wide range of wavelengths

Hazardous locales

Images

pixels

DNs

scanners, orbits

image geometry, parallax

resolution

color vs. intensity and texture

The spectrum and wavelength regions

Units of radiance, irradiance, spectral radiance

Color mixing, RGB false color images

Color is due to absorption: e-kz (Beer Law)

Hue, saturation, intensity

Radiative transfer

Sunlight, atmospheric absorption & scatteringRayleigh, Mie, Non-selective

Reflection – 1st surface (Fresnel’s Law), volume

Planck function: -5 (exp(c/T)-1)

Atmospheric windows

DN = g·(e·r · i·Itoa·cos(i)/ + e· r·Is↓/ + Ls↑) + o

r I cos(i)/: Lambert’s law

When do you need atmospheric compensation?dark object subtractionModtran model

Interaction of Energy and Matter

Rotational absorption (gases)

Electronic absorption Charge-Transfer Absorptions

Vibrational absorption

Spectra of common Earth-surface materials

Image processing algorithmsradiometrygeometrySpectral analysisStatistical analysisModeling

Algorithms:RatioingSpectral mixture analysis

max number of endmembers = n+1shade

NDVI

Classification – spectral similaritysupervised vs. unsupervisedmaximum likelihood vs parallelipipedthemes & land usevalidationconfusion matrix

Confusion matricesWell-named. Also known as contingency tables or error matricesHere’s how they work…

Training areasA B C D E F

A

B

C

D

EF

Cla

ssif

ied

data

Col sums

Row sums

Grand sum

All non diagonal elementsare errors

Row sums give “commission”errors

Column sums give “omission” errors

Overall accuracy is the diagonal sum over the grand total

This is the assessment only for the training areas

What do you do for the rest of the data?

p 586, LKC 6th

480 0 5 0 0 0 485

0

0

0

0

0

0

0

0

480

52

16

68 1992

0 20 0 0 72

Crater counting – relative dating on the moon and Mars

Forest remote sensing

SMA in forest studiesShade endmember vs. canopy vs. topography

What can Lidar do for forest characterization?

LayoverShadowsPolarizationSensitivity to

- dielectric- roughness

ih

cos8

Corner reflectorsInterferometry

LiDAR

Thermal

Planck’s Law: R = (() ) c1-1 -5[exp(c2 -1TT-1 )-1] -1

Emissivity

Blackbody radiation

What compositions can be What compositions can be determined in the TIR?determined in the TIR?

Mostly vibrational resonance, not electronic processestherefore, relatively large molecules

Silicate minerals (SiO4-4); quartz (SiO2)

Sulfates (SO4=); sulfur dioxide (SO2)

Carbonates (CO3=); carbon dioxide (CO2)

Ozone (O3) Water (H2O)Organic molecules

Mauna Loa, Hawaii

MASTER VNIRdaytime

ASTER TIR,daytime

MTI TIR,nighttime