remote sensing & photogrammetry...
TRANSCRIPT
Remote Sensing & Photogrammetry
L6
Beata HejmanowskaBuilding C4, room 212,
phone: +4812 617 22 72605 061 510
Image processing
1. Visual interpretation of single spectral band• Readout of DN and coordinates: x,y
2. Image enhancement• Histogram calculation• Linear histogram streatching• Image comparison before and after stretching• Different parameters of linear stretching• Histogram saturation and equalization
3. Visualization of multispectral bands• RGB• FCC
Image processing4. Multi bands operation
• Ratio – Vegetation Index (VI)• Normalized ratio – Normalized Vegetation Index (NDVI)• Multi chanel statistics• Principal Componemt Analysis (PCA) (presented live – Lecture 5)• Map algebra• Image fusion
5. Image classification• Density slicing• piece-wise linear stretchning• Mulispectral image classification
• Sampling• Different algorithms• Classification accuracy assessement• Post classification operation
KB 234
TM4
TM2
TM3
N
VI= TM4 / TM3
Vegetation index
Wykłady TiF II -2010/11
Regina Tokarczyk
Ratio Vegetation Index VI=NIR/REDNDVI Normalized Difference Vegetation IndexNDVI=(NIR-RED)/(NIR+RED)
NDVI – Normalized DifferentialVegetation Index
NDVI=(TM4-TM3)/(TM4+TM3)
Normalized Burn Ratio
• Normalized Burn Ratio
NBR = (TM4 - TM7) / (TM4 + TM7)
• Normalized Difference Burn Ratio (NDBR)
NDBR = NBRpre – NBRpost
Wykłady TiF II -2010/11
Regina Tokarczyk
SI radiometry units
IrradianceIrradinace – ratio of incidient radiant flux on elementar unit flux stosunek strumienia padającego w elementarnej jednostce czasu na element powierzchni odbiornika do wielkości tej powierzchni dla wąskiego przedziału spektralnego p.e.m. (emitancja spektralna)
E = dQ/dt/dA=Φ/dA W/m2
Constant on the top of atmosphere : mean value 1366,1 W/(m2) – solar constant
Eλ
= dQ /dt/dA/ kąt bryłowy W/(m2 sr µm)
AlbedoAlbedo (reflectance coefficient) = Energy reflected fr om the Earth/ Energy incident on the Earth = Q ρλρλρλρλ/Qλλλλ=Lλλλλ/Eλλλλ
(in all EM range)
Albedo depends on:-Enegry incident (solar zenith angle) – on horizontal and sloping surfaces-Reflecting object surface (color, charakter, roughness, wetness)
Lambert’s law:
Energy incident on the Earth = Energy incident on the Eart h (vertical) * cos (Vo)
- Vo – local zenith angle
Example albedo: • Soil 5-10% • Conifer forest 15-20% • Grass 20-25% • Snow: fresh 75-95%, old 50-60% • antopological materials ( 5-20% asphalt, 10-35% concrete, 20-35% stone, 10-35% tile
Map algebra - radiance• Radiance (luminance) calculation:
• Lλ – spectral radinace recorded by sensor• Lmin – minimal radiance of detectors in PAN: – 5.00 • Lmax – maximal radiance of detectors in PAN: 244.00• DN – of channel 8, PAN
( )( ) minminmax 255/ LDNLLoffsetDNgainL +⋅−=+⋅=λ
SESUN
dL
θπρ
λ
λ
cos
2
⋅⋅⋅
=
where:ρ– albedoLλ – spectral radiance recorded by sensord – distance between Earth and Sun in astronomical unitsfor given day of the yearESUNλ – mean irradinace = 1368.00 θS – Sun zenith angle
Map algebra - albedo
Albedo
DNPANBand 8Landsat ETM+
Albedo(0.52 −0.90 µm)
Map algebra - albedo
60%
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00,4 0,6 0,8 1,0 1,2 1,4 1,6 1,8 2,0 2,2 2,4
gleba
roślinno ść
wody
B G Rśrednia
podczerwień
długość fali
bliskapodczerwień
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krzywa spektralna - las li ściasty
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T
Spectral curves
Eρ (λ) =ρ (λ) E (λ) Es (λ) = ε (λ) B(λ,Ts) + (1-ε (λ)) E (λ)
VIR, SWIR, TIR
EM laws TIR
E=εσT4
σ - Stefan-Boltzmann constant,)/(1067,5 28 KmW ⋅⋅ −
EM laws TIR
Aluminium kinetic temerature100C +273= 283 0K
Powierzchnia wypolerowanawsp. emisyjności 0.06
Powierzchnia pomalowanawsp. emisyjności 0.97
Temperatura radiacyjna(0.06)1/4 283 0K = - 133 oC
Temperatura radiacyjna(0.97)1/4 283 0Κ = +8 οΧ
rzeczTT ⋅= 4 ε
Ε= σΤ4=σ[(ε)1/4Τrzecz]4=σεΤ4rzecz
Radiant temperature
Map algebra - temperature
Wykłady TiF II -2010/11
Regina Tokarczyk
Radiant temperature
• where:
• Lλ – spectral radiance of the sensor, • Lmin – minimum spectral radiance , in
thermal band 0.00, • Lmax – maximum spectral radiance , in
thermal band 17.04
• DN – of thermal band
( )( ) minminmax 255/ LDNLLoffsetDNgainL +⋅−=+⋅=λ( )112 −−− ⋅⋅⋅ msrmW µ
Temperature
Map algebra - temperature
DN band 6 Landsat ETM+
Radiant temperature
Map algebra - temperature
Image processing4. Multi bands operation
• Ratio – Vegetation Index (VI)• Normalized ratio – Normalized Vegetation Index (NDVI)• Multi chanel statistics• Principal Componemt Analysis (PCA) (presented live – Lecture 5)• Map algebra• Image fusion
5. Image classification• Density slicing• piece-wise linear stretchning• Mulispectral image classification
• Sampling• Different algorithms• Classification accuracy assessement• Post classification operation
Image fusion
merging, band sharpening …
+
Multispectral imagecompositionlow spatialresolution
PANHigh spatial
resoluion
=
IHS TRANSFORMATION
KB 123 H SI
Image fusion
KB 123 H SI
Image fusion
IHS TRANSFORMATION
Image fusion
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Image fusion