Remote Sensing

Prof. Guido D’Urso, Phd

University of Naples Federico II

Earth Observation

platforms

Documento Acrobat

Sun-synchronous polar orbit

Sun-synchronous polar orbit

Electromagnetic radiation

Visible spectrum is only 0.3 nm wide

Sensor types

Passive optical systems

• multispectral scanners

• imaging sensors

Whiskbroom

(Landsat)

Pushbroom

(SPOT)

Passive optical systems

• multispectral ?

Surface reflectance

Hyperspectral

Multispectral

Water bodies - reflectance

Snow & Clouds

Jensen, 2000

What is a digital image ?

72808492979485787581

72707478859397888179

71616770768290979387

727479777579798910396

4459778785848897110105

563951839195101100104104

7558435684106106938693

78797541406587867988

78828672453244698280

85858684775938457779

87918881858464415370Pixel

Cosa vediamo noi…Cosa vede il computer…

Digital Number (DN)

I Digital numbers (DNs) 0 -255; 0 - 511; 0 - 1023, etc.Binary ranges 28=256; 29=512; 210=1024.

72808492979485787581

72707478859397888179

71616770768290979387

727479777579798910396

4459778785848897110105

563951839195101100104104

7558435684106106938693

78797541406587867988

78828672453244698280

85858684775938457779

87918881858464415370

A multispectral image

72808492979485787581

72707478859397888179

71616770768290979387

727479777579798910396

4459778785848897110105

563951839195101100104104

7558435684106106938693

78797541406587867988

78828672453244698280

85858684775938457779

87918881858464415370

72808492979485787581

72707478859397888179

71616770768290979387

727479777579798910396

4459778785848897110105

563951839195101100104104

7558435684106106938693

78797541406587867988

78828672453244698280

85858684775938457779

87918881858464415370

columns (x)rows (y)

bands (z)

72808492979485787581

72707478859397888179

71616770768290979387

727479777579798910396

4459778785848897110105

563951839195101100104104

7558435684106106938693

78797541406587867988

78828672453244698280

85858684775938457779

87918881858464415370

72808492979485787581

72707478859397888179

71616770768290979387

727479777579798910396

4459778785848897110105

563951839195101100104104

7558435684106106938693

78797541406587867988

78828672453244698280

85858684775938457779

87918881858464415370

72808492979485787581

72707478859397888179

71616770768290979387

727479777579798910396

4459778785848897110105

563951839195101100104104

7558435684106106938693

78797541406587867988

78828672453244698280

85858684775938457779

87918881858464415370

Synthetic color vision

R = 255

G = 0

B = 0

R = 255

G = 0

B = 0

R = 127

G = 0

B = 0

R = 0

G = 0

B = 0

R = 255

G = 127

B = 255

R = 255

G = 0

B = 255

R = 0

G = 0

B = 127

R = 0

G = 127

B = 0

R = 255

G = 255

B = 255

R = 0

G = 0

B = 255

R = 0

G = 255

B = 255

R = 0

G = 255

B = 0

R = 255

G = 255

B = 255

R = 255

G = 255

B = 255

R = 127

G = 255

B = 255

R = 0

G = 255

B = 0

Banda 3visibile

Banda 4infrarosso vicino

Banda 5infrarosso medio

vegetazione

suolo nudo

Il Molise visto dal satellite Landsat 5; immagini a falsi colori(Rosso= TM 3; Verde=TM4; Blu= TM5)

Foce del Biferno

Autostrada A14

Porto di Termoli

Spatial resolution

Landsat 7 ETM+ => 30 m

SPOT5 => 10 m

Quick Bird => 2,8 m

Temporal resolution: 16 gg.

Swath: 185 km

450 – 515 nm

525 – 605 nm

630 – 690 nm

750 – 900 nm

1.55 – 1.75 µm

2.09 – 2.35 µm

30 m

BandsSpatialresolution

10.4 – 12.5 µm60 m

520 – 900 nm15 m

Landsat ETM+

β

∆

A

Vegetation indexes

NDVI (Normalized Difference Vegetation Index)

rnir

rnirNDVIρρ

ρρ

+

−=

NDVI and vegetation growth