UNIVERSITÀ DEGLI STUDI DI NAPOLI “FEDERICO II”

FACOL

TESI DI LAUREA

Evaluation of geometrical parameters of buildingsfrom SAR images

RELATORE: CANDIDATO:CH.MO PROF. FEDERICO MARIA ARIU’ANTONIO IODICE MATR. 528/1127

CORRELATORE:ING. GERARDO DI MARTINO

ANNO ACCADEMICO 2009/2010

Summary

Introduction and goals

Models description

Developed algorithm

Results

Pros:• Image quality not depending on:Solar illuminationWeather trends

• Wide coverage area• High resolution

Cons:• Need of processing data to obtain the image

SAR images

Geometrical distorsions

Layover

Shadowing

Electromagnetic diffusionmodel

Single scattering

Electromagnetic diffusionmodel

Double scattering

EM scattering from buildings

BW=Backscattering from WallBR= Backscattering from RoofBG=Backscattering from GroundD= Double scattering

T= Triple scatteringLr =Range size of LayoverSr =Range size of ShadowS= Shadow

Scattering modelDouble scattering

)0(''2

sintanexp

)0(''2

1

cos4

sintan1

4costan

2

22

222

222

2

0

CCkS

khl

pq

2

0

22

0

4

E

ErS

θ: detector angle φ: building orientation angle in respect to the detector azimuthk: propagation constantσ2: standard deviationh: buildings height

l: buildings length

Spq: scattering matrix

Evaluation of orientationangle:usefulness

Geometrical knowledge

Geometrical and electromagnetic parameters retrieval

Height retrieval

Geometrical method:

Radiometric method:

cos

rL

h cosr

Sh

b

ah

0where

)0(''2

sintanexp

)0(''2

1

cos4

sintan1costan

2

22

222

22

CCklb

22

4

pqSk

a

Double scattering line retrieval

M

Scanning equiazimuth

ith row

Zero-Padding

correlation

Retrieval ofmaxima

Ideal sinc

Double scattering line analysis

The software returns coordinates and intensity of the dotsforming the double scattering line.

y=mx+q

m=tanα

Linear regression

Given a cloud of sampled dots, the linear regression supplies the straight line that rounds best the trend of the cloud of dots.

iiiuXY

Choosing the linearregression algorithm

The chosen algorithm minimizes minimizza lo scarto assoluto.

ABSOLUTE DEVIATION STANDARD DEVIATION

y

x

SAR images simulations: 512 x 512 SENSOR OVERVIEW

Platform height h = 20 Km

Platform speed v = 0.9 Km/s

View angle θ = 28°

Antenna dim(azimuth)

Antenna dim (range)

Carrier frequency f = 1.282 GHz

Pulse duration τ = 1.9 μs

Chirp pulse bandwidth Δf = 14 MHz

Sampling frequency fsamp = 31 MHz

Pulse repetitionfrequency

p.r.f. = 350 Hz

Azimuth resolution Δx = 2.5714 m

Range resolution Δy = 10.3067 m

mLSARx

5.8

mLSARr

5.1

SAR images simulations: 512x512 sensor

Simulation 1: φ = 10

φs = 15.0°

Simulation 2: φ = 25

φs = 26.6°

SAR images simulations: ERS-1 C SENSOR OVERVIEW

Platform height h = 775 Km

Platform speed v = 6.7 Km/s

View angle θ = 23°

Antenna dim(azimuth)

Antenna dim (range)

Carrier frequency f = 5.3 GHz

Pulse duration τ = 37.1 μs

Chirp pulse bandwidth Δf = 15.55 MHz

Sampling frequency fsamp = 18.98 MHz

Pulse repetitionfrequency

p.r.f. = 1.68 kHz

Azimuth resolution Δx = 3.9860 m

Range resolution Δy = 19.9285 m

mLSARx

1.11

mLSARr

0.1

SAR images simulations: ERS-1 C sensor

Simulation 1: φ = 10

φs = 10.1°

Simulation 2: φ = 30

φs = 30.0°

Conclusions

Pros:

• Good accuracy depending on the numbers of dotsthat belong to the line.

Cons:

• Range of angles to be evaluate low.