Diagnosi delle carie del legnosu piante in piedi mediantetecniche tomografiche

Luigi Sambuelli

Incontri Fitoiatrici 2011/226 settembre 2011

In ricordo di Giovanni NICOLOTTI

What could supply?

• non invasive fast surveying technique

•accurate detection of size and extent of decay

•quantitative determination of ultrasonic velocity distribution in the investigated section

Wood Longitudinal Wave Velocity

m / s

Ash (Along Fiber) 4670

Birch (Along Fiber) 3340

Cork 500

Douglas Fir (Cross Grain) 1400

Douglas Fir (With Grain) 4800

Elm (Wood) 1400

Maple (Along Fiber) 4110

Oak 4470

Pine (Along Fiber) 3320

Poplar (Along Fiber) 4280

Sycamore (Along Fiber) 4460

Equipment and acquisition geometry

•PUNDIT (Portable Ultrasonic Non-destructive Digital Indicating Tester)

•54 kHz exponential probes

•oscilloscope

•personal computer

•perimeter gage

16 equidistant measuring points 120 indipendentmeasurements for each investigated section.

Coordinate definition of source and receiver

travel time reading

0 0.0001 0.0002 0.0003 0.0004 0.0005 0.0006 0.0007 0.0008 0.0009 0.001 0.0011

time [s]

-0.0015

-0.001

-0.0005

0

0.0005

0.001

0.0015

Amplitude [V]

0 0.0001 0.0002 0.0003 0.0004 0.0005 0.0006 0.0007 0.0008 0.0009 0.001 0.0011

time [s]

-0.003

-0.002

-0.001

0

0.001

0.002

0.003

Amplitude [V]

first arrival

??

1° open problem: attenuation

Signal attenuation deeply affect travel time detection reliability and automatic arrival picking is no more adequate

bad signal-noise ratio traces need signal processing technique application for travel time detection and uncertainty determination

statistical pre-processing

2° open problem: anisotropyvelocity histogram of field tomographic data

0

2

4

6

8

10

12

14

16

18

20

0.48 0.6 0.72 0.84 0.96 1.08 1.2 1.32 1.44 1.56 1.68 1.8 1.92 2.04 2.16 2.28 2.4 2.52 2.64

velocity classes [km/s]

Frequency

C

E1

E2

E3

E4

N1

N2

NE1

NE2

NW1

NW2

NW3

NW4*

S1

S2

S3*

SE1

SE2

SE3

SE4

SW1

SW2

SW3

W1*

W2

W3*

sample labels

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

velocity [km/s]

tang. velocity (mean value = 1.4 km/s)

rad. velocity (mean value =1.65 km/s )

laboratoy measurements of tangential and radial sample velocity

Statistical pre-processing of tomographic data can supply information about anisotropy influence on tomographic results.

Comparison with sample data confirms the validity of the proposed approach.

(quasi)Cylindrical symmetry of wood anisotropy

Longitudinal velocity

Tangential velocity

Radial velocity

statistical pre-processing3° open problem: resolution

0.00 94.85 189.70 284.55 379.40

[mm]

0.00

45.88

91.76

137.64

183.52

229.40

275.27

321.15

367.03

[mm]

0.20

0.40

0.60

0.80

1.00

1.20

1.40

1.60

1.80

2.00

km/s

0.00 94.84 189.68 284.52 379.36

[mm]

0.00

45.88

91.76

137.64

183.52

229.40

275.27

321.15

367.03

[mm]

Fresnel rays distribution

0

5

10

15

20

25

2.00 2.26 2.53 2.79 3.06 3.32 3.59 3.85 4.11 4.38 4.64 4.91 5.17 5.44 5.70

Fresnel ray classes [cm]

Frequency

Spatial resolution has been taken into account both from the physical and the mathematical point of view.

Discretisation for tomographic imaging is based on these evaluations.

Fresnel radius histogram

Radius class [cm]

results

C E1 E2 E3 E4W1W2W3

S1

S2

S3

S4

N1

N2

N3

SE1

SE2

SE3

SE4

SE5

SW1

SW2

SW3

SW4

NE1

NE2

NW1

NW2

NW3

NW4

0 100 200 300 400 500 600

[mm]

0

100

200

300

400

500

600

[mm]

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

2.2

2.4

bagolaro - tomografia rotella 1 laboratorio

km/s

C E1 E2 E3 E4W1W2W3

S1

S2

S3

S4

N1

N2

N3

SE1

SE2

SE3

SE4

SE5

SW1

SW2

SW3

SW4

NE1

NE2

NW1

NW2

NW3

NW4

0 100 200 300 400 500 600

[mm]

0

100

200

300

400

500

600

[mm]

0.40

0.60

0.80

1.00

1.20

1.40

1.60

1.80

veloc.km/s

mappa velocità dedotta dai provini(velocità media radiale - tangenziale)

C E1 E2 E3 E4W1W2W3

S1

S2

S3

S4

N1

N2

N3

SE1

SE2

SE3

SE4

SE5

SW1

SW2

SW3

SW4

NE1

NE2

NW1

NW2

NW3

NW4

0 100 200 300 400 500 600

[mm]

0

100

200

300

400

500

600

[mm]

0.20

0.40

0.60

0.80

1.00

1.20

1.40

1.60

1.80

2.00

tomografia bagolaro in situ

veloc.km/s

a)

d)c)

b)

a)investigated section;

b) in situ tomography;

c) laboratory tomography on a wood disk;

d) velocity map obtained by samples measurements (radial - tangential mean velocity).

results

result comparison

C

E1

E2

E3

E4

W1

W2

W3

S1

S2

S3

S4

N1

N2

N3

SE1

SE2

SE3

SE4

SE5

SW1

SW2

SW3

SW4

NE1

NE2

NW1

NW2

NW3

NW4

sample labels

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

velocity [km/s]

v tang.

v rad.

v tomo.

Comparison between tomographic velocity and sample velocity

outlayers due to boundary cells

4° open problem: underestimation of velocity contrast

Time lapse tomography

0 50 100 150 200 250 300 350 400

[mm]

0

50

100

150

200

250

300

350

[mm]

0.70

0.90

1.00

1.10

1.20

1.35

1.45

1.55

1.65

1.75

1.85

1.96

2.09

2.21

2.34

2.50

km/s

0 50 100 150 200 250 300 350 400

[mm]

0

50

100

150

200

250

300

350

[mm]

-0.30

-0.15

-0.08

-0.00

0.08

0.19

0.26

0.34

0.41

0.49

0.60

0.70

0.85

0.95

1.10

diff. km/s

0 50 100 150 200 250 300 350 400

[mm]

0

50

100

150

200

250

300

350

[mm]

-0.70

-0.55

-0.48

-0.40

-0.25

-0.14

-0.06

0.05

0.20

0.28

0.39

0.46

0.60

diff. km/s

Evolving condition monitoring tested with laboratory measurements of velocity variation maps.

resuming: advantages

•totally non invasive;

• good accuracy and reliability in determination of size and extent of decay;

• quantitative results;

• possible automation of the acquisition and processing for non expert end-users.

resuming: open problems

estrinsic problem (could be solved byengineering improvement):• attenuation;• spatial resolution;• anisotropy;

intrinsic problem:• anisotropy;• underestimation of velocity contrasts;

SOLVED ! Maurer et al. 2006

further development: technical

• multi-channel ultrasonic equipment and “instrumented belt” to speed up the acquisition;

• measuring device for accurate sensors positioning;

• amplified and sharp energising pulse for good s/n ratio signals and autopicking procedure;

• automation of statistical pre-processing and tomographic imaging;

Only partially solved

0.01 0.1 1 10 100 1000 10000

Frequency [kHz]

1E+002

1E+003

1E+004

1E+005

1E+006

1E+007

1E+008

1E+009

Resistivity [ohm m

]

Resistivity vs frequency

umidity 8.4%

umidity 27.6%

umidity 35.5%

umidity 66.8%

Variation of electric properties with frequency and degradation

Settimane di incubazione

Tessuto fungo 2 4 8 16

Resistenza * elettrica del legno (in kΩΩΩΩ)

Alburno Nessuno 275 195 240 190

Carie bianca 72 70 52 26

Carie bruna 75 73 72 35

Durame Nessuno >500 >500 >500 >500

Carie bianca 168 70 63 30

Carie bruna 142 62 80 34

Some resistance * values of Douglasiaunder mushrooms attack

* In literature one can often find resistance as there is a kind of standard measuring device

Electric tomography device

Data acquisition

system

Test on wood in laboratory

Test on wood in laboratory

-0.2 -0.1 0 0.1 0.2

-0.25

-0.2

-0.15

-0.1

-0.05

0

0.05

0.1

0.15

0.2

0.25

100

200

300

400

500

600

700

800

900

1000

Test on trees in field

Test on trees in field

Test on poles in field

Sound

Decayed

resuming: advantages

• fast;

• reduced sensors-wood coupling problems;

• sensitive to humidity and ionicconcentration;

• possible automation of the acquisition and processing for non expert end-users.

resuming: open problems

• partially invasive;

• partial accuracy and reliability in determination of size and extent of decay;

• season dependent;

• some ambiguities in interpretation.

MARTINIS R.; SOCCO L.V.; SAMBUELLI L.; NICOLOTTI G.; SCHMITT O.; BUCUR V. (2004). Tomographie ultrasonore pour les arbres sur pied.

ANNALS OF FOREST SCIENCE, vol. 61; p. 1-9, ISSN: 1286-456015 CITATIONS15 CITATIONS

SOCCO L.V.; SAMBUELLI L.; MARTINIS R.; COMINO E.; NICOLOTTI G. (2004). Feasibility of ultrasonic tomography for nondestructive testing of decay on living trees. RESEARCH IN NONDESTRUCTIVE EVALUATION, vol. 15; p. 31-54, ISSN: 0934-9847

13 13 CITATIONSCITATIONS

NICOLOTTI G; SOCCO L. V.; MARTINIS R.; GODIO A.; SAMBUELLI L. (2003). Application and comparison of three tomographic techniques for detection of decay in trees.

JOURNAL OF ARBORICULTURE, vol. 29; p. 66-78, ISSN: 0278-522641 41 CITATIONSCITATIONS

SAMBUELLI L.; SOCCO L.V.; GODIO A.; NICOLOTTI G.; MARTINIS R. (2003). Ultrasonic, electric and radar measurements for living trees assessment.

BOLLETTINO DI GEOFISICA TEORICA E APPLICATA, vol. 44; p. 253-279, ISSN: 0006-67294 4 CITATIONSCITATIONS

Acknowledgements

Alberto GodioLaura Valentina SoccoRoberto Martinis