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Table 1 In-lab measurements of cracks in the mm range with calliper, comparator and 2D image-based crack monitoring technique

From: 2D image-based crack monitoring: an affordable, sufficient and non-invasive technique for the democratization of preventive conservation of listed buildings

 

Comparator

(reference)

[mm]

Calliper

2D image-based

Measurement [mm]

Difference [mm]

Measurement [mm]

Difference [mm]

Step 6 mm

7.50

6.81

− 0.69

7.27

− 0.23

Step 8 mm

8.88

8.22

− 0.66

8.8

− 0.08

Step 10 mm

10.55

10.11

− 0.44

10.45

− 0.10

Step 12 mm

13.33

12.74

− 0.59

13.23

− 0.10

Step 14 mm

15.15

14.45

− 0.70

14.99

− 0.16

Step 16 mm

17.16

16.52

− 0.64

17.07

− 0.09

Step 18 mm

19.82

18.59

− 1.23

19.36

− 0.46

Mean value

− 0.71

− 0.15

Statistical variance

0.06

0.03

Standard Deviation

0.25

0.17