86
L. L. Ting et al.
Fig. 8.7 Procedure of the
proposed method to locate
leak
when there is a modification on decomposed coefficients. Therefore, in this proposed
scheme, shift-invariant DTCWT has introduced in pursuance to overcome the shortcomings of DWT. After DTCWT decomposition, a soft threshold will be applied to
restrain noise. The decomposition level of DTCWT and a level-dependent threshold
value can be calculated by using Eqs. (8.2) and (8.3), respectively.
8.3 Experimental Setup
An experiment was conducted on a 46 m long galvanized iron pipeline which its
inner diameter and thickness are 80.4 mm and 4 mm, respectively. The leak hole
is created by threading using a screw. A linear array of seven identical AE sensors
were used in this experiment and Fig. 8.8 shows their mounting positions. Data was
Fig. 8.8 Schematic diagram of experimental setup
L. L. Ting et al.
Fig. 8.7 Procedure of the
proposed method to locate
leak
when there is a modification on decomposed coefficients. Therefore, in this proposed
scheme, shift-invariant DTCWT has introduced in pursuance to overcome the shortcomings of DWT. After DTCWT decomposition, a soft threshold will be applied to
restrain noise. The decomposition level of DTCWT and a level-dependent threshold
value can be calculated by using Eqs. (8.2) and (8.3), respectively.
8.3 Experimental Setup
An experiment was conducted on a 46 m long galvanized iron pipeline which its
inner diameter and thickness are 80.4 mm and 4 mm, respectively. The leak hole
is created by threading using a screw. A linear array of seven identical AE sensors
were used in this experiment and Fig. 8.8 shows their mounting positions. Data was
Fig. 8.8 Schematic diagram of experimental setup