# Research on Leakage Location of Pipeline Based on Module Maximum Denoising
## 4 Conclusions  
The noise contained in the leakage signal of water supply pipeline makes it difficult to locate the leakage. To solve the problem of noise interference, this paper proposes a signal adaptive noise reduction method based on module maximum, which effectively improves the accuracy of pipeline leakage location. Some main conclusions can be drawn as follows:  
(1) The method proposed in this paper was to perform a wavelet transformation on the noisy signal, and find the module maximum value of the transformation coefficient on each scale. Finally, a new module maximum sequence on the maximum scale can be obtained. This method effectively improves the lack of adaptability of the traditional methods. The method proposed by this paper can obtain a clear NPW inflection point. By using the same data, the SNR is as follows: VMD is 40.87, wavelet threshold is 43.90, module maximum is 44.01, and improved module maximum is 50.97, respectively. Thus, the noise suppression of our method is more effective. (2) The proposed method performs well in leakage location experiments under different leakage conditions. The maximum relative positioning error is 2.5%, and the minimum is 0.9%. Therefore, the practicability of the proposed method is verified. (3) Research shows that noise and signal have different characteristics at different scales. Since noise tends to have a large impact on the signals at a small scale, the proposed method in this paper adaptively increases the threshold value as the scale decreases in the process of module maximum processing, in order to set different thresholds for each scale, and finally achieve signal noise reduction processing. module maximum sequences can be treated with a soft threshold, which can overcome the phenomenon of \"glitches and slight oscillations\" of the singularity. The selection of wavelet basis and the difference of \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline \multirow{2}{*}{\(L\)} & \multirow{2}{*}{\(L\)**a**} & \multirow{2}{*}{\(L\)**a**} & \multirow{2}{*}{\(L\)**a**} & \multirow{2}{*}{\(L\)**a**} & \multirow{2}{*}{\(L\)**a**} & \multirow{2}{*}{\(L\)**a**} & \multirow{2}{*}{\(L\)**a**} & \multirow{2}{*}{\(L\)**a**} & \multirow{2}{*}{\(L\)**a**} & \multirow{2}{*}{\(L\)**a**} \\  & & & & & & & & & & \\ \cline{5-10} \multirow{-1}{*}{(m)} & \multirow{2}{*}{\(L\)**a**} & \multirow{2}{*}{**Experiment**} & \multirow{2}{*}{**SAND**} & \multirow{2}{*}{**Error**} & \multirow{2}{*}{**SAND**} & \multirow{2}{*}{**Error**} & \multirow{2}{*}{**SAND on**} & \multirow{2}{*}{**SAND on**} & \multirow{2}{*}{**Error**} & \multirow{2}{*}{**SAND on**} \\  & & & & & & & & & & \\ \cline{5-10} \multirow{-1}{*}{(m)} & \multirow{2}{*}{\(L\)**a**} & \multirow{2}{*}{**Number**} & \multirow{2}{*}{**VMD**} & \multirow{2}{*}{**\%**} & \multirow{2}{*}{**Wavelet**} & \multirow{2}{*}{**(m)**} & \multirow{2}{*}{**\%**} & \multirow{2}{*}{**Maximum**} & \multirow{2}{*}{**MCM**} \\  & & & & & & & & & & \\ \hline \multirow{4}{*}{16.95} & \multirow{4}{*}{11.155} & Leak 1 (45\({}^{\circ}\)) & 10.55 & 5.4 & 10.88 & 2.5 & 10.94 & 1.9 & 10.99 & 1.5 \\ \cline{5-10}  & & Leak 1 (90\({}^{\circ}\)) & 10.68 & 4.3 & 10.88 & 2.5 & 10.95 & 1.8 & 11.25 & 0.9 \\ \cline{5-10}  & \multirow{4}{*}{8.275} & Leak 2 (45\({}^{\circ}\)) & 8.52 & 3.0 & 8.61 & 4.0 & 8.51 & 2.8 & 8.48 & 2.5 \\ \cline{5-10}  & & Leak 2 (90\({}^{\circ}\)) & 8.53 & 3.1 & 8.59 & 3.8 & 8.53 & 3.1 & 8.48 & 2.5 \\ \cline{5-10}  & \multirow{4}{*}{4.74} & Leak 3 (45\({}^{\circ}\)) & 4.88 & 3.0 & 4.92 & 3.8 & 4.91 & 3.6 & 4.86 & 2.5 \\ \cline{5-10}  & & Leak 3 (90\({}^{\circ}\)) & 4.85 & 2.3 & 4.91 & 3.6 & 4.83 & 1.9 & 4.81 & 1.5 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Leak Localization Results. the number of decomposition layers will affect the denoising effect, which needs further analysis in the future work. Formal analysis, Z.J. ; Investigation, Y.Z. and J.L. ; Resources, J.L. ; Data curation, Y.Z. and Z.J. ; Writing--original draft, Y.Z. ; Writing--review & editing, Z.J. ; Project administration, J.L.