Determination of Best Grading of Wavelet Transform in Deformation Measurement Data Filtering

Wavelet transform is widely used in deformation measurement data filtering,but there is still no definite solution to determine the best grading of its decomposition and reconstruction.Firstly,four parameters,the gap of mean square error variances between two adjacent gradings,correlation coefficient,signal-noise ratio and flatness,are integrated in as evaluation indexes.Then they are transformed to according to their contributions to the best grading.Finally,these four transformed parameters are added up to as a collective evaluation index,and the grading corresponding to the maximum value of the collective evaluation index is the best.Two examples,the one is a stimulant siginal,and the other is from actual deformation measurement,are used to test the new method,which prove the method is feasible and reliable.