Application of improved threshold denoising method in anchor bolt parameter detection

Anchor bolt has been used widely in large-scale geotechnical engineering,so,its quality detection is important,especially for parameter detection.Due to the influence of the environment、equipment and other conditions,detecting signal is corrupted greatly with additive noise,which causes great errors between the calculation results and the actual results.According to the shortcomings of the traditional soft 、hard threshold methods and other threshold methods designed in some literature,a new wavelet threshold denoising method which improves the threshold functions and threshold is presented.The improved threshold function divides wavelet coefficients that less than the threshold into two parts:ones less than half of threshold is set to zero;the others reduce respectively,which could remain useful signal in high frequency.Since the selected threshold directly affects the denoising effect,an adaptive threshold method is proposed which selects adaptively different thresholds with the change of decomposition scale.The experimeny results show that,the improved threshold denoising method is more accurate than tranditional ones.