Digital speckle correlation method based on wavelet-packet noise-reduction processing

The wavelet-packet noise-reduction process was used to reduce noise from displacement or deformation data obtained from the digital speckle correlation method (DSCM). In the wavelet-packet noise-reduction process, the input signal is first decompose with a wavelet filter and the entropy of the sequences of the wavelet coefficients is then computed. The largest of the wavelet coefficients are selected and are used to reconstruct the de-noising signal. © 1999 Optical Society of America