The double-density DWT is an improvement upon the critically sampled DWT with important additional properties: (1) It employs one scaling function and two distinct wavelets, which are designed to be offset from one another by one half, (2) The double

single level ,two level, multi level dwt for the denoising

In this paper, a robust DWPT based adaptive bock algorithm with modified threshold for denoising the sounds of musical instruments is proposed. The signal is first segmented into multiple blocks depending upon the minimum mean square criteria in each