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Rafat Hussain edited this page Apr 8, 2019 · 13 revisions

C Implementation of Discrete Wavelet Transform

C Implementation of Discrete Wavelet Transform (DWT,SWT and MODWT), Continuous Wavelet transform (CWT) and Discrete Packet Transform ( Full Tree Decomposition and Best Basis DWPT).

Git Repository

git clone https://github.com/rafat/wavelib

Or Download Zip File From Here

https://github.com/rafat/wavelib/archive/master.zip

Discrete Wavelet Transform Methods Implemented

DWT/IDWT A decimated Discrete Wavelet Transform implementation using implicit signal extension and up/downsampling so it is a fast implementation. A FFT based implementation is optional but will not be usually needed. Both periodic and symmetric options are available.

SWT/ISWT Stationary Wavelet Transform. It works only for signal lengths that are multiples of 2^J where J is the number of decomposition levels. For signals of other lengths see MODWT implementation.

MODWT/IMODWT Maximal Overlap Discrete Wavelet Transform is another undecimated transform. It is implemented for signals of any length but only orthogonal wavelets (Daubechies, Symlets and Coiflets) can be deployed. This implementation is based on the method laid out in "Wavelet Methods For Wavelet Analysis" by Donald Percival and Andrew Walden.

2D Wavelet Transform Methods

Check the wt2 object page to learn how the memory is managed.

DWT2/IDWT2 A decimated 2D Discrete Wavelet Transform implementation using implicit signal extension and up/downsampling so it is a fast implementation.

SWT2/ISWT2 Stationary Wavelet Transform. It works only for signal lengths that are multiples of 2^J where J is the number of decomposition levels. For signals of other lengths see MODWT2 implementation.

MODWT2/IMODWT2 Maximal Overlap Discrete Wavelet Transform is another undecimated transform. It is implemented for signals of any length but only orthogonal wavelets (Daubechies, Symlets and Coiflets) can be deployed. This implementation is based on the method laid out in "Wavelet Methods For Wavelet Analysis" by Donald Percival and Andrew Walden.

Discrete Wavelet Packet Transform Methods Implemented

WTREE A Fully Decimated Wavelet Tree Decomposition. This is a highly redundant transform and retains all coefficients at each node. This is not recommended for compression and denoising applications.

DWPT/IDWPT Is a derivative of WTREE method which retains coefficients based on entropy methods. This is a non-redundant transform and output length is of the same order as the input.

Continuous Wavelet Transform Method Implemented

CWT/ICWT C translation ( with some modifications) of Continuous Wavelet Transform Software provided by C. Torrence and G. Compo, and is available at URL: http://atoc.colorado.edu/research/wavelets/'. A generalized Inverse Transform with approximate reconstruction is also added.

Online Demo of Wavelib Using Emscripten

Usage How to integrate wavelib in your code
wave object Wavelet Object, Parameters and Functions
wt object Discrete Wavelet Transform Object, Parameters and Functions
cwt object Continuous Wavelet Transform Object, Parameters and Functions
wtree object Wavelet Tree Decomposition and Functions
wpt object Wavelet Packet Transform Object, Parameters and Functions
wt2 object 2D Discrete Wavelet Transform Object, Parameters and Functions
DWT Example Code 1D DWT/IDWT Demo Code
SWT Example Code 1D SWT/ISWT Demo Code
MODWT Example Code 1D MODWT/IMODWT Demo Code
WTREE Example Code WTREE Demo Code
DWPT Example Code 1D DWPT/IDWPT Demo Code
CWT Example Code 1D CWT/ICWT Demo Code
DWT2 Example Code 2D DWT/IDWT Demo Code
SWT2 Example Code 2D SWT/ISWT Demo Code
MODWT2 Example Code 2D MODWT/IMODWT Demo Code
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