Generating MATLAB Code for 2-D Wavelet Packet Denoising and Compression

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2-D Wavelet Packet Compression

2-D Wavelet Packet Compression

You can generate MATLAB code to reproduce GUI–based 2-D wavelet packet compression at the command line. You must perform this operation in the Wavelet 2-D - - Compression tool. You must first compress your image before you can enable the File > Generate Matlab Code (Compression Process) operation.

1. Enter wavemenu at the MATLAB command prompt.

2. Select Wavelet Packet 2-D.

3. Select File > Load > Example Analysis > Indexed Images, and load the tire.

   

4. Using the default parameter settings, click Best Tree.

   

5. Click Compress.

6. Set Select thresholding method to Bal.sparsity-norm (sqrt).

7. Click Compress.

   

8. File > Generate Code (Compression Process) generates the following code.

   function [XCMP,wptCMP] = func_compress_wp2d(X)
   % FUNC_COMPRESS_WP2D Saved Compression Process.
   %   X: matrix of data
   %   -----------------
   %   XCMP: matrix of compressed data
   %   wptCMP: wavelet packet decomposition (wptree object)
   
   % Analysis parameters.
   %---------------------
   Wav_Nam = 'haar';
   Lev_Anal = 2;
   Ent_Nam = 'shannon';
   Ent_Par = 0;
   
   % Compression parameters.
   %-----------------------
   % meth = 'sqrtbal_sn';
   sorh = 'h';    % Specified soft or hard thresholding
   thrSettings = {sorh,'nobest',16.499999999999886,1};
   roundFLAG = true;
   
   % Decompose using WPDEC2.
   %-----------------------
   wpt = wpdec2(X,Lev_Anal,Wav_Nam,Ent_Nam,Ent_Par);
   
   % Nodes to merge.
   %-----------------
   n2m = [2  3];
   for j = 1:length(n2m)
       wpt = wpjoin(wpt,n2m(j));
   end
   
   % Compression using WPDENCMP.
   %----------------------------
   [XCMP,wptCMP] = wpdencmp(wpt,thrSettings{:});
   if roundFLAG , XCMP = round(XCMP); end
   if isequal(class(X),'uint8') , XCMP = uint8(XCMP); end

9. Save the generated MATLAB code as func_compress_wp2d.m in a folder on the MATLAB search path, and execute the following code.

   load tire;
   [XCMP,wptCMP] = func_compress_wp2d(X);

10. Save the compressed image from the Wavelet 2-D -- Compression tool as compressed_tire.mat in a folder on the MATLAB search path. Use File > Save > Compressed Image to save the compressed image.

11. Execute the following code to compare the command line and GUI result.

    load compressed_tire.mat;
    norm(XCMP-X,2)

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Generating MATLAB Code for 1-D Wavelet Packet Denoising and Compression

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