function?denoisedemo
%?DENOISEDEMO???Denoise?demo
%?Compare?the?denoise?performance?of?wavelet?and?contourlet?transforms
%?Note:?Noise?standard?deviation?estimation?of?PDFB?（function?pdfb_nest）?
%?can?take?a?while...

%?Parameters
pfilt?=?‘9-7‘;
dfilt?=?‘pkva‘;
nlevs?=?[0?0?4?4?5];????%?Number?of?levels?for?DFB?at?each?pyramidal?level
th?=?3;?????????????????????%?lead?to?3*sigma?threshold?denoising
rho?=?3;????????????????????%?noise?level

%?Test?image:?the?usual?suspect...
im?=?imread（‘lena.png‘）;
im?=?double（im）?/?256;

%?Generate?noisy?image.?
sig?=?std（im（:））;
sigma?=?sig?/?rho;
nim?=?im?+?sigma?*?randn（size（im））;


%%%%%?Wavelet?denoising?%%%%%
%?Wavelet?transform?using?PDFB?with?zero?number?of?level?for?DFB
y?=?pdfbdec（nim?pfilt?dfilt?zeros（length（nlevs）?1））;
[c?s]?=?pdfb2vec（y）;

%?Threshold?（typically?3*sigma）
wth?=?th?*?sigma;
c?=?c?.*?（abs（c）?>?wth）;

%?Reconstruction
y?=?vec2pdfb（c?s）;
wim?=?pdfbrec（y?pfilt?dfilt）;


%%%%%?Contourlet?Denoising?%%%%%
%?Contourlet?transform
y?=?pdfbdec（nim?pfilt?dfilt?nlevs）;
[c?s]?=?pdfb2vec（y）;

%?Threshold
%?Require?to?estimate?the?noise?standard?deviation?in?the?PDFB?domain?first?
%?since?PDFB?is?not?an?orthogonal?transform
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