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commit : sureshrink init

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This commit is contained in:
Rafat Hussain 2017-08-08 18:20:20 +05:30
parent ede7d68eb0
commit cb01ae39ec
2 changed files with 129 additions and 1 deletions
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127
denoise/denoise.c
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@ -41,6 +41,23 @@ double mad(double *x, int N) {
return sigma;
}
int minindex(double *arr, int N) {
double min;
int index,i;
min = DBL_MAX;
index = 0;
for(i = 0; i < N;++i) {
if (arr[i] < min) {
min = arr[i];
index = i;
}
}
return index;
}
void getDWTAppx(wt_object wt, double *appx,int N) {
/*
Wavelet decomposition is stored as
@ -89,6 +106,7 @@ void visushrink(double *signal,int N,char *wname,char *method,char *ext,char *th
double sigma,td,tmp;
wave_object wave;
wt_object wt;
double *dout;
wave = wave_init(wname);
@ -110,11 +128,17 @@ void visushrink(double *signal,int N,char *wname,char *method,char *ext,char *th
iter = wt->length[0];
dlen = wt->length[J];
dout = (double*)malloc(sizeof(double) * dlen);
for (i = 1; i < J; ++i) {
iter += wt->length[i];
}
sigma = mad(wt->output+iter,dlen);
for(i = 0; i < dlen;++i) {
dout[i] = wt->output[iter+i];
}
sigma = mad(dout,dlen);
dwt_len = wt->outlength;
td = sqrt(2.0 * log(dwt_len)) * sigma / 0.6745;
@ -139,6 +163,107 @@ void visushrink(double *signal,int N,char *wname,char *method,char *ext,char *th
idwt(wt,denoised);
free(dout);
wave_free(wave);
wt_free(wt);
}
void sureshrink(double *signal,int N,char *wname,char *method,char *ext,char *thresh,double *denoised) {
int J, filt_len,i,it,len,dlen,dwt_len,min_index,sgn;
double sigma,norm,td,tv,te,ct,thr,temp,x_sum;
wave_object wave;
wt_object wt;
double *dout,*risk;
wave = wave_init(wname);
filt_len = wave->filtlength;
J = (int) (log((double)N / ((double)filt_len - 1.0)) / log(2.0));
if (J > 50) {
J = 50;
}
wt = wt_init(wave,method,N,J);
setDWTExtension(wt,ext);
dwt(wt,signal);
len = wt->length[0];
dlen = wt->length[J];
dout = (double*)malloc(sizeof(double) * dlen);
risk = (double*)malloc(sizeof(double) * dlen);
for(it = 0; it < J;++it) {
dwt_len = wt->length[it+1];
for(i = 0; i < dlen;++i) {
dout[i] = wt->output[len+i];
}
sigma = mad(dout,dwt_len);
if ( sigma < 0.00000001) {
td = 0;
} else {
tv = sqrt(2.0 * log(dwt_len));
norm = 0.0;
for(i = 0; i < dwt_len;++i) {
norm += (wt->output[len+i] *wt->output[len+i]);
}
te =(norm - (double) dwt_len)/(double) dwt_len;
ct = pow(log((double) dwt_len)/log(2.0),1.5)/sqrt((double) dwt_len);
if (te < ct) {
td = tv;
} else {
x_sum = 0.0;
for(i = 0; i < dwt_len;++i) {
dout[i] = (dout[i]*dout[i]);
x_sum += dout[i];
}
for(i = 0;i < dwt_len;++i) {
risk[i] = ((double)dwt_len + 1 - 2 * ((double)i + 1) +x_sum +
dout[i]*((double)dwt_len - 1 -(double) i))/(double)dwt_len;
}
min_index = minindex(risk,dwt_len);
thr = sqrt(dout[min_index]);
td = thr < tv ? thr : tv;
}
}
td = td * sigma / 0.6745;
if(!strcmp(thresh,"hard")) {
for(i = 0; i < dwt_len;++i) {
if (fabs(wt->output[len+i]) < td) {
wt->output[i] = 0;
}
}
} else if(!strcmp(thresh,"soft")) {
for(i = 0; i < dwt_len;++i) {
if (fabs(wt->output[len + i]) < td) {
wt->output[i] = 0;
} else {
sgn = wt->output[len+i] >= 0 ? 1 : -1;
temp = sgn * (fabs(wt->output[len+i]) - td);
wt->output[i] = temp;
}
}
}
len += wt->length[it+1];
}
idwt(wt,denoised);
free(dout);
free(risk);
wave_free(wave);
wt_free(wt);
}

3
denoise/denoise.h
View File

@ -7,6 +7,7 @@ Copyright (c) 2017, Rafat Hussain
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <float.h>
#include <math.h>
#include "../header/wavelib.h"
@ -17,6 +18,8 @@ extern "C" {
void visushrink(double *signal,int N,char *wname,char *method,char *ext,char *thresh,double *denoised);
void sureshrink(double *signal,int N,char *wname,char *method,char *ext,char *thresh,double *denoised);
double mad(double *x, int N);