matlab如何添加自定义信噪比的噪声信号？

clear all

close all

x=0:0.2:10

data1=sin(x)

plot(x,data1)

hold on

data2=awgn(data1,10*log10(0.05))

plot(x,data2,'r-')

hold off

扩展资料

matlab添加白噪声叠加到信号：

function [Y,NOISE] = noisegen(X,SNR)

% noisegen add white Gaussian noise to a signal.

% [Y, NOISE] = NOISEGEN(X,SNR) adds white Gaussian NOISE to X.  The SNR is in dB.

NOISE=randn(size(X))

NOISE=NOISE-mean(NOISE)

signal_power = 1/length(X)*sum(X.*X)

noise_variance = signal_power / ( 10^(SNR/10) )

NOISE=sqrt(noise_variance)/std(NOISE)*NOISE

Y=X+NOISE

其中X是纯信号，SNR是要求的信噪比，Y是带噪信号，NOISE是叠加在信号上的噪声。

1、添加的是20%的随即噪声

image=double(image)

I=image+20*randn(size(image))

figureimshow(uint8(I))

title('noised image')

[a1,h1,v1,d1]=dwt2(I,'sym8')

[a2,h2,v2,d2]=dwt2(a1,'sym8')

[a3,h3,v3,d3]=dwt2(a2,'sym8')

sigma=median(abs(d1(:)))/0.6745

thr1=thr*2^(-(3-1)/2)

thr2=thr*2^(-(3-2)/2)thr3=thr*2^(-(3-3)/2)

ccch=soft_t(h3,thr1)cccv=soft_t(v3,thr1)cccd=soft_t(d3,thr1)cch=soft_t(h2,thr2)ccv=soft_t(v2,thr2)ccd=soft_t(d2,thr2)ch=soft_t(h1,thr3)cv=soft_t(v1,thr3)cd=soft_t(d1,thr3)

cca=idwt2(a3,ccch,cccv,cccd,'sym8')ca=idwt2(cca,cch,ccv,ccd,'sym8')J1=idwt2(ca,ch,cv,cd,'sym8')J1=uint8(J1)

figureimshow(J1)title('denoised image')p=psnr(image,J1)

2、加高斯白噪声

image=double(image)

I=awgn(image,5)%加入信噪比为5分贝的高斯白噪声

figureimshow(uint8(I))title('noised image')

注：源代码是计算机语言，不能随便用自己语言的。

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