如何在matlab程序的图像中添加高斯白噪声?

如何在matlab程序的图像中添加高斯白噪声?% 小波变换,加噪,去噪,增强% 《Denoising and contrast enhancement via wavelet shrinkage and nonlinear adaptive gain》clear; clcimage=imread('555.jpg');image=imread('555.jpg');figure; imshow(image); title('the original image');% 加噪image=double(image);I=image+20*randn(size(image));figure; imshow(uint8(I)); title('noised image');% 小波分解dwtmode('per');[a1,h1,v1,d1]=dwt2(I,'sym8'); % 从1到3分辨率递减[a2,h2,v2,d2]=dwt2(a1,'sym8');[a3,h3,v3,d3]=dwt2(a2,'sym8');% 计算去噪时的阈值sigma=median(abs(d1(:)))/0.6745; % 确定噪声标准差thr=2*sigma; % 权值根据实际情况选取thr1=thr*2^(-(3-1)/2); % 分层阈值,从1到3分辨率递增,即这里的th1对应于小波系数的第3层thr2=thr*2^(-(3-2)/2);thr3=thr*2^(-(3-3)/2);% 去噪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);% 重构去噪图像cca=idwt2(a3,ccch,cccv,cccd,'sym8');ca=idwt2(cca,cch,ccv,ccd,'sym8');J1=idwt2(ca,ch,cv,cd,'sym8');J1=uint8(J1);figure; imshow(J1); title('denoised image');p=psnr(image,J1)就是这个程序,它原本是添加随即噪声的,我想问下怎么改成添加高斯白噪声?我自己试着添加了一下 结果出现?Error using ==> imnoiseA double-class image must have values between zero and one.