SRAD去斑点噪声程序

%CCTV笔记本基于各向异性扩散的b超图像去噪 % Implementation of SRAD Filter % Ref :Yongjian Yu and Scott T. Acton, "Speckle Reducing Anisotropic % Diffusion",IEEE TRANSACTIONS ON IMAGE PROCESSING, VOL. 11, NO. 11, NOVEMBER 2002 % Jeny Rajan, Chandrashekar P.S % usage S=srad(I,T) % I- noisy image % T - threshold (greater than 0). function S=srad(I,T) tic%tic加toc求程序运算时间 [x y]=size(I); %I=double(I);%处理是要把图像转为double型 Ic=double(I); delta_t = 0.08; t=1; eps=0.00000000001;%srad处理时不能出现像素为0的点，因此在图像基础上加上eps值 for t=1:T qt=exp(-t*.2);%srad中估计均匀区域的q0（t）值 [Ix,Iy] = gradient(Ic); %求图像的梯度值 di=sqrt(Ix.^2+Iy.^2);%合成梯度两个方向的总梯度值 di2=del2(Ic);%拉普拉斯算子 T1=0.5*((di./(Ic+eps)).^2); T2=0.0625*((di2./(Ic+eps)).^2); T3=(1+(0.25*(di2./(Ic+eps)))).^2; T=sqrt((T1-T2)./(T3+eps)); dd=(T.^2-qt.^2)./((qt.^2*(1+qt.^2)+eps)); cq=1./(1+dd); [D1,D2]=gradient(cq.*Ix);% .*完成矩阵对应元素相乘 [D3,D4]=gradient(cq.*Iy); D=D1+D4; Ic=real(Ic+delta_t .*D); end toc %%for j=3:y-2 %Ic(i-2,j-2)=Ic(i,j); %end %end S=uint8(Ic);