Codes.rar_gauss_mothert4r_乘性噪声 matlab_双边滤波_双边滤波快速

%% ENL和EPI随着sigma_r的变化 clear; clc; %% 读取相应的图像和配置参数 f = imread('test.jpg'); if size(f,3) ~=1 f=f(:,:,1); end if ~strcmp( class(f),'double' ) f=im2double(f); end N = 5; % bilateral filtering half-window % draw the ENL and EPI variation with sigma_r ENL=zeros(10,1); EPI=zeros(10,1); %设置收敛条件，即精度 epsilon = 0.0001; %计时开始 tic %对每个sigma_r进行双边滤波 for i=1:10 sigma_r=0.05+0.05*i; img1 = bilateral(f,N,2,sigma_r); ENL(i)=enl(img1); EPI(i) = epi(f,img1); end %归一化 ENL=ENL/max(ENL); EPI=EPI/max(EPI); % 指定sigma_r的初始值 start=0.1; %对归一化后的ENL和EPI进行四次多项式拟合 x=linspace(0.1,0.55,10); enlc=polyfit(x',ENL,4); epic=polyfit(x',EPI,4); %判断起始点位于交点的左边还是右边 1表示左边，0表示右边 direction = 1; enly1=enlc(1)*start^4+enlc(2)*start^3+enlc(3)*start^2+enlc(4)*start+enlc(5); epiy1=epic(1)*start^4+epic(2)*start^3+epic(3)*start^2+epic(4)*start+epic(5); if enly1 > epiy1 direction = 0; end %开始进行迭代 constant = 1; if direction == 1 enlx1=start; loop_counter=0; while(constant == 1) epix2=solve_equation(epic,enly1); enly3=enlc(1)*epix2^4+enlc(2)*epix2^3+enlc(3)*epix2^2+enlc(4)*epix2+enlc(5); epix4=solve_equation(epic,enly3); enly1=enlc(1)*epix4^4+enlc(2)*epix4^3+enlc(3)*epix4^2+enlc(4)*epix4+enlc(5); loop_counter=loop_counter+1 abs(enlx1-epix4) if abs(enlx1-epix4) < epsilon epix4 break; end enlx1=epix4; end else epix1=start; while(constant == 1) enly2=enlc(1)*epix1^4+enlc(2)*epix1^3+enlc(3)*epix1^2+enlc(4)*epix1+enlc(5); epix3=solve_equation(epic,enly2); enly4=enlc(1)*epix3^4+enlc(2)*epix3^3+enlc(3)*epix3^2+enlc(4)*epix3+enlc(5); epix5=solve_equation(epic,enly4); abs(epix1-epix5) if abs(epix1-epix5) < epsilon epix5 break; end epix1=epix5; end end %计时结束 toc