基于matlab数字图像处理之高通滤波器.doc

实践二: 理想高通滤波器、Butterworth高通滤波器、高斯高通滤波器2.1.1 理想高通滤波器实践代码： I=imread(girl.bmp);subplot(221),imshow(I);title(原图像);s=fftshift(fft2(I);subplot(223),imshow(abs(s),);title(图像傅里叶变换所得频谱);subplot(224),imshow(log(abs(s),);title(图像傅里叶变换取对数所得频谱);a,b=size(s);a0=round(a/2);b0=round(b/2);d=10;p=0.2;q=0.5;for i=1:a for j=1:b distance=sqrt(i-a0)2+(j-b0)2); if distance=d h=0; else h=1; end; s(i,j)=(p+q*h)*s(i,j); end;end;s=uint8(real(ifft2(ifftshift(s);subplot(222),imshow(s);title(高通滤波所得图像);I=imread(girl.bmp);f1,f2=freqspace(size(I),meshgrid);Hd=ones(size(I);r=sqrt(f1.2+f2.2);Hd(r0.2)=0;figuresurf(Hd,Facecolor,interp,Edgecolor,none,Facelighting,phong); % 画三维曲面（色）图2.1.2 理想高通滤波器实践结果截图：2.2.1 Butterworth高通滤波器实践代码：I1=imread(flower.bmp);subplot(121),imshow(I1);title(原始图像);f=double(I1);g=fft2(f);g=fftshift(g);N1,N2=size(g);n=2;d0=5;n1=fix(N1/2);n2=fix(N2/2);for i=1:N1 for j=1:N2 d=sqrt(i-n1)2+(j-n2)2); if d=0 h=0; else h=1/(1+(d0/d)(2*n); end result(i,j)=h*g(i,j); endendresult=ifftshift(result);X2=ifft2(result);X3=uint8(real(X2);subplot(122),imshow(X3) ;title(Butterworth高通滤波);I1=imread(flower.bmp);f1,f2=freqspace(size(I1),meshgrid);D=0.3;r=f1.2+f2.2;n=4;for i=1:size(I1,1) for j=1:size(I1,2) t=(D*D)/r(i,j); Hd(i,j)=1/(tn+1); endendfiguresurf(Hd,Facecolor,interp,Edgecolor,none,Facelighting,phong); % 画三维曲面（色）图2.2.2 Butterworth高通滤波器实践结果截图：2.3.1 高斯高通滤波器实践代码：clear allIA=imread(girl.bmp); f1,f2=freqspace(size(IA),meshgrid);%D=100/size(IA,1);D=0.3;r=f1.2+f2.2;for i=1:size(IA,1) for j=1:size(IA,2) t=r(i,j)/(D*D); Hd(i,j)=1-exp(-t); endendY=fft2(double(IA);Y=fftshift(Y);Ya=Y.*Hd;Ya=ifftshift(Ya);Ia=real(ifft2(Ya);figuresubplot(2,2,1),imshow(uint8(IA);title(原始图像);subplot(2,2,2),imshow(uint8(Ia);title(高斯高通滤