1、醫(yī)學(xué)圖像處理 實(shí)驗(yàn)三1、 計(jì)算圖像的梯度，梯度值和梯度角。I=imread('C:UsersAdministratorDesktopcat.jpg');B=rgb2gray(I);C=double(B);e=1e-6;%10-6dx,dy=gradient(C);%計(jì)算梯度G=sqrt(dx.*dx+dy.*dy);%梯度幅值figure,imshow(uint8(G),title('梯度圖像');pha=atan(dy./(dx+e)figure,imshow(pha,)圖 1圖 2 梯度角圖2、 計(jì)算圖像邊緣檢測(cè)，用濾波器方式實(shí)現(xiàn)各種算子。（1）Robert

2、s算子clear;I=imread('C:UsersadminDesktopmao.jpg');B=rgb2gray(I);m,n=size(B);nB=B;robertsnum=0;%經(jīng)roberts算子計(jì)算得到的每一個(gè)像素的值robertsthreshold=0.6;%設(shè)定閾值for j=1:m-1;%進(jìn)行邊界提取 for k=1:n-1 robertsnum=abs(B(j,k)-B(j+1,k+1)+abs(B(j+1,k)-B(j,k+1); if(robertsnum>robertsthreshold) nB(j,k)=255; else nB(j,k)=0;

3、 end endendsubplot(1,2,1);imshow(B);title('原圖');subplot(1,2,2);imshow(nB,);title('Robert算子處理后的圖像');圖 3（2）Sobel算子clear;I=imread('C:UsersadminDesktopmao.jpg');B=rgb2gray(I);m,n=size(B);f=double(B);u=double(B);usobel=B;for i=2:m-1%sobel邊緣檢測(cè) for j=2:n-1; gx=(u(i+1,j-1)+2*u(i+1,j)

4、+f(i+1,j+1)-(u(i-1,j-1)+2*u(i-1,j)+f(i-1,j+1); gy=(u(i-1,j+1)+2*u(i,j+1)+f(i+1,j+1)-(u(i-1,j-1)+2*u(i,j-1)+f(i+1,j-1); usobel(i,j)=sqrt(gx2+gy2); endendsubplot(1,2,1);imshow(B);title('原圖');subplot(1,2,2);imshow(im2uint8(usobel);title('Sobel邊緣檢測(cè)后的圖像');圖 4（3）Prewitt算子clear;I=imread(

5、9;C:UsersadminDesktopmao.jpg');B=rgb2gray(I);m,n=size(B);nB=B;prewittnum=0;%經(jīng)prewitt算子計(jì)算得到的每一個(gè)像素的值prewittthreshold=0.6;%設(shè)定閾值for j=2:m-1;%進(jìn)行邊界提取 for k=2:n-1 prewittnum=abs(B(j-1,k+1)-B(j+1,k+1)+B(j-1,k)-B(j+1,k)+B(j-1,k-1)-B(j+1,k-1)+abs(B(j-1,k+1)+B(j,k+1)+B(j+1,k+1)-B(j-1,k-1)-B(j,k-1)-B(j+1,k-

6、1); if(prewittnum>prewittthreshold) nB(j,k)=255; else nB(j,k)=0; end endendsubplot(1,2,1);imshow(B);title('原圖');subplot(1,2,2);imshow(nB,);title('Prewitt算子處理后的圖像');圖 5（4）Laplace邊緣檢測(cè)function flapEdge=LaplaceEdge(pic,Moldtype,thresh)m,n=size(pic);flapEdge=zeros(m,n);%四鄰域拉普拉斯邊緣檢測(cè)算子if

7、 4=Moldtype for i=2:m-1 for j=2:n-1 temp=-4*pic(i,j)+pic(i-1,j)+pic(i+1,j)+pic(i,j-1)+pic(i,j+1); if temp>thresh flapEdge(i,j)=255; else flapEdge(i,j)=0; end end endend%八鄰域拉普拉斯邊緣檢測(cè)算子if 8=Moldtype for i=2:m-1 for j=2:n-1 temp=-8*pic(i,j)+pic(i-1,j)+pic(i+1,j)+pic(i,j-1)+pic(i,j+1)+pic(i-1,j-1)+pic

8、(i+1,j+1)+pic(i+1,j-1)+pic(i-1,j+1); if temp>thresh flapEdge(i,j)=255; else flapEdge(i,j)=0; end end endend主函數(shù)：clear;I=imread('C:UsersadminDesktopmao.jpg');B=rgb2gray(I);C=double(B);t=60;Lapmodtype=8;%設(shè)置模板方式flapEdge=LaplaceEdge(C,Lapmodtype,t);fgrayLapedge=uint8(flapEdge);figure()imshow(f

9、grayLapedge),title('laplace邊緣檢測(cè)圖像');圖 6（4）Kirsch算子clear clc close all I=imread('C:UsersadminDesktopmao.jpg');B=rgb2gray(I);figure(1) imshow(B,) title('原始圖象') %對(duì)圖象進(jìn)行均值濾波 bw2=filter2(fspecial('average',3),B); %對(duì)圖象進(jìn)行高斯濾波 bw3=filter2(fspecial('gaussian'),bw2); %利用

10、小波變換對(duì)圖象進(jìn)行降噪處理 thr,sorh,keepapp=ddencmp('den','wv',bw3); %獲得除噪的缺省參數(shù) bw4=wdencmp('gbl',bw3,'sym4',2,thr,sorh,keepapp);%圖象進(jìn)行降噪處理 %- %提取圖象邊緣 t=3000; %設(shè)定閾值 bw5=double(bw4); m,n=size(bw5); g=zeros(m,n); d=zeros(1,8); %利用Kirsch算子進(jìn)行邊緣提取 for i=2:m-1 for j=2:n-1 d(1) =(5*bw5(i-

11、1,j-1)+5*bw5(i-1,j)+5*bw5(i-1,j+1)-3*bw5(i,j-1)-3*bw5(i,j+1)-3*bw5(i+1,j-1)-3*bw5(i+1,j)-3*bw5(i+1,j+1)2; d(2) =(-3)*bw5(i-1,j-1)+5*bw5(i-1,j)+5*bw5(i-1,j+1)-3*bw5(i,j-1)+5*bw5(i,j+1)-3*bw5(i+1,j-1)-3*bw5(i+1,j)-3*bw5(i+1,j+1)2; d(3) =(-3)*bw5(i-1,j-1)-3*bw5(i-1,j)+5*bw5(i-1,j+1)-3*bw5(i,j-1)+5*bw5(

12、i,j+1)-3*bw5(i+1,j-1)-3*bw5(i+1,j)+5*bw5(i+1,j+1)2; d(4) =(-3)*bw5(i-1,j-1)-3*bw5(i-1,j)-3*bw5(i-1,j+1)-3*bw5(i,j-1)+5*bw5(i,j+1)-3*bw5(i+1,j-1)+5*bw5(i+1,j)+5*bw5(i+1,j+1)2; d(5) =(-3)*bw5(i-1,j-1)-3*bw5(i-1,j)-3*bw5(i-1,j+1)-3*bw5(i,j-1)-3*bw5(i,j+1)+5*bw5(i+1,j-1)+5*bw5(i+1,j)+5*bw5(i+1,j+1)2; d(

13、6) =(-3)*bw5(i-1,j-1)-3*bw5(i-1,j)-3*bw5(i-1,j+1)+5*bw5(i,j-1)-3*bw5(i,j+1)+5*bw5(i+1,j-1)+5*bw5(i+1,j)-3*bw5(i+1,j+1)2; d(7) =(5*bw5(i-1,j-1)-3*bw5(i-1,j)-3*bw5(i-1,j+1)+5*bw5(i,j-1)-3*bw5(i,j+1)+5*bw5(i+1,j-1)-3*bw5(i+1,j)-3*bw5(i+1,j+1)2; d(8) =(5*bw5(i-1,j-1)+5*bw5(i-1,j)-3*bw5(i-1,j+1)+5*bw5(i,

14、j-1)-3*bw5(i,j+1)-3*bw5(i+1,j-1)-3*bw5(i+1,j)-3*bw5(i+1,j+1)2; g(i,j) = max(d); end end %顯示邊緣提取后的圖象 for i=1:m for j=1:n if g(i,j)>t bw5(i,j)=255; else bw5(i,j)=0; end end end figure(2) imshow(bw5,) title('Kirsch ') 圖 7（5）LoG和canny算子clear;I=imread('C:UsersadminDesktopmao.jpg');B=rgb2gray(I);bw1=edge(B,'log',0.01);bw3=edge(B,'canny',0.1);figure;subplot(1,2,1);imsho