【数据分析】焊缝边缘检测算法对比分析 【含Matlab源码 260期】.zip

%% Canny clc,clear,close all im=imread('1.jpg'); % 载入图像 im=im2double(im); r=im(:,:,1);g=im(:,:,2);b=im(:,:,3); % 滤波器平滑系数 filter= [2 4 5 4 2; 4 9 12 9 4; 5 12 15 12 5; 4 9 12 9 4; 2 4 5 4 2]; filter=filter/115; % N-dimensional convolution smim= convn(im,filter); % imshow(smim);title('Smoothened image'); % 计算梯度 gradXfilt=[-1 0 1; % 卷积模板convolution mask -2 0 2; -1 0 1]; gradYfilt=[1 2 1; % 卷积模板 convolution mask 0 0 0; -1 -2 -1]; GradX= convn(smim,gradXfilt); GradY= convn(smim,gradYfilt); absgrad=abs(GradX)+abs(GradY); % computing angle of gradients [a,b]=size(GradX); theta=zeros([a b]); for i=1:a for j=1:b if(GradX(i,j)==0) theta(i,j)=atan(GradY(i,j)/0.000000000001); else theta(i,j)=atan(GradY(i,j)/GradX(i,j)); end end end theta=theta*(180/3.14); for i=1:a for j=1:b if(theta(i,j)<0) theta(i,j)= theta(i,j)-90; theta(i,j)=abs(theta(i,j)); end end end for i=1:a for j=1:b if ((0<theta(i,j))&&(theta(i,j)<22.5))||((157.5<theta(i,j))&&(theta(i,j)<181)) theta(i,j)=0; elseif (22.5<theta(i,j))&&(theta(i,j)<67.5) theta(i,j)=45; elseif (67.5<theta(i,j))&&(theta(i,j)<112.5) theta(i,j)=90; elseif (112.5<theta(i,j))&&(theta(i,j)<157.5) theta(i,j)=135; end end end %non-maximum suppression nmx = padarray(absgrad, [1 1]); [a,b]=size(theta); for i=2:a-2 for j=2:b-2 if (theta(i,j)==135) if ((nmx(i-1,j+1)>nmx(i,j))||(nmx(i+1,j-1)>nmx(i,j))) nmx(i,j)=0; end elseif (theta(i,j)==45) if ((nmx(i+1,j+1)>nmx(i,j))||(nmx(i-1,j-1)>nmx(i,j))) nmx(i,j)=0; end elseif (theta(i,j)==90) if ((nmx(i,j+1)>nmx(i,j))||(nmx(i,j-1)>nmx(i,j))) nmx(i,j)=0; end elseif (theta(i,j)==0) if ((nmx(i+1,j)>nmx(i,j))||(nmx(i-1,j)>nmx(i,j))) nmx(i,j)=0; end end end end nmx1=im2uint8(nmx); % 图像数据类型转换 tl=85; % 阈值下限lower threshold th=100; % 阈值上限upper threshold % grouping edges based on threshold [a,b]=size(nmx1); gedge=zeros([a,b]); for i=1:a for j=1:b if(nmx1(i,j)>th) gedge(i,j)=nmx1(i,j); elseif (tl<nmx1(i,j))&&(nmx1(i,j)<th) gedge(i,j)=nmx1(i,j); end end end [a,b]= size(gedge); finaledge=zeros([a b]); for i=1:a for j=1:b if (gedge(i,j)>th) finaledge(i,j)=gedge(i,j); for i2=(i-1):(i+1) for j2= (j-1):(j+1) if (gedge(i2,j2)>tl)&&(gedge(i2,j2)<th) finaledge(i2,j2)=gedge(i,j); end end end end end end %clearing the border finaledge= im2uint8(finaledge(10:end-10,10:end-10)); subplot(131);imshow(absgrad);title('image gradients'); subplot(132);imshow(nmx);title('NonMaximum Suppression'); subplot(133);imshow(finaledge(:,1:452-10));title('canny edge detection');