本文系《数字图像处理原理与实践（MATLAB版）》一书之代码系列的Part4，辑录该书第135至第183页之代码，供有需要读者下载研究使用。代码执行结果请参见原书配图，建议下载代码前阅读下文：关于《数字图像处理原理与实践（MATLAB版）》一书代码发布的说明P139original = imread(‘snowflakes.png’);figure, imshow(original);se = strel(‘disk’,5);afterOpening = imopen(original,se);figure, imshow(afterOpening,[]);P140originalBW = imread(‘circles.png’);imshow(originalBW);se = strel(‘disk’,10);closeBW = imclose(originalBW,se);figure, imshow(closeBW)P144bw = imread(‘bw.bmp’);shape1 = [0 0 0 0 1 0 0 0 1 1 0 0 1 1 1 0 1 1 1 1 1 1 1 1 1];shape2 = [1 1 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0];bw2 = bwhitmiss(bw, shape1, shape2);imshow(bw2)P146-1I = imread(‘letter2.jpg’);I = im2bw(I);I1 = bwmorph(I, ‘thin’,inf);figure(1), imshow(I1);P146-2I = imread(‘letter2.jpg’);I = im2bw(I);I2 = bwmorph(I, ‘skel’,inf);figure(2), imshow(I2);P153I = imread(‘lena.jpg’);I = rgb2gray(I);BW1 = edge(I, ‘roberts’);BW2 = edge(I, ‘sobel’);BW3 = edge(I, ‘prewitt’);figuresubplot(2,2,1),imshow(I),title(‘original’)subplot(2,2,2),imshow(BW1),title(‘roberts’)subplot(2,2,3),imshow(BW2),title(‘sobel’)subplot(2,2,4),imshow(BW3),title(‘prewitt’)P157I = imread(‘einstein.bmp’);I = rgb2gray(I);N = [1, 2, 1 0, 0, 0 -1,-2,-1];edge_n = imfilter(I,N,’symmetric’,’conv’);imwrite(edge_n, ‘edge_n.jpg’);P160I = rgb2gray(imread(‘lena.jpg’));M = [1,1,1 1,-8,1 1,1,1];img=imfilter(I,M);[x,y]=size(I);img2 = img;for i = 2:x-1 for j = 2:y-1 a = [img(i,j+1),img(i,j-1),img(i+1,j+1),img(i+1,j-1), … img(i-1,j+1),img(i-1,j-1),img(i+1,j),img(i-1,j)]; if ( (max(a)-min(a))>64 && max(a)>img(i,j) && min(a)<img(i,j)) img2(i,j)=255; else img2(i,j)=0; end endendP165I = imread(‘lena.jpg’);IMG = rgb2gray(I);Edge_LoG = edge(IMG, ‘log’);imshow(Edge_LoG);figuresubplot(1,2,1), imshow(IMG);subplot(1,2,2), imshow(Edge_LoG);P167I = double(rgb2gray(imread(‘lena.jpg’)));figure, imshow(uint8(I))DoG=fspecial(‘gaussian’,5,0.8)-fspecial(‘gaussian’,5,0.6);ImageDoG=imfilter(I,DoG,’symmetric’,’conv’);figure, imshow(ImageDoG)% threshold = 2proc_Img1 = ImageDoG;proc_Img1(find(proc_Img1 < 2))=0;figure, imshow(proc_Img1)% threshold = 3proc_Img2 = ImageDoG;proc_Img2(find(proc_Img2 < 3))=0;figure, imshow(proc_Img2)P172img = edge(I, ‘canny’,[0.032,0.08], 3);P183RGB= imread(‘building.jpg’);I = rgb2gray(RGB);BW = edge(I, ‘canny’);[H, T, R]=hough(BW, ‘RhoResolution’,0.5,’ThetaResolution’,0.5);figure, imshow(imadjust(mat2gray(H)), ‘XData’, T, …’YData’, R, ‘InitialMagnification’, ‘fit’);xlabel(‘\theta’), ylabel(‘\rho’);axis on; axis normal; hold on;colormap(hot);peaks = houghpeaks(H, 15);figure, imshow(BW);hold on;lines = houghlines(BW, T, R, peaks, ‘FillGap’,25, ‘MinLength’,15);max_len = 0;for k=1:length(lines)xy = [lines(k).point1; lines(k).point2]; plot(xy(:,1),xy(:,2),’LineWidth’,3,’Color’,’b’); plot(xy(1,1),xy(1,2),’x’,’LineWidth’,3,’Color’,’yellow’); plot(xy(2,1),xy(2,2),’x’,’LineWidth’,3,’Color’,’red’); len = norm(lines(k).point1 – lines(k).point2); if ( len > max_len) max_len = len; xy_long = xy; endend（代码发布未完，，请待后续…）
人之所以能，是相信能。
