计算机视觉实验报告Experiment3.doc

Experiment 3：Edge DetectionClass: 电子1203班 Student ID: 1210910322 Name: 王影 . AimThe aim of this laboratory session is to learn to deal with image data by Matlab. By the end of this session, you should be able to perform image preprocessing of edge detection in spatial domain and frequency domain. Knowledge required in the Experiment.You are supposed to have learned the basic skills of using Matlab;.You need to review Matlab programming language and M-file format. You should have studied edge detection methods. Experiment ContentsDemand: Please show the figure on the left and list the codes on the right respectively bellow each question.(请将运行结果(图片)和程序代码贴在每题下方).Read “car.jpg” file (to do this by imread function), convert the color image into grayscale image, and then perform edge detection using Roterts, Prewitt, Sobel operator separately in spatial domain and display the results in a Matlab window.程序：clear;im=imread(car.jpg); I=rgb2gray(im);subplot(3,2,1);imshow(I); title(Gray image); Y,X=size(I);im_edge=zeros(Y,X);T=30;for k=2:Y-1 for kk=2:X-1 im_edge(k,kk)=abs(I(k+1,kk+1)-I(k,kk)+abs(I(k,kk+1)-I(k+1,kk); if (im_edge(k,kk)T) im_edge(k,kk)=1; else im_edge(k,kk)=0; end endendsubplot(3,2,2);imshow(im_edge,);% 0255title(Robert image); Y X=size(I);imedge=zeros(Y,X); for k=2:Y-1 for kk=2:X-1 imedge(k,kk)=abs(I(k-1,kk+1)-I(k-1,kk-1)+abs(I(k,kk+1)-im(k,kk-1) + abs(I(k+1,kk+1)-I(k+1,kk-1)+. abs(I(k+1,kk -1)-I(k-1,kk-1)+abs(I(k+1, kk)-I(k-1, kk)+abs(I(k+1,kk+1)-I(k-1,kk+1) ; endendsubplot(3,2,3);imshow(imedge,);title(Prewit image); Y X=size(I);im_edge=zeros(Y,X); for k=2:Y-1 for kk=2:X-1 im_edge(k,kk)=abs(I(k-1,kk+1)-I(k-1,kk-1)+2*abs(I(k,kk+1)-I(k,kk-1) + abs(I(k+1,kk+1)-I(k+1,kk-1)+. abs(I(k+1,kk -1)-I(k-1,kk-1)+2*abs(I(k+1, kk)-I(k-1, kk)+abs(I(k+1,kk+1)-I(k-1,kk+1) ; endendsubplot(3,2,4);imshow(im_edge,);title(Sobel image);图像如下: . Read “car.jpg” file (to do this by imread function), convert the color image into grayscale image, then perform edge detection in frequency domain using Gaussian Highpass filter and display the result in a Matlab window.第二题程序：%频域边缘检测，利用Gassian高通滤波器进行滤波，进行边缘检测%频域边缘检测，利用Gassian高通滤波器进行滤波，进行边缘检测clear;im=imread(car.jpg);I=rgb2gray(im);subplot(1,2,1);imshow(I);title(gray image);%shifting image (multiply the image by (-1)x+y)row,col=size(I);Y,X=meshgrid(1:col,1:row);II=double(I).*(-1).(X+Y);F=fft2(II);%subplot(2,2,2);%title(Fourier spectrum);%creat highpass filterD=zeros(row,col);u0=floor(row/2); %傅立叶变换中心v0=floor(col/2); D0=40; %截止频率n=2;for i=1:row for j=1:col d=(i-u0)2+(j-v0)2)0.5; % D(i,j)=1/(1+(D0/d)(2*n); D(i,j)=1-exp(-d2)/(2*(D0)2); endend%filteringG=F.*D;%Invert the result an