計算機視覺實驗報告Experiment3

1、Experiment 3 : Edge DetectionClass:電子 1203 班 Student ID:1210910322 Name: 王影I . AimThe aim of this laboratory sessi on is to lear n to deal with image data by Matlab. By the end of thissessi on, you should be able to perform image preprocess ing of edge detect ion in spatial doma in and freque ncy do

2、ma in.n . Knowledge required in the Experimenti .You are supposed to have learned the basic skills of using Matlab;ii .You need to review Matlab programming Ianguage and M-file format.iii. You should have studied edge detect ion methods.川.Experiment ContentsDema nd: Please show the figure on the lef

3、t and list the codes on the right respectively bellow eachquestion.(請將運行結果(圖片)和程序代碼貼在每題下方)i . Read car.jpg file (to do this by imread function), convert the color image into grayscale image, and the n perform edge detecti on using Roterts, Prewitt, Sobel operator separately in spatial doma in and di

4、splay the results in a Matlab win dow.程序：clear;im=imread( 'car.jpg' );I=rgb2gray(im);subplot(3,2,1);imshow(I);title( 'Gray image' );Y,X=size(l);im_edge=zeros(Y,X);T=30;for k=2:Y-1for kk=2:X-1im_edge(k,kk)=abs(l(k+1,kk+1)-l(k,kk)+abs(l(k,kk+1)-l(k+1,kk);if (im_edge(k,kk)>T)im_edge(

5、k,kk)=1;elseim_edge(k,kk)=0;endendend subplot(3,2,2);imshow(im_edge,);% e ? e y?YX ? _ ? ?卩?0255 卩? ? §title( 'Robert image' );Y X=size(I);imedge=zeros(Y,X);for k=2:Y-1for kk=2:X-1imedge(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,

6、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-1for kk=2:X-1im_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(

7、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' );圖像如下ii. Read Car.jpg file (to do this by imread function), con vert the color image into grayscale image, the n perform edge detect ion in freque ncy

8、 doma in using Gaussia n Highpass filter and display the result i n a Matlab win dow.第二題程序：%頻域邊緣檢測，利用Gassian高通濾波器進行濾波，進行邊緣檢測%頻域邊緣檢測，利用Gassian高通濾波器進行濾波，進行邊緣檢測clear; im=imread('car.jpg');I=rgb2gray(im); subplot(1,2,1); imshow(I); title('gray image');%shifting image (multiply the image

9、by (_1)x+y)row,col=size(l);Y,X=meshgrid(1:col,1:row);Il=double(l).*(-1)A(X+Y);F=fft2(II);%subplot(2,2,2);%title('Fourier spectrum');%creat highpass filter% 傅立葉變換中心D=zeros(row,col);u0=floor(row/2);v0=floor(col/2);D0=40;%截止頻率n=2;for i=1:rowfor j=1:cold=(i-u0)A2+(j-v0)A2)A0.5;% D(i,j)=1/(1+(D0/d)A(2* n);D(i,j)=1-exp(-dA2)/(2*(D0)A2);endend%filteringG=F.*D;%Invert the result and shifting