I=imread('C:\Documents and Settings\lishurui\桌面\lena.bmp');
subplot(2,2,1);
imshow(I);
title('原始圖像');
h1=fspecial('sobel');
I1=filter2(h1,I);
subplot(2,2,2);
imshow(I1);title('sobel算子濾波');
h1=fspecial('prewitt');
I2=filter2(h1,I);
subplot(2,2,3);
imshow(I2);title('prewitt算子濾波');
h1=fspecial('log');
I3=filter2(h1,I);
subplot(2,2,4);
imshow(I1);title('log算子濾波');