I = imread('rice.tif');
BW1 = edge(I,'sobel');
BW2 = edge(I,'roberts');
BW3 = edge(I,'prewitt');
BW4 = edge(I,'log');
BW5 = edge(I,'canny');
h=fspecial(‘gaussian’,5);
BW6 = edge(I,'zerocross',[],h);
subplot(2,3,1),imshow(BW1)
subplot(2,3,2),imshow(BW2)
subplot(2,3,3),imshow(BW3)
subplot(2,3,4),imshow(BW4)
subplot(2,3,5),imshow(BW5)
subplot(2,3,6),imshow(BW6)