Matlab實作圖像的輪廓提取

以二值圖像circles.png（黑色背景白色前景）為例，根據掏空内部點算法，運用Matlab程式設計實作二值圖像的輪廓提取。

I=imread('circles.png');   
[M,N]=size(I);
buffer=I;
for i=:M-
    for j=:N-
       if(I(i,j)==&I(i-,j)==&I(i+,j)==&I(i,j-)==&I(i,j+)==&I(i-,j-)==&I(i-,j+)==&I(i+,j-)==&I(i+,j+)==)%÷‹Œß8∏ˆµ„æ˘Œ™∞◊…´
            buffer(i,j)=;
       end
    end
end
subplot(,,);
imshow(I);
subplot(,,);
imshow(buffer);