MyYuanLaiPic = imread('e:/image/matlab/darkMouse.jpg');%讀取RGB格式的圖像?
MyFirstGrayPic = rgb2gray(MyYuanLaiPic);%用已有的函數進行RGB到灰度圖像的轉換?
?
[rows , cols , colors] = size(MyYuanLaiPic);%得到原來圖像的矩陣的參數?
MidGrayPic = zeros(rows , cols);%用得到的參數創建一個全零的矩陣，這個矩陣用來存儲用下面的方法產生的灰度圖像?
MidGrayPic = uint8(MidGrayPic);%將創建的全零矩陣轉化為uint8格式，因為用上面的語句創建之后圖像是double型的?
?
for i = 1:rows?
??? for j = 1:cols?
??????? sum = 0;?
??????? for k = 1:colors?
??????????? sum = sum + MyYuanLaiPic(i , j , k) / 3;%進行轉化的關鍵公式，sum每次都因為后面的數字而不能超過255?
??????? end?
??????? MidGrayPic(i , j) = sum;?
??? end?
end?
imwrite(MidGrayPic , 'E:/image/matlab/DarkMouseGray.png' , 'png');?
?
%顯示原來的RGB圖像?
figure(1);?
imshow(MyYuanLaiPic);?
?
%顯示經過系統函數運算過的灰度圖像?
figure(2);?
imshow(MyFirstGrayPic);?
?
%顯示轉化之后的灰度圖像?
figure(3);?
imshow(MidGrayPic);

?

當然還可以用RGB轉YUV圖像，從而可以獲取得到Y圖像，以此獲得灰度圖像