cv::是名稱空間，如果程式頭部添上using namespace cv;那麼imread和cv::imread就一樣了。　　函式imread用於讀取圖片檔案中的資料。在matlab的命令視窗中輸入doc imread或者help imread即可獲得該函式的幫助資訊。　　呼叫格式　　A = imread(filename,fmt)　　[X,map] = imread(filename,fmt)　　[...] = imread(filename)　　[...] = imread(URL,...)　　[...] = imread(...,idx) (CUR, GIF, ICO, and TIFF only)　　[...] = imread(...,"PixelRegion",{ROWS, COLS}) (TIFF only)　　[...] = imread(...,"frames",idx) (GIF only)　　[...] = imread(...,ref) (HDF only)　　[...] = imread(...,"BackgroundColor",BG) (PNG only)　　[A,map,alpha] = imread(...) (ICO, CUR, and PNG only