The contour of marbling standards, referring to the outer boundary of meat, was obtained by using a thresholding technique and an edge detection algorithm. The thresholding technique (Jain, 1989) transforms a gray-level image (the green channel of marbling standards) to a binary image (i.e. black and white image). The grey-level of 200 was used as threshold (the range of gray-levels varies from 0 to 255). Pixels whose values are higher than the threshold are closed (set to 0), otherwise are open (set to 1). The obtained binary images of the marbling standards were used to extract the contour of marbling samples on these standards by employing the Sobel edge detector (Jain, 1989).