Abstract: Label location detection is an important part of intelligent manufacturing based on the computer vision. The author used ROI technology to choose the label area quickly，and enhanced the edge detection after label image preprocessing by the Gaussian filtering and morphological method，then obtained the maximum contour with the external minimum polygon encircling method， it achieved fast and accurate location detection of the label by calculating the centroid and direction features of the maximum contour.

Key words: computer vision, image preprocessing, location and detection