Abstract: According to the actual requirements of automatic processing of fabric drape images,a simple but practical radial scan algorithm is proposed.First,identify the center of the disk on the sample,cut the valid area from the original image,and conduct the necessary preprocessing,and then,use the radial scan algorithm to find out the preliminary contour points.By removing the points which are not on the contour and connecting the points remained with lines in sequence,a curve can be formed.When the contour points are adequate enough,the curve can be thought as the contour of the sample.Compared with the traditional gradient operator algorithm,the radial scan algorithm is more applicable and reliable.The design,execution process,and characteristics of the radial scan algorithm are expounded with examples.