Abstract: This paper proposes a practical algorithm for estimating discrete curvature of 8-connected curve in 2D space based on adaptive fuzzy segments.The algorithm estimates digital curvature based on tangent orientation,where tangents are approximated by the longest fuzzy segments grown from points on the curve with a given order of d.The adaptive choice of order d at each point according to the local curve coarse degree makes our algorithm particularly suitable for noisy curves. Experimental results show that our algorithm can substantially improve the performance of curvature estimation in keypoints’detection,and the obtained results manifest a better consistency with the features in continuous space.