Image following using optical flow the feature-based approach

Visual servo can be achieved by extracting motion information from the optical flow, defined as the apparent motion of brightness patterns of an image. Because the optical-flow-based approach does not require knowledge of targets in advance, it is suitable for versatile tracking and positioning purposes. For most robotic tasks, steady position of the end-effector with respect to its working environment is essential to successful and efficient operations. In this paper, application of the optical flow technique to following of a moving image is presented. In addition, more accurate values of the optical flow are usually observed along image features. In order to achieve better estimation of the optical flow, feature-based optical flow computation approaches are also proposed. Image following tasks are demonstrated by three-dimensional tracking experiments driven by stepping motors.