Soccer Ball Speed Estimation using Optical Flow for Humanoid Soccer Player

In this paper we present an implementation of an efficient algorithm to calculate the optical flow in real time; with the aim to get the move speed of an orange ball which is used to play soccer in kidsize category within RoboCup's league. This gives to robot the ability to estimate the direction of movement of the ball and its speed. As a first version, the vision system consists of a webcam Logitech Quickcam Pro 9000 with 2 megapixel and autofocus which provides the image or images to be processed in "real time". The algorithm implemented is based on the Lucas-Kanade method, as this is easily applied to a subset of image's points, In addition, it is computationally faster compared with other techniques and it can be adapted to a stereoscopic vision system. Finally, we present experimental results that support the good performance of the algorithm.