Direct Computation of the FOE with Confidence Measures

We propose a direct method for locating the focus of expansion (FOE), based on simple parallel computations in selected regions of the image; each is a circular patch around an estimated FOE. Simple computations allow determining the direction from the estimated to the true FOE. The best estimate of the intersection of the so-called FOE constraint lines for several regions gives the location of the FOE. Some analysis allows us to assign a confidence measure to the information from each local region, in order to give more weighting to the most reliable data. Hence, the FOE can be located with more accuracy, even when the data from various local regions lacks sufficient information. Results of experiments with real images of various texture content are given to demonstrate the performance of the method.