Recognition of Bicycles in Traffic
Due to the good properties of the presented method for circle recognition, I had the idea to use this method to recognize bicycle wheels, which are ideal circles. However, if the bike is positioned so that the plane of its frame makes an acute angle with the viewing direction, then the wheels look like ellipses rather than circles. We thus also need a method of recognizing ellipses. Unfortunatelly we have not succeded with generalizing our method of circle recognition (see Chapter 12) for ellipses. We have tried to use the well-known method of conjugate gradients, but our experiments have shown that this method is not robust: Sometimes it fails when the points to which the ellipse is to be fitted do not lie near an ellipse.