Visual servoing from robust direct color image registration

To date, there exist only few works on the use of color images for visual servoing. Perhaps, this is due to the difficulties usually found to cope with illumination changes in these images. This paper presents new parametric models and optimization methods for robustly and directly registering color images. Direct methods refer to those that exploit the pixel intensities, without resorting to image features. We then show how a robust and generic visual servoing scheme can be constructed using the obtained optimal parameters. The proposed models ensure robustness to arbitrary illumination changes in color images, do not require prior knowledge (including the spectral ones) of the object, illuminants or camera, and naturally encompass gray-level images. Furthermore, the exploitation of all information within the images, even from areas where no features exist, allow the algorithm to achieve high levels of accuracy. Various results are reported to show that visual servoing can indeed be highly accurate and robust despite unknown objects and unknown imaging conditions.