Joint Spatial and Tonal Mosaic Alignment for Motion Detection with PTZ Camera

Scene segmentation among background and foreground (moving) regions represents the first layer of many applications such as visual surveillance. Exploiting PTZ cameras permits to widen the field of view of a surveyed area and to achieve real object tracking through pan and tilt movements of the observer point of view. Having a mosaiced background allows a system to exploit the background subtraction technique even with moving cameras. Although spatial alignment issues have been thoroughly investigated, tonal registration has been often left out of consideration. This work presents a robust general purpose technique to perform spatial and tonal image registration to achieve a background mosaic without exploiting any prior information regarding the scene or the acquisition device. Accurate experiments accomplished on outdoor and indoor scenes assess the visual quality of the mosaic. Finally, the last experiment proves the effectiveness of using such a mosaic in our visual surveillance application.