The invention relates to methods and apparatus for monitoring movement and breathing of two or more subjects occupying common bedding. Particularly the invention relates to a method for monitoring movement of subjects located in a common bedding the method comprising the steps of: imaging the bedding by an optical sensor performing a motion estimation by producing motion vectors indicating the local displacement of corresponding image blocks between consecutive images or images that are several frames apart received from said optical sensor calculating motion clusters by measuring spatial and temporal correlations of the motion vectors segmenting the calculated motion clusters by assignment of each motion cluster to a corresponding subject wherein the assignment of the motion clusters to the corresponding subject is based on the spatial and/or temporal similarity of the motion clusters among each other and on previous segmentation results.
