1. A method of forming a refined depth map D R from a high-resolution image I of a scene and a low-resolution depth map D I of said image, said method comprising the steps of: segmenting the high-resolution image into a plurality of superpixels, being connected sets of pixels of the high-resolution image I, to form a superpixel segmented image S REP ; determining at least one depth measure associated with the superpixels in the superpixel segmented image S REP to thereby form a superpixel depth map D S having a foreground region and a background region; intersecting the foreground region and the background region of the superpixel depth map D S with the respective foreground region and the background region of the low-resolution binary depth map D I to define a trimap T having a foreground region, a background region and an unknown region; and reclassifying pixels in the unknown region of the trimap as either foreground or background pixels of the trimap based on a comparison of the pixel values in the unknown region of the trimap with pixel values in at least one of the other regions of the trimap, thereby forming said refined depth map D R .