A photorefractive compositions of the present invention includes a copolymer component that provides both photoconductive ability and non-linear optical ability, and optionally sensitizer and plasticizer components. A preferred embodiment is prepared with a series of depressions or wells into which water-insoluble adhesive or glue is introduced before the insertion of the pages therein, the pages being tightly bound together and to the cover backing by a combination of adhesive or glue and water-insoluble thread. The model selector and model bank selects at least one motion model for use in estimating the state for a segment of the motion of the object.