Method and apparatus for communicating and recovering motion information

Abstract

This invention describes a method for communicating crude motion information using tracking metadata and recovering more accurate motion information from the received tracking metadata and partial video frame data; in particular, we use metadata to convey crude boundaries of objects in the scene and signal motion information for these objects. The proposed method leaves the task of identifying the exact boundaries of an object to the decoder/client. The proposed method is particularly appealing when metadata itself carries semantics that the client is interested in, such as tracking information in surveillance applications, because, in this case, metadata does not constitute an overhead. The proposed method involves motion descriptions that can be used to predict the appearance of an object in any one frame from its appearance in any other frame that contains the object. That is, the motion information itself allows locations within an object to be invertibly mapped to locations within the same object in any other relevant frame. This is a departure from conventional motion coding schemes, which tightly-couple motion information to the prediction strategy. This property makes the proposed method particularly suitable for applications which require flexible access to the content.