Global motion compensation in video coding

As a motion compensation method for video coding, a global motion estimation method is proposed that estimates and compensates general image motion caused by camera pan and zoom. By utilizing block displacement vectors derived from the widely utilized block‐matching method, global motion parameters are computed with a noniterative process requiring few multiply‐add operations. Parameters associated with pairs of blocks symmetrically located with respect to the center of the image are calculated, and the histogram of these parameters is then used to efficiently compute accurate motion values that depend on nothing but camera pan and zoom. A corresponding block‐by‐block ON/OFF control method is also proposed for the global motion compensation scheme. By utilizing these methods, a relatively simple and efficient coding technique with global motion estimation is realized.