Algorithm-based low-power VLSI architecture for 2D mesh video-object motion tracking
The new VLSI architecture for video object (VO) motion tracking uses a novel hierarchical adaptive structured mesh topology. The structured mesh offers a significant reduction in the number of bits that describe the mesh topology. The motion of the mesh nodes represents the deformation of the VO. Motion compensation is performed using a multiplication-free algorithm for affine transformation, significantly reducing the decoder architecture complexity. Pipelining the affine unit contributes a considerable power saving. The VO motion-tracking architecture is based on a new algorithm. It consists of two main parts: a video object motion-estimation unit (VOME) and a video object motion-compensation unit (VOMC). The VOME processes two consequent frames to generate a hierarchical adaptive structured mesh and the motion vectors of the mesh nodes. It implements parallel block matching motion-estimation units to optimize the latency. The VOMC processes a reference frame, mesh nodes and motion vectors to predict a video frame. It implements parallel threads in which each thread implements a pipelined chain of scalable affine units. This motion-compensation algorithm allows the use of one simple warping unit to map a hierarchical structure. The affine unit warps the texture of a patch at any level of hierarchical mesh independently. The processor uses a memory serialization unit, which interfaces the memory to the parallel units. The architecture has been prototyped using top-down low-power design methodology. Performance analysis shows that this processor can be used in online object-based video applications such as MPEG-4 and VRML.