Variable sized block matching for in vivo musculoskeletal motion analysis

We propose a 2D variable sized block matching algorithm with hierarchical exhaustive search to examine tissue deformations in dynamic musculoskeletal ultrasonography. Novel aspects include improved matching by updating reference and candidate blocks at each scale and the application area. Performance is quantified on controlled in vitro gold standard (groundtruth) sequences and clinical in vivo data. We extend the process by refining displacements to sub-pixel accuracy. The proposed technique is validated, by application, to yield quantitatively reliable results.