Motion Modeling with Geometry and Quad-tree Leaf Merging

Abstract

Quad-tree structures are often used to model motion between frames of a video sequence. However, a fundamental limitation of the quadtree structure is that it can only capture horizontal and vertical edge discontinuities at dyadically related locations. In this paper we seek to address this limitation by introducing geometry information into the nodes of a pruned quad-tree. We start with a typical optimally pruned quad-tree where each node is allowed to model motion. Then for each node in the tree, we consider augmenting the node's motion model with a linear geometry model. Experimental results show that the introduction of geometry information improves the performance of quad-trees in representing motion. Recent work into quad-tree representations have highlighted the benefits of leaf merging. In this paper we extend the leaf merging paradigm to incorporate both geometry and motion information, allowing the creation of regions that have both motion and geometry attributes.