Effective shape contour extraction, and multiresolution representation and matching methods

In this paper we are going to present end to end algorithms that address curvature extraction, shape representation and shape similarity retrieval. Our novel shape contour tracing algorithm can trace open, ill-defined and closed shapes and return an ordered set of background points adjacent to the shape’s contour. Our shape descriptor builds a multi-resolution equal segmentation polygonal based shape representation that uses the center of the shape as a reference point and is invariant to scale, rotation and translation, and efficient in terms of time and space. The shape descriptor captures three contour primitives including distance and slope at regular intervals around the center. The dual stage novel shape matching algorithm works in two stages. The first is data driven and uses a shape signature metric to factor out dissimilar shapes while the second stage linearly scans the remaining shapes and measures the similarity using elasticity with a distance and a user-friendly fuzzy measure. We have applied our algorithms on the MPEG-7 shape core experiment and achieved the best result reported based on the number of queries. Our algorithms achieved 83.23% for the similarity test of part B where the optimized CSS shape descriptor came second at 81.12%.