A Multiscale Circum-ellipse Area Representation for Planar Shape Retrieval

In this paper, we propose a new Multiscale Circum-ellipse Area Representation (MCAR) for planar contours. The proposed representation deals with a multiscale shape signature defined from the local area delimited by the circumscribed ellipse of the triangle formed by three contour points and the contour. This shape signature describes, at each scale level, the concavity/convexity at each contour point. Then, Fourier descriptors are obtained by applying Fourier transform to the proposed multiscale signature. Thus, the proposed MCAR based Fourier Descriptors handle the local and global shape characteristics. Furthermore, it is invariant to affine transformation and robust to local deformations. The performance of our proposed method was evaluated through the precision recall and bull’s-eye tests on the two well-known databases (MCD and MPEG7-setB). Obtained results indicate that our method outperforms the shape signatures based Fourier descriptor proposed in the literature.