A rotation-insensitive multiscale image representation based on the wavelet transform: Definition and image recovery algorithm

Abstract

This paper aims at a multiscale image representation which is rotation- and shift-invariant. The wavelet energy distribution is defined, and an image recovery algorithm is proposed based on the representation. In order to derive the image representation, which is almost rotation-invariant, two or three components in different directions of the discrete binary wavelet transform are integrated into a wavelet energy distribution. The image is recovered from the wavelet energy distribution by iterative operations. It is guaranteed in the proposed iterative operation that the error between the wavelet energy distribution of the recovered image and the given wavelet energy distribution decreases and converges. This paper proposes a coarse-to-fine recovery method which is based on the multiscale property of the wavelet transform, and reduces the danger that the procedure is trapped by a local minimum. The usefulness of the proposed coarse-to-fine recovery method is verified through several image recovery examples. As an application example, the method is applied to contour extraction coding by sampling the wavelet energy distribution along the contour of an image. © 1999 Scripta Technica, Electron Comm Jpn Pt 3, 82(12): 65–78, 1999