Object signatures invariant to affine distortions derived from the Trace transform
The Trace transform is a generalisation of the Radon transform that allows one to construct image features that are invariant to a chosen group of image transformations. In this paper we use some functionals on the image function, and derive a set of signatures for each object that can be used to describe the object in an affine invariant way. The functionals are computed along batches of parallel lines tracing the image in all possible orientations. We demonstrate the usefulness of the constructed image descriptors in retrieving images from an image database and compare it with the moments based method.
invariance affine distortions trace transform moments database image retrieval