An energy spreading transform approach to efficient image retrieval

When searching a large database of images for ones that are visually similar to a particular reference images, it is desirable to have efficient means for making coarse comparisons between images. This paper describes an approach for efficient image retrieval using a recently discovered energy-spreading Hadamard transform arising from an orthogonal basis of unimodular sequences called the Prometheus Orthonormal Set (PONS). The energy-spreading properties of this PONS transform suggest that global comparison of key features of images can be accomplished using any subset of the PONS transform coefficients.