Pyramid-based multisensor image data fusion

In this work, a multi-resolution procedure based on a generalized Laplacian pyramid (GLP), with p : q (i.e. rational) scale factor, is proposed to merge image data of any resolution and represent them at any scale. The GLP-based data fusion is shown to be slightly superior to those of a similar scheme based on the discrete wavelet transform, (WT) according to a set of parameters established in the literature. Not only fused images look sharper than their original versions, but also textured regions are enhanced without losing their spectral signatures. The pyramid-generating filters can be easily designed for data of any resolutions, differently from the WT, whose filter-bank design is non-trivial when the ratio between the scales of the images to be merged is not a power of two. Eventually, remotely sensed images from LandSat TM and from Panchromatic SPOT are fused together. The resulting bands capture multi-spectral features with enhanced contrast and texture, and an increased spatial resolution, thereby expediting automatic analyses for contextual interpretation of the environment.