Decision-Driven Pyramid Fusion of Multispectral and Panchromatic Images

This work presents a general and formal solution to the problem of fusion of multispectral data with high-resolution panchromatic images. The method relies on the generalised Laplacian pyramid, which is an oversampled structure obtained by subtracting from an image its low-pass version, and selectively performs spatial-frequencies spectrum substitution from an image to another. The novelty of the present work is that a decision based on thresholding the local CC is utilized to check the physical congruence of fusion, while the ratio of local RMSs between the two images provides a space-varying gain factor by which the injected high-pass contribution is equalized. Since the pyramid decomposition is not critically-subsampled, possible impairments in the fused images, due to missing cancellation of aliasing terms, are avoided. Quantitative results are presented and discussed on simulated SPOT 5 data of an urban area (2.5m P, 10m XS) obtained from the MIVIS airborne imaging spectrometer.