Introduction of sensor spectral response into image fusion methods. Application to wavelet-based methods

TLDR

Typical image fusion methods inject high‑resolution panchromatic features into each low‑resolution multispectral band to preserve spectral signatures and enhance spatial resolution, but they ignore the physical spectral responses of the sensors and introduce features from spectral regions not covered by the multispectral sensors. The authors aim to produce an image that would be observed by a sensor with the multispectral sensor’s spectral response while attaining the panchromatic sensor’s spatial resolution. They propose a wavelet‑based fusion technique that incorporates the physical electromagnetic spectrum responses of the sensors during the fusion process. Compared with conventional wavelet‑based fusion, the new method reduces resolution over‑injection artifacts and preserves spectral signatures, yielding images closer to those obtained by an ideal sensor.

Abstract

Usual image fusion methods inject features from a high spatial resolution panchromatic sensor into every low spatial resolution multispectral band trying to preserve spectral signatures and improve spatial resolution to that of the panchromatic sensor. The objective is to obtain the image that would be observed by a sensor with the same spectral response (i.e., spectral sensitivity and quantum efficiency) as the multispectral sensors and the spatial resolution of the panchromatic sensor. But in these methods, features from electromagnetic spectrum regions not covered by multispectral sensors are injected into them, and physical spectral responses of the sensors are not considered during this process. This produces some undesirable effects, such as resolution overinjection images and slightly modified spectral signatures in some features. The authors present a technique which takes into account the physical electromagnetic spectrum responses of sensors during the fusion process, which produces images closer to the image obtained by the ideal sensor than those obtained by usual wavelet-based image fusion methods. This technique is used to define a new wavelet-based image fusion method.