For local environmental applications we need both the spectral resolution (i.e., at least three distinct spectral bands: G,R,NIR) and good spatial resolution. Therefore, a fusion between the well resolved panchromatic and the four times coarser multispectral images is necessary.
Numerous efforts have been made to fuse data received from the same scene but different sensors [Shen et al. (1994), Darvishsefat (1995), Zhukov et al. (1995), Patterson et al. (1996), Peytavin (1996), Zhukov et al. (1996)]. Particular respect has been paid to the merging of image data with differing spatial resolution. If the two sensors do not operate from the same platform, the geometric rectification and registration of the images is a prerequisite to data fusion. Experience has shown this to be a relatively easy process for satellite imagery (stable orbits and altitudes, small swath angles), but a rather cumbersome procedure for airborne line scanner imagery (flight track and altitude variations). In the particular case of the expected high resolution satellites this is not an issue since both the panchromatic and the multispectral image data are recorded from the same platform.