A method for processing imagery includes receiving data for a first image associated with a first spectral band and second images associated with second spectral bands. The method also includes obtaining first reflectance functions for pixels in the second images, generating a second reflectance function for pixels in the first image based on the first reflectance functions, and obtaining a third reflectance function for pixels in the first image based on the second reflectance function, the imagery data for the first image, and at least one facet orientation constraint. The method further includes modifying the first reflectance functions to generate fourth reflectance functions for pixels in the second images based on a difference between the second and the third reflectance functions, and computing imagery data defining third images associated with the second spectral bands and having the first spatial resolution based on the fourth reflectance functions.