1. An image processing system, comprising: a computer running image processing software to: select a series of color-balanced images to use as reference images; on an oblique image by image basis performing the following steps: locate a portion(s) of a reference image(s) that overlaps the oblique image; create multiple color-balancing transformations that approximately match a color distribution of the oblique image to a color distribution of overlapping portion(s) of the reference image(s); transform pixels in the oblique image according to more than one of the multiple color-balancing transformations created for the oblique image; and store the transformed pixel value in at least one of the oblique image or a copy of the oblique image.