1. A method of using a computer to separate an object or pattern in a scene, comprising the steps of: acquiring two or more images of the scene, each image from a different sensor, spectral band, or recording medium, and each image being comprised of a set of pixels, each pixel having intensity values; defining at least one region of interest (ROI) in the scene, each ROI comprising a subset of the pixels; displaying a parallel axis plot representing pixel traces of intensity values of each image, wherein the pixel traces are from at least one ROI, and wherein each of the images is represented as an axis on the plot, and wherein and each pixel trace is traced across the axes; graphically constraining an axis of the plot by selecting a range of intensity values on that axis; and graphically identifying, on the parallel axis plot, the pixel traces that satisfy the constraint.