Abstract: A system, method, and computer program product compare images of a physical activity or object. Pixel data from first and second registered color images defined in an N-dimensional color model are concatenated to form an image in a 2N-dimensional color model. Principal component analysis is performed on the composite image and those components representing a change rather than a correlation are identified. In the composite image, coordinates for each pixel are determined along the principal components representing change, and a normalized pixel change value is computed. Pixels in the composite image may be segmented according to their respective normalized pixel change values, where segments do not cross pre-defined geospatial parcel boundaries. Parcel change probabilities are calculated as a function of segment change probabilities, themselves functions of the normalized pixel change values. Finally, parcels are ranked by their change probabilities and highlighted in a graphical user interface.