An automatic digital image characterization system has a feature extractor, including a segment processor and a feature processor. The segment processor is connected for receiving an image in the form of digitized pixel values; each pixel value having an amplitude and being associated with positional information in the form of column and row values. The feature processor converts the image information into column and row axis functions having calculated values of statistical mean amplitude and standard deviation. A system processor registers images, senses image changes, locates objects and detects hidden information.