1. A method for binarizing an image, the method comprising: acquiring a copy of the image in an electronic memory in an input device; establishing boundaries of image objects of the image based on contrast values for the image objects; classifying each image object as either suspect or non-suspect; creating a local binarization threshold map, the local binarization threshold map comprising threshold binarization values associated with image objects classified as non-suspect; and creating a global binarization threshold map for the entire image by expanding the local binarization threshold map to cover the entire image.