1. A method for the extraction of shadows in noisy images, comprising the following steps: capture of an image, subdivision of the image in a plurality of pixels, definition of a square odd matrix for every pixel having said pixel in the center, application of an algorithm to the matrixes of every pixel, displaying of an error map of said image, wherein the algorithm is a contour algorithm comprising the follow steps: computation of the averages for each corner of the matrix, computation of the averages for the top, bottom, left and right sides, computation of the maximum variance between these eight averages, comparison with a present value (max variance).