A method for the extraction of shadows in noisy images includes capture of an image, subdivision of the image into 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, and displaying of an error map of the image. The algorithm is a contour algorithm that includes the operations of =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, and comparison with a present value (max variance).