Method for automatically characterizing the texture of a digital image, characterized in that this method comprises: - acquiring a digital image formed from a plurality of pixels; - defining, within the acquired digital image, a plurality of different analysis windows, each window being formed from pixels of the digital image; - estimating, for each defined window, a Hurst exponent H i from the pixels of this window alone, where the index i uniquely identifies the analysis window used to estimate the exponent H i, this estimation of the Hurst exponent H i for each analysis window comprising computing operations carried out between values: - of the so-called central pixel of said analysis window, which pixel is located at the geometric centre of said analysis window, and - of other pixels contained in said analysis window, said other pixels being located at different distances from the central pixel; - computing (100, 100', 100") a signature, taking the form of a single numerical value, characteristic of the texture of the digital image, by combining the exponents H i estimated for each window of the digital image, and in that: - the method comprises computing a discrete value h i of each exponent H i, this computation being carried out by means of a given predetermined function f having as argument the exponent H i, this function f associating, for each possible value that a Hurst exponent is able to take, a single discrete value comprised between two predetermined positive integer values A and B; - the combination of the exponents H i comprises constructing a co-occurrence matrix M o using the following formula: M o m l = ∑ l w i, i + o m l where: - M o (m,l) is the value of the coefficient of the mth row and of the Ith column of the matrix M o, - w i,i+o is a numerical value equal to 1 if H i = h l and H i+o = h m and equal to zero in the contrary case, h l and h m being the discrete values of the exponents H i estimated for index values i = l and i = m, respectively, the summation being carried out for all the analysis windows of the image of geometric centre X i that are such that the point X i, after translation by a vector o in the plane of the image, still belongs to the image, o being a predefined parameter that is constant whatever the values of i, m and l. - acquiring a digital image formed from a plurality of pixels; - defining, within the acquired digital image, a plurality of different analysis windows, each window being formed from pixels of the digital image; - estimating, for each defined window, a Hurst exponent H i from the pixels of this window alone, where the index i uniquely identifies the analysis window used to estimate the exponent H i, this estimation of the Hurst exponent H i for each analysis window comprising computing operations carried out between values: - of the so-called central pixel of said analysis window, which pixel is located at the geometric centre of said analysis window, and - of other pixels contained in said analysis window, said other pixels being located at different distances from the central pixel; - of the so-called central pixel of said analysis window, which pixel is located at the geometric centre of said analysis window, and - of other pixels contained in said analysis window, said other pixels being located at different distances from the central pixel; - computing (100, 100', 100") a signature, taking the form of a single numerical value, characteristic of the texture of the digital image, by combining the exponents H i estimated for each window of the digital image, - the method comprises computing a discrete value h i of each exponent H i, this computation being carried out by means of a given predetermined function f having as argument the exponent H i, this function f associating, for each possible value that a Hurst exponent is able to take, a single discrete value comprised between two predetermined positive integer values A and B; - the combination of the exponents H i comprises constructing a co-occurrence matrix M o using the following formula: M o m l = ∑ l w i, i + o m l where: - M o (m,l) is the value of the coefficient of the mth row and of the Ith column of the matrix M o, - w i,i+o is a numerical value equal to 1 if H i = h l and H i+o = h m and equal to zero in the contrary case, h l and h m being the discrete values of the exponents H i estimated for index values i = l and i = m, respectively, the summation being carried out for all the analysis windows of the image of geometric centre X i that are such that the point X i, after translation by a vector o in the plane of the image, still belongs to the image, o being a predefined parameter that is constant whatever the values of i, m and l. - M o (m,l) is the value of the coefficient of the mth row and of the Ith column of the matrix M o, - w i,i+o is a numerical value equal to 1 if H i = h l and H i+o = h m and equal to zero in the contrary case, h l and h m being the discrete values of the exponents H i estimated for index values i = l and i = m, respectively, the summation being carried out for all the analysis windows of the image of geometric centre X i that are such that the point X i, after translation by a vector o in the plane of the image, still belongs to the image, o being a predefined parameter that is constant whatever the values of i, m and l.