A method for processing a finger image acquired by a fingerprint sensor of direct view type and comprising at least one fingerprint in order to implement an authentication or identification of an individual by comparison of fingerprints, said image comprising a set of pixels, each pixel being associated with a grey level, the method comprising a step of segmentation of the image to generate a modified image only containing regions of the image having an alternation of bright zones and dark zones at a frequency greater than a minimum frequency, characterized in that said step of segmentation comprises: o the allocation, to each pixel of the image, of a frequency response level, corresponding to a frequency of alternations of bright zones and dark zones in the vicinity of the pixel, by evaluating the variabilities of the grey levels of the pixels contained in a window of determined size positioned around each pixel, the allocation, to a pixel, of a frequency response level by evaluating the variabilities of the grey levels of the pixels contained in a window of determined size positioned around each pixel comprising the determination of a gradient of grey levels corresponding to the difference between the gray level of said pixel and the maximum gray level among the minimum gray levels of the pixels contained in a window surrounding each pixel of the window surrounding said pixel, the frequency response level allocated to said pixel being the absolute value of said gradient of grey levels, o the definition of regions of the image by grouping together neighbouring pixels of same frequency response level previously allocated to each pixel, o the determination of a threshold frequency response level, o selection, from the regions of the image defined previously by grouping together neighbouring pixels of same frequency response level, of regions of which the pixels have a frequency response level greater than or equal to the threshold frequency response level, and o the generation of a modified image only comprising, among the regions of the image defined previously by grouping together neighbouring pixels of same frequency response level, regions of which the pixels have a frequency response level greater than or equal to the threshold frequency response level, the method then comprising a step of authentication or identification of an individual by comparison of fingerprints on the basis of the modified image. o the allocation, to each pixel of the image, of a frequency response level, corresponding to a frequency of alternations of bright zones and dark zones in the vicinity of the pixel, by evaluating the variabilities of the grey levels of the pixels contained in a window of determined size positioned around each pixel, the allocation, to a pixel, of a frequency response level by evaluating the variabilities of the grey levels of the pixels contained in a window of determined size positioned around each pixel comprising the determination of a gradient of grey levels corresponding to the difference between the gray level of said pixel and the maximum gray level among the minimum gray levels of the pixels contained in a window surrounding each pixel of the window surrounding said pixel, the frequency response level allocated to said pixel being the absolute value of said gradient of grey levels, o the definition of regions of the image by grouping together neighbouring pixels of same frequency response level previously allocated to each pixel, o the determination of a threshold frequency response level, o selection, from the regions of the image defined previously by grouping together neighbouring pixels of same frequency response level, of regions of which the pixels have a frequency response level greater than or equal to the threshold frequency response level, and o the generation of a modified image only comprising, among the regions of the image defined previously by grouping together neighbouring pixels of same frequency response level, regions of which the pixels have a frequency response level greater than or equal to the threshold frequency response level,