Method for processing an image representative of at least one finger, said image being delivered by a thin-film-transistor image sensor of a fingerprint-capturing system, with a view to identification or authentication of the print, said system comprising a transparent plate comprising a face on which is placed each finger and said image sensor being positioned so as to generate an image of each finger, the method comprising: obtaining an image of each finger, said image being delivered by the image sensor, said image being referred to as the first image; obtaining a second image by removing each and every continuous component from the first image by applying a high-pass filter; obtaining a third image by applying an averaging filter to the second image; applying connected-component analysis to the third image in order to define regions in said third image, each region comprising pixels having an identical value, referred to as the representative value; organizing the regions into a hierarchical tree in which the regions are organized according to a parent-child relationship, a first region being a parent of a second region, which is then a child of the first region, when at least one pixel of the second region neighbours a pixel of the first region and when a deviation between the representative values of the first and second regions is smaller than a deviation between the representative values of the first region and of all other regions having at least one pixel neighbouring a pixel of the first region, the child region having a representative value lower than its parent region; traversing the hierarchical tree in increasing order of representative values and clustering each child region with its parent region when a growth coefficient C is lower than a first predetermined threshold, the growth coefficient being computed in the following way: C = a × S + b × ΔS where a and b are predetermined constants, S is an area of the child region and Δ S is a percentage increase in the area of the clustered region with respect to the area of the child region; determining a convex hull for each obtained clustered region; generating a fourth image by preserving pixels located in each convex hull in the second image. obtaining an image of each finger, said image being delivered by the image sensor, said image being referred to as the first image; obtaining a second image by removing each and every continuous component from the first image by applying a high-pass filter; obtaining a third image by applying an averaging filter to the second image; applying connected-component analysis to the third image in order to define regions in said third image, each region comprising pixels having an identical value, referred to as the representative value; organizing the regions into a hierarchical tree in which the regions are organized according to a parent-child relationship, a first region being a parent of a second region, which is then a child of the first region, when at least one pixel of the second region neighbours a pixel of the first region and when a deviation between the representative values of the first and second regions is smaller than a deviation between the representative values of the first region and of all other regions having at least one pixel neighbouring a pixel of the first region, the child region having a representative value lower than its parent region; traversing the hierarchical tree in increasing order of representative values and clustering each child region with its parent region when a growth coefficient C is lower than a first predetermined threshold, the growth coefficient being computed in the following way: C = a × S + b × ΔS where a and b are predetermined constants, S is an area of the child region and Δ S is a percentage increase in the area of the clustered region with respect to the area of the child region; determining a convex hull for each obtained clustered region; generating a fourth image by preserving pixels located in each convex hull in the second image.