1. A method for detecting a fake finger for fingerprint acquisition software comprising: using a processor to perform the steps of: acquiring an image of a finger; static analysis of said image, said static analysis comprising calculation and analysis of any one of a Gray Level Run Length (GLRL) matrices corresponding to said image; constructing a first characteristic vector of the image comprising at least partially said GLRL matrix; and determining, as a function of results of the static analysis, a first score corresponding to a confidence index related to a probability that a finger at an origin of the analyzed image is genuine or fake.