1. Holographic method with numerical reconstruction for obtaining an image of a three-dimensional object, said method employing a digitalised hologram of an object or of a portion of an object, and being characterised in that it comprises the following steps: A. starting from the digitalised hologram, extracting an phase image of said object of portion of object, the image corresponding to a matrix MD of distance values, said distance values corresponding to distances from the image plane or to the depths relevant to said object or object portion; B. selecting a subassembly SD of the distance value assembly present in matrix MD of the method step A, subassembly SD containing distance values d k , with k_having a value between 1 and a whole number N SD >1; C. for each distance value d k , extracting from matrix MD a iso-level assembly IQd k of corresponding bidimensional coordinate of said object or object portion; D. for each distance value d k , reconstructing, starting from the digitalised hologram, a bidimensional matrix IMd k of intensity values relevant to said object or object portion; E. extracting, from each bidimensional matrix IMd k of the method step D, a bidimensional IFd k of intensity values corresponding to the bidimensional coordinates of the iso-level assembly IQd k extracted in method step C; F. starting from intensity values of said IFd k assemblies of the method phase E, from the coordinate bidimensional of the iso-level assembly IQd k and from the relevant distance values d k , for all values of k between 1 and N SD , reconstructing the three-dimensional intensity image of said object or object portion; resolution of bidimensional matrix IMd k for all values of k between 1 and N SD being identical to the resolution of matrix MD of distance value.