The system of generating geometric characteristics of a digitally encoded image comprises a display device (2) capable of displaying a digitized image, communicating with a control unit (4), and comprising a man-machine interface (6) and means of supplying data (3) to the system via said man-machine interface (6). The system also comprises: a display means (7) for displaying a digitally encoded image on the display device (2), a first delimiting means (8) for delimiting a portion of the image representing a substantially flat surface, a processing means (9) for applying a predetermined deformable geometric pattern to the image in the position of said delimited image portion and deforming the pattern so as to make it correspond to said image portion, and a determination means (10) for determining geometric characteristics of said surface from the deformation of the pattern.