A validation method for validating that an element is covered with true skin and implemented by a validation device comprising a light source at at least one wavelength, a sensor, an analysis module and a decision-making module, said validation method comprising: - a positioning step in which a surface of said element is placed in front of the light source and the sensor, - an illumination step in which the light source illuminates said element with non-uniform illumination, - a capture step for capturing, by means of said sensor, for the or each wavelength, an image (200a-b) of said element thus positioned which encompasses an illuminated zone (202a-b) of said element directly illuminated by the light beam emitted by the light source and a peripheral zone called the scattering zone (204a-b) of said element which extends on the periphery of the illuminated zone (202a-b), - an analysis step in which the or each image (200a-b) thus captured is analyzed, and - a decision-making step in which the decision-making module makes a decision as to whether said element is covered by a true skin based on the results of the analysis step, characterized in that the analysis step consists, for the or each image (200a-b), of cutting an analysis zone (206a-b) that covers the illuminated zone (202a-b) and the scattering zone (204a-b) into several concentric calculation zones (208a-b) having a shape dependent on a shape of the light source, at least one calculation zone being located in the illuminated zone and at least one calculation zone being located in the scattering zone, of establishing an average intensity for each calculation zone (208a-b), an intensity curve and an intensity gradient curve as a function of a distance of the calculation zone (208a-b) to an origin fixed on a boundary between the illuminated zone (202a-b) and the scattering zone, and of comparing characteristics of these curves with those extracted from reference curves, said boundary being determined by a calibration process based on the acquisition of a non-diffusing white test image through the sensor under said non-uniform illumination provided by said light source, the boundary being defined at each boundary point of an intensity tray measured on the non-diffusing white test image. - a positioning step in which a surface of said element is placed in front of the light source and the sensor, - an illumination step in which the light source illuminates said element with non-uniform illumination, - a capture step for capturing, by means of said sensor, for the or each wavelength, an image (200a-b) of said element thus positioned which encompasses an illuminated zone (202a-b) of said element directly illuminated by the light beam emitted by the light source and a peripheral zone called the scattering zone (204a-b) of said element which extends on the periphery of the illuminated zone (202a-b), - an analysis step in which the or each image (200a-b) thus captured is analyzed, and - a decision-making step in which the decision-making module makes a decision as to whether said element is covered by a true skin based on the results of the analysis step, characterized in that the analysis step consists, for the or each image (200a-b), of cutting an analysis zone (206a-b) that covers the illuminated zone (202a-b) and the scattering zone (204a-b) into several concentric calculation zones (208a-b) having a shape dependent on a shape of the light source, at least one calculation zone being located in the illuminated zone and at least one calculation zone being located in the scattering zone, of establishing an average intensity for each calculation zone (208a-b), an intensity curve and an intensity gradient curve as a function of a distance of the calculation zone (208a-b) to an origin fixed on a boundary between the illuminated zone (202a-b) and the scattering zone, and of comparing characteristics of these curves with those extracted from reference curves, said boundary being determined by a calibration process based on the acquisition of a non-diffusing white test image through the sensor under said non-uniform illumination provided by said light source, the boundary being defined at each boundary point of an intensity tray measured on the non-diffusing white test image.