1. A device for acquiring images of a print of at least a portion of a user's hand, the device comprising a stand defining an acquisition zone extending substantially in a plane, an optical acquisition member that is fastened to the stand to have a field of view covering the acquisition zone, and a processor unit connected to the acquisition member to process an image signal coming therefrom, wherein: the stand is arranged to provide an empty space zone containing the acquisition zone and forming a passage for said portion of the hand while it is moving parallel to the plane; the device includes at least one projector member for projecting a light test pattern of at least two colors into the acquisition zone; the optical acquisition member has a depth of field extending on either side of the acquisition zone and it possesses a color sensor having an acquisition speed that is sufficient to capture at least one color image of said portion of the hand moving at a predetermined maximum speed of movement; and the processor unit is arranged to extract from the color image signal a monochrome image in each of the projected colors, to reconstitute a texture of said portion of the hand from at least one of the monochrome images, and to reconstitute a shape from at least one of the monochromic images.