The invention relates to a device for acquisition of images for a biometric system, which includes an optical assembly and at least one imager for acquisition of an image of an object to be analysed presented in front of the assembly at a non-determined distance from the latter. The assembly includes at least one diaphragm with a coded aperture. The optical assembly allows acquisition by the sensor(s) of an image of the object capable of being exploited to deduce therefrom the searched biometric information, and of an image of the object acquired via the coded aperture of the diaphragm. The device also includes a processing unit to determine the distance of the object to be analysed as a function of the image of the object acquired via the coded aperture of the diaphragm.
