Interface system for assisting an operator during a work stage comprising a support structure wearable by the operator, with a transparent screen placed in front of the operator's eyes to permit him to see a portion of a background; a virtual image generator for producing an optical signal directed towards the operator's retina so as to form a virtual image at a predetermined distance from the operator's eyes and superimposed on the background; a recording device integral with the operator's head, to record part of the operator's visual field and make available a signal representative of the visual field; a processing device for processing the signal from the recording device and generating a visual information signal of use to the operator for carrying out the work stage; and a device of reception/transmission for sending the signal from the recording device to the processing device, and rendering the information signal to the virtual image generator.