The solution described in the patent can be adopted on board of any vehicle, in an operational scenario which includes seeking and aiming activities. The video stream, acquired by a camera placed outside the cockpit, is shown on the operator's display and overlapped with an aiming reticle. Some parts of the reticle will change color, based on the algorithms specified in the patent, in the case where the aiming reticle has a colour easily confused with that of the target or with the background in the displayed video stream.