The present invention relates to a method for slaving the activation of a set of infrared emitters of a sensor of venous networks to the presence of a living body between this set and an image acquisition means of the sensor. The method is characterized in that each infrared emitter (E) is activated if the presence of a part of the living body (CV) is detected by at least one presence detector (DP) which is associated therewith and each infrared emitter (E) is deactivated as long as the presence of a part of the living body (CV) is not detected.
