1. A method for detecting an obscuration caused by the formation of condensation, icing or grime on an optical system of a vehicle, comprising at least two sensors for image capture, wherein the following steps are being performed: a) image capture by the first sensor b) image capture by the second sensor c) detection of an obscuration by measuring the grayscale distribution in the images captured by the two sensors d) initiation of a warning annunciation and/or heating of the optical system when an obscuration is detected.