Patent ID: 8643843

Claim:
A method of estimating a degree of contamination of a front screen of a laser scanner, which comprises the steps of: transmitting a plurality (p) of transmission radiation pulses into a detection zone; generating a reception signal (f 1 , f 2 ) for each transmission radiation pulse which includes a plurality (q) of sampled values, wherein a sampled value respectively indicates the intensity (I) of the received back radiation of the respective transmission pulse at a point in time (t 1 . . . tq) at a predefined time interval from the transmission of the transmission radiation pulse, generating an averaged reception signal (fΣ) having a plurality (q) of sampled values from the plurality of reception signals (f 1 , f 2 ) generated from the transmission radiation pulses, with those respective sampled values of the reception signals (f 1 , f 2 ) being added which were determined at mutually corresponding points in time (t 1 . . . tq) to determine a sampled value of the averaged reception signal (fΣ); and generating at least one front screen contamination value by evaluating at least one of an amplitude value and a measured peak shape value of the averaged reception signal (fΣ).