Patent ID: 7791713

Claim:
A method of distance measurement, comprising: transmitting pulsed electromagnetic radiation ( 13 ) using at least one transmitter ( 11 ); detecting reflected signal pulses ( 15 ) using at least one receiver ( 17 ); measuring distances from objects ( 19 ) at which the transmitted radiation pulses ( 13 ) are reflected by determining a pulse propagation time; measuring noise using the receiver ( 17 ) with specific points in time ( 33 ) being determined at which at least one threshold ( 21 ) of the receiver ( 17 ) lying in the noise is passed through and with changes in the noise caused by the signal pulses ( 15 ) being detected by averaging a plurality of individual measurements respectively including the specific points in time ( 33 ); wherein a sequence of logical pulses ( 23 ) is generated by means of the threshold ( 21 ) of the receiver ( 17 ) lying in the noise from the analog received signal ( 37 ) containing the noise pulses and/or noise pulses changed by the signal pulses ( 15 ), with the individual measurement being derived from this sequence; wherein the flanks of the logical pulses ( 23 ) are used as points in time ( 33 ) of the individual measurement; wherein a distinction is made in the averaging between points in time ( 33 ) at which the threshold ( 21 ) of the receiver ( 17 ) is exceeded and points in time ( 33 ) at which the threshold ( 21 ) of the receiver ( 17 ) is fallen below, with a point in time ( 33 ) of an exceeding being evaluated as positive and a point in time ( 33 ) of a falling below being evaluated negatively; wherein the average value is integrated into an amplitude function ( 29 ) subsequent to the averaging of the individual measurements; wherein a detection threshold ( 31 ) is applied to the amplitude function ( 29 ) for the detection of the changes in the noise caused by the signal pulses ( 15 ); and wherein the respective associated object distance is determined in the amplitude function ( 29 ) for the signal pulses ( 15 ) on the basis of at least one point in time ( 65 ) at which the detection threshold ( 31 ) is passed through.