The invention relates to a method for the dynamic measurement of
noise level, in the method, the threshold value (12) is adapted to a
signal output of a sensor by means of an echo procedure, and particularly the
distance measurement is carried out by means of an ultrasonic procedure, wherein, a transmission
signal (2) of the radiated object is sent back to the sensor in form of an
echo signal (5), wherein, the
time distance between sending of the transmission
signal and the reception of the
echo signal is measured, wherein, between the time of the decay of the transmission signal and the time of the arrival of the first
echo signal (5), a time interval (6) is measured, and a threshold value (13) in the time interval (6) is gradually changed, wherein, the input
noise signal is monitored according to compare of
current threshold value (13), wherein, the
current threshold value (13) becomes lowered, so long the input
noise signal is below the
current threshold value, and wherein, the current threshold value (13) becomes increased, so long the input noise signal is above the current threshold value (13), wherein, the current threshold value (13) becomes registered within the time interval (6) and wherein from the registered threshold values (13) a threshold value line (12) is determined.