Method for optical measurement of the optical reflection properties of an object and / or the transmission properties of a transmission path for use in motor vehicles

摘要

The invention relates to a method and a device for optical measurement of the optical transmission path (I1, I2, I3, I4). A transmitter (H1) transmits a first optical signal (s1) as a function of a transmission signal (S9) into a transmission path (I1, I2) in which it is converted by the optical properties of the transmission path (I1, I2) into a second optical signal (S1). s2) is modified. At the same time, these transmitters (H1) transmit a third optical signal (s3) as a function of a transmission signal (S9) into a further transmission path (I3, I4) in which it is modified to form a fourth optical signal (S4). Depending on a receiver (D1, D2) each converts one of these optical signals (s2, s4) respectively to receiver output signals (S0A, S0B). It follows in each case the multiplication of the respective receiver output signal (S0A, S0B) with the transmission signal (S9) in a respective multiplication device (M1A, M1B) to a respective one (S3A, S3B). A switch switches between the intermediate signals (S3A, S3B) in response to a feedback signal (S8) explained later to form a filter input signal (S4). A filter (F1), which is preferably an integrator, filters the filter input signal (S4) to a filter output signal (S5). The conversion to a discrete-value filter output signal (S6) and the multiplication by -1 or, in the case of a binary discrete-value filter output signal (S6), preferably follow the inversion to the feedback signal (S8) which controls the switch. The value-discrete filter output signal (S6) represents, for example, the measured value. Sampling with the transmission signal (S9) makes sense.