Method for processing receiver signal and optical sensor

An optical sensor system for implementing a method for processing a receiver output signal of an optical sensor comprising:

• at least one transmitter for emitting light rays;
• at least one optical receiver for receiving the light rays transmitted by the at least one transmitter, wherein the optical receiver outputs a receiver output signal based on the transmitted light rays;
• and
• an evaluation unit including:
• a memory for storing the receiver output signal, a computer unit for scanning the receiver output signal in a predetermined time interval Δt to create scanning values, correlating the scanning values with a filtering matrix, the matrix being composed of a sequence of matrix values, and generating a filtered receiver output signal composed of a discrete sequence of receiver output signal values;
• and a threshold value unit for evaluating the filtered receiver output signal, with respect to at least one threshold value, for generating an object detection signal.

A method for processing receiver output signals for a light grid having a predetermined number of beam axes, wherein each beam axis comprises a transmitter for emitting light rays and an associated receiver, and wherein the transmitters and the receivers are activated cyclically, one after another, the method comprising:

• storing a course of a receiver output signal during a cycle, the cycle comprising a sequence in time of individual receiver output signals from the receivers;
• scanning the receiver output signal in scanning steps offset by a predetermined time interval Δt, wherein a partial sequence of N scanning values, respectively offset by the time interval Δt, is determined during each scanning step;
• correlating the scanning values with a filtering matrix, the filtering matrix comprising a sequence of N matrix values for generating a filtered receiver output signal comprising a discrete sequence of receiver output signal values, by forming a linear combination of the products of the sequence of scanning values and the sequence of matrix values, wherein the filtering matrix has an averaging share and a differential-forming share in order to eliminate interference signal shares in the receiver output signal;
• and
• evaluating the filtered receiver output signal with at least one threshold value for generating an object detection signal.