METHOD AND SYSTEM FOR CONTROLLING ANGULAR ACCURACY IN OPTICAL SENSING ARRAYS

摘要

An optical sensing array and method of operation for controlling the acceptance angle of light beams which are iteratively strobed in side-by-side channels between light transmitters and light receivers. The light beams in at least a pair of channels are directed along axes which are intentionally mispointed or squinted. A control circuit measures the amplitudes of signals produced responsive to light being received by the light receivers and compares the ratio of those amplitudes to the ratio of predetermined high and low amplitude values which provide a threshold window. When the ratio of the signal amplitudes exceeds the ratio of the window threshold values, an output signal is produced indicative of an unsafe operating condition. The control circuit further maintains the gain of the signals from the light receivers to stay within the range of the predetermined window threshold values.