Abstract
When part of the scattering light from a target is incident to the laser cavity, the terminal voltage of a
semiconductor laser diode slightly fluctuates. This voltage fluctuation has information related to the
distance to the target. However, terminal voltage fluctuation also has much noise. Since the
discrimination of distance signals with much noise is very difficult, we propose a statistical signal
processing that utilizes all of the information in terminal voltage fluctuation. We constructed a system
using a Field-Programmable Gate Array (FPGA) that can measure a distance of 21 to 45 cm with an
average error of about 2%.
