Distance measuring device with increased signal-to-noise ratio and method thereof

摘要

A method of increasing signal-to-noise ratio of a distance-measuring device includes a light-emitting component emitting a detecting light to a measured object during an emitting period for generating a reflected light, a delay period after the light-emitting component emitting the detecting light, a light-sensing component sensing the energy of the reflected light to generate a light-sensing signal, and obtaining a measured distance between the distance-measuring device and the measured object according to the energy of the detecting light and the light-sensing signal. Since the measured distance is longer than a predetermined shortest measured distance, the method can accordingly calculate a proper delay period for ensuring that the reflected light reaches the light-sensing component after the delay period. In this way, the light-sensing component does not sense the background light during the delay period, so that the signal-to-noise ratio of the light-sensing signal is improved.

主权项

1. A method of increasing signal-to-noise ratio of a distance-measuring device, the distance-measuring device being utilized for measuring a measured distance between the distance-measuring device and a measured object, the measured distance being longer than a predetermined shortest measured distance and shorter than a predetermined longest measured distance, the distance-measuring device having a light-emitting component for emitting a detecting light, and a first light-sensing component for sensing and accumulating energy of light according to a first shutter periodic signal to generate a light-sensing signal, the method comprising:
the light-emitting component continuously emitting the detecting light to the measured object to generate a reflected light during an emitting period; a delay period after the light-emitting component starts to emit the detecting light, the first light-sensing component sensing and accumulating energy of the reflected light during a sensing period to generate the light-sensing signal; obtaining a time of flight of light going back and forth between the distance-measuring device and the measured object according to the light-sensing signal and energy of the detecting light emitted by the light-emitting component during the emitting period; and obtaining the measured distance according to the time of flight;
wherein:the delay period is calculated according to the predetermined shortest measured distance;a relationship between the predetermined longest measured distance and the sensing period is represented by DMAX=2×(TSEN1+TDELAY)/C;DMAX represents the predetermined longest measured distance;TSEN1 represents the sensing period;TDELAY represents the delay period; andC represents speed of light.