The invention discloses a
laser ranging method. The
laser ranging method includes that an initial threshold value is set by an MCU (microprogrammed
control unit), and a first pulse is emitted to trigger a time-to-
digital converter to start timing; a second pulse is emitted after a certain time
delay to trigger an emitting module to emit
laser, and simultaneously, a receiving module is opened to receive an
echo signal of the laser; when the
echo signal received by the receiving module is larger than the initial threshold value, a high-speed
comparator outputs a measurement timing stop pulse to the time-to-
digital converter, the MCU reads
time difference of the measured earlier pulse and the measured later pulse of the time-to-
digital converter so as to compute the measurement distance and drive an LCD (
liquid crystal display) to display a measurement result in real time, if the
echo signal received by the receiving module is not larger than the initial threshold value, the MCU sets the threshold value to a
lower threshold value, the time-to-digital converter and the receiving module are initiated to enter a
ranging procedure with the low threshold, when an echo
signal is larger than the low threshold value, the high-speed
comparator outputs a measurement timing stop pulse to the time-to-digital converter, and if the echo
signal is not larger than the low threshold value, the ranging procedure is terminated.