LASER RANGE FINDING DEVICE AND DISTANCE MEASUREMENT METHOD THEREOF
A distance measurement method for use in a laser range finding device to measure a distance between the laser range finding device and a target is disclosed. The method comprises the following steps. A laser signal is sent to the target in a first time point. A reflected laser signal reflected by the target is then received. A digital signal having a plurality of signal values ranging from 0 to N is obtained by sampling the reflected laser signal with a sampling signal, wherein N is an integer larger than two. A maximum signal value among the signal values is obtained. The distance is calculated according to the first time point and a second time point where the maximum signal value is generated.
1 . A distance measurement method for use in a laser range finding device to measure a distance between the laser range finding device and a target, comprising:
transmitting a laser signal to the target at a first time point;
receiving a reflected laser signal reflected by the target;
generating a digital signal by sampling the reflected laser signal and creating a plurality of different non-zero magnitude values for the digital signal that are each associated with a time for the received reflected laser signal and have a magnitude that corresponds to a magnitude of the received reflected laser signal at the associated time; and
calculating the distance between the laser range finding device and the target based on the generated digital signal.
2 . The method of claim 1 , wherein:
the digital signal is generated based on one reflected laser signal.
3 . The distance measurement method of claim 1 , wherein:
the digital signal is a signal with eight bits per data value.
4 . The distance measurement method of claim 1 , wherein:
the digital signal is a signal with more than one bit per data value.
5 . The distance measurement method of claim 1 , wherein:
the digital signal is generated by sampling the reflected laser signal with a sampling signal.
6 . The distance measurement method of clam 1 , wherein:
the generated digital signal has a waveform that is similar to a waveform of the received reflected laser signal.
7 . A laser range finding device for measuring a distance between the laser range finding device and a target, comprising:
a transmitter that transmits a laser signal to the target at a first time point;
a receiver that receives a reflected laser signal reflected by the target;
an analog-to-digital converter that samples the reflected laser signal and generates a digital signal by sampling the received reflected laser signal and creating a plurality of different non-zero magnitude values that are each associated with a time for the received reflected signal and have a magnitude that corresponds to a magnitude of the received reflected laser signal at the associated time such that the generated digital signal has a waveform that is similar to a waveform of the received reflected laser signal; and
a processing unit that calculates the distance between the laser range finding device and the target based on the generated digital signal.
8 . The laser range finding device of claim 7 , wherein the transmitter comprises:
a laser diode; and
a driving circuit that controls the laser diode to transmit the laser signal to the target.
9 . The laser range finding device of claim 7 , wherein the receiver comprises:
an avalanche photodiode that receives the reflected laser signal reflected by the target;
a signal amplifier that amplifies the reflected laser signal received by the avalanche photodiode; and
a filter circuit that performs a noise filtering to the amplified reflected laser signal.
10 . The laser range finding device of claim 7 , further comprising:
a memory unit in communication with the processing unit, the memory unit stores the digital signal; and
a control circuit in communication with the processing unit, the control circuit receives a trigger signal from the processing unit so as to drive the transmitter to transmit the laser signal and activate the analog-to-digital converter.
11 . The laser range finding device of claim 7 , further comprising:
a displaying unit coupled to the processing unit for displaying the distance between the laser range finding device and the target calculated by the processing unit.
12 . The laser range finding device of claim 14 , wherein:
the digital signal is a signal with more than one bit per data value.
13 . The laser range finding device of claim 7 , wherein:
the digital signal is a signal with eight bits per magnitude for the plurality of different non-zero magnitude values.
14 . The laser range finding device of claim 7 , wherein:
the analog-to-digital converter samples the reflected laser signal with a sampling signal to generate the digital signal.
15 . The laser range finding device of claim 7 , wherein:
the analog-to-digital converter generates the digital signal based on one reflected laser signal.
16 . A distance measurement method for use in a laser range finding device to measure a distance between the laser range finding device and a target, comprising:
transmitting a laser signal to the target at a first time point;
receiving a reflected laser signal reflected by the target;
generating a digital signal having a plurality of signal values by sampling the reflected laser signal, the signal values range from 0 to N where N is a positive integer greater than two; and
calculating the distance between the laser range finding device and the target based on the generated digital signal.
17 . The method of claim 16 , wherein:
the digital signal is generated based on one reflected laser signal.
18 . The distance measurement method of claim 16 , wherein:
the digital signal is a signal with more than one bit per data value.
19 . The distance measurement method of claim 16 , wherein:
the digital signal is generated by sampling the reflected laser signal with a sampling signal.
20 . The distance measurement method of claim 16 , wherein:
the generated digital signal has a waveform that is similar to a waveform of the received reflected laser signal.