Systems and methods for light detection and ranging
A light detection and ranging system is provided for improving imaging accuracy and measurement range. The light detection and ranging system may comprise: a light source configured to emit a multi-pulse sequence into a three-dimensional environment, in which the multi-pulse sequence comprises multiple light pulses having a temporal profile; a photosensitive detector configured to detect light pulses returned from the three-dimensional environment and generate an output signal indicative of an amount of optical energy associated with a subset of the light pulses; and one or more processors electrically coupled to the light source and the photosensitive detector, and the one or more processors are configured to: generate the temporal profile based on one or more real-time conditions; and determine one or more parameters for selecting the subset of light pulses.
1. A method for laser pulse emission, comprising:
at a first time point, emitting a first laser pulse;
at a second time point, emitting a second laser pulse, wherein a peak power of the first laser pulse is less than a peak power of the second laser pulse, and a time interval between the first time point and the second time point is longer than a delay time for a laser pulse reflected by an obstacle in a near field;
determining, based on a waveform of detected signals, whether a clear and non-overlapping waveform is present following a second voltage signal caused by stray light; and
upon determining the clear and non-overlapping waveform is present, analyzing the waveform to determine the clear and non-overlapping waveform comprises (i) a second pulse waveform, and acquiring a distance information of an obstacle in a far field based on a reflection delay of the second pulse waveform, or (ii) a first pulse waveform, and acquiring a distance information of an obstacle in a near field based on a reflection delay of the first pulse waveform;
upon determining the clear and non-overlapping waveform is not present after the second voltage signal, determining whether a clear and non-overlapping waveform is present between a first voltage signal caused by stray light and the second voltage signal.
2. The method of claim 1 , wherein the near field corresponds to a measurement blind zone that a laser pulse echo signal reflected by an obstacle in the area is in the measurement blind zone.
3. An apparatus for laser pulse emission comprising: a waveform generator and a laser coupled thereto, wherein
the waveform generator is configured for outputting the first drive current to the laser at the first time point, and outputting the second drive current to the laser at the second time point, wherein the current value of the second drive current is greater than the current value of the first drive current, and the time interval between the second time point and the first time point is longer than the delay time for the laser pulse reflected by the obstacle in the near field;
the laser is configured for producing and emitting the first laser pulse at the first time point based on the first drive current input by the waveform generator, and producing and emitting the second laser pulse at the second time point based on the second drive current input by the waveform generator;
wherein the apparatus acquires the distance information using the method of claim 1 .
4. The apparatus of claim 3 , wherein the near field corresponds to a measurement blind zone that a laser pulse echo signal reflected by an obstacle in the area is in the measurement blind zone.
5. The apparatus of claim 3 or 4 , wherein the laser is a semiconductor laser.
6. An apparatus for laser pulse emission, comprising: a laser and a first branch and a second branch coupled thereto, wherein
the first branch comprises: a first branch optical fiber and a first attenuator mutually coupled;
the second branch comprises: a second branch optical fiber and a second attenuator mutually coupled, the attenuation value of the second attenuator is less than the attenuation value of the first attenuator, and the time delay introduced by the second branch optical fiber is greater than the time delay introduced by the first splitter optical fiber, and the time delay difference is the time interval between the first time point and the second time point;
wherein the apparatus acquires the distance information using the method of claim 1 .
7. The apparatus of claim 6 , wherein the near field corresponds to a measurement blind zone that a laser pulse echo signal reflected by an obstacle in the area is in the measurement blind zone.
8. An apparatus for laser pulse emission, comprising:
a first emission unit configured to emit the first laser pulse at the first time point;
a second emission unit configured to emit the second laser pulse at the second moment;
the apparatus acquires the distance information using the method of claim 1 .
9. The apparatus of claim 8 , wherein the near field corresponds to a measurement blind zone that a laser pulse echo signal reflected by an obstacle in the area is in the measurement blind zone.
10. A method for acquiring obstacle information, comprising:
the method of claim 1 ;
acquiring the distance information of the obstacle in the near field based on an echo signal of the first laser pulse;
acquiring the distance information of the obstacle in the far field based on an echo signal of the second laser pulse.