LiDAR systems for near-field and far-field detection, and related methods and apparatus
A light detection and ranging (LiDAR) method may include generating, by a first transmitter, a first light illumination signal; generating, by a second transmitter, a second light illumination signal; receiving first return signals corresponding to the first light illumination signal; receiving second return signals corresponding to the second light illumination signal; and sampling the first return signals or the second return signals during a short-range sampling period, such that the short-range sampling period avoids a period of dazzle.
1. A light detection and ranging (LiDAR) system comprising:
a first transmitter adapted to generate and emit a first light illumination signal into a long-range scan area at a first degree of divergence;
a second transmitter adapted to generate and emit a second light illumination signal into a short-range scan area at a second degree of divergence greater than the first degree of divergence;
a receiver comprising an optical detector adapted to receive first return signals corresponding to light from the first light illumination signal reflected from surfaces within the long-range scan area and to receive second return signals corresponding to light from the second light illumination signal reflected off surfaces within the short-range scan area; and
circuitry configured to: (i) during a first time period, fire the first transmitter to generate the first light illumination signal and receive and detect the first return signals by the optical detector, and (ii) during a second time period, fire the second transmitter to generate the second illumination signal and receive and detect the second return signals by the optical detector, wherein the first and second time periods are non-overlapping.
2. The system of claim 1 , wherein the short-range scan area is spatially distant from the long-range scan area.
3. The system of claim 1 wherein the circuitry is configured to time firing of the second transmitter such that short-range returns resulting from the pulses of light generated by the second transmitter are not affected by dazzle created by the first transmitter.
4. The system of claim 3 further comprising a data analysis and interpretation module structured and arranged to process data received from the receiver.
5. The system of claim 1 , wherein the second transmitter comprises at least one vertical-cavity surface-emitting laser (VCSEL).
6. The system of claim 1 , wherein the range of the second light illumination signal is between about 10 meters and about 20 meters.
7. The system of claim 1 , wherein the range of second light illumination signal is less than about 2 meters.
8. The system of claim 1 , wherein the range of the second light illumination signal is between about 1 meter and about 20 meters.
9. The system of claim 1 further comprising a diffuser disposed between the second transmitter and the short-range scan area.
10. The system of claim 1 , wherein the second transmitter comprises a baffle configured to reduce transmission of light from the second transmitter to the receiver along an optical path internal to the LiDAR system.