Velodyne Lidar USA, Inc.

A light detection and ranging (LIDAR) device including a laser source configured to provide a transmit beam, the laser source being positioned with a first offset relative to a reference line, a transmit/receive (T/R) interface configured to pass the transmit beam and reflect received light towards a detector, the T/R interface being positioned with a second offset relative to the reference line, and a lens positioned between the laser source and the T/R interface, the lens being positioned with a third offset relative to the reference line, wherein the laser source and the lens, as positioned, are configured to steer the transmit beam.

Systems and methods for detecting extrinsic parameter miscalibration for light detection and ranging (“LiDAR”) devices are disclosed. According to one embodiment, a LiDAR detection method includes scanning, by a LiDAR system comprising one or more LiDAR devices, a field-of-view during one or more time periods, wherein the LiDAR system moves along a non-linear path during at least a subset of the one or more time periods. Return signal data obtained during at least the subset is aggregated and fiducial markers represented by the aggregated return signal data are identified. Each of the identified fiducial markers are compared to a respective reference fiducial marker of a plurality of reference fiducial markers. Based on the comparison, miscalibration of an extrinsic parameter associated with a position and/or an orientation of at least one of the LiDAR devices is detected. An action is initiated to remediate the detected miscalibration of the extrinsic parameter.

Methods and systems for improved simultaneous localization and mapping based on 3-D LIDAR image data. In one aspect, LIDAR image frames are segmented and clustered before feature detection to improve computational efficiency while maintaining both mapping and localization accuracy. Segmentation involves removing redundant data before feature extraction. Clustering involves grouping pixels associated with similar objects together before feature extraction. In another aspect, features are extracted from LIDAR image frames based on a measured optical property associated with each measured point. The pools of feature points comprise a low resolution feature map associated with each image frame. Low resolution feature maps are aggregated over time to generate high resolution feature maps. In another aspect, the location of a LIDAR measurement system in a three dimensional environment is slowly updated based on the high resolution feature maps and quickly updated based on the low resolution feature maps.

LiDAR-based immersive 3D reality capture systems and methods are disclosed. The reality capture system includes a set of LiDAR sensors disposed around an environment and configured to capture one or more events occurring within the environment. The reality capture system also includes a corresponding set of cameras disposed around the environment. Each camera is mounted on a same gimbal with a corresponding LiDAR sensor and has a same optical axis as the corresponding LiDAR sensor. The reality capture system further includes a base station viewpoint generator coupled to the set of LiDAR sensors and the cameras to generate a video feed based on data received from the LiDAR sensors and the cameras. The reality capture system additionally includes a virtual reality device coupled to the base station viewpoint generator to receive and display the video feed generated by the base station viewpoint generator.

Described herein are systems and methods that may efficiently detect multi-return light signals. A light detection and ranging system, such as a LIDAR system, may fire a laser beam that may hit multiple objects with a different distance in one line, causing multi-return light signals to be received by the system. Multi-return detectors may be able to analyze the peak magnitude of a plurality of peaks in the return signals and determine a multitude of peaks, such as the first peak, the last peak and the maximum peak. One embodiment to detect the multi-return light signals may be a multi-return recursive matched filter detector. This detector comprises a matched filter, peak detector, centroid calculation and a zeroing out function. Other embodiments may be based on a maximum finder that algorithmically selects the highest magnitude peaks from samples of the return signal and buffers for regions of interests peaks.

A light detection and ranging (LIDAR) system may include a transceiver disposed on a first substrate and comprising a plurality of receiver detectors; and a shared clock source disposed remotely from the transceiver on a second substrate and comprising a shared clock that is structured and arranged to control and synchronize operation of the plurality of receiver detectors to determine time-of-flight or reflectance.

Disclosed herein are systems and methods for linearizing frequency chirp in a frequency-modulated continuous wave (FMCW) coherent LiDAR system. Exemplary methods can include generating a continuous wave laser signal having a frequency characteristic, in which the frequency characteristic can include a frequency chirp over a frequency band in at least one period; and receiving a signal based on the generated laser signal. The methods can further include mixing the received signal with a local oscillator signal, the local oscillator signal having the frequency characteristic; determining at least one beat frequency based on the mixed signal; sampling the mixed signal at a rate equal to at least two times the beat frequency; determining a correction signal based on the sampled signal; and applying the correction signal to the laser signal.

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.

A LIDAR system may include a transmitter, a photodetector, and a receiver. The receiver may transmit an optical signal having a signature. The photodetector may detect a return signal and generate a captured signal representing the return signal. The receiver may process the captured signal to determine a propagation time of the optical signal between the transmitter and the surface. The receiver may include signal processing components and timing circuitry. The signal processing components may digitize the captured signal and determine whether a signature of the digitized signal matches the signature of the optical signal. The timing circuitry may determine the propagation time of the optical signal between the transmitter and the surface based on the digitized signal when the signature of the digitized signal is determined to match the signature of the optical signal.

Methods and systems for controlling illumination power of a LIDAR based, three dimensional imaging system based on discrete illumination power tiers are described herein. In one aspect, the illumination intensity of a pulsed beam of illumination light emitted from a LIDAR system is varied in accordance with a set of illumination power tiers based on the difference between a desired and a measured return pulse. In a further aspect, the illumination power tier is selected based on whether an intensity difference exceeds one of a sequence of predetermined, tiered threshold values. In this manner, the intensity of measured return pulses is maintained within a linear range of the analog to digital converter for objects detected over a wide range of distances from the LIDAR system and a wide range of environmental conditions in the optical path between the LIDAR system and the detected object.