Abstract: To dynamically control power in a lidar system, a controller identifies a triggering event and provides a control signal to a light source in the lidar system adjusting the power of light pulses provided by the light source. Triggering events may include exceeding a threshold speed, being within a threshold distance of a person or other object, an atmospheric condition, identifying residue on a surface of a window of the lidar system, etc. In some scenarios, the power is adjusted to address eye-safety concerns.

Abstract: Amplifier input protection circuits are described. In one embodiment, a photoreceiver for a lidar system has a photodetector configured to generate an output current in response to received light. A transimpedance amplifier is configured to receive the output current and generate a voltage output corresponding to the output current in response thereto, and a diode circuit has a cathode coupled at a node between the photodetector output and the transimpedance amplifier input.

Abstract: A device includes a controller with a processor and memory with instructions for controlling power to a light source such that the light source emits a frequency-modulated continuous light beam that, over time, includes an up region, a down region, and a flat region. The up region includes increasing a frequency of the continuous light beam, the down region includes decreasing the frequency of the continuous light beam, and the flat region includes maintaining the frequency of the continuous light beam at a constant frequency.

Abstract: Implementations described and claimed herein provide a mechanically-scanning 3-dimensional light detection and ranging (3D LiDAR) system including a galvo mirror assembly, wherein the galvo mirror assembly includes a mirror attached to an armature of a galvanometer to reflect a light signal generated by a light generator and received from a target, at least one permanent magnet, and at least one coil configured to carry a current to move the armature.

Abstract: A waveguide grating antenna apparatus includes a substrate layer, an asymmetric waveguide array layer upon the substrate layer, and a waveguide grating array layer formed above the asymmetric waveguide array layer. The waveguide array layer is composed of two forms of waveguide structures arranged in parallel. Each waveguide of the first form extends continuously, has a first width, and is laterally separated from each adjacent waveguide of the first form by a gap distance. Each waveguide of the second form extends parallel to and between adjacent waveguides of the first form within the first gap distance and is narrower than each of the first width and the gap distance. Pairs of the second form are closer to lateral sides of a first alternating set of the first form. The waveguide grating is composed of adjacent, separated elements extending axially along each waveguide of the first form.

Abstract: The technology disclosed herein includes a system having a light source configured to generate a laser signal, an optical signal splitter circuit configured to split the laser signal into a first laser signal for transmission to a plurality of targets and a second laser signal, an optical signal scanner configured to transmit the first laser signal to the plurality of targets, two or more optical delay lines configured to receive the second laser signal, wherein each of the two or more optical delay lines adds a predetermined time delay to the second laser signal to generate a delayed second laser signal, and a detector configured to receive a reflected laser signal from the plurality of targets, wherein the reflected laser signal includes a reflection of the first laser signal from the plurality of targets, and the delayed second laser signal.

Abstract: In one embodiment, a lidar system includes a light source configured to emit an optical signal. The light source includes a seed laser diode configured to produce a seed optical signal and a semiconductor optical amplifier (SOA) configured to amplify the seed optical signal to produce an amplified seed optical signal, where the emitted optical signal includes the amplified seed optical signal. The lidar system also includes a scanner configured to direct the emitted optical signal into a field of regard of the lidar system and a receiver configured to detect a portion of the emitted optical signal scattered by a target located a distance from the lidar system. The lidar system further includes a processor configured to determine the distance from the lidar system to the target.

Abstract: The bit depth of the pixels in a camera image are reduced. In one embodiment, the number of pixels for each of a set of multiple bit intensity values is counted. A pixel intensity value with a lowest count is selected and a mapping function is generated that combines the pixels with the lowest count with pixels having an adjacent pixel intensity value. This is repeated until a total number of pixel intensity value counts is reduced to a predetermined number. A reduced bit depth image is generated using the predetermined number of pixel intensity value counts by assigning a new pixel intensity value to each of the pixels using the mapping function and the reduced bit depth image is sent to an image analysis system.

Abstract: A computer-implemented method of determining relative velocity between a vehicle and an object. The method includes receiving sensor data generated by one or more sensors of the vehicle configured to sense an environment by following a scan pattern comprising component scan lines. The method includes obtaining, based on the sensor data, a point cloud frame. Additionally, the method includes identifying a first pixel and a second pixel that are co-located within a field of regard and overlap a point cloud object within the point cloud frame and calculating a difference between a depth associated with the first pixel and a depth associated with the second pixel. The method includes determining a relative velocity of the point cloud object by dividing the difference in depth data by a time difference between when the depth associated with the first pixel was sensed and the depth associated with the second pixel was sensed.

Abstract: In one embodiment, a lidar system includes a light source configured to emit (i) local-oscillator light and (ii) pulses of light, where each emitted pulse of light is coherent with a corresponding portion of the local-oscillator light. The lidar system also includes a receiver configured to detect the local-oscillator light and a received pulse of light, the received pulse of light comprising light from one of the emitted pulses of light that is scattered by a target located a distance from the lidar system. The local-oscillator light and the received pulse of light are coherently mixed together at the receiver. The receiver includes one or more detectors configured to produce one or more respective photocurrent signals corresponding to the coherent mixing of the local-oscillator light and the received pulse of light. The receiver also includes a pulse-detection circuit configured to determine a time-of-arrival for the received pulse of light.

Abstract: A method for processing point clouds having variable spatial distributions of scan lines includes receiving a point cloud frame generated by a sensor configured to sense an environment through which a vehicle is moving. The point cloud frame includes scan lines arranged according to a particular spatial distribution. The method also includes either generating an enhanced point cloud frame with a larger number of points than the received point cloud frame, or constructing, by one or more processors and based on points of the received point cloud frame, a three-dimensional mesh. The method also includes generating, by performing an interpolation function on the enhanced point cloud frame or a virtual surface provided by the three-dimensional mesh, a normalized point cloud frame, and generating, using the normalized point cloud frame, signals descriptive of a current state of the environment through which the vehicle is moving.

Abstract: A method for processing point clouds having variable spatial distributions of scan lines includes receiving a point cloud portion corresponding to an object in a vehicle environment, the point cloud portion including scan lines arranged according to a particular spatial distribution. The method also includes constructing a voxel grid corresponding to the received point cloud portion. The voxel grid includes a plurality of volumes in a stacked, three-dimensional arrangement, and constructing the voxel grid includes (i) determining an initial classification of the object, (ii) setting one or more parameters of the voxel grid based on the initial classification, and (iii) associating each volume of the plurality of volumes with an attribute specifying how many points, from the point cloud portion, fall within that volume. The method also includes generating, using the constructed voxel grid, signals descriptive of a current state of the environment through which the vehicle is moving.

Abstract: A detector system within a lidar receiver is configured to compensate for range walk error by detecting both the rising edge and the falling edge of a received light pulse as the envelope of the received light pulse passes through a particular detection (magnitude) threshold. Detection circuitry within the detector system then determines the center of the received light pulse as the point equidistant in time between the detected rising and falling edges of the received light pulse, and uses the time associated with the center of the received light pulse to determine the range to the target from which the scattered light pulse was received.

Abstract: In one embodiment, a laser system includes a seed laser diode configured to produce a free-space seed-laser beam and a seed-laser focusing lens configured to focus the seed-laser beam. The laser system also includes a semiconductor optical amplifier (SOA) that includes a front facet, a back facet, and a waveguide extending from the front facet to the back facet. The SOA is configured to: receive, at the front facet, light from the focused seed-laser beam; amplify the received light as the received light propagates along the SOA waveguide from the front facet to the back facet; and emit, from the back facet, an amplified free-space beam that includes the amplified received light. The laser system further includes a mounting platform, where one or more of the seed laser diode, the seed-laser focusing lens, and the SOA are mechanically attached to the mounting platform.

Abstract: A lidar system includes a light source configured to emit pulses of light, a scanner configured to direct the pulses of light along a scan direction, and a receiver with a detector configured to detect the pulses of light scattered by remote targets. For a pulse of light emitted by the light source, the receiver is configured to detect the scattered pulse of light returning to the receiver during a ranging time interval between (i) when the pulse of light leaves the lidar system and (ii) when the scattered pulse of light returns from a remote target positioned at a maximum distance RMAX. For at least a portion of the ranging time interval, the lidar system directs the scattered pulse of light toward the active region of the detector at an oblique angle to reduce an amount of light impinging on the active region.

Abstract: A computer-implemented method of detecting object distortion. The method includes receiving sensor data generated by one or more sensors of the vehicle. The one or more sensors are configured to sense an environment through which the vehicle is moving by following a scan pattern. The method also includes obtaining, based on the sensor data, a point cloud frame representative of the environment and identifying a point cloud object within the point cloud frame. Additionally, the method includes analyzing the point cloud object to identify a feature of the point cloud object that has an expected shape and comparing the feature of the point cloud object to the expected shape. The method also includes identifying that the point cloud object is distorted based on the feature of the point cloud object not matching the expected shape.

Abstract: A system includes a lidar, a camera, and a controller communicatively coupled to the camera and the lidar. The lidar includes a laser configured to emit pulses of light, a scanner configured to direct the emitted pulses in accordance with a scan pattern, and a receiver configured to detect the emitted pulse of light scattered by one or more remote targets to collect a set of lidar pixels of a scan frame, in a sequence defined by the scan pattern. The camera has a field of regard that at least partially overlaps the field of regard of the lidar. The controller is configured to cause the camera to capture images while the receiver of the lidar module collects the complete set of lidar pixels of the scan frame, and align lidar pixels with corresponding pixels in the captured images.

Abstract: A technique for manufacturing highly balanced rotatable polygon mirrors for use in scanners includes forming a block having a first wall, a second wall, and reflective surfaces extending between the first and second walls, the surfaces being angularly offset from one another along a periphery of the block. The technique includes applying a coarse balancing procedure to the block, making the surfaces reflective, mating the block to a motor, and applying a precise balancing procedure to the block. The technique also includes imparting rotation to the block and removing material from the block via the first wall using high-energy laser pulses.

Abstract: To generate an image that captures a 360-degree horizontal view around a vehicle in a lidar system, four or more lidar sensors may be placed at the four corners of the vehicle. Each lidar sensor is phased 90 degrees apart and synchronously scans a respective 90-degree field of regard. The 90 degree fields of regard from each of the four or more lidar sensors may combine to scan a complete 360-degree field of regard around the vehicle.

Abstract: A lidar system includes a lighting module configured to (i) select a wavelength from among a plurality of wavelength values, for a particular time period, and (ii) emit light at the selected wavelength. The lighting module emits light at different wavelengths during at least two adjacent periods of time. The lidar system further includes a scanner configured to direct the pulse of light to illuminate a respective region within a field of regard of the lidar system and a receiver module configured to (i) receive a light signal and (ii) determine whether the received light signal includes the light emitted by the lighting module and scattered by a remote target, based at least in part on the wavelength selected by the lighting module.