Abstract: A scanning imaging sensor is configured to sense an environment through which a vehicle is moving. A method for determining one or velocities associated with objects in the environment includes generating features from the first set of scan lines and the second set of scan lines, the two sets corresponding to two instances in time. The method further includes generating a collection of candidate velocities based on feature locations and time differences, the features selected pairwise with one from the first set and another from the second set. Furthermore, the method includes analyzing the distribution of candidate velocities, for example, by identifying one or more modes from the collection of the candidate velocities.

Abstract: In one embodiment, a lidar system includes a light source configured to emit pulses of light. The emitted pulses of light include one or more series of standard-resolution pulses alternating with one or more series of high-resolution pulses. Each series of the standard-resolution pulses includes multiple pulses having a standard pulse period, and each series of the high-resolution pulses includes multiple pulses having a high-resolution pulse period. The standard pulse period is greater than or equal to a round-trip time associated with a maximum range of the lidar system, and the high-resolution pulse period is less than the standard pulse period. The lidar system also includes a scanner configured to scan at least a portion of the emitted pulses of light across a field of regard.

Abstract: LiDAR optical paths, particularly in co-located emitter/receiver path configurations, can introduce unintended and unwanted reflections due to mirrors, lenses, and/or enclosure materials or glass that can fall on one or more photosensors. These un-desirable signals can cause significant disruptions in output amplifier biasing and/or severe channel saturation. Autonomous vehicle LiDAR is particularly challenging as packaging requirements require complex optics to direct the laser source; the target size, shape, and relative velocity, and distance to the autonomous vehicle are unknown; and the location of the target objects within range are potentially rapidly changing over time. The presently disclosed dual photodiode LiDAR systems are used to separate and compensate for errors introduced by LiDAR optics to improve the accuracy and reliability of LiDAR systems, including but not limited to autonomous vehicle LiDAR systems.

Abstract: A metasurface includes a plurality of Bragg mirrors, each having a defect cavity therein, arrayed in a grid. A heat source is provided for each of the plurality of Bragg mirrors. Each heat source is positioned to selectively modulate heat applied to its respective Bragg mirror and to impart a different phase shift via the applied heat from the heat source.

Abstract: A sequence of images generated at respective times by one or more sensors configured to sense an environment through which objects are moving relative to the one or more sensors is received. A message passing graph having a multiplicity of layers associated with the sequence of images is constructed. A neural network supported by the message passing graph is trained. The training includes performing a pass through the message passing graph in a forward direction including by adding a new feature node based on a feature detection and a new edge node and performing a pass through the message passing graph in a backward direction, including by updating at least one edge node of the message passing graph. Multiple features are tracked through the sequence of images, including passing messages through the message passing graph.

Abstract: In one embodiment, a lidar system includes a light source configured to emit pulses of light. The lidar system also includes a scanner configured to scan at least a portion of the emitted pulses of light along an interlaced scan pattern, including: (i) scanning the portion of the emitted pulses of light substantially parallel to a first scan axis to produce multiple scan lines of the interlaced scan pattern; and (ii) distributing the scan lines along a second scan axis in an interlaced manner, where the interlaced scan pattern is an n-fold interlaced scan pattern that includes n sub-scans, where: n is an integer greater than or equal to 2, each sub-scan includes two or more of the scan lines of the interlaced scan pattern, and the n sub-scans are scanned sequentially where a first sub-scan of the n sub-scans is scanned prior to a second sub-scan.

Abstract: In one embodiment, a lidar system includes a light source configured to emit optical pulses using multiple pulse intervals (PIs) that include a first PI and a second PI, where the first PI and the second PI are not equal. The lidar system also includes a receiver configured to detect multiple input optical pulses. The lidar system further includes a processor configured to generate multiple pixels, where each pixel of the multiple pixels corresponds to one of the multiple input optical pulses and is associated with one of the PIs. The processor is further configured to (i) determine, for a particular pixel of the multiple pixels, a group of nearby pixels and (ii) determine whether the particular pixel is range-wrapped based at least in part on the PI associated with each pixel of the group of nearby pixels.

Abstract: An optical receiver including an ASIC, a light detector element, and a protective mask is disclosed. The light detector element is disposed on the ASIC and has a top surface oriented toward incident light, the top surface including a portion configured to receive the incident light and via which the incident light reaches an active area of the light detector element. The protective mask is placed over the ASIC so as to (i) cover, from the incident light, a portion of the ASIC, and (ii) provide an aperture that defines an optical path for the incident light through the protective mask to the portion of the top surface of the light detector element.

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 including 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 lidar system further includes a processor configured to determine the distance to the target based at least in part on a time-of-arrival for the received pulse of light.

Abstract: A lidar system includes one or more light sources configured to generate a first beam of light and a second beam of light, a scanner configured to scan the first and second beams of light across a field of regard of the lidar system, and a receiver configured to detect the first beam of light and the second beam of light scattered by one or more remote targets. The scanner includes a rotatable polygon mirror that includes multiple reflective surfaces angularly offset from one another along a periphery of the polygon mirror, the reflective surfaces configured to reflect the first and second beams of light to produce a series of scan lines as the polygon mirror rotates. The scanner also includes a pivotable scan mirror configured to (i) reflect the first and second beams of light and (ii) pivot to distribute the scan lines across the field of regard.

Abstract: An active metasurface that provides low-loss and high-bandwidth modulation control of light includes a number of cells arranged on a substrate. A controller dynamically alters a voltage differential supplied to the electrodes of each of the cells is adapted to alter refractive index of each of the high-index dielectric blocks in order to controllably steer light exiting the cell.

Abstract: An active metasurface that provides low-loss and high-bandwidth modulation control of light includes a number of cells arranged on a substrate. A controller dynamically alters a voltage differential supplied to the electrodes of each of the cells is adapted to alter refractive index of each of the high-index dielectric blocks in order to controllably steer light exiting the cell.

Abstract: In one embodiment, a method for dynamically varying receiver characteristics in a lidar system includes emitting light pulses by a light source in a lidar system. The method further includes detecting, by a receiver in the lidar system, light from one of the light pulses scattered by one or more remote targets to identify a return light pulse. The method also includes determining an atmospheric condition at or near a geolocation of a vehicle that includes the lidar system. The method further includes providing a control signal to the receiver adjusting one or more characteristics of the receiver to compensate for attenuation or distortion of the return light pulses associated with the atmospheric condition.

Abstract: To clear the line-of-sight (LOS) on a window in a lidar system within a vehicle, ultrasonic transducers are physically attached to the interior surface of the window to remove debris. When debris is detected at the window, the ultrasonic transducers are directed to vibrate at an ultrasonic frequency thereby generating an ultrasonic wave which causes the debris to bounce off the window. In some scenarios, the ultrasonic transducers vibrate with a particular phase shift to generate a travelling wave that causes the debris to sweep across the window. Additionally, windshield wipers, spray from a nozzle, and/or a hydrophobic or oleophobic coating may be used in combination with the ultrasonic transducers to remove the debris from the window.

Abstract: In one embodiment, a lidar system includes a light source configured to emit pulses of light and a scanner configured to scan the emitted pulses of light along a high-resolution scan pattern located within a field of regard of the lidar system. The scanner includes one or more scan mirrors configured to (i) scan the emitted pulses of light along a first scan axis to produce multiple scan lines of the high-resolution scan pattern, where each scan line is associated with multiple pixels, each pixel corresponding to one of the emitted pulses of light and (ii) distribute the scan lines of the high-resolution scan pattern along a second scan axis. The high-resolution scan pattern includes one or more of: interlaced scan lines and interlaced pixels.

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: 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.