Abstract: The present disclosure relates to light detection and ranging (lidar) systems, lidar-equipped vehicles, and associated methods. An example method includes causing a firing circuit to trigger emission of an initial group of detection pulses from at least one light-emitter device of a lidar system in accordance with an initial set of one or more light-emission parameters. The method also includes causing the firing circuit to trigger emission of one or more test pulses and receiving, from at least one detector, information indicative of one or more return test pulses. The method yet further includes determining, based on the received information, a presence of a retroreflector based on an intensity of the return test pulse. The method additionally includes determining a subsequent set of light-emission parameters and causing the firing circuit to trigger emission of a subsequent group of detection pulses in accordance with the subsequent set of light-emission parameters.

Abstract: Example embodiments relate to light detectors for nearby object detection in light detection and ranging (lidar) devices. An example embodiment includes a lidar device. The lidar device includes a light emitter configured to emit a light signal at a first time. The lidar device also includes a light detector configured to detect the emitted light signal. Additionally, the lidar device includes a biasing circuit configured to modify a detector bias using a bias signal. The bias signal ramps the detector bias from a first bias level at the first time to a second bias level at a second time. The second time is separated from the first time by a ramp duration. The ramp duration is sufficient to prevent any internal feedback within the lidar device caused by the emitted light signal from saturating the light detector or detection circuitry associated with the light detector.

Abstract: The present disclosure relates to light detection and ranging (lidar) systems, lidar-equipped vehicles, and associated methods. An example method includes causing a firing circuit to trigger emission of an initial group of detection pulses from at least one light-emitter device of a lidar system in accordance with an initial set of one or more light-emission parameters. The method also includes causing the firing circuit to trigger emission of one or more test pulses and receiving, from at least one detector, information indicative of one or more return test pulses. The method yet further includes determining, based on the received information, a presence of a retroreflector based on an intensity of the return test pulse. The method additionally includes determining a subsequent set of light-emission parameters and causing the firing circuit to trigger emission of a subsequent group of detection pulses in accordance with the subsequent set of light-emission parameters.

Abstract: Described herein is a LIDAR device that may include a transmitter, first and second receivers, and a rotating platform. The transmitter may be configured to emit light having a vertical beam width. The first receiver may be configured to detect light at a first resolution while scanning the environment with a first FOV and the second receiver may be configured to detect light at a second resolution while scanning the environment with a second FOV. In this arrangement, the first resolution may be higher than the second resolution, the first FOV may be at least partially different from the second FOV, and the vertical beam width may encompass at least a vertical extent of the first and second FOVs. Further, the rotating platform may be configured to rotate about an axis such that the transmitter and first and second receivers each move based on the rotation.

Abstract: Example embodiments relate to differential methods for determining environment estimation, lidar impairment detection, and filtering. An example embodiment includes dividing a plurality of lidar device channels into a first group and a second group and interleaving the channels. The embodiment includes applying a threshold to the first group. The embodiment further includes emitting light pulses from a lidar device into an environment surrounding the lidar device, and detecting return light pulses. The return light pulses in the first group of channels are sampled from the signals that exceed the threshold. The embodiment may further include determining a differential in a statistical distribution between the return light pulses in the first group and the return light pulses in the second group. Based on the differential, the method can include detecting an atmospheric scattering medium in the environment surrounding the lidar device.

Abstract: Example embodiments relate to controlling detection time in photodetectors. An example embodiment includes a device. The device includes a substrate. The device also includes a photodetector coupled to the substrate. The photodetector is arranged to detect light emitted from a light source that irradiates a top surface of the device. A depth of the substrate is at most 100 times a diffusion length of a minority carrier within the substrate so as to mitigate dark current arising from minority carriers photoexcited in the substrate based on the light emitted from the light source.

Abstract: Example embodiments relate to differential methods for determining environment estimation, lidar impairment detection, and filtering. An example embodiment includes dividing a plurality of lidar device channels into a first group and a second group and interleaving the channels. The embodiment includes applying a threshold to the first group. The embodiment further includes emitting light pulses from a lidar device into an environment surrounding the lidar device, and detecting return light pulses. The return light pulses in the first group of channels are sampled from the signals that exceed the threshold. The embodiment may further include determining a differential in a statistical distribution between the return light pulses in the first group and the return light pulses in the second group. Based on the differential, the method can include detecting an atmospheric scattering medium in the environment surrounding the lidar device.

Abstract: Example embodiments relate to light detection and ranging (lidar) devices having a light-guide manifold. An example lidar device includes a transmit subsystem. The transmit subsystem includes a light emitter. The transmit subsystem also includes a light-guide manifold optically coupled to the light emitter. Further, the transmit subsystem includes a telecentric lens assembly optically coupled to the light-guide manifold. The lidar device also includes a receive subsystem. The receive subsystem includes the telecentric lens assembly. The receive subsystem also includes an aperture plate having an aperture defined therein. The aperture plate is positioned at a focal plane of the telecentric lens assembly. Further, the receive subsystem includes a silicon photomultiplier (SiPM) positioned to receive light traveling through the aperture.

Abstract: Example embodiments relate to light detection and ranging (lidar) devices having a light-guide manifold. An example lidar device includes a transmit subsystem. The transmit subsystem includes a light emitter. The transmit subsystem also includes a light-guide manifold optically coupled to the light emitter. Further, the transmit subsystem includes a telecentric lens assembly optically coupled to the light-guide manifold. The lidar device also includes a receive subsystem. The receive subsystem includes the telecentric lens assembly. The receive subsystem also includes an aperture plate having an aperture defined therein. The aperture plate is positioned at a focal plane of the telecentric lens assembly. Further, the receive subsystem includes a silicon photomultiplier (SiPM) positioned to receive light traveling through the aperture.

Abstract: The present disclosure relates to limitation of noise on light detectors using an aperture. One example embodiment includes a system. The system includes a lens disposed relative to a scene and configured to focus light from the scene onto a focal plane. The system also includes an aperture defined within an opaque material disposed at the focal plane of the lens. The aperture has a cross-sectional area. In addition, the system includes an array of light detectors disposed on a side of the focal plane opposite the lens and configured to intercept and detect diverging light focused by the lens and transmitted through the aperture. A cross-sectional area of the array of light detectors that intercepts the diverging light is greater than the cross-sectional area of the aperture.

Abstract: An optical system may include a substrate and a plurality of silicon photomultipliers (SiPMs) monolithically integrated with the substrate. Each SiPM may include a plurality of single photon avalanche diodes (SPADs). The optical system also includes an aperture array having a plurality of apertures. The plurality of SiPMs and the aperture array are aligned so as to define a plurality of receiver channels. Each receiver channel includes a respective SiPM of the plurality of SiPMs optically coupled to a respective aperture of the plurality of apertures.

Abstract: The present disclosure relates to devices, systems, and methods relating to configurable silicon photomultiplier (SiPM) devices. An example device includes a substrate and a plurality of single photon avalanche diodes (SPADs) coupled to the substrate. The device also includes a plurality of outputs coupled to the substrate and a plurality of electrical components coupled to the substrate. The plurality of electrical components are configured to selectively connect the plurality of SPADs to the plurality of outputs by selecting which output of the plurality of outputs is connected to each SPAD of the plurality of SPADs and to thereby define a plurality of SiPMs in the device such that each SiPM of the plurality of SiPMs comprises a respective set of one or more SPADs connected to a respective output of the plurality of outputs.

Abstract: Example embodiments relate to pulse energy plans for light detection and ranging (lidar) devices based on areas of interest and thermal budgets. An example lidar device includes a plurality of light emitters configured to emit light pulses into an environment in a plurality of different emission directions. The lidar device also includes circuitry configured to power the plurality of light emitters. Further, the lidar device includes a plurality of detectors configured to detect reflections of light pulses emitted by the plurality of light emitters. In addition, the lidar device includes a controller configured to (i) determine a pulse energy plan based on one or more regions of interest in the environment and a thermal budget and (ii) control the circuitry based on the pulse energy plan. The pulse energy plan specifies a pulse energy level for each light pulse emitted by each light emitter in the plurality of light emitters.

Abstract: An example method and system for filtering point cloud data includes obtaining point cloud data from a LIDAR device. The point cloud data may include at least a first pulse-length range and a second pulse-length range. The first range may include one or more first-length pulses and the second range may include one or more second-length pulses. The method may further include filtering the point cloud data by determining respective magnitudes of each of the one or more first-length pulses and each of the one or more second-length pulses, comparing the magnitudes of the first-length pulses to a first threshold, comparing the magnitudes of the second-length pulses to a second threshold, and removing any pulses having a magnitude less than the respective thresholds. The method may further include determining, based on the filtered point cloud data, objects in an environment around the LIDAR.

Abstract: An optical system may include a substrate and a plurality of silicon photomultipliers (SiPMs) monolithically integrated with the substrate. Each SiPM may include a plurality of single photon avalanche diodes (SPADs). The optical system also includes an aperture array having a plurality of apertures. The plurality of SiPMs and the aperture array are aligned so as to define a plurality of receiver channels. Each receiver channel includes a respective SiPM of the plurality of SiPMs optically coupled to a respective aperture of the plurality of apertures.

Abstract: The present disclosure relates to limitation of noise on light detectors using an aperture. One example embodiment includes a system. The system includes a lens disposed relative to a scene and configured to focus light from the scene onto a focal plane. The system also includes an aperture defined within an opaque material disposed at the focal plane of the lens. The aperture has a cross-sectional area. In addition, the system includes an array of light detectors disposed on a side of the focal plane opposite the lens and configured to intercept and detect diverging light focused by the lens and transmitted through the aperture. A cross-sectional area of the array of light detectors that intercepts the diverging light is greater than the cross-sectional area of the aperture.

Abstract: The present disclosure relates to devices, systems, and methods relating to configurable silicon photomultiplier (SiPM) devices. An example device includes a substrate and a plurality of single photon avalanche diodes (SPADs) coupled to the substrate. The device also includes a plurality of outputs coupled to the substrate and a plurality of electrical components coupled to the substrate. The plurality of electrical components are configured to selectively connect the plurality of SPADs to the plurality of outputs by selecting which output of the plurality of outputs is connected to each SPAD of the plurality of SPADs and to thereby define a plurality of SiPMs in the device such that each SiPM of the plurality of SiPMs comprises a respective set of one or more SPADs connected to a respective output of the plurality of outputs.

Abstract: An example method includes receiving point cloud information about a field of view of a lidar system. The point cloud information includes spatiotemporal and amplitude information about return light received. The method also includes determining, based on the point cloud information, a set of bright light returns from at least one highly reflective object. The bright light returns include return light having an amplitude above a photon threshold and a corresponding bright light return range. The method yet further includes determining, based on the point cloud information, a set of crosstalk returns. The crosstalk returns include return light having a corresponding crosstalk return range. The method includes adjusting, based on a normalized number of crosstalk returns, at least one of: a cleaning system, an operating mode of a lidar system, or an operating mode of a vehicle.

Abstract: A system includes a near-infrared (NIR) illuminator, an NIR image sensor, a light detection and ranging (LIDAR) device, and control circuitry configured to perform operations. The operations include causing the NIR illuminator to illuminate a portion of an environment, and obtaining, from the NIR image sensor, NIR image data representing the portion of the environment illuminated by the NIR illuminator. The operations also include detecting a retroreflector within the NIR image data and, based on detecting the retroreflector within the NIR image, determining a position of the retroreflector within the environment. The operations further include, based on the position of the retroreflector within the environment, adjusting at least one parameter of the LIDAR device in connection with scanning the retroreflector.

Abstract: An example method includes receiving point cloud information about a field of view of a lidar system. The point cloud information includes spatiotemporal and amplitude information about return light received. The method also includes determining, based on the point cloud information, a set of bright light returns from at least one highly reflective object. The bright light returns include return light having an amplitude above a photon threshold and a corresponding bright light return range. The method yet further includes determining, based on the point cloud information, a set of crosstalk returns. The crosstalk returns include return light having a corresponding crosstalk return range. The method includes adjusting, based on a normalized number of crosstalk returns, at least one of: a cleaning system, an operating mode of a lidar system, or an operating mode of a vehicle.