Patent Description:
Light Detection and Ranging (LIDAR or lidar) systems emit light into the environment so as to determine information about objects based on emitted light that is reflected from those objects. LIDAR range and sensitivity is fundamentally constrained by the amount of energy emitted into the environment. That is, increasing the amount of energy per light pulse or continuous light signal generally enables unambiguous detection of objects at longer ranges. However, the laser emissions are themselves constrained by laser safety considerations that limit accessible laser emissions as well as by operational parameters of the laser light source that limit its average light pulse power.

Conventional LIDAR systems may scan laser light over a nominal vertical angle range of +/- <NUM> degrees (pitch). At a distance of <NUM> meters from the LIDAR system, such an angle range may scan a vertical extent of approximately <NUM> meters in height. In many situations, semi- or fully-autonomous vehicles need not detect objects within such a large vertical extent. As such, it is desirable to distribute light energy into an environment of a LIDAR system more efficiently.

<CIT> discusses a laser radar apparatus. The laser radar apparatus includes: a light transmission unit configured to output a laser pulse by using a light source; a light reception unit configured to receive a reflected laser pulse in connection with the laser pulse; and a controller configured to adjust a repetition rate of the laser pulse of the light source, in which the controller adjusts the repetition rate of the laser pulse based on at least one of reception power, a target distance, a movement speed, a vertical angle, and a radiation angle.

The matter for protection is defined by the appended claims.

The present disclosure generally relates to light detection and ranging (LIDAR) systems, which may be configured to obtain information about an environment. Such LIDAR devices may be implemented in vehicles, such as autonomous and semi-autonomous automobiles, trucks, motorcycles, and other types of vehicles that can move within their respective environments.

In a first aspect of the description, a system is provided. The system includes a vehicle and a light source coupled to the vehicle. The light source is configured to emit light at least one light pulse toward an environment of the vehicle. The system also includes a controller operable to determine an emission vector of the at least one light pulse, determine an elevation angle component of the emission vector, and dynamically adjust a per pulse energy of a subsequent light pulse based on the determined elevation angle component.

In a second aspect, a method is provided. The method includes causing a light source of a light detection and ranging (LIDAR) system to emit light along an emission vector. The method includes adjusting the emission vector of the emitted light according to a scanning pattern. The method yet further includes determining an elevation angle component of the emission vector. The method also includes dynamically adjusting an energy of the emitted light based on the determined elevation angle component.

Other aspects, embodiments, and implementations will become apparent to those of ordinary skill in the art by reading the following detailed description, with reference where appropriate to the accompanying drawings.

Example methods, devices, and systems are described herein. It should be understood that the words "example" and "exemplary" are used herein to mean "serving as an example, instance, or illustration. " Any embodiment or feature described herein as being an "example" or "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments or features.

In an example embodiment, a LIDAR system may dynamically adjust a per pulse energy of the emitted light based on local terrain and/or an elevation angle of an emission vector. As a result, the LIDAR system may more efficiently and controllably emit laser power into its environment. For example, such a LIDAR system may provide higher-energy laser pulses when scanning at elevation angles corresponding to the few meters at and above the road surface. Furthermore, the LIDAR system may provide lower-energy laser pulses at other elevation angles or emission vectors, such as those expected to emit light toward objects near the vehicle (e.g., a ground surface or another type of close-range object).

In such a manner, the LIDAR system may more efficiently distribute light energy within its environment while maintaining the same or similar average power over timescales of relevance to laser classification and the operational limitations of the laser light source.

Some embodiments of this disclosure may include LIDAR systems that mechanically scan in both elevation (pitch) and yaw. However, it will be understood that the systems and methods described herein could be applied to any LIDAR system with dynamically-controllable scanning, and which could also be subject to laser safety classifications based on an average amount of laser light emission power.

<FIG> illustrates a system <NUM>, according to an example embodiment. System <NUM> includes a vehicle <NUM> and a light source <NUM> coupled to the vehicle <NUM>. The light source <NUM> is configured to emit light along an emission vector <NUM> toward an environment <NUM> of the vehicle <NUM>. In some embodiments, the emitted light could include a plurality of light pulses. Additionally or alternatively, the light source <NUM> could emit the emitted light as a continuous light beam. In some embodiments, the light source <NUM> could include a fiber laser operable to emit light having a wavelength of <NUM> nanometers or <NUM> nanometers. It will be understood that other types of light-emitter devices and/or emission wavelengths are possible and contemplated herein.

In some embodiments, system <NUM> could include a light detection and ranging (LIDAR) system. In such scenarios, the light source <NUM> could represent an element of the LIDAR system. In some embodiments, the system <NUM> may be incorporated as part of a sensing system of an autonomous or semi-autonomous vehicle, such as vehicle <NUM> as illustrated and described below in reference to <FIG>.

Returning to <FIG>, as described herein, the emission vector <NUM> could represent the magnitude and the direction of light emitted from the light source <NUM>. As an example, the direction of light emitted from the light source <NUM> could be based on a reference plane, which could include a horizontal plane and/or a plane corresponding with, and/or parallel with at least a portion of a ground surface. In some embodiments, the emission vector <NUM> could include an elevation angle component and a yaw angle component. In such scenarios, the elevation angle component could include a positive or negative angle value based on an angular difference between the direction of light emitted from the light source <NUM> and the reference plane. Furthermore, the yaw angle component could include, for example, a positive or negative angle value based on an angular difference between the direction of light emitted from the light source <NUM> and at least one of: a front of a vehicle or a direction of travel of the vehicle.

The light source <NUM> could include a pulser circuit <NUM>, which could be configured to provide current pulses so as to cause the light source <NUM> to emit light pulses. In an example embodiment, the pulser circuit <NUM> could include one or more field effect transistors (FETs). For instance, the pulser circuit <NUM> may include a plurality of GaN FETs that could be operable to control one or more characteristics of light emitted from the light source <NUM>. For example, the controllable characteristics could include a pulse duration, pulse power, etc..

Additionally or alternatively, the light source <NUM> could include a power supply <NUM>. The power supply <NUM> could provide the appropriate operating conditions (e.g., supply voltage/current) for the light source <NUM>. In some scenarios, the power supply <NUM> could be operable to control one or more characteristics of a laser power amplifier and/or a seed laser. In some embodiments, the power supply <NUM> could be operable to adjust an average energy and/or wavelength of light emitted by the light source <NUM>.

The system <NUM> also includes a controller <NUM>. The controller <NUM> may include an on-board vehicle computer, an external computer, or a mobile computing platform, such as a smartphone, tablet device, personal computer, wearable device, etc. Additionally or alternatively, the controller <NUM> may include, or be connected to, a remotely-located computer system, such as a cloud server network. In an example embodiment, the controller <NUM> may be configured to carry out some or all method blocks or steps described herein.

The controller <NUM> may include one or more processors <NUM> and at least one memory <NUM>. The processor <NUM> may include, for instance, an application-specific integrated circuit (ASIC) or a field-programmable gate array (FPGA). Other types of processors, computers, or devices configured to carry out software instructions are contemplated herein. The memory <NUM> may include a non-transitory computer-readable medium, such as, but not limited to, read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), non-volatile random-access memory (e.g., flash memory), a solid state drive (SSD), a hard disk drive (HDD), a Compact Disc (CD), a Digital Video Disk (DVD), a digital tape, read/write (R/W) CDs, R/W DVDs, etc..

The one or more processors <NUM> of controller <NUM> may be configured to execute instructions stored in the memory <NUM> so as to carry out various operations described herein.

Additionally or alternatively, the controller <NUM> could include a circuit (e.g., a synchronous digital circuit) operable to carry out the various operations described herein. For example, the circuit may include a shot table. Other functions of the circuit (e.g., reading and sequencing) may be performed by a synchronous digital logic circuit. In some embodiments, the circuit and its operation may be specified in Verilog or another hardware description language. In such scenarios, the controller <NUM> need not include a processor.

In some embodiments, the operations carried out by the controller <NUM> could include determining the emission vector <NUM> of at least one light pulse and/or the corresponding light source <NUM>. In some examples, the emission vector <NUM> could be determined based on a location and/or an orientation of the light source <NUM> with respect to the environment.

The operations carried out by the controller <NUM> include determining an elevation angle component of the emission vector <NUM>. As an example, determining the elevation angle component of the emission vector <NUM> could include calculating a length of a vector projection of the emission vector <NUM> on a reference plane and/or a reference axis. Other ways to determine the elevation angle component of the emission vector <NUM> are possible and contemplated.

The operations carried out by the controller <NUM> could include dynamically adjusting a per pulse energy of one or more subsequent light pulses based on the determined elevation angle component.

In some embodiments, the light source <NUM> could be configured to emit light in a scanning pattern according to a desired scanning path. In such scenarios, the controller <NUM> could be operable to adjust the emission vector <NUM> of the emitted light according to the scanning pattern and the desired scanning path. In such scenarios, the controller <NUM> could dynamically adjust the energy of emitted light provided according to various portions of the scanning pattern and desired scanning path. For example, for portions of the desired scanning path that correspond to an elevation angle component less than a threshold angle (e.g., zero degrees elevation) or plane, the controller <NUM> could provide emitted light with a first energy. In such a scenario, for portions of the desired scanning path that correspond to an elevation angle component greater than the threshold angle, the controller <NUM> could provide emitted light having a second energy.

While the above example includes a threshold angle, it will be understood that other angle threshold values, angle ranges, spatial regions, and/or target locations could be considered while the controller <NUM> dynamically adjusts the energy of emitted light from light source <NUM>.

In some embodiments, the controller <NUM> could be operable to dynamically adjust the energy of the emitted light further based on at least one of: point cloud data, map data, image data, object data, retroreflector location data, time of day, ambient light condition, sun position, a pose of the vehicle <NUM>, a heading of the vehicle <NUM>, or an operating condition of the vehicle <NUM>. For example, an effective "dose" of light pulses that can be safely provided to a human subject (e.g., a pedestrian) may depend on the human subject's pupil dilation, which, in turn, could be affected by such factors as time of day or ambient lighting conditions. In particular, in dark conditions, a person's dilated pupils (e.g., mydriasis) could transmit a larger amount of a given light pulse to the person's retina as compared to bright conditions, where a person's pupils may be more constricted (e.g., miosis).

In other examples, the controller <NUM> could adjust the energy of emitted light based on a location or type of objects in the environment <NUM>. For instance, if another vehicle is within the same roadway as vehicle <NUM>, a relatively higher energy of emitted light may be provided so as to maintain positive identification of the other vehicle within the scanning range. However, if a road sign (e.g., stop sign, pedestrian-crossing sign, etc.) or other type of static object is observed, subsequent light emitted toward such an object may be provided with relative lower energy. Adjustment of emitted light energy values according to other such "priority" or "regions of interest" are possible and contemplated herein.

As noted above, retroreflectors may represent objects in the environment <NUM> that reflect a higher-than-average portion of the emitted light back toward the system <NUM>. In some cases, retroreflectors can temporarily "blind" LIDAR systems by saturating detectors or introducing cross-talk interference in the system. In order to reduce these effects, the controller <NUM> could reduce the energy of emitted light provided to locations with known retroreflectors. For example, the controller <NUM> could provide emitted light toward retroreflectors with <NUM>/<NUM>th or <NUM>/<NUM>th the energy of light provided to other regions of the environment.

In scenarios that include light emitted as a plurality of light pulses, the plurality of light pulses could include a pulse length of at least one light pulse of the plurality of light pulses as being between <NUM> picoseconds to <NUM> nanoseconds. Other pulse lengths are possible and contemplated herein.

Additionally or alternatively, the controller <NUM> could be operable to dynamically adjust a pulse energy of at least one light pulse of the plurality of light pulses. The pulse energy of at least one light pulse could be between <NUM> nanojoules and <NUM> microjoules. Other pulse energies are contemplated and possible. In an example embodiment, the controller <NUM> could dynamically adjust the pulse energy by adjusting at least one of the pulser circuit <NUM> and/or the power supply <NUM> of the light source <NUM>. Other ways to dynamically adjust the pulse energy are possible and contemplated.

In some embodiments, a pulse repetition rate of at least a portion of the plurality of light pulses is between <NUM> kilohertz and <NUM> megahertz. Other pulse repetition rates are contemplated and possible.

In embodiments that include the light source <NUM> being a fiber laser, the controller <NUM> could be operable to dynamically adjust the energy of the emitted light by adjusting at least one of a seed laser parameter (e.g., a seed laser energy) or a pump laser parameter (e.g., a pump laser energy). In some embodiments, the light source <NUM> could include one or more laser diodes, light-emitting diodes, or other types of light-emitting devices. In an example embodiment, the light source <NUM> could include InGaAs/GaAs laser diodes configured to emit light at a wavelength around <NUM> nanometers. In some embodiments, the light source <NUM> includes at least one of: a laser diode, a laser bar, or a laser stack. Additionally or alternatively, the light source <NUM> may include one or more master oscillator power amplifier (MOPA) fiber lasers. Such fiber lasers may be configured to provide light pulses at or around <NUM> nanometers and may include a seed laser and a length of active optical fiber configured to amplify the seed laser light to higher power levels. However, other types of light-emitting devices, materials, and emission wavelengths are possible and contemplated.

In some embodiments, the light source <NUM> is configured to emit light into an environment along a plurality of emission vectors toward respective target locations so as to provide a desired resolution. In such scenarios, the light source <NUM> is operable to emit light along the plurality of emission vectors such that the emitted light interacts with an external environment <NUM> of the system <NUM>.

<FIG> illustrate respective light emission scenarios <NUM> and <NUM>. It will be understood that while <FIG> include a rectangular coordinate system, other coordinate systems are possible, such as a polar coordinate system. <FIG> illustrates a light emission scenario <NUM>, according to example embodiments. Scenario <NUM> includes a light source <NUM> emitting light (e.g., light pulses or continuous light radiation) along an emission vector 210a. The emission vector 210a could be directed at a target location 220a in the environment, such as environment <NUM> of the vehicle <NUM>, as illustrated and described in reference to <FIG>. Emission vector 210a can be represented as a sum of vectors 212a and 214a.

As illustrated, vector 212a could be the vector projection of emission vector 210a along a direction of travel or a heading of vehicle <NUM> (illustrated here as being parallel to the x-axis). In such a scenario, vector 214a could include a vector projection of emission vector 210a along an axis perpendicular to the direction of travel or heading of vehicle <NUM> (illustrated here as being parallel to the z-axis). In some embodiments, vectors 212a and/or 214a could be used to determine an elevation angle component 216a of the emission vector 210a. As illustrated in <FIG>, the elevation angle component 216a could include a positive angle value with respect to the x-y plane.

<FIG> illustrates a light emission scenario <NUM>, according to example embodiments. Scenario <NUM> includes a light source <NUM> emitting light (e.g., light pulses or continuous light radiation) along an emission vector 210b. The emission vector 210b could be directed at a target location 220b in the environment, such as environment <NUM> of the vehicle <NUM>, as illustrated and described in reference to <FIG>. Emission vector 210b can be represented as a sum of vectors 212b and 214b.

For example, vector 212b could be the vector projection of emission vector 210b along a direction of travel or a heading of vehicle <NUM> (illustrated here as being parallel to the x-axis). In such a scenario, vector 214b could include a vector projection of emission vector 210b along an axis perpendicular to the direction of travel or heading of vehicle <NUM> (illustrated here as being parallel to the z-axis). In some embodiments, vectors 212b and/or 214b could be used to determine an elevation angle component 216b of the emission vector 210b. As illustrated in <FIG>, the elevation angle component 216a could include a negative angle value with respect to the x-y plane.

It will be understood that while <FIG> each illustrate particular light emission scenarios with respective elevation angle components, the light source <NUM> could emit light in rapidly changing directions and towards various target locations so as to scan the environment <NUM> of the vehicle <NUM>. Accordingly, the elevation angle could be determined by the controller <NUM> continuously and dynamically in real-time, or at various times (e.g., periodically and/or in response to determining a target region of interest).

<FIG> illustrates a vehicle, according to an example embodiment. The vehicle <NUM> may include one or more sensor systems <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>. The one or more sensor systems <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> could be similar or identical to sensor system <NUM>, as illustrated and described below with reference to <FIG>. As an example, sensor systems <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> may include transmit block <NUM>. Namely, sensor systems <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> could include LIDAR sensors having a plurality of light-emitter devices arranged over a range of angles with respect to a given plane (e.g., the x-y plane).

One or more of the sensor systems <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> may be configured to rotate about an axis (e.g., the z-axis) perpendicular to the given plane so as to illuminate an environment around the vehicle <NUM> with light pulses. Based on detecting various aspects of reflected light pulses (e.g., the elapsed time of flight, polarization, etc.,), information about the environment may be determined.

In an example embodiment, sensor systems <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> may be configured to provide respective point cloud information that may relate to physical objects within the environment of the vehicle <NUM>. While system <NUM>, vehicle <NUM> and sensor systems <NUM> and <NUM> are illustrated as including certain features, it will be understood that other types of systems are contemplated within the scope of the present disclosure.

An example embodiment may include a system having a plurality of light-emitter devices. The system may include a transmit block of a LIDAR device. For example, the system may be, or may be part of, a LIDAR device of a vehicle (e.g., a car, a truck, a motorcycle, a golf cart, an aerial vehicle, a boat, etc.). Each light-emitter device of the plurality of light-emitter devices is configured to emit light pulses along a respective beam elevation angle. The respective beam elevation angles could be based on a reference angle or reference plane, as described elsewhere herein. In some embodiments, the reference plane may be based on an axis of motion of the vehicle.

While certain description and illustrations herein describe systems with multiple light-emitter devices, LIDAR systems with fewer light-emitter devices (e.g., a single light-emitter device) are also contemplated herein. For example, light pulses emitted by a laser diode may be controllably directed about an environment of the system. The angle of emission of the light pulses may be adjusted by a scanning device such as, for instance, a mechanical scanning mirror and/or a rotational motor. For example, the scanning devices could rotate in a reciprocating motion about a given axis and/or rotate about a vertical axis. In another embodiment, the light-emitter device may emit light pulses towards a spinning prism mirror, which may cause the light pulses to be emitted into the environment based on an angle of the prism mirror angle when interacting with each light pulse. Additionally or alternatively, scanning optics and/or other types of electro-opto-mechanical devices are possible to scan the light pulses about the environment.

In some embodiments, a single light-emitter device may emit light pulses according to a variable shot schedule and/or with variable power per shot, as described herein. That is, emission power and/or timing of each laser pulse or shot may be based on a respective elevation angle of the shot. Furthermore, the variable shot schedule could be based on providing a desired vertical spacing at a given distance from the LIDAR system or from a surface (e.g., a front bumper) of a given vehicle supporting the LIDAR system. As an example, when the light pulses from the light-emitter device are directed downwards, the power-per-shot could be decreased due to a shorter anticipated maximum distance to target. Conversely, light pulses emitted by the light-emitter device at an elevation angle above a reference plane may have a relatively higher power-per-shot so as to provide sufficient signal-to-noise to adequately detect pulses that travel longer distances.

In some embodiments, the power/energy-per-shot could be controlled for each shot in a dynamic fashion. In other embodiments, the power/energy-per-shot could be controlled for successive set of several pulses (e.g., <NUM> light pulses). That is, the characteristics of the light pulse train could be changed on a per-pulse basis and/or a per-several-pulse basis.

<FIG> illustrates a sensing system <NUM>, according to an example embodiment. Sensing system <NUM> could include some or all of the elements of system <NUM>, as illustrated and described in reference to <FIG>. The sensing system <NUM> may be a light detection and ranging (LIDAR) system. The sensing system includes a housing <NUM> that houses an arrangement of various components, such as a transmit block <NUM>, a receive block <NUM>, a shared space <NUM>, and a lens <NUM>. The sensing system <NUM> includes an arrangement of components configured to provide emitted light beams <NUM> from the transmit block <NUM> that are collimated by the lens <NUM> and transmitted into an environment of the sensing system <NUM> as collimated light beams <NUM>. Furthermore, the sensing system <NUM> includes an arrangement of components configured to collect reflected light <NUM> from one or more objects in the environment of the sensing system <NUM> by the lens <NUM> for focusing towards the receive block <NUM> as focused light <NUM>. The reflected light <NUM> includes light from the collimated light beams <NUM> that was reflected by the one or more objects in the environment of the sensing system <NUM>.

The emitted light beams <NUM> and focused light <NUM> may traverse the shared space <NUM> also included in the housing <NUM>. In some embodiments, the emitted light beams <NUM> propagate along a transmit path through the shared space <NUM> and the focused light <NUM> propagates along a receive path through the shared space <NUM>.

The sensing system <NUM> can determine an aspect of the one or more objects (e.g., location, shape, etc.) in the environment of the sensing system <NUM> by processing the focused light <NUM> received by the receive block <NUM>. For example, the sensing system <NUM> can compare a time when pulses included in the emitted light beams <NUM> were emitted by the transmit block <NUM> with a time when corresponding pulses included in the focused light <NUM> were received by the receive block <NUM> and determine the distance between the one or more objects and the sensing system <NUM> based on the comparison.

The housing <NUM> included in the sensing system <NUM> can provide a platform for mounting the various components included in the sensing system <NUM>. The housing <NUM> can be formed from any material capable of supporting the various components of the sensing system <NUM> included in an interior space of the housing <NUM>. For example, the housing <NUM> may be formed from a structural material such as plastic or metal.

In some examples, the housing <NUM> may include optical shielding configured to reduce ambient light and/or unintentional transmission of the emitted light beams <NUM> from the transmit block <NUM> to the receive block <NUM>. The optical shielding can be provided by forming and/or coating the outer surface of the housing <NUM> with a material that blocks the ambient light from the environment. Additionally, inner surfaces of the housing <NUM> can include and/or be coated with the material described above to optically isolate the transmit block <NUM> from the receive block <NUM> to prevent the receive block <NUM> from receiving the emitted light beams <NUM> before the emitted light beams <NUM> reach the lens <NUM>.

In some examples, the housing <NUM> can be configured for electromagnetic shielding to reduce electromagnetic noise (e.g., Radio Frequency (RF) Noise, etc.) from ambient environment of the sensor system <NUM> and/or electromagnetic noise between the transmit block <NUM> and the receive block <NUM>. Electromagnetic shielding can improve quality of the emitted light beams <NUM> emitted by the transmit block <NUM> and reduce noise in signals received and/or provided by the receive block <NUM>. Electromagnetic shielding can be achieved by forming and/or coating the housing <NUM> with one or more materials such as a metal, metallic ink, metallic foam, carbon foam, or any other material configured to appropriately absorb or reflect electromagnetic radiation. Metals that can be used for the electromagnetic shielding can include for example, copper or nickel.

In some examples, the housing <NUM> can be configured to have a substantially cylindrical shape and to rotate about an axis of the sensing system <NUM>. For example, the housing <NUM> can have the substantially cylindrical shape with a diameter of approximately <NUM> centimeters. In some examples, the axis is substantially vertical. By rotating the housing <NUM> that includes the various components, in some examples, a three-dimensional map of a <NUM> degree view of the environment of the sensing system <NUM> can be determined without frequent recalibration of the arrangement of the various components of the sensing system <NUM>. Additionally or alternatively, the sensing system <NUM> can be configured to tilt the axis of rotation of the housing <NUM> to control the field of view of the sensing system <NUM>.

Although not illustrated in <FIG>, the sensing system <NUM> can optionally include a mounting structure for the housing <NUM>. The mounting structure can include a motor or other means for rotating the housing <NUM> about the axis of the sensing system <NUM>. Alternatively, the mounting structure can be included in a device and/or system other than the sensing system <NUM>.

In some examples, the various components of the sensing system <NUM> such as the transmit block <NUM>, receive block <NUM>, and the lens <NUM> can be removably mounted to the housing <NUM> in predetermined positions to reduce burden of calibrating the arrangement of each component and/or subcomponents included in each component. Thus, the housing <NUM> acts as the platform for the various components of the sensing system <NUM> to provide ease of assembly, maintenance, calibration, and manufacture of the sensing system <NUM>.

The transmit block <NUM> includes a plurality of light sources <NUM> that can be configured to emit the plurality of emitted light beams <NUM> via an exit aperture <NUM>. In some examples, each of the plurality of emitted light beams <NUM> corresponds to one of the plurality of light sources <NUM>. The transmit block <NUM> can optionally include a mirror <NUM> along the transmit path of the emitted light beams <NUM> between the light sources <NUM> and the exit aperture <NUM>.

The light sources <NUM> can include laser diodes, light emitting diodes (LED), vertical cavity surface emitting lasers (VCSEL), organic light emitting diodes (OLED), polymer light emitting diodes (PLED), light emitting polymers (LEP), liquid crystal displays (LCD), microelectromechanical systems (MEMS), or any other device configured to selectively transmit, reflect, and/or emit light to provide the plurality of emitted light beams <NUM>. In some examples, the light sources <NUM> can be configured to emit the emitted light beams <NUM> in a wavelength range that can be detected by detectors <NUM> included in the receive block <NUM>. The wavelength range could, for example, be in the ultraviolet, visible, and/or infrared portions of the electromagnetic spectrum. In some examples, the wavelength range can be a narrow wavelength range, such as provided by lasers. In one example, the wavelength range includes wavelengths that are approximately <NUM>. Additionally, the light sources <NUM> can be configured to emit the emitted light beams <NUM> in the form of pulses. In some examples, the plurality of light sources <NUM> can be disposed on one or more substrates (e.g., printed circuit boards (PCB), flexible PCBs, etc.) and arranged to emit the plurality of light beams <NUM> towards the exit aperture <NUM>.

In some examples, the plurality of light sources <NUM> can be configured to emit uncollimated light beams included in the emitted light beams <NUM>. For example, the emitted light beams <NUM> can diverge in one or more directions along the transmit path due to the uncollimated light beams emitted by the plurality of light sources <NUM>. In some examples, vertical and horizontal extents of the emitted light beams <NUM> at any position along the transmit path can be based on an extent of the divergence of the uncollimated light beams emitted by the plurality of light sources <NUM>.

The exit aperture <NUM> arranged along the transmit path of the emitted light beams <NUM> can be configured to accommodate the vertical and horizontal extents of the plurality of light beams <NUM> emitted by the plurality of light sources <NUM> at the exit aperture <NUM>. It is noted that the block diagram shown in <FIG> is described in connection with functional modules for convenience in description. However, the functional modules in the block diagram of <FIG> can be physically implemented in other locations. For example, although illustrated that the exit aperture <NUM> is included in the transmit block <NUM>, the exit aperture <NUM> can be physically included in both the transmit block <NUM> and the shared space <NUM>. For example, the transmit block <NUM> and the shared space <NUM> can be separated by a wall that includes the exit aperture <NUM>. In this case, the exit aperture <NUM> can correspond to a transparent portion of the wall. In one example, the transparent portion can be a hole or cutaway portion of the wall. In another example, the wall can be formed from a transparent substrate (e.g., glass) coated with a non-transparent material, and the exit aperture <NUM> can be a portion of the substrate that is not coated with the non-transparent material.

In some examples of the sensing system <NUM>, it may be desirable to minimize size of the exit aperture <NUM> while accommodating the vertical and horizontal extents of the plurality of light beams <NUM>. For example, minimizing the size of the exit aperture <NUM> can improve the optical shielding of the light sources <NUM> described above in the functions of the housing <NUM>. Additionally or alternatively, the wall separating the transmit block <NUM> and the shared space <NUM> can be arranged along the receive path of the focused light <NUM>, and thus, the exit aperture <NUM> can be minimized to allow a larger portion of the focused light <NUM> to reach the wall. For example, the wall can be coated with a reflective material (e.g., reflective surface <NUM> in shared space <NUM>) and the receive path can include reflecting the focused light <NUM> by the reflective material towards the receive block <NUM>. In this case, minimizing the size of the exit aperture <NUM> can allow a larger portion of the focused light <NUM> to reflect off the reflective material with which the wall is coated.

To minimize the size of the exit aperture <NUM>, in some examples, the divergence of the emitted light beams <NUM> can be reduced by partially collimating the uncollimated light beams emitted by the light sources <NUM> to minimize the vertical and horizontal extents of the emitted light beams <NUM> and thus minimize the size of the exit aperture <NUM>. For example, each light source of the plurality of light sources <NUM> can include a cylindrical lens arranged adjacent to the light source. The light source may emit a corresponding uncollimated light beam that diverges more in a first direction than in a second direction. The cylindrical lens may precollimate the uncollimated light beam in the first direction to provide a partially collimated light beam, thereby reducing the divergence in the first direction. In some examples, the partially collimated light beam diverges less in the first direction than in the second direction. Similarly, uncollimated light beams from other light sources of the plurality of light sources <NUM> can have a reduced beam width in the first direction and thus the emitted light beams <NUM> can have a smaller divergence due to the partially collimated light beams. In this example, at least one of the vertical and horizontal extents of the exit aperture <NUM> can be reduced due to partially collimating the light beams <NUM>.

Additionally or alternatively, to minimize the size of the exit aperture <NUM>, in some examples, the light sources <NUM> can be arranged along a shaped surface defined by the transmit block <NUM>. In some examples, the shaped surface may be faceted and/or substantially curved. The faceted and/or curved surface can be configured such that the emitted light beams <NUM> converge towards the exit aperture <NUM>, and thus the vertical and horizontal extents of the emitted light beams <NUM> at the exit aperture <NUM> can be reduced due to the arrangement of the light sources <NUM> along the faceted and/or curved surface of the transmit block <NUM>.

In some examples, a curved surface of the transmit block <NUM> can include a curvature along the first direction of divergence of the emitted light beams <NUM> and a curvature along the second direction of divergence of the emitted light beams <NUM>, such that the plurality of light beams <NUM> converge towards a central area in front of the plurality of light sources <NUM> along the transmit path.

To facilitate such curved arrangement of the light sources <NUM>, in some examples, the light sources <NUM> can be disposed on a flexible substrate (e.g., flexible PCB) having a curvature along one or more directions. For example, the curved flexible substrate can be curved along the first direction of divergence of the emitted light beams <NUM> and the second direction of divergence of the emitted light beams <NUM>. Additionally or alternatively, to facilitate such curved arrangement of the light sources <NUM>, in some examples, the light sources <NUM> can be disposed on a curved edge of one or more vertically-oriented printed circuit boards (PCBs), such that the curved edge of the PCB substantially matches the curvature of the first direction (e.g., the vertical plane of the PCB). In this example, the one or more PCBs can be mounted in the transmit block <NUM> along a horizontal curvature that substantially matches the curvature of the second direction (e.g., the horizontal plane of the one or more PCBs). For example, the transmit block <NUM> can include four PCBs, with each PCB mounting sixteen light sources, so as to provide <NUM> light sources along the curved surface of the transmit block <NUM>. In this example, the <NUM> light sources are arranged in a pattern such that the emitted light beams <NUM> converge towards the exit aperture <NUM> of the transmit block <NUM>.

The transmit block <NUM> can optionally include the mirror <NUM> along the transmit path of the emitted light beams <NUM> between the light sources <NUM> and the exit aperture <NUM>. By including the mirror <NUM> in the transmit block <NUM>, the transmit path of the emitted light beams <NUM> can be folded to provide a smaller size of the transmit block <NUM> and the housing <NUM> of the sensing system <NUM> than a size of another transmit block where the transmit path that is not folded.

The receive block <NUM> includes a plurality of detectors <NUM> that can be configured to receive the focused light <NUM> via an entrance aperture <NUM>. In some examples, each of the plurality of detectors <NUM> is configured and arranged to receive a portion of the focused light <NUM> corresponding to a light beam emitted by a corresponding light source of the plurality of light sources <NUM> and reflected of the one or more objects in the environment of the sensing system <NUM>. The receive block <NUM> can optionally include the detectors <NUM> in a sealed environment having an inert gas <NUM>.

The detectors <NUM> may comprise photodiodes, avalanche photodiodes, singlephoton avalanche diodes (SPADs), phototransistors, silicon photomultipliers (SiPMs), cameras, active pixel sensors (APS), charge coupled devices (CCD), cryogenic detectors, or any other sensor of light configured to receive focused light <NUM> having wavelengths in the wavelength range of the emitted light beams <NUM>.

To facilitate receiving, by each of the detectors <NUM>, the portion of the focused light <NUM> from the corresponding light source of the plurality of light sources <NUM>, the detectors <NUM> can be disposed on one or more substrates and arranged accordingly. For example, the light sources <NUM> can be arranged along a curved surface of the transmit block <NUM>. Detectors <NUM> can be arranged along a curved surface of the receive block <NUM>. In some embodiments, the curved surface of the receive block <NUM> may include a similar or identical curved surface as that of transmit block <NUM>. Thus, each of the detectors <NUM> may be configured to receive light that was originally emitted by a corresponding light source of the plurality of light sources <NUM>.

To provide the curved surface of the receive block <NUM>, the detectors <NUM> can be disposed on the one or more substrates similarly to the light sources <NUM> disposed in the transmit block <NUM>. For example, the detectors <NUM> can be disposed on a flexible substrate (e.g., flexible PCB) and arranged along the curved surface of the flexible substrate to each receive focused light originating from a corresponding light source of the light sources <NUM>. In this example, the flexible substrate may be held between two clamping pieces that have surfaces corresponding to the shape of the curved surface of the receive block <NUM>. Thus, in this example, assembly of the receive block <NUM> can be simplified by sliding the flexible substrate onto the receive block <NUM> and using the two clamping pieces to hold it at the correct curvature.

The focused light <NUM> traversing along the receive path can be received by the detectors <NUM> via the entrance aperture <NUM>. In some examples, the entrance aperture <NUM> can include a filtering window that passes light having wavelengths within the wavelength range emitted by the plurality of light sources <NUM> and attenuates light having other wavelengths. In this example, the detectors <NUM> receive the focused light <NUM> substantially comprising light having the wavelengths within the wavelength range.

In some examples, the plurality of detectors <NUM> included in the receive block <NUM> can include, for example, avalanche photodiodes in a sealed environment that is filled with the inert gas <NUM>. The inert gas <NUM> may comprise, for example, nitrogen.

The shared space <NUM> includes the transmit path for the emitted light beams <NUM> from the transmit block <NUM> to the lens <NUM>, and includes the receive path for the focused light <NUM> from the lens <NUM> to the receive block <NUM>. In some examples, the transmit path at least partially overlaps with the receive path in the shared space <NUM>. By including the transmit path and the receive path in the shared space <NUM>, advantages with respect to size, cost, and/or complexity of assembly, manufacture, and/or maintenance of the sensing system <NUM> can be provided.

While the exit aperture <NUM> and the entrance aperture <NUM> are illustrated as being part of the transmit block <NUM> and the receive block <NUM>, respectively, it is understood that such apertures may be arranged or placed at other locations. In some embodiments, the function and structure of the exit aperture <NUM> and the entrance aperture <NUM> may be combined. For example, the shared space <NUM> may include a shared entrance/exit aperture. It will be understood that other ways to arrange the optical components of system <NUM> within housing <NUM> are possible and contemplated.

In some examples, the shared space <NUM> can include a reflective surface <NUM>. The reflective surface <NUM> can be arranged along the receive path and configured to reflect the focused light <NUM> towards the entrance aperture <NUM> and onto the detectors <NUM>. The reflective surface <NUM> may comprise a prism, mirror or any other optical element configured to reflect the focused light <NUM> towards the entrance aperture <NUM> in the receive block <NUM>. In some examples, a wall may separate the shared space <NUM> from the transmit block <NUM>. In these examples, the wall may comprise a transparent substrate (e.g., glass) and the reflective surface <NUM> may comprise a reflective coating on the wall with an uncoated portion for the exit aperture <NUM>.

In embodiments including the reflective surface <NUM>, the reflective surface <NUM> can reduce size of the shared space <NUM> by folding the receive path similarly to the mirror <NUM> in the transmit block <NUM>. Additionally or alternatively, in some examples, the reflective surface <NUM> can direct the focused light <NUM> to the receive block <NUM> further providing flexibility to the placement of the receive block <NUM> in the housing <NUM>. For example, varying the tilt of the reflective surface <NUM> can cause the focused light <NUM> to be reflected to various portions of the interior space of the housing <NUM>, and thus the receive block <NUM> can be placed in a corresponding position in the housing <NUM>. Additionally or alternatively, in this example, the sensing system <NUM> can be calibrated by varying the tilt of the reflective surface <NUM>.

The lens <NUM> mounted to the housing <NUM> can have an optical power to both collimate the emitted light beams <NUM> from the light sources <NUM> in the transmit block <NUM>, and focus the reflected light <NUM> from the one or more objects in the environment of the sensing system <NUM> onto the detectors <NUM> in the receive block <NUM>. In one example, the lens <NUM> has a focal length of approximately <NUM>. By using the same lens <NUM> to perform both of these functions, instead of a transmit lens for collimating and a receive lens for focusing, advantages with respect to size, cost, and/or complexity can be provided. In some examples, collimating the emitted light beams <NUM> to provide the collimated light beams <NUM> allows determining the distance travelled by the collimated light beams <NUM> to the one or more objects in the environment of the sensing system <NUM>.

While, as described herein, lens <NUM> is utilized as a transmit lens and a receive lens, it will be understood that separate lens and/or other optical elements are contemplated within the scope of the present disclosure. For example, lens <NUM> could represent distinct lenses or lens sets along discrete optical transmit and receive paths.

In an example scenario, the emitted light beams <NUM> from the light sources <NUM> traversing along the transmit path can be collimated by the lens <NUM> to provide the collimated light beams <NUM> to the environment of the sensing system <NUM>. The collimated light beams <NUM> may then reflect off the one or more objects in the environment of the sensing system <NUM> and return to the lens <NUM> as the reflected light <NUM>. The lens <NUM> may then collect and focus the reflected light <NUM> as the focused light <NUM> onto the detectors <NUM> included in the receive block <NUM>. In some examples, aspects of the one or more objects in the environment of the sensing system <NUM> can be determined by comparing the emitted light beams <NUM> with the focused light beams <NUM>. The aspects can include, for example, distance, shape, color, and/or material of the one or more objects. Additionally, in some examples, by rotating the housing <NUM>, a three-dimensional map of the surroundings of the sensing system <NUM> can be determined.

In some examples where the plurality of light sources <NUM> are arranged along a curved surface of the transmit block <NUM>, the lens <NUM> can be configured to have a focal surface corresponding to the curved surface of the transmit block <NUM>. For example, the lens <NUM> can include an aspheric surface outside the housing <NUM> and a toroidal surface inside the housing <NUM> facing the shared space <NUM>. In this example, the shape of the lens <NUM> allows the lens <NUM> to both collimate the emitted light beams <NUM> and focus the reflected light <NUM>. Additionally, in this example, the shape of the lens <NUM> allows the lens <NUM> to have the focal surface corresponding to the curved surface of the transmit block <NUM>. In some examples, the focal surface provided by the lens <NUM> substantially matches the curved shape of the transmit block <NUM>. Additionally, in some examples, the detectors <NUM> can be arranged similarly in the curved shape of the receive block <NUM> to receive the focused light <NUM> along the curved focal surface provided by the lens <NUM>. Thus, in some examples, the curved surface of the receive block <NUM> may also substantially match the curved focal surface provided by the lens <NUM>.

<FIG> illustrate several views of various sensing scenarios involving a vehicle and one or more sensor systems for better explaining the invention. <FIG> illustrates a side view of vehicle <NUM> in a sensing scenario <NUM>, according to an example embodiment. In such a scenario, sensor system <NUM> may be configured to emit light pulses into an environment of the vehicle <NUM> over an elevation angle range <NUM> between a maximum elevation angle <NUM> and a minimum elevation angle <NUM>. In some embodiments, sensor system <NUM> may include a light source (e.g., a fiber laser) configured to emit light into the environment of vehicle <NUM> within an adjustable scanning region.

Additionally or alternatively, sensor system <NUM> may include a plurality of light-emitter devices that are arranged in a non-linear elevation angle distribution. That is, to achieve a desired vertical beam resolution, the plurality of light-emitter devices of sensor system <NUM> may be arranged over beam elevation angles that include heterogeneous elevation angle differences between adjacent beams.

In example embodiments, light emitted from sensor system <NUM> with an elevation angle component below a threshold angle or plane (e.g., a horizontal plane corresponding to axis <NUM>) could be provided at a first energy. In such a scenario, light emitted from sensor system <NUM> with an elevation angle component above the threshold angle or plane could be provided at a second energy that could be higher or lower than that of the first energy.

As a further example, sensor system <NUM> may be configured to emit light pulses into an environment of the vehicle <NUM> over an elevation angle range <NUM>, which may be defined between a maximum elevation angle <NUM> and a minimum elevation angle <NUM>. In some embodiments, one or more light-emitter devices of sensor system <NUM> may illuminate the environment about the vehicle <NUM> by reflecting light from a spinning mirror (e.g., a prism mirror).

In such example embodiments, a controller (e.g., controller <NUM> as illustrated and described in reference to <FIG>) could determine an elevation angle component of the emission vector of the light pulses or continuous light beam and dynamically adjust an energy of the emitted light based on the determined elevation angle component.

In example embodiments, light emitted from sensor system <NUM> with an elevation angle component below a threshold angle or plane (e.g., a horizontal plane corresponding to axis <NUM> and/or the "ground-skimming" beam elevation angle <NUM> as described with reference to <FIG>) could be provided at a first energy (e.g., <NUM> microjoule). In such a scenario, light emitted from sensor system <NUM> with an elevation angle component above the threshold angle or plane could be provided at a second energy (e.g., <NUM> nanojoules). It will be understood that the first and second energy values could be higher or lower that the values described herein.

<FIG> illustrates a back view of vehicle <NUM> in a sensing scenario <NUM>. As illustrated in sensing scenario <NUM>, the sensor systems <NUM>, <NUM> and <NUM> may be configured to detect objects over an elevation angle range <NUM> having a maximum elevation angle <NUM> and a minimum elevation angle <NUM>. Similarly, sensor systems <NUM> and <NUM> may provide respective elevation angle ranges 570a and 570b, which may be bounded by respective maximum elevation angles 572a and 572b and respective minimum elevation angles 574a and 574b.

Example embodiments may include adjusting various aspects of an emitted light pulse (e.g. pulse energy) based on a changing environment around the vehicle as it moves around the world. Specifically, aspects of the emitted light pulses may be varied based on, without limitation, an undulating roadway (e.g., grade changes when driving uphill or downhill, driving around a curve, etc.), objects on or adjacent to the roadway (e.g., pedestrians, other vehicles, buildings, etc.), or other static or dynamically-varying environmental conditions or contexts.

<FIG> illustrates a sensing scenario <NUM>, according to an example embodiment. Vehicle <NUM> may be in contact with an uphill roadway surface <NUM>. In such a scenario, objects of interest for sensing may include other vehicles in contact with the same roadway surface <NUM> (e.g., oncoming traffic over the hill). Such objects and/or other vehicles, which may interfere with a vehicle path of travel, could be between <NUM> to <NUM> meters above the roadway surface <NUM>. As such, while sensor <NUM> may be operable to sense objects between a minimum beam elevation angle <NUM> to a maximum beam elevation angle <NUM>, in some embodiments, data obtained between the minimum beam elevation angle <NUM> and a dynamically-changing "ground-skimming" beam elevation angle <NUM> may be designated as being more important or as having a higher priority in an effort to detect other vehicles and objects along the undulating roadway surface <NUM>. The "ground-skimming" beam elevation angle <NUM> could be dynamically defined as a scanning angle that corresponds to a specific location <NUM>, which may be at a predetermined height <NUM> above the roadway and a predetermined distance away from the vehicle <NUM>. In an example embodiment, the specific location <NUM> could be about <NUM> meters from the vehicle <NUM> and predetermined height <NUM> could be approximately <NUM> meters above the roadway surface <NUM>.

In some embodiments and under some conditions, systems and methods described herein need not always scan the entire range of possible beam elevation angles (e.g., angles between an entire angle range between minimum beam elevation angle <NUM> and the maximum beam elevation angle <NUM>). Instead, the beam-scanning range, scan rate, scan resolution, and beam energy (among other characteristics of the emitted light) may be varied based on the dynamically-changing yaw-dependent contours of the roadway and/or other portions of the environment around the vehicle <NUM>.

For example, in some scenarios, the beam elevation angles between the "ground-skimming" beam elevation angle <NUM> and the maximum beam elevation angle <NUM> need not be scanned at all. That is, for a given yaw angle, light pulses need not be emitted into elevation ranges that might be predicted to not include objects that might interfere with progress of the vehicle <NUM>. Additionally or alternatively, the light pulses could be emitted into those angle ranges could be shortened, provided at lower energy, and/or eliminated altogether.

Furthermore, for the light pulses that are emitted into the angles between the minimum beam elevation angle <NUM> and the "ground-skimming" beam elevation angle <NUM>, certain aspects of the emitted light could be adjusted in an effort to increase the likelihood that objects on or close to the ground will be detected. For example, in some scenarios, the per pulse energy and/or the continuous beam energy could be increased so as to increase a potential return signal from objects present within that angle range.

In some embodiments, systems and methods described herein may include adjusting an emission energy of light emitted from various sensor systems based on a contour line that extends around the vehicle (e.g., through <NUM> degrees or a plurality of yaw angles) and may be defined as a substantially continuous line that is located at a predetermined distance away from the vehicle <NUM> (e.g., <NUM>, <NUM>, or <NUM> meters away) and/or at a predetermined height above a ground surface. Such a contour line may be dynamically adjusted as the vehicle <NUM> moves around its environment. The contour line could be determined based on a topographic map or current or prior point cloud information obtained by the vehicle <NUM> and/or other vehicles. In some embodiments, the contour line could pass through one or more specific locations on or above the ground, such as location <NUM> shown in <FIG> or location <NUM> shown in <FIG>.

For example, consider a scenario where the contour line represents a predetermined height of one meter from the ground at <NUM> meters distance from the vehicle <NUM>. When the vehicle <NUM> is on level terrain with no objects at one meter from the ground, the contour line could be represented by a two-dimensional circle with <NUM> meter radius that is centered on the vehicle. However, when the vehicle <NUM> encounters hilly terrain and/or objects at one meter from the ground, the contour line could include a three-dimensional circle, oval, or irregular shape based on dynamically changing topographical features and/or object data. In some embodiments, the energy of emitted light could be dynamically adjusted based on a shape of the contour line.

<FIG> illustrates a sensing scenario <NUM>, according to an example embodiment. Vehicle <NUM> may be in contact with a downhill roadway surface <NUM>. As described above with reference to Figure 4E, some beam angles of sensor <NUM> may be "prioritized" over others. For example, a "ground-skimming" beam elevation angle <NUM> may dynamically change based on a specific location <NUM> (which may be defined for each yaw angle) that corresponds to a predetermined distance away from the vehicle <NUM> and a predetermined height about a ground surface. A range of beam angle elevations between the "ground-skimming" beam elevation angle <NUM> and minimum beam elevation angle <NUM> may be prioritized over other beam elevations (e.g., beam elevation angles between the "ground-skimming" beam elevation angle <NUM> and the maximum beam elevation angle <NUM>).

As described above, in some embodiments, light pulses need not be emitted into beam elevation angles above the "ground-skimming" beam elevation angle <NUM>. Additionally or alternatively, the per pulse energy for light pulses emitted into such an elevation angle range may be reduced or eliminated altogether. Other distinctions between transmission and reception of light pulses into yaw-dependent beam angles ranges are possible based on, for instance, a topographic map, point cloud information, or other knowledge about objects and/or ground surfaces within an environment of the vehicle <NUM>. In some embodiments, the point cloud information may be gathered by a vehicle utilizing the LIDAR system (from a previous scan earlier in the drive and/or from a scan from a prior drive of the vehicle along the same route) or another vehicle utilizing a LIDAR system. The other vehicle could be part of a common fleet of vehicles or could be be associated with a different fleet.

<FIG> illustrates a method <NUM>, according to an example embodiment. It will be understood that the method <NUM> may include fewer or more steps or blocks than those expressly illustrated or otherwise disclosed herein. Furthermore, respective steps or blocks of method <NUM> may be performed in any order and each step or block may be performed one or more times. In some embodiments, some or all of the blocks or steps of method <NUM> may be carried out by controller <NUM> as illustrated and described in relation to <FIG>.

Block <NUM> includes causing a light source of a light detection and ranging (LIDAR) system to emit light along an emission vector. In some embodiments, block <NUM> could include causing the light source to emit a plurality of light pulses. In example embodiments, a pulse length of at least one light pulse of the plurality of light pulses could be within a range between <NUM> picoseconds to <NUM> nanoseconds. It will be understood that other pulse lengths are possible and contemplated.

Block <NUM> include adjusting the emission vector of the emitted light according to a scanning pattern. As an example, adjusting the emission vector of the emitted light could include adjusting a mechanical mirror of the LIDAR system that interacts with the emitted light. By adjusting the mechanical mirror, the emission vector of the emitted light can be changed with respect to an external environment of the LIDAR system. Additionally or alternatively, adjusting the emission vector could include adjusting another type of optical element (e.g., a lens, an aperture, etc.). The emission vector could be adjusted according to a scanning path, a desired spatial resolution, and/or a region of interest, among other possibilities.

Block <NUM> includes determining an elevation angle component of the emission vector. As described herein, determining the elevation angle component could include determining a vector projection of the emission vector onto a reference axis or reference plane (e.g., a horizontal plane). Additionally or alternatively, determining the elevation angle component could include querying a lookup table that provides the elevation angle component based on, for instance, a current position of a mechanical mirror, a mounting position of a given light source, a current position within a predetermined scanning pattern within a field of view, a pose of a vehicle (e.g., uphill or downhill angle of vehicle), among other possibilities. In such a scenario, the lookup table could be stored in memory <NUM>, as illustrated and described with reference to <FIG>. Additionally or alternatively, the lookup table could be stored elsewhere (e.g., at a cloud server or another location).

Block <NUM> includes dynamically adjusting an energy of the emitted light based on the determined elevation angle component. Block <NUM> could include adjusting a pulse energy of at least one light pulse of the plurality of light pulses. For example, the pulse energy of at least one light pulse could be between <NUM> nanojoules and <NUM> microjoules. In some scenarios, the energy of the emitted light could be adjusted so as to account for different predicted values of the range to a target object. For example, light emitted from a vehiclemounted LIDAR with a negative elevation angle component (e.g., a substantially downwardpointing beam) could be anticipated to interact with a ground surface or another object along the ground surface. As such, the energy of the emitted light provided at such elevation angles need not be as high as other elevation angles, such as those corresponding to "ground-skimming" angles and other elevation angles with longer predicted ranges to a target object.

In some embodiments, dynamically adjusting the energy of the emitted light could be further based on a laser safety standard. For example, the laser safety standard could include the American National Standard for Safe Use of Lasers (ANSI Z136. <NUM>-<NUM>) or other international laser safety standards. As an example, the laser safety standard could include standards established by the International Electrotechnical Commission (IEC), such as IEC <NUM>-<NUM> and/or IEC <NUM>-<NUM>-<NUM>, and other similar standards. In some cases, the laser safety standard could include recommended and/or required thresholds for optical energy emitted into a particular area for a given time and at a given wavelength. Such laser safety standards could specifically be provided over the IR-A (~<NUM>-<NUM> nanometers) and IR-B (~<NUM>-<NUM> nanometers) wavelength ranges. However, other wavelength ranges are possible and contemplated.

Additionally or alternatively, dynamically adjusting the energy of the emitted light could be based on another type of laser safety program or standard, even if not current established, such as an autonomous vehicle laser safety program or standard.

The applicable laser safety standards could be incorporated into system and methods herein by setting minimum or maximum dwell times, dose limits, energy per pulse, mechanical slew rates, and other limitations so as to conform to the applicable laser safety standard.

Furthermore, dynamically adjusting the energy of the emitted light could be based on a class of the light source (e.g., Class <NUM> laser, Class 3B laser, etc.), time of day, whether pedestrians are present, urban/rural locale, enclosed/open roadway, vehicle speed, vehicle density, among other possibilities.

Additionally or alternatively, in some embodiments where the LIDAR system is coupled to a vehicle, the method <NUM> could include dynamically adjusting the energy of the emitted light is further based on at least one of: point cloud data, map data, image data, object data, retroreflector location data, time of day, ambient light condition, sun position, a pose of the vehicle, a heading of the vehicle, or an operating condition of the vehicle.

In some embodiments, a pulse repetition rate of at least a portion of the plurality of light pulses could be between <NUM> kilohertz and <NUM> megahertz. Other pulse repetition rates are possible and contemplated.

In some scenarios, the light source includes a fiber laser operable to emit light having a wavelength of <NUM> nanometers or <NUM> nanometers. In such scenarios, dynamically adjusting the energy of the emitted light could include adjusting at least one of a seed laser operating parameter or a pump laser operating parameter. As a specific example, for a laser emitting light at a wavelength of <NUM> nanometers, a maximum energy limit of <NUM>µJ provided to a target area of <NUM><NUM> corresponding to a maximum optical power of about <NUM> milliwatts could be established (e.g., based on a laser safety standard). In such a scenario, the light source could be controlled such that light emitted into the environment remains below the maximum energy limit. To achieve this, a mechanical mirror and/or a rotational mount could be moved so that the emitted light does not dwell on a given location for longer than a threshold time. Additionally or alternatively, a pulser circuit or a power supply could be adjusted such that the light source emits less than <NUM> nJ at <NUM> nanometers toward a given location. It will be understood that other scenarios, wavelengths, and maximum energy limits are possible and contemplated.

The particular arrangements shown in the Figures should not be viewed as limiting. It should be understood that other embodiments may include more or less of each element shown in a given Figure. Further, some of the illustrated elements may be combined or omitted. Yet further, an illustrative embodiment may include elements that are not illustrated in the Figures.

A step or block that represents a processing of information can correspond to circuitry that can be configured to perform the specific logical functions of a herein-described method or technique. Alternatively or additionally, a step or block that represents a processing of information can correspond to a module, a segment, a physical computer (e.g., a field programmable gate array (FPGA) or application-specific integrated circuit (ASIC)), or a portion of program code (including related data). The program code can include one or more instructions executable by a processor for implementing specific logical functions or actions in the method or technique. The program code and/or related data can be stored on any type of computer readable medium such as a storage device including a disk, hard drive, or other storage medium.

Claim 1:
A system comprising:
a vehicle (<NUM>);
a light source (<NUM>) being part of a LIDAR device of the vehicle, wherein the light source is configured to emit at least one light pulse toward an environment of the vehicle; and
a controller operable to:
determine an emission vector of the at least one light pulse;
determine an elevation angle component of the emission vector;
dynamically determine a ground-skimming beam elevation angle (<NUM>) based on a predetermined height (<NUM>) above a roadway at a predetermined distance away from the vehicle;
compare the elevation angle component to the ground-skimming beam elevation angle (<NUM>); and
dynamically adjust a per pulse energy of at least one subsequent light pulse based on the comparison.