US20220276384A1 - Time-of-Flight Sensor with Structured Light Illuminator - Google Patents

Abstract

The present disclosure relates to systems and methods that provide information about a scene based on a time-of-flight (ToF) sensor and a structured light pattern. In an example embodiment, a sensor system could include at least one ToF sensor configured to receive light from a scene. The sensor system could also include at least one light source configured to emit a structured light pattern and a controller that carries out operations. The operations include causing the at least one light source to illuminate at least a portion of the scene with the structured light pattern and causing the at least one ToF sensor to provide information indicative of a depth map of the scene based on the structured light pattern.

Description

CROSS-REFERENCE TO RELATED APPLICATION
• The present application is a continuation of U.S. patent application Ser. No. 16/177,626, filed Nov. 1, 2018, the content of which is herewith incorporated by reference.
BACKGROUND
• Time-of-Flight (ToF) sensors typically provide low-resolution depth information about a scene, but can be subject to stray light “blooming” and/or provide inaccurate depth information when imaging highly reflective or highly absorbing materials.
• Structured light can include light emitted according to a desired or predetermined illumination pattern and/or illumination schedule. Some light sources may be configured to illuminate a scene with structured light.
SUMMARY
• The present disclosure beneficially combines aspects of ToF sensors and structured light to provide more accurate, higher-resolution depth information.
• In a first aspect, a sensor system is provided. The sensor system includes at least one time-of-flight (ToF) sensor configured to receive light from a scene. The sensor system also includes at least one light source configured to emit a structured light pattern. Furthermore, the sensor system includes a controller that carries out operations. The operations include causing the at least one light source to illuminate at least a portion of the scene with the structured light pattern. The operations also include causing the at least one ToF sensor to provide information indicative of a depth map of the scene based on the structured light pattern.
• In a second aspect, a system is provided. The system includes a plurality of sensor systems configured to be coupled to a vehicle. Each sensor system includes at least one time-of-flight (ToF) sensor and at least one imaging sensor. The at least one ToF sensor and the at least one imaging sensor are configured to receive light from a scene. Each sensor system also includes at least one light source configured to emit a structured light pattern and a controller that carries out operations. The operations include causing the at least one light source to illuminate at least a portion of the scene with the structured light pattern. The operations also include causing the at least one ToF sensor to provide information indicative of a depth map of the scene based on the structured light pattern. The operations additionally include causing the imaging sensor to provide information indicative of an image of the scene based on the structured light pattern.
• In a third aspect, a method is provided. The method includes causing at least one light source to illuminate a scene with a structured light pattern. The method additionally includes receiving, from a time-of-flight (ToF) sensor, information about the scene based on the structured light pattern. The method also includes determining a depth map of the scene based on the received information. The method yet further includes determining at least one inference about the scene based on the depth map of the scene.
• In a fourth aspect, a method is provided. The method includes providing prior information. The prior information includes three-dimensional information of a scene. The method includes causing at least one light source to illuminate the scene with a structured light pattern. The method also includes causing the at least one ToF sensor to provide time of flight information indicative of a depth map of the scene based on the structured light pattern.
• 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.
BRIEF DESCRIPTION OF THE FIGURES
• FIG. 1 illustrates a system, according to an example embodiment.
• FIG. 2 illustrates an operating scenario of a system, according to example embodiments.
• FIG. 3A illustrates a vehicle, according to an example embodiment.
• FIG. 3B illustrates a sensor unit, according to an example embodiment.
• FIG. 3C illustrates a light source, according to an example embodiment.
• FIG. 4A illustrates a sensing scenario, according to an example embodiment.
• FIG. 4B illustrates a sensing scenario, according to an example embodiment.
• FIG. 4C illustrates various structured light patterns, according to example embodiments.
• FIG. 4D illustrates a structured light pattern, according to an example embodiment.
• FIG. 5 illustrates a method, according to an example embodiment.
• FIG. 6A illustrates a sensing scenario, according to an example embodiment.
• FIG. 6B illustrates a sensing scenario, according to an example embodiment.
• FIG. 7 illustrates amethod700, according to an example embodiment.
DETAILED DESCRIPTION
• 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. Other embodiments can be utilized, and other changes can be made, without departing from the scope of the subject matter presented herein.
• Thus, the example embodiments described herein are not meant to be limiting. Aspects of the present disclosure, as generally described herein, and illustrated in the figures, can be arranged, substituted, combined, separated, and designed in a wide variety of different configurations, all of which are contemplated herein.
• Further, unless context suggests otherwise, the features illustrated in each of the figures may be used in combination with one another. Thus, the figures should be generally viewed as component aspects of one or more overall embodiments, with the understanding that not all illustrated features are necessary for each embodiment.
I. Overview
• Imaging sensors typically provide high quality, high-resolution, two-dimensional images of a scene, but do not typically provide independent depth information. Time-of-Flight (ToF) sensors typically provide low-resolution depth information about a scene, but can be subject to artifacts such as image blooming in the presence of highly reflective objects or inaccurate depth measurements in the presence of mixed scenes with reflective and absorptive objects. The present disclosure beneficially combines the desirable aspects of both types of sensors to provide more accurate, higher-resolution depth information.
• In some examples, blooming can occur when a given sensor pixel absorbs enough photons such that the number of photo-generated charge carriers exceeds a full well capacity (FWC). In such scenarios, upon reaching FWC, excess charge carriers can “overflow” into neighboring sensor pixels, producing a smearing or blurring effect, which may reduce image quality and/or reduce confidence in depth information.
• A hybrid imaging system could include: 1) at least one ToF sensor; 2) an optional imaging sensor; 3) at least one light source for illuminating the scene with structured light using continuous wave (CW), pulsed, or aperiodic illumination; and 4) a controller, which may include a computer, a processor, and/or a Deep Neural Net. The ToF sensor and the imaging sensor may be spatially registered to one another and may utilize overlapping portions of the same optical path. For example, the ToF sensor and the imaging sensor could be spatially registered to one another such that they have a similar (e.g., roughly identical) field of view and their relative position and orientation could be known and/or fixed with respect to one other.
• Each sensor unit of a plurality of sensor units of such a hybrid imaging system could be mounted on each side (or corner) of a vehicle. Respective sensor units could also be mounted in one or more spinning platforms at various locations on the vehicle. In an example embodiment, each sensor unit may include a 180 degree field of view of a scene around the vehicle. In some embodiments, sensor units could be positioned on the vehicle so as to have partially overlapping fields of view of the environment around the vehicle.
• In an example embodiment, to avoid blooming or other depth information artifacts, a plurality of ToF sensors could be associated with one or more image sensors in a given sensor unit. The respective ToF sensors could be spread out (e.g., spaced apart by 10 cm or more) so as to reduce the effects of blooming from specular reflections and other bright light sources. In some embodiments, the ToF sensors could be operated between 10-100 MHz, however other operating frequencies are contemplated and possible. In some embodiments, the operating frequency of the respective ToF sensor may be adjusted based on a desired maximum depth sensing range. For instance, a ToF sensor could be operated at 20 MHz for a desired depth sensing range (e.g., unambiguous range) of approximately 7.5 meters. In some embodiments, the ToF sensor could have a maximum desired depth sensing range of 100 meters or more.
• In some embodiments, the ToF sensor could include CMOS or CCD photo-sensitive elements (e.g., silicon PIN diodes). However, other types of ToF sensors and ToF sensor elements are contemplated. In some cases, the ToF sensor could be operated using various phase shift modes (e.g., a 2x or 4x phase shift).
• In some embodiments, the imaging sensor could include an RGB imaging sensor, such as a megapixel-type camera sensor. The imaging sensor could include a plurality of CMOS or CCD photo-sensitive elements.
• In some examples, one or more light sources could be used to illuminate the scene (or respective portions of the scene). In such scenarios, the light sources could be modulated to provide a predetermined light pulse (or series of light pulses) that could be used in conjunction with the ToF sensor to provide depth information. Additionally or alternatively, the series of light pulses (e.g., a pulse repetition rate, a pulse duration, and/or a duty cycle) could be selected so as to provide a desired exposure for the imaging sensor.
• The one or more light sources could include a light strip that is disposed along a portion of the vehicle. Additionally or alternatively, the one or more light sources could include a grid of light panels, each segment of which could individually provide different light pulses. Yet further, the one or more light sources could provide one or more light beams that can be moved in a point-wise and/or scanning fashion.
• The one or more light sources could be operated in CW and/or in pulsed (e.g., sine wave, sawtooth, or square wave) operation mode. Without limitation, the one or more light sources could include at least one of: a laser diode, a light-emitting diode, a plasma light source, a strobe, a solid-state laser, a fiber laser, or another type of light source. The one or more light sources could be configured to emit light in the infrared wavelength range (e.g., 850, 905, 940, and/or 1550 nanometers). In some embodiments, multiple illumination light wavelengths could be used to disambiguate between multiple light sources, etc. Additionally or alternatively, the illumination wavelength may be adjusted based on an amount of ambient light in the environment and/or a time of day.
• In another example embodiment, the one or more light sources could emit a structured light pattern into the environment. The structured light pattern could provide improved registration and/or resistance to blooming effects. As an example, the structured light pattern could be formed by transmitting light through a diffractive optic element. In another embodiment, a laser light pattern (e.g., random laser speckle or predetermined laser light pattern) could be used to provide the structured light pattern. In yet further embodiments, a deformable or adjustable reflective, diffractive, or refractive surface (e.g., a micromirror array) could be used to provide the structured light pattern and/or to shift the pattern with respect to the scene.
• Additionally or alternatively, the one or more light sources could be configured to emit one or more classes of structured light patterns. For instance, the classes of structured light patterns could include one or more spatial classes, where some regions of a field of view are illuminated (or not illuminated) according to a predetermined spatial light pattern. Other classes of structured light patterns could include temporal classes, where various regions of a field of view are illuminated at different times according to a predetermined temporal illumination schedule. Yet other classes of structured light could include spectral classes, where various regions of a field of view are illuminated with different wavelengths—or wavebands—of light according to a predetermined spectral illumination pattern. However, other ways to form a structured light pattern are possible and contemplated herein.
• In some embodiments, the structured light pattern could be used to disambiguate spatial locations within a scene. For example, the structured light pattern could include circular and/or oval-shaped light “spots”. Each spot could have a different shape or orientation (e.g., rotation, spatial extent, radius of curvature, elongation, etc.) based on, for example, an emission angle of light through the diffractive optic element or a spatial position in the scene with respect to the light source. In some embodiments, a predetermined astigmatism of the optical element could be utilized to disambiguate between light spots in the structured light pattern.
• The controller could be operable to combine outputs of the respective sensors (e.g., using sensor fusion) and/or make inferences about the three-dimensional scene around the vehicle. For example, the controller could make inferences to provide a grayscale or color-intensity map of the vehicle's surroundings. The inferences may additionally or alternatively provide information about objects in the vehicle's environment. In an example embodiment, the object information could be provided at a refresh rate of 60 or 120 Hz. However, other refresh rates are possible and contemplated.
• In an example embodiment, the system could include one or more deep neural networks. The deep neural networks(s) could be utilized to provide the inferences based on training data and/or an operating context of the vehicle. In some cases, the low-resolution depth information and the image information may be provided to the deep neural network. Subsequently, the deep neural network could make inferences based on the received information and/or provide output depth maps (e.g., point clouds) at a high-resolution.
• In some embodiments, two or more of: the ToF sensor, the image sensor, the light source, and the controller could be coupled to the same substrate. That is, the system could include a monolithic chip or substrate so as to provide a smaller sensor package and/or provide other performance improvements.
II. Example Systems
• FIG. 1 illustrates asystem100, according to an example embodiment. Thesystem100 includes at least one Time-of-Flight (ToF)sensor110, or ToF camera. In an example embodiment, the at least oneToF sensor110 could include a plurality of complementary metal-oxide semiconductor (CMOS) or charge-coupled device (CCD) photosensitive elements (e.g., silicon PIN diodes). Other types of photosensitive elements could be utilized by theToF sensor110.
• In some embodiments, the at least oneToF sensor110 could be configured to actively estimate distances to environmental features in its respective field of view based on the speed of light. For instance, theToF sensor110 could measure the time-of-flight of a light signal (e.g., a light pulse) upon traveling between a light source (e.g., light source130) and an object in the scene. Based on estimating the time-of-flight of light pulses from a plurality of locations within a scene, a range image or depth map can be built up based on the ToF sensor's field of view. While the distance resolution can be 1 centimeter or less, the lateral resolution can be low as compared to standard 2D imaging cameras.
• In some embodiments, theToF sensor110 can obtain images at 120 Hz or faster. Without limitation, theToF sensor110 could include a range-gated imager or a direct time-of-flight imager.
• Optionally, thesystem100 may also include at least oneimaging sensor120. In an example embodiment, theimaging sensor120 could include a plurality of photosensitive elements. In such a scenario, the plurality of photosensitive elements could include at least one million photosensitive elements. The at least oneToF sensor110 and the at least oneimaging sensor120 are configured to receive light from a scene.
• Thesystem100 also includes at least onelight source130. In an example embodiment, the at least onelight source130 could include at least one of: a laser diode, a light-emitting diode, a plasma light source, a strobe light, a solid-state laser, or a fiber laser. Other types of light sources are possible and contemplated in the present disclosure. The at least onelight source130 could include a light strip (e.g., disposed along a portion of a vehicle). Additionally or alternatively, the at least onelight source130 could include, for example, a grid of light panels, each segment of which could individually provide different light pulses. Yet further, the at least onelight source130 could provide one or more light beams that can be moved in a point-wise and/or scanning fashion. The at least onelight source130 could be operated in a continuous wave (CW) mode and/or in a pulsed (e.g., sine wave, sawtooth, or square wave) operation mode.
• In an example embodiment, the at least onelight source130 could be configured to emit infrared light (e.g., 900-1600 nanometers). However, other wavelengths of light are possible and contemplated.
• In some embodiments, the at least onelight source130 could be configured to emit light into the environment according to a desired structured light pattern. The structured light pattern could include, for example, aperiodic and/or inhomogeneous illumination of the environment by the at least onelight source130. For example, the desired structured light pattern could include a checkerboard pattern, a dot pattern, a stripe pattern, a speckle pattern, or another predetermined light pattern. Additionally or alternatively, in some embodiments, pseudorandom light patterns are possible and contemplated. The desired structured light pattern could be defined by light pulses, or shots, emitted along a predetermined pointing angle and/or within a predetermined field of view. In some embodiments, the light pulses could be provided at different temporal and/or spatial/angular densities based on the desired structured light pattern.
• The at least onelight source130 and theToF sensor110 could be temporally synchronized. That is, a trigger signal to cause thelight source130 to emit light could also be provided to theToF imager110 as a temporal reference signal. As such, theToF sensor110 may have information about a time of the actual onset of the light emitted from thelight source130. Additionally or alternatively, theToF sensor110 could be calibrated based on a reference target at a known distance from theToF sensor110.
• In scenarios with multiple light sources and/or multiple ToF imagers, the multiple light sources could utilize time multiplexing or other types of signal multiplexing (e.g., frequency or code multiplexing) so as to disambiguate time-of-flight information (light pulses) obtained by a given ToF imager from the various light sources.
• In some embodiments, the at least onelight source130 could be configured to emit light into an environment along a plurality of emission vectors toward various target locations so as to provide a desired resolution. In such scenarios, the at least onelight source130 could be operable to emit light along the plurality of emission vectors such that the emitted light interacts with an external environment of thesystem100.
• In an example embodiment, the respective emission vectors could include an azimuthal angle and/or an elevation angle (and/or corresponding angular ranges) with respect to a heading or location of a vehicle (e.g.,vehicle300 as illustrated and described with reference toFIG. 3A). In some embodiments, light emitted by the at least onelight source130 could be directed along the respective emission vectors by adjusting a movable mount and/or a movable mirror.
• For example, the at least onelight source130 could emit light toward a movable mirror. By adjusting an orientation of the movable mirror, the emission vector of the light could be controllably modified. It will be understood that many different physical and optical techniques may be used to direct light toward a given target location. All such physical and optical techniques for adjusting an emission vector of light are contemplated herein.
• Optionally, thesystem100 may includeother sensors140. Theother sensors140 may include a LIDAR sensor, a radar sensor, or other types of sensors. For instance,system100 could include a Global Positioning System (GPS), an Inertial Measurement Unit (IMU), a temperature sensor, a speed sensor, a camera, or a microphone. In such scenarios, any of the operational scenarios and/or methods described herein could include receiving information from theother sensors140 and carrying out other operations or method steps based, at least in part, on the information received from theother sensors140.
• In an example embodiment, at least two of: the at least oneToF sensor110, theimaging sensor120, and the at least onelight source130 could be coupled to a common substrate. For example, the at least oneToF sensor110, theimaging sensor120, and the at least onelight source130 could be coupled to a vehicle. In some embodiments, some or all elements ofsystem100 could provide at least a portion of the object detection and/or navigation capability of the vehicle. The vehicle could be a semi-autonomous or fully-autonomous vehicle (e.g., a self-driving car). For instance,system100 could be incorporated intovehicle300 as illustrated and described in reference toFIGS. 3A, 4A, 4B, 6A, and 6B.
• In some embodiments,system100 could be part of a vehicle control system utilized to detect and potentially identify nearby vehicles, road boundaries, weather conditions, traffic signs and signals, and pedestrians, among other features within the environment surrounding thevehicle300. For example, a vehicle control system may use depth map information to help determine control strategy for autonomous or semi-autonomous navigation. In some embodiments, depth map information may assist the vehicle control system to avoid obstacles while also assisting with determining proper paths for navigation.
• While some examples described herein includesystem100 as being incorporated into a vehicle, it will be understood that other applications are possible. For example,system100 could include, or be incorporated into, a robotic system, an aerial vehicle, a smart home device, a smart infrastructure system, etc.
• System100 includes acontroller150. In some embodiments, thecontroller150 could 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, thecontroller150 can include, or could be connected to, a remotely-located computer system, such as a cloud server network. In an example embodiment, thecontroller150 may be configured to carry out some or all of the operations, method blocks, or steps described herein. Without limitation, thecontroller150 could additionally or alternatively include at least one deep neural network, another type of machine learning system, and/or an artificial intelligence system.
• Thecontroller150 may include one ormore processors152 and at least onememory154. Theprocessor152 may include, for instance, a microprocessor, an application-specific integrated circuit (ASIC), or a field-programmable gate array (FPGA). Other types of processors, circuits, computers, or electronic devices configured to carry out software instructions are contemplated herein.
• Thememory154 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 ormore processors152 ofcontroller150 may be configured to execute instructions stored in thememory154 so as to carry out various operations and method steps/blocks described herein. The instructions may be stored in a permanent or transitory manner in thememory154.
• FIG. 2 illustrates anoperating scenario200 of thesystem100, according to example embodiments. While theoperating scenario200 illustrates certain operations or blocks being in a certain order and being carried out by certain elements ofsystem100, it will be understood that other functions, orders of operations, and/or timing arrangements are contemplated herein.
• Block210 may include thecontroller150 causing the at least onelight source130 to illuminate at least a portion of the scene with illumination light according to a structured light pattern. The structured light pattern could include, for example, at least one of: a predetermined light pulse repetition rate, a predetermined light pulse duration, a predetermined light pulse intensity, or a predetermined light pulse duty cycle.
• In some embodiments, the structured light pattern could remain static over one or more scans within a given field of view. Alternatively or additionally, the structured light pattern could change dynamically. For example, the structured light pattern could be adjusted based on objects within the environment, a region of interest within the field of view; a time of day, presence of retroreflectors, etc. In some embodiments, the structured light pattern could include a checkerboard pattern, a speckle pattern, or a striped pattern.
• In some example embodiments, in response to determining a retroreflector within a portion of a given field of view, the intensity of the sector that had illuminated the retroreflector could be “dialed down” (e.g., reducing a preamplifier gain or otherwise changing how a photosignal from that sector is processed in the analog and/or digital domain) and/or completely turned off or ignored to avoid blooming effects. In such a manner, the sensor may be better able to recover the remaining portions of the scene.
• Periodically (e.g., once every few of frames within a maximum latency), the portion of field of view with the retroreflector could be illuminated again to track the presence of the retroreflector. If the sensor continues to indicate strongly saturated pixels in response to illumination (e.g., indicating that the retroreflective object is still present in that region of the field of view), high energy illumination will not be provided to the given region until such time that the system no longer observes a retroreflector in that region. Such dynamic illumination could reduce or eliminate stray light from retroreflectors and more reliably recover the remainder of the scene which might otherwise not produce reliable depth values. Without limitation, other types of spatial, temporal, and/or spectral light patterns are contemplated herein.
• In an example embodiment,instruction212 could include, for example, a signal from thecontroller150 to thelight source130 at time to. Theinstruction212 could be indicative of the desired structured light pattern and/or an illumination schedule, an illumination level, or an illumination direction or sector, among other examples.
• In response to receiving theinstruction212, thelight source130 could carry outblock214 to illuminate the scene according to the structured light pattern. In some examples, thelight source130 could illuminate one or more light-emitter elements, which could be light-emitting diodes (LEDs), lasers, strobe lights, or another type of light source. Such light-emitter elements could be illuminated so as to provide the desired structured light pattern (e.g., provide light along a desired set of pointing/cone angles, illuminate light-emitter elements for a desired time, illuminate light-emitter elements at a desired frequency and duty cycle, etc.). In some embodiments, thelight source130 could include an optical element, such as one or more lenses, and/or a baffle so as to direct light toward a desired set of pointing angles and/or cone angle.
• Block220 includes causing the at least oneToF sensor110 to provide information (e.g., time of flight information) indicative of a depth map of the scene based on the structured light pattern provided by thelight source130. For example, at time t₁, block220 could include providing aninstruction222 from thecontroller150 to theToF sensor110. Theinstruction222 could include a signal to trigger a depth mapping function of theToF sensor110. Additionally or alternatively, theinstruction222 could include information indicative of a desired field of view for scanning, a desired range for scanning, a desired resolution, and/or other desired aspects of the depth map and/or ToF sensor scan.
• Block224 could include theToF sensor110 obtaining a depth map based, at least in part, on the structured light pattern provided by thelight source130. That is, in response to receiving theinstruction222, theToF sensor110 may carry out a depth-mapping scan of a field of view of a scene. In an example embodiment, theToF sensor110 could be operated between 10-100 MHz, however other operating frequencies are possible. In some embodiments, the operating frequency of theToF sensor110 may be adjusted based on a desired maximum depth sensing range. For instance, theToF sensor110 could be operated at 20 MHz for a desired depth sensing range of approximately 7.5 meters. In some embodiments, theToF sensor110 could have a maximum desired depth sensing range of100 meters or more. In some embodiments that involve multiple ToF sensors, the ToF sensors could be configured to and/or instructed to carry out depth-mapping scans of different fields of view of the scene and/or over different distance ranges.
• At time t₂, upon obtaining the depth map according to block224, theToF sensor110 could provideinformation226 to thecontroller150. Theinformation226 may be indicative of the depth map of the scene. For example, theinformation226 could include a distance-based point map of the scene. Additionally or alternatively, theinformation226 could include a surface map of objects determined within the scene. Other types ofinformation226 are possible and contemplated.
• Block230 includes causing theimaging sensor120 to provide information indicative of an image of the scene based on the structured light pattern provided by thelight source130. As an example, at time t₃, thecontroller150 could provide aninstruction232 to theimaging sensor120. Theinstruction232 could include a signal for triggering an image capture function of theimaging sensor120. Furthermore, theinstruction232 could include information regarding a desired exposure, ambient lighting level, ambient lighting color temperature, time of day, etc. While t₁and t₃are illustrated inFIG. 2 as being different, in some embodiments, times t₁and t₃could be similar or identical. That is, in some embodiments, at least some portions of the depth mapping and image capture processes could be triggered and conducted in parallel.
• Block234 includes, in response to receiving theinstruction232, theimaging sensor120 obtaining an image of the scene illuminated by the structured light pattern. In other words,instruction232 could trigger a physical shutter mechanism or a digital shutter so as to initiate an image capture process.
• Upon capturing the image, at time t₄, theimage sensor120 could provideinformation236 to thecontroller150. Theinformation236 could include, for example, the captured image as well as other information, such as metadata regarding the captured image (e.g., exposure time, aperture setting, imager sensitivity (ISO), field of view extents, etc.). In some embodiments, theinformation236 could include RAW image data, however other uncompressed and compressed image data formats (BMP, JPEG, GIF, PNG, TIFF, etc.) are possible and contemplated.
• Block240 could include determining a high-resolution depth map of the scene based on the depth map of the scene (e.g., information226) and the image of the scene (e.g., information236). In an example embodiment, thedepth map information226 and theimage information236 could be compared and/or correlated using various image processing algorithms. Such algorithms may include, without limitation, texture synthesis, image resampling algorithms, interpolation algorithms, image sharpening algorithms, edge-detection algorithms, and image blurring algorithms, etc. As such, the high-resolution depth map could include depth information about the scene with a higher spatial resolution than that of the depth map obtained by theToF sensor110. In some embodiments, the spatial resolution could relate to a target resolution at a given distance away from thesystem100. Other spatial resolutions, both along a two-dimensional surface and within three-dimensional space, are possible and contemplated herein. As an example, the depth map obtained by theToF sensor110 could provide a spatial resolution between adjacent sampling points of 10 centimeters at a range of 20 meters. The high-resolution depth map could provide a spatial resolution of less than 5 centimeters at a range of 20 meters. In other embodiments, a high-resolution depth map could include other spatial resolutions that may be sufficient to sense objects (e.g., other vehicles, pedestrians, obstacles, signs, signals, etc.) within a field of view of thesystem100.
• Block250 may include determining at least one inference about the scene based on the depth map of the scene and, optionally, the image of the scene. For example, thecontroller150 could determine at least one inference about the scene based on the high-resolution depth map determined in block240. In such a scenario, the at least one inference may include information about one or more objects in an environment of a vehicle or an operating context of the vehicle. In scenarios where thecontroller150 includes a deep neural network, block250 could be performed, at least in part, by the deep neural network.
• While theoperating scenario200 describes various operations or blocks210,220,230,240, and250 as being carried out by thecontroller150, it will be understood that at least some of the operations ofoperating scenario200 could be executed by one or more other computing devices.
• Whileoperating scenario200 describes various operations, it will be understood that more or fewer operations are contemplated. For example, the operations could further include selecting an illumination schedule from among a plurality of possible illumination schedules so as to provide a desired exposure for theimaging sensor120.
• FIGS. 3A, 3B, and 3C illustrate various embodiments of thesystem100 and its elements.FIG. 3A illustrates avehicle300, according to an example embodiment. Thevehicle300 may include one ormore sensor systems302,304,306,308,310,354a-d, and356a-d. In some examples, the one ormore sensor systems302,304,306,308, and310 could include LIDAR and/or radar sensor units. One or more of thesensor systems302,304,306,308, and310 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 thevehicle300 with light pulses and/or radar energy. Additionally or alternatively, one or more of thesensor systems302,304,306,308, and310 could include a movable mirror so as to direct emitted light pulses and/or radar energy in the environment of thevehicle300. For LIDAR-based sensors, determining various aspects of reflected light pulses (e.g., the elapsed time of flight, polarization, etc.,) may provide information about the environment as described herein. Similarly, radar-based sensors may determine information about a given scene based on how radar energy interacts with the environment.
• In an example embodiment,sensor systems302,304,306,308, and310 may be configured to provide respective point cloud information or other types of information (e.g., maps, object databases, etc.) that may relate to physical objects within the environment of thevehicle300. Whilevehicle300 andsensor systems302 and304 are illustrated as including certain features, it will be understood that other types of sensors are contemplated within the scope of the present disclosure.
• FIG. 3B illustrates a front view ofsensor unit350, according to an example embodiment.Sensor unit350 could include ahousing352. In some embodiments, thehousing352 could be coupled to, or integrated into, thevehicle300. In an example embodiment, thesensor unit350 may optionally include animaging sensor354, which could be similar or identical toimaging sensor120, as illustrated and described in reference toFIG. 1. Additionally, thesensor unit350 could include aToF sensor356, which could be similar or identical toToF sensor110, as illustrated and described in reference toFIG. 1. WhileFIG. 3B illustratesimaging sensor354 andToF sensor356 as being disposed within acommon housing352, theimaging sensor354 andToF sensor356 could be disposed in different locations. It will be understood that other arrangements of such elements are possible and contemplated herein.
• FIG. 3C illustrates alight source370, according to an example embodiment.Light source370 could include ahousing372. In some embodiments, thehousing372 could be coupled to, or integrated into, thevehicle300. In an example embodiment, thelight source370 may include a plurality of light-emitting elements374a-h, which could be similar or identical tolight source130, as illustrated and described in reference toFIG. 1. Light-emitting elements374a-hcould be disposed in an array or in another spatial arrangement. In an example embodiment, the light-emitting elements374a-hcould be light-emitting diodes (LEDs) or laser diodes. Other types of light sources are possible and contemplated.
• The light-emitting elements374a-hcould be configured to emit light in the infrared (e.g., near infrared 700-1050 nm) wavelength range. However, in some embodiments, other wavelengths of light are contemplated (e.g., 1550 nm). In some embodiments, the light-emitting elements374a-hcould be configured to emit light at different wavelengths from each other. That is, the light-emitting elements374a-hcould be configured to emit light at eight different wavelengths. In such scenarios,system100 and/orvehicle300 could be configured to disambiguate light signals emitted by discrete light-emitting elements (or between different light sources370) based on its wavelength. In some embodiments, the multi-color light could be received by multi-color imaging sensors and/or multi-color ToF sensors.
• In some embodiments, light-emitting elements374a-hcould include one or more optical elements configured to interact with the light emitted from the light-emitting elements374a-h. Without limitation, the one or more optical elements could be configured to redirect, shape, attenuate, amplify, or otherwise adjust the emitted light. For example, the one or more optical elements could include a mirror, an optical fiber, a diffractive optic element, an aspherical lens, a cylindrical lens, or a spherical lens. Other types of optical elements are possible and contemplated.
• In some example embodiments, the light-emitting elements374a-hcould be operable so as to emit light toward different spatial sectors (e.g., including different azimuthal angle ranges and/or elevation angle ranges) of the environment aroundvehicle300. Furthermore, in some embodiments, the light-emitting elements374a-hcould be operable to emit light at different times during a given period of time. That is, each of the light-emitting elements374a-hcould be controlled to emit light during respective time periods over a given time span. For example, the light-emitting elements374a-hcould emit light in a serial pattern (e.g., one light-emitting element lit after another in a “chase” pattern). Additionally or alternatively, one or more of the light-emitting elements374a-hcould emit light in a parallel fashion (e.g., several light-emitting element emitting light simultaneously).
• Returning toFIG. 3A,vehicle300 could include a plurality of sensor units, which could be similar or identical tosensor unit350, as illustrated and described in reference toFIG. 3B. Furthermore, the respective sensor units could each includeimaging sensors354a-dandToF sensors356a-d. As illustrated, the respective pairs ofimaging sensors354a-dandToF sensors356a-dcould be coupled to, or integrated into, a front, right side, left side, and rear portion of thevehicle300. Other mounting types and mounting locations are contemplated for theimaging sensors354a-dandToF sensors356a-d. For example, in some embodiments, theimaging sensors354a-dandToF sensors356a-dcould be disposed in a rotatable mount configured to rotate about the z-axis so as to obtain imaging information and ToF information from an environment around thevehicle300.
• Whilesensor systems354a/356a,354b/356b,354c/356c, and354d/356dare illustrated as being collocated, it will be understood that other sensor arrangements are possible and contemplated. Furthermore, while certain locations and numbers of sensor systems are illustrated inFIGS. 3A-3C, it will be understood that different mounting locations and/or different numbers of the various sensor systems are contemplated.
• Vehicle300 could include a plurality oflight sources370a-d, which could be similar or identical tolight source130, as illustrated and described in reference toFIG. 1. As illustrated,light source370a-dcould be coupled to, or integrated into, a front, right side, left side, and rear portion of thevehicle300. Other mounting types and mounting locations are contemplated for the plurality oflight sources370a-d. For example, in some embodiments, thelight source370 could be disposed in a rotatable mount configured to rotate about the z-axis so as to emit light toward a controllable azimuthal angle range.
• FIG. 4A-4B illustratevarious sensing scenarios400 and420. In each case, for purposes of clarity, thesensing scenarios400 and420 may illustrate a subset of possible spatial sectors and sensor profiles/ranges. It will be understood that other spatial sectors are possible and contemplated within the scope of the present disclosure. Furthermore, it will be understood that thesensing scenarios400 and420 may illustrate only single “snapshots” in time and that spatial sectors and sensor profiles/ranges could be dynamically adjusted so as to periodically or continuously change based on, among other factors, a dynamically-changing operating context of thevehicle300.
• FIG. 4A illustrates an overhead/top view ofvehicle300 in asensing scenario400, according to an example embodiment.Sensing scenario400 includes illuminating a front-facing sector of an environment of thevehicle300 with structuredlight pattern402. For example,light source370acould emit light from one or more light-emitting elements so as to illuminate the front-facing sector of thevehicle300 with the structuredlight pattern402.
• The structuredlight pattern402 could be provided according to a pulsed illumination schedule or a continuous-wave illumination schedule. Other types of illumination schedules are contemplated. For example, the structuredlight pattern402 could be provided “on-demand” fromcontroller150 or based on the operating context of thevehicle300. As an example, the structuredlight pattern402 could be provided in low-light conditions (e.g., at night) or in response to determining an object in the environment of thevehicle300. As a non-limiting example, another sensor system of thevehicle300 could identify an ambiguous or unknown object (not illustrated) ahead of thevehicle300. The ambiguous or unknown object could be identified for further analysis. In such a scenario, thecontroller150 could cause thelight source370ato provide the structuredlight pattern402 to the front-facing sector.
• WhileFIG. 4A illustrates a front-facing sector as being illuminated, in some embodiments, thelight source370amay be configured to adjust a pointing direction of the structuredlight pattern402. It will also be understood that the otherlight sources370b-dcould provide similar structured light patterns into various spatial sectors corresponding with their respective positions. For example,light source370dcould emit light according to the structured light pattern into a rear-facing spatial sector.
• It will be understood that while the structuredlight pattern402 and spatial sectors appear as being two-dimensional inFIG. 4A-4B, three-dimensional spatial volumes are contemplated. For example, the structuredlight pattern402 and/or spatial sectors could be defined as between an azimuthal angle range and also between a maximum elevation angle and a minimum elevation angle.
• FIG. 4B illustrates an overhead/top view of thevehicle300 in asensing scenario420, according to an example embodiment.Sensing scenario420 could includeimaging sensor354aobtaining light from a field ofview404. At least a portion of the light obtained by theimaging sensor354acould include reflected or refracted light after the structuredlight pattern402 interacts with the environment of thevehicle300. The field ofview404 could include a front-facing spatial sector of thevehicle300. In some embodiments, the field ofview404 of theimaging sensor354acould partially or fully overlap with the volume illuminated by the structuredlight pattern402. Based on the light obtained from field ofview404, theimaging sensor354amay provide an image of the scene based, at least in part, on the structuredlight pattern402.
• Sensing scenario420 also illustratesToF sensor356aobtaining light from a field ofview406. At least a portion of the light obtained by theToF sensor356acould be from structuredlight pattern402 that has interacted with the environment of thevehicle300. The field ofview406 could include a front-facing spatial sector of thevehicle300. In some embodiments, the field ofview406 of theToF sensor356acould partially or fully overlap with the volume illuminated by structuredlight pattern402. Based on the light obtained from field ofview406, theToF sensor356amay provide a depth map of the scene based, at least in part, on the structuredlight pattern402.
• FIG. 4C illustrates various structuredlight patterns430, according to example embodiments. The various structuredlight patterns430 could include, for example, a vertical striped structuredlight pattern432, a dot array structuredlight pattern434, a checkerboard structuredlight pattern436, a diagonal striped structuredlight pattern438, a “dropout” structuredlight pattern440, and/or a speckle structuredlight pattern442.
• FIG. 4D illustrates a structuredlight pattern444, according to an example embodiment. As an example, structuredlight pattern444 could include a horizontal striped structured light pattern446. It will be understood that other structured light patterns are possible and each is contemplated without limitation.
• In some embodiments, an illumination level (e.g., brightness) of some or all portions of thestructure light patterns430 could be dynamically adjusted based on objects within the scene and/or prior information about the scene. As an example, the amount of illumination provided to various portions of the scene could be based on the presence of predicted or known highly-retroreflective objects. In a scenario, the ToF sensor could capture an initial scan of the scene while illuminating the scene at a relatively low illumination level. As an example, the initial scan could include a brief (e.g., 10 microsecond) illumination period. Such an initial scan could provide information about retroreflectors present within the scene. A subsequent scan of the scene could be performed at a relatively high illumination level (e.g., 100 microsecond illumination period, or longer) for portions of the scene where the retroreflectors are not present. The subsequent scan could include illuminating the portions of the scene having the retroreflectors at a relatively low illumination level to confirm the presence of a highly reflective object.
• For example, in reference toFIG. 4C, if aretroreflective region435ais identified within a given scene during an initial scan, then illumination of thatretroreflective region435acould be reduced with respect toother regions435bof the scene during a subsequent scan. By dynamically adjusting the illumination level within the scene, potential blooming issues and/or other problems relating to retroreflectors could be avoided or reduced on a near-real-time basis. Other ways to differentially illuminate certain portions of the scene with respect to other portions of the scene are contemplated and possible.
III. Example Methods
• FIG. 5 illustrates amethod500, according to an example embodiment. It will be understood that themethod500 may include fewer or more steps or blocks than those expressly illustrated or otherwise disclosed herein. Furthermore, respective steps or blocks ofmethod500 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 ofmethod500 may be carried out by elements ofsystem100. For example, some or all ofmethod500 could be carried out bycontroller150, ToF sensor(s)110, and/or imaging sensor(s)120 as illustrated and described in relation toFIG. 1. Furthermore,method500 may be described, at least in part, by theoperating scenario200, as illustrated in relation toFIG. 2. Yet further,method500 may be carried out, at least in part, byvehicles300 or400 as illustrated and described in relation toFIG. 3A, 4A, 4B, 6A, or6B.Method500 may be carried out in scenarios similar or identical toscenario400 as illustrated and described in relation toFIGS. 4A, 4B, and 4C. It will be understood that other scenarios are possible and contemplated within the context of the present disclosure.
• Block502 includes causing at least one light source to illuminate a scene with a structured light pattern. The structured light pattern could be similar or identical to structuredlight pattern402,432,434,436,438,440, and442, as illustrated and described inFIGS. 4A, 4B, and 4C. In example embodiments, the structured light pattern could include at least one of: a temporal light pattern, a spatial light pattern, a predetermined light pulse repetition rate, a predetermined light pulse duration, a predetermined light pulse intensity, or a predetermined light pulse duty cycle.
• Block504 includes receiving, from a time-of-flight (ToF) sensor, information (e.g., time of flight information) about the scene based on the structured light pattern. In an example embodiment, thecontroller150 could cause the ToF sensor to initiate a depth scan based on the structured light pattern. In some embodiments, a clock signal or trigger signal could be provided to the ToF sensor to synchronize it with the one or more light pulses emitted into the environment. Upon obtaining depth map information, the ToF sensor could provide to thecontroller150 information indicative of the depth map to thecontroller150 or another element of thesystem100.
• Block506 includes determining a depth map of the scene based on the received information. For example, determining the depth map of the scene could include calculating distances to objects in the environment based on the time of flight of light pulses emitted into the environment. Other ways to determine the depth map of the scene based on the received information are contemplated.
• Optionally,method500 could include causing an imaging sensor to provide information indicative of an image of the scene based on the structured light pattern. In some embodiments, thecontroller150 could trigger a mechanical or electronic shutter of the imaging sensor to open and obtain an image of the scene. Additionally or alternatively, thecontroller150 could provide information about the scene (e.g., ambient light level, specific sectors of concern, desired resolution, time of day, etc.). Furthermore, thecontroller150 or thelight source130 could provide a clock signal or trigger signal so as to synchronize the imaging sensor and light source. Upon obtaining the image of the scene, the imaging sensor could provide information indicative of the image to thecontroller150 or another element ofsystem100.
• Additionally or alternatively,method500 could include selecting a desired structured light pattern from among a plurality of possible structured light patterns. In some embodiments, the desired structured light pattern could be selected so as to provide a desired exposure for the imaging sensor. Additionally or alternatively, selecting the desired structured light pattern could be based on a number of variables, including external light level, other light sources, angle of sun, etc. As such,method500 could include selecting and/or adjusting the structured light pattern based on an amount of ambient light (e.g., as measured from an ambient light sensor), a time of day, and/or weather condition.
• Optionally,method500 could include determining a high-resolution depth map (e.g., a depth map with higher resolution than that provided by the ToF sensor individually) of the scene based on the depth map of the scene and the image of the scene.
• Block508 includes determining at least one inference about the scene based on the depth map of the scene and, optionally, the image of the scene. In some embodiments, the at least one inference could include information about one or more objects in an environment of a vehicle or an operating context of the vehicle.
• In example embodiments, determining the at least one inference could be performed by at least one deep neural network. Additionally or alternatively, some or all blocks ofmethod500 could be carried out by computing systems implementing other types of artificial intelligence-based algorithms.
• FIGS. 6A and 6B illustrate sensing scenarios in the context of the present disclosure. The sensing scenarios could relate to system100 (e.g., as illustrated and described in reference toFIG. 1), vehicle300 (e.g., as illustrated and described in reference toFIGS. 3A, 4A, and 4B), and method500 (e.g., as illustrated and described in reference toFIG. 5).
• FIG. 6A illustrates asensing scenario600, according to an example embodiment. As illustrated inFIG. 6A, avehicle300 could be operating in an environment that includes one or more objects. As shown, thevehicle300 includessensor units302,306,308, and310. For instance, thesensor unit302 may include a first LIDAR (not shown) and a second LIDAR (not shown). Further, for instance, each of thesensor units306,308, and310 may also include a LIDAR. As shown, thevehicle300 may additionally includeimaging sensors354a-d,ToF sensors356a-dandlight sources370a-d. It will be understood that thevehicle300 could include different numbers and/or arrangements ofimaging sensors354a-d,ToF sensors356a-d, and/orlight sources370a-d.
• As shown, the environment of thevehicle300 includes various objects such ascars614 and616,road sign618,tree620, building622,street sign624,pedestrian626,dog628,car630,driveway632, and lane lines includinglane line634. In some embodiments, these objects have different reflectivities, which can make it more difficult to obtain accurate depth map information. In accordance with the present disclosure, thevehicle300 may perform the methods and processes herein, such asmethod500, to facilitate autonomous operation of thevehicle300 and/or accident avoidance by thevehicle300.
• FIG. 6B illustrates asensing scenario650, according to an example embodiment. In some embodiments, thevehicle300 and its associated light sources could emit light into its environment according to one or more structuredlight patterns652 and654. For example, as illustrated, a right-facing light source could illuminate the environment with structuredlight pattern654, which could include a checkerboard pattern. Furthermore, a front-facing light source could illuminate the environment with structuredlight pattern652.
• Other scenarios are possible as well. Thus, the present methods and systems may facilitate autonomous operation and/or accidence avoidance for a vehicle such as thevehicle300 by utilizing one or more ToF sensors in combination with light sources that are configured to illuminate the environment with structured light patterns.
• Systems and methods described herein may involve prior information about the environment. Such prior information could include a high-fidelity three-dimensional model of the local environment of a vehicle and/or within a scene of the ToF sensor. In such scenarios, the prior information could reside, at least in part, at the vehicle and/or at a central or regional server.
• In some embodiments, the prior information may be utilized in combination with the ToF information/depth map to better calibrate the sensors and/or to better localize the vehicle. That is, a comparison between the prior information and at least one depth map could help determine intrinsic and extrinsic characteristics of the ToF sensor. In such scenarios, the determined intrinsic and/or extrinsic characteristics could be used to calibrate the ToF sensor. Additionally or alternatively, a comparison between the prior information and the at least one depth map could include aligning or registering the prior information with the at least one depth map. In so doing, the alignment/registration process could help determine a more-accurate absolute position, heading, speed, or other characteristics of the vehicle and/or other aspects of its environment. In other words, the prior information could be utilized in conjunction with the at least depth map to provide more accurate information about the vehicle than the sensor information taken alone. In such scenarios, the prior information could represent a reference frame within which the vehicle could be localized.
• FIG. 7 illustrates amethod700, according to an example embodiment. Blocks and/or elements ofmethod700 could be similar or identical to corresponding elements ofmethods500 or600, as illustrated and described in reference toFIGS. 5 and 6
• Block702 includes providing prior information, which includes three-dimensional information of a scene. The prior information could include, for example, image, ToF, and/or LIDAR data obtained previously. Prior information could additionally or alternatively include a map, a point cloud, or depth map, or other types of information.
• Block704 includes causing at least one light source to illuminate the scene with a structured light pattern. The structured light pattern could be similar or identical to other structured light patterns described herein.
• Block706 includes causing the at least one ToF sensor to provide time of flight information indicative of a depth map of the scene based on the structured light pattern. As described herein, the ToF sensor could be operated while illuminating the scene with the structured light pattern. Doing so may provide more detailed information about the depth of objects in the scene.
• Additionally or alternatively, the prior information could be utilized to improve depth estimation. In such a scenario, the prior information could be projected into the depth map(s). Various methods (e.g., ray tracing, Principle Components Ordination (PCoA), Non-metric Multidimensional Scaling (NMDS), or other methods) could be used to perform the projection of three-dimensional prior information onto the depth map, each of which are contemplated herein. By projecting the prior information into the depth map, depth information could double-checked, calibrated, verified, and/or estimated more accurately.
• Yet further, the prior information could be utilized to perform background subtraction. In such a scenario, the prior information could include information about objects that are outside a relevant sensor depth (e.g., far away from the vehicle). In such situations, depth map information corresponding to objects that are outside the relevant sensor depth could be ignored, discounted, deleted, and/or processed at a lower resolution than other, more relevant, regions of the environment.
• Additionally, the prior information could be used, at least in part, to determine where retroreflective objects may be within a given environment. When a vehicle (and its ToF imaging system(s)) enter such an environment, it can adjust operation of the system so as to mitigate the effects of the retroreflective objects. For instance, the system could illuminate the environment corresponding to a known retroreflective object at a lower intensity level as compared to other regions of the environment. In such a scenario, the hybrid imaging system can avoid “blooming” or “blinding” effects that can occur due to retroreflective objects. Additionally or alternatively, the hybrid imaging system may operate at a different modulation frequency and/or illuminate the illumination source at a different rate. Other ways to mitigate the effects of retroreflectors are possible and contemplated herein.
• In some embodiments, a plurality of frames/scans from the ToF sensor could be utilized to obtain information about the scene, which could be utilized together with other information described in the present disclosure. For example, “optical flow” can be obtained by a pattern of apparent motion of an object between two consecutive ToF frames. The optical flow could include, for example, a two-dimensional vector field that includes the displacement of corresponding objects in the scene between a first ToF frame and a second ToF frame. Based on the optical flow, distances to the objects can be inferred and/or predicted. Such distance information from the optical flow could be utilized to constrain the range of depths estimated using ToF information. That is, the optical flow could provide further information about ranges of objects in a given scene. The rough depth information could be used to determine operating parameters for the ToF sensor and/or the illumination source. Additionally or alternatively, the rough depth information could be used to bound or constrain a set of operating parameters used by the system more generally.
• 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.
• The computer readable medium can also include non-transitory computer readable media such as computer-readable media that store data for short periods of time like register memory, processor cache, and random access memory (RAM). The computer readable media can also include non-transitory computer readable media that store program code and/or data for longer periods of time. Thus, the computer readable media may include secondary or persistent long term storage, like read only memory (ROM), optical or magnetic disks, compact-disc read only memory (CD-ROM), for example. The computer readable media can also be any other volatile or non-volatile storage systems. A computer readable medium can be considered a computer readable storage medium, for example, or a tangible storage device.
• While various examples and embodiments have been disclosed, other examples and embodiments will be apparent to those skilled in the art. The various disclosed examples and embodiments are for purposes of illustration and are not intended to be limiting, with the true scope being indicated by the following claims.

Claims (20)

What is claimed is:

1. A sensor system comprising:

at least one time-of-flight (ToF) sensor configured to receive light from a scene;

at least one light source configured to emit a structured light pattern; and

a controller that carries out operations, the operations comprising:

dynamically adjusting the structured light pattern based on one or more retroreflective regions in the scene;

causing the at least one light source to illuminate at least a portion of the scene with the structured light pattern; and

causing the at least one ToF sensor to provide time of flight information indicative of a depth map of the scene based on the structured light pattern.

2. The sensor system ofclaim 1, wherein dynamically adjusting the structured light pattern comprises lowering illumination levels for portions of the scene where the one or more retroreflector regions are present.

3. The sensor system ofclaim 1, wherein the at least one ToF sensor comprises a plurality of complementary metal-oxide semiconductor (CMOS) or charge-coupled device (CCD) photosensitive elements.

4. The sensor system ofclaim 1, wherein the structured light pattern comprises at least one of: a predetermined spatial distribution of light, a predetermined temporal distribution of light, or a predetermined spectral distribution of light.

5. The sensor system ofclaim 1, wherein the structured light pattern comprises at least one of: a predetermined light pulse repetition rate, a predetermined light pulse duration, a predetermined light pulse intensity, or a predetermined light pulse duty cycle.

6. The sensor system ofclaim 1, wherein the at least one light source comprises at least one of: a laser diode, a light-emitting diode, a plasma light source, a strobe light, a solid-state laser, or a fiber laser.

7. The sensor system ofclaim 1, wherein dynamically adjusting the structured light pattern comprises selecting a desired structured light pattern from among a plurality of possible structured light patterns, wherein causing the at least one light source to illuminate at least a portion of the scene with the structured light pattern comprises illuminating the portion of the scene according to the desired structured light pattern.

8. The sensor system ofclaim 1, further comprising an imaging sensor, wherein the imaging sensor comprises a plurality of photosensitive elements, wherein the plurality of photosensitive elements comprises at least one million photosensitive elements, wherein the operations further comprise causing the imaging sensor to provide information indicative of an image of the scene based on the structured light pattern.

9. The sensor system ofclaim 8, wherein the operations further comprise determining a high-resolution depth map of the scene based on the depth map of the scene and the image of the scene.

10. The sensor system ofclaim 8, wherein the at least one ToF sensor, the imaging sensor, and the at least one light source are coupled to a common substrate.

11. The sensor system ofclaim 1, wherein the operations further comprise determining at least one inference about the scene based on the depth map of the scene.

12. The sensor system ofclaim 11, wherein the at least one inference comprises information about objects in an environment of a vehicle or an operating context of the vehicle.

13. The sensor system ofclaim 11, wherein the controller comprises at least one deep neural network, wherein the determining the at least one inference is performed by the at least one deep neural network.

14. A system comprising:

a plurality of sensor systems configured to be coupled to a vehicle, wherein each sensor system comprises:

at least one time-of-flight (ToF) sensor;

at least one imaging sensor, wherein the at least one ToF sensor and the at least one imaging sensor are configured to receive light from a scene;

at least one light source configured to emit a structured light pattern; and

a controller that carries out operations, the operations comprising:

dynamically adjusting the structured light pattern based on one or more retroreflective regions in the scene;

causing the at least one light source to illuminate at least a portion of the scene with the structured light pattern;

causing the at least one ToF sensor to provide time of flight information indicative of a depth map of the scene based on the structured light pattern; and

causing the imaging sensor to provide information indicative of an image of the scene based on the structured light pattern.

15. The system ofclaim 14, wherein the operations further comprise determining a high-resolution depth map of the scene based on the depth map of the scene and the image of the scene.

16. The system ofclaim 14, wherein at least one of the sensor systems comprises at least one ToF sensor and at least one imaging sensor in a common housing.

17. A method comprising:

dynamically adjusting a structured light pattern based on one or more retroreflective regions in a scene;

causing at least one light source to illuminate the scene with the structured light pattern;

receiving, from a time-of-flight (ToF) sensor, time of flight information about the scene based on the structured light pattern;

determining a depth map of the scene based on the received information; and

determining at least one inference about the scene based on the depth map of the scene.

18. The method ofclaim 17, wherein the at least one inference comprises information about objects in an environment of a vehicle or an operating context of the vehicle.

19. The method ofclaim 17, wherein dynamically adjusting the structured light pattern comprises selecting a desired structured light pattern from among a plurality of possible structured light patterns, wherein causing the at least one light source to illuminate the scene with the structured light pattern comprises illuminating the scene according to the desired structured light pattern.

20. The method ofclaim 17, wherein dynamically adjusting the structured light pattern further comprises adjusting the structured light pattern based on an amount of ambient light or a time of day.

Images