Patent Description:
<CIT> discloses an autonomous guidance system that operates a vehicle in an autonomous mode. The system includes a camera module, a radar module, and a controller. The camera module outputs an image signal indicative of an image of an object in an area about a vehicle. The radar module outputs a reflection signal indicative of a reflected signal reflected by the object. The controller determines an object-location of the object on a map of the area based on a vehicle-location of the vehicle on the map, the image signal, and the reflection signal. The controller classifies the object as small when a magnitude of the reflection signal associated with the object is less than a signal-threshold.

<CIT> discloses an adaptive ladar receiver and associated method whereby the active pixels in a photodetector array used for reception of ladar pulse returns can be adaptively controlled based at least in part on where the ladar pulses were targeted.

<CIT> relates to a sensor device for a driver assistance system of a vehicle with at least two sensors. The two sensors are arranged at and aligned with the rear region of the same vehicle and such that the detection regions of the two sensors overlap at least partially.

<CIT> discloses a vehicle surroundings recognition system. The vehicle comprises a front radar sensor and a blind spot radar sensor that operate synchronously in overlapping areas. Both sensors are arranged at the same vehicle.

It is an object of the present invention to provide an improved guiding system for guiding an autonomous movable object and a method for guiding an autonomous movable object. Autonomous movable objects may be autonomous road vehicles, autonomous unmanned aerial vehicles and the like. The claimed subject matter is defined by the independent claims.

The guiding system according to the claimed invention comprises a time-of-flight imaging system. The imaging system comprises a first light source. The first light source is arranged to illuminate a first field of detection. The imaging system comprises at least one light sensor. The at least one light sensor is arranged to detect reflected light. The detected reflected light comprises first reflected light and second reflected light. The first reflected light comprises light emitted by the first light source reflected at the first field of detection. The second reflected light originates from a second field of detection illuminated by a second light source. The second light source is independent from the first light source. The second light source is a light source coupled to a different movable object especially a different autonomous movable object. The imaging system is arranged to differentiate between the first reflected light and the second reflected light. The imaging system is arranged to determine a depth map of the first field of detection based on the detected first reflected light. The imaging system is arranged to generate a feedback signal for triggering a feedback action based on (in response to and/or indicative of) the detected second reflected light. The depth map is calculated based on the time-of-flight measurements performed. The time-of-flight measurements are performed by recording a time of emission of the light emitted by the first light source to the first field of detection, and the time of detection of light by means of the at least one light sensor, wherein the detected light is emitted by the first light source and reflected by an object in the first field of detection.

The light sensor may be arranged to provide a nonlinear response upon detection of the received light. The nonlinear response may enable detection of very low optical intensities resulting from the received light. The light sensor may, for example, comprise one or more (e.g. array) single photon avalanche diodes (SPAD) which are well-suited to detect time-of-flight signals.

The first light source may comprise a single light emitter in a scanning arrangement. The first light source may alternatively or in addition comprise a multitude of light emitters (array arrangement) which are arranged to emit light to the first field of detection. The first light source may comprise one or more optical devices (e.g. lenses and the like) to illuminate the first field of detection.

The imaging system may improve performance of detection by taking into account that determination of the depth map may be affected by, for example, other light-emitting autonomous movable objects especially autonomous vehicles within detection range. Existing solutions for the removal of, for example, noise may be complex and do not actively respond to the imaging behavior of other vehicles. These systems also fail to take advantage of the information that can be obtained from the light reflections created by other vehicles, which can be used for various purposes including imaging, scanning, mapping, route planning and navigation as further described below.

The field-of-view of the light sensor may, for example, be more extended as the first field of detection. The light sensor may in this case detect light reflected from the first field of detection and neighboring areas which are not illuminated by the first light source. This may enable detection of a second reflected light prior to an overlap. The corresponding feedback signal may in this case be generated prior to an interaction and a potential disturbance caused by light emitted by the second light source.

The light sensor of the imaging system may comprise at least a first light sensing device and a second light sensing device, wherein the first light sensing device is arranged to detect the first reflected light and wherein the second light sensing device is arranged to detect the second reflected light. The first light sensing device is arranged to detect self-induced illumination. The second light sensing device is arranged to detect externally-induced illumination. The first and the second light sensing device may have different fields of detection, different spectral sensitivity, or some other detection parameter. The imaging system may optionally comprise two, three, four or more light sensing devices.

The second reflected light may comprise light emitted by a time-of-flight detection system. The imaging system is arranged to identify light originating from the time-of-flight detection system based on the detected second reflected light. The feedback signal is adapted in accordance with the detected light emitted by the time-of-flight detection system. Light emitted by the time-of-flight detection system may, for example be identified based on the short pulse length and other characteristic imaging parameters. The feedback signal may comprise information about the detection pattern and optionally information to adapt the detection pattern of the time-of-flight detection system. The time-of-flight detection system may optionally be an imaging system as described above and below.

The imaging system may be arranged such that the second reflected light is received from an overlap of the first field of detection and the second field of detection. Light received from an overlap of the first field of detection and the second field of detection indicates that a second autonomous movable object (e.g. autonomous car) may scan or observe at least a part of the first field of detection. Knowledge about this overlap enables a multitude of feedback signals and corresponding reactions.

The imaging system may, for example, be arranged to modify the first field of detection based on the feedback signal. The imaging system may especially be arranged to modify the first field of detection such that the overlap between the first field of detection and the second field of detection is reduced if the second light is emitted by a time-of-flight detection system. Decreasing the overlap may reduce disturbance caused by the time-of-flight detection system.

The imaging system may alternatively or in addition be arranged to modify an emission wavelength of the first light source. The emission wavelength may be changed in order to reduce cross talk with the second light source. The first light source may comprise a tunable light emitter or groups of light emitters which are characterized by different emission wavelengths. The light sensor may be tunable (e.g. tunable filter) in accordance with the emission wavelength of the first light source. The light sensor may alternatively comprise light sensing devices which are sensitive in different wavelength ranges. The light sensing device or devices comprised by the light sensor may be selected depending on the emission wavelength of the first light source.

The imaging system may be arranged to modulate the light source to integrate an optical information signal in the first field of detection in reaction to the detected second reflected light. The optical information may, for example, comprise an information about time of emission, position at time of emission, velocity, intended driving direction etc. The information may in a simple embodiment be a sign like an arrow. The information may alternatively or in addition comprise coded information (pulse pattern) which can be detected by means of a second imaging system comprised by a second (optionally autonomous) movable object.

The imaging system may comprise or be coupled with a communication module. The communication module is arranged to establish a communication channel in reaction to the detected second reflected light to exchange information data related to the detected second reflected light. The communication channel is independent from the first light source. The communication channel may be based on any suitable communication technology (radio frequency based communication, optical communication and the like). Exchange of information related to the detected second reflected light may enable interaction of the imaging system with, for example, a time-of-flight detection or imaging system of a second, third or fourth (autonomous) movable objects as, for example, autonomous road vehicle.

The imaging system may, for example, be arranged to modify the first field of detection based on information data received via the communication channel. The imaging system may (optionally in corporation with a system of an autonomous movable object comprising the imaging system) be arranged to adapt the first field of detection in accordance with a corresponding adaption of a field of detection of, for example, a vehicle being in communication with the imaging system. Two vehicles may, for example, adapt the corresponding field of detections in order to suppress cross talk. The imaging system may be further arranged to exchange data describing a surrounding of the, for example, vehicle (e.g. time-of-flight measurement data, part of the depth map etc.). The imaging system may therefore share information and optionally also receive information via the other communication channel to improve knowledge about the surrounding of the autonomous movable object. The imaging system may further be arranged to exchange driving data comprising information about the intended moving or driving direction, intended acceleration, intended break events and the like. Detection of the second reflected light enables verification of the information source. The source of the second reflected light has to be nearby to the autonomous movable object comprising the imaging system. Furthermore, information may be integrated in the second reflected light in order to verify a communication partner which is contacted via the communication channel. An authentication code may be exchanged via the received second reflected light to authenticate the autonomous mobile object comprising the imaging system. The data or information exchanged by means of the communication channel may be further used (especially in combination with the second reflected light) to verify driving or more generally information related to movements received from other information sources.

The first light source comprises at least one laser. The at least one laser may preferably be a semiconductor-based laser like, for example, an edge emitting laser or a VCSEL or VCSEL array. Especially VCSEL arrays may be well suited to enable a cost-effective imaging system. The at least one laser may be arranged to illuminate the first field of detection with infrared laser light. The wavelength range of the infrared laser light may be, for example, between <NUM> and <NUM>. The first reflected light and the second reflected light may be in the same wavelength range.

According to the claimed invention a guiding system for guiding the autonomous movable object is provided. The guiding system comprises the imaging system according to anyone of the embodiments described above. The guiding system further comprises a motion control module. The motion control module is arranged to receive the feedback signal (based on or indicative of the second detected light). The motion control module is arranged to modify a motion of the autonomous movable object based on the feedback signal. The motion control system may use the feedback signal to trigger a feedback action. The feedback action may, for example, be an adaption of a driving direction. The driving direction may be adapted in order to reduce cross talk with another time-of-flight detection system and/or to increase security. Adapting a driving direction may comprise adapting a velocity of the autonomous movable object. An autonomous movable object may refer to a fully autonomous movable object or a partially autonomous movable object, for example a vehicle providing driver assistance such as assisted steering and/or (emergency) braking. For example, the guiding system may adapt the driving detection to perform collision avoidance or collision mitigation based on detection of the second detected light. For example, the second detected light may originate from a second time-of-flight imaging system of a second vehicle.

According to the claimed invention a first system comprising a first autonomous movable object and a second autonomous movable object is provided. Each of the first and the second autonomous movable object comprises an imaging system according to any embodiment described above or a guiding system. The first autonomous movable object and the second autonomous movable object are arranged to exchange data in reaction to the feedback signal. The first autonomous movable object or the second autonomous movable object is/are arranged to modify a corresponding field of detection, or to modify a motion of the first autonomous movable object or the second autonomous movable object, or to take into account data of a depth map determined by the other autonomous movable object in reaction to the exchanged data. The data which may be generated by the first of the second autonomous movable object may be exchanged via the field of detection or by means of a separate communication channel as described above. The communication module may be part of the imaging system or the guiding system or a separate communication module in communication with the imaging system or guiding system. The data may optionally comprise information which of the first or the second autonomous movable object may act as master and which as a slave.

According to the claimed invention a second system is provided. The second system comprises a multitude of autonomous movable objects. Each of the autonomous movable objects comprises a guiding system described above. Each of the autonomous movable objects is arranged to modify the motion of the respective autonomous movable object in reaction to the feedback signal generated upon detection of at least one field of detection of another autonomous movable object. There may be two, three, four or more fields of detection of two, three, four or more other autonomous movable objects. The second system may be arranged to enable a swarm behavior of the multitude of autonomous movable objects. Swarm behavior may be advantageous with respect to autonomous road vehicles but especially with respect to unmanned aerial vehicles.

According to the claimed invention a method of guiding an autonomous movable object is provided. The method comprises the steps of:.

According to the claimed invention a computer program product is provided. The computer program product comprises code means which can be saved on at least one memory device of the imaging system in accordance with any embodiment discussed above or on at least one memory device of a device comprising the imaging system. The code means are arranged such that the method presented above can be executed by means of at least one processing device of the imaging system or by means of at least one processing device of the device comprising the imaging system.

The memory device or the processing device may be comprised by the imaging system (e.g. electrical driver, evaluator etc.) or the device comprising the time-of-flight depth camera. A first memory device and/or first processing device of the device comprising the imaging system may interact with a second memory device and/or second processing device comprised by the imaging system.

The memory device or devices may be any physical device being arranged to store information, especially digital information. The memory device may be selected out of the group solid-state memory or optical memory.

The processing device or devices may be any physical device being arranged to perform data processing, especially processing of digital data. The processing device may be selected out of the group processor, microprocessor or application-specific integrated circuit (ASIC).

It shall be understood that the imaging system according to any embodiment described above and the method of guiding an autonomous movable object have similar and/or identical embodiments, in particular, as described by means of the difference embodiments above and as defined in the dependent claims.

It shall be understood that a preferred embodiment of the invention can also be any combination of the dependent claims with the respective independent claim.

Further advantageous embodiments are defined below.

The invention will now be described, by way of example, based on embodiments with reference to the accompanying drawings.

In the Figures, like numbers refer to like objects throughout. Objects in the Figures are not necessarily drawn to scale.

Various embodiments of the invention will now be described by means of the Figures.

<FIG> shows a principal sketch of a first autonomous vehicle <NUM> comprising an imaging system <NUM> according to a first embodiment. The imaging system <NUM> comprises a light source (an array of VCSELs which is not shown) which is arranged to project a pattern of laser beams to a first field of detection <NUM>. The imaging system <NUM> further comprises a light sensor which comprises a first light sensing device (SPAD array which is not shown) which is arranged to detect laser light reflected from the first field of detection <NUM>. The detection signal is generated by means of the SPAD array are processed by means of the imaging system <NUM> to determine distances to objects in the first field of detection <NUM> based on time-of-flight measurements. The imaging system <NUM> determines a depth map of the first field of detection <NUM> based on the time-of-flight measurements. The optical sensor further comprises a second light sensing device. The second light sensing device detects light which is reflected from a field of observation <NUM>. The field of observation <NUM> comprises in this embodiment the first field of detection <NUM>. The second light sensing device comprises an array of photo diodes which are arranged to generate electrical signals in reaction to light received from the field of observation <NUM>. The imaging device <NUM> is further arranged to process the generated electrical signals to determine whether the light received from the field of observation <NUM> comprises light projected by means of a second vehicle to a second field of detection (not shown) which overlaps with the field of observation <NUM>. The imaging system <NUM> generates a feedback signal in reaction to the detection of light emitted by a second vehicle. The feedback signal is used to trigger feedback actions. Several examples of feedback actions are discussed with respect to <FIG>.

<FIG> shows a principal sketch of a first and a second autonomous vehicle according to a second embodiment. The first vehicle <NUM> comprises an imaging system <NUM> similar as discussed with respect to <FIG>. A first field of detection <NUM> coincides in this embodiment with a field of observation. The imaging system <NUM> comprises a VCSEL array which is arranged to emit laser beams to the first field of detection <NUM>. The light sensor comprises in this embodiment one SPAD array which is arranged to detect first reflected light and second reflective light. The imaging system <NUM> is arranged to read out the SPAD array in a first time period to detect the first reflected light comprising reflected laser light emitted by the VCSEL array. The measurement data is used to determine a depth map of (a part) of the surrounding the first vehicle <NUM>. The imaging system <NUM> is further arranged to read out the SPAD array in a second time period to detect second reflected light. The second reflected light results from the light which is emitted by a second vehicle <NUM> which may comprise a similar imaging system as discussed with respect to the first vehicle. The second vehicle emits light to a second field of detection <NUM> which overlaps with the first field of detection <NUM> in overlap region or field <NUM>'. The imaging system <NUM> of the first vehicle detects reflected light from the overlap region <NUM>' in the second time period. The imaging system <NUM> is arranged to determine that the second reflected light which is caused by light emitted by the second vehicle does not comprise any reflected light originating from the VCSEL array. The differentiation may, for example, be performed by choosing a duration between a time of emission of laser light emitted by the VCSEL array and the starting time of the second time period sufficiently long such that it is essentially impossible that the second reflected light comprises reflected laser light emitted by the VCSEL array. The imaging system <NUM> generates a feedback signal in reaction to the second reflected light originating from the light emitted by the second vehicle to the second field of detection <NUM>. The feedback signal may be used to trigger a feedback action as, for example, described with respect to <FIG> or <FIG>.

<FIG> shows a principal sketch of a first system comprising first autonomous vehicle <NUM> comprising an imaging system <NUM> according to a third embodiment and a second autonomous vehicle <NUM> comprising an imaging system (not shown). The first vehicle <NUM> comprises a guiding system <NUM>. The guiding system <NUM> comprises the imaging system <NUM> and a motion control module <NUM> which is arranged to communicate with the imaging system <NUM>. The imaging system <NUM> comprises an imaging parameters control module <NUM> that sets the imaging parameters <NUM>, e.g. the pulse modulation frequency, the illumination direction, the scanning rotation speed, etc.. The imaging system <NUM> further comprises a first light source <NUM> which is arranged to emit light to a first field of detection <NUM>. The emissions of the first light source <NUM> are controlled to produce pulses, bursts or flashes as required. The light emitted to the first field of detection <NUM> reflects from the various surfaces surrounding the first vehicle <NUM>. The imaging system <NUM> further comprises a light sensor <NUM> which is arranged to detect light emissions from the first light source that are reflected back to the first vehicle <NUM>. The light sensor <NUM> may be arranged to calculate depth information using the principles of time-of-flight, whereby the flight time of the emitted and reflected light indicates the distance that light has travelled. Information or measurement data obtained by the light sensor <NUM> may be used to determine the distance separating the first vehicle <NUM> and another object, locate an object in the surrounding environment, or to build a point cloud of that environment for navigation. The light sensor <NUM> communicates light sensor data <NUM> to an illumination analysis module <NUM>. The light sensor <NUM> is further arranged to detect light reflections created by an active light source of at least one additional imaging system. A second vehicle <NUM> comprises one additional imaging system (not shown) which is arranged to emit light for time-of-flight measurements to a second field of detection <NUM>. The second field of detection <NUM> overlaps with the first field of detection <NUM> in an overlap region <NUM>' similar as discussed with respect to <FIG>. Detection of second reflected light by means of light sensor <NUM> may be achieved through a dual-capability light sensor <NUM>. Alternatively, different types of light sensors may be used for separately detecting emissions from the first vehicle <NUM> and for detecting emissions from the second vehicle <NUM>, e.g. using wide field-of-view or single pixel sensors. An illumination analysis algorithm comprised by an illumination analysis module <NUM> receives the light sensor data <NUM> from the light sensor <NUM> and the imaging parameters <NUM> from the imaging parameters control module <NUM>, and uses this data to identify the components of the light sensor data <NUM> resulting from:.

A mapping module <NUM> is arranged to receive self-induced illumination data <NUM> from the illumination analysis module <NUM> and uses it to create and augment a map of the surrounding environment. The mapping module <NUM> receives the self-induced illumination data <NUM> containing time-of-flight measurements generated by the first vehicle <NUM>. The mapping module <NUM> uses the time-of-flight data to generate spatial information ('spatial data <NUM>') on the surrounding environment, indicating the locations of objects within detection range of the light sensor <NUM> illuminated by the first light source <NUM>. A map database <NUM> is arranged to receive and store spatial data <NUM> received from the mapping module <NUM>. The spatial data <NUM> is incorporated into or combined with any existing data on the surrounding area held in the map database <NUM>. The map database <NUM> may in an alternative embodiment be a cloud-based storage location that can receive spatial data <NUM> from all vehicles comprising detection systems which can provide spatial data <NUM> (especially LIDAR enabled autonomous vehicles). The map database <NUM> may be populated as LIDAR-enabled autonomous vehicles travel through new locations. Gaps in the map database <NUM> may be filled collaboratively, by, for example, initiating a request to another vehicle which already possesses the relevant spatial data <NUM> minimizing unnecessary scanning or distributing the scanning load between two or more autonomous vehicles travelling through the area and sharing the spatial data <NUM> for increased scanning efficiency. The imaging system <NUM> further comprises a subsystem ('feedback module <NUM>') that receives the externally-induced illumination data <NUM> from the illumination analysis module <NUM>. The externally-induced illumination data <NUM> is used to generate a feedback signal which may trigger a number of feedback actions. The externally-induced illumination data <NUM> may, for example, indicate the scanning behavior of the second vehicle <NUM> (or other vehicles), providing information such as:.

The feedback module <NUM> receives and analyses the externally-induced illumination data <NUM>. This analysis may enable a range of actions designed to enhance or alter the performance or behavior of the first vehicle <NUM> or its various components. The analysis and subsequent action may be conducted via two or more subsystems, which may include a component that takes the externally-induced illumination data <NUM> as input and extracts one or more relevant parameters from the data. The feedback module <NUM> may further comprise a component that receives the extracted relevant parameters and triggering or enacting one or more actions or behaviors in the first vehicle <NUM>.

The feedback module <NUM> may, for example, provide imaging parameters feedback data <NUM> to imaging parameters control module <NUM>. The imaging parameters <NUM> prepared by the imaging parameters control module <NUM> may be adapted by means of the imaging parameters feedback data <NUM>. The imaging parameters control module <NUM> of the first vehicle may adjust the imaging parameters <NUM> to optimize the mapping behavior of the first vehicle <NUM>. This may include:.

The feedback module <NUM> may be further arranged to initiate data communication to the second vehicle <NUM> (or other vehicles) such that transmitted data <NUM> may be received by the second vehicle <NUM> or the cloud via a communication module comprised by the first vehicle <NUM> (not shown). Collaborative scanning between the first vehicle <NUM> and the second vehicle <NUM> may be achieved via control by means of a communication module. Collaborative actions may include:.

The feedback module <NUM> may further enable predictive driving assistance. Information obtained from a second vehicle <NUM> may be used to predict its behavior and enact certain actions in response. Information may indicate:.

Feedback information provided by the feedback module <NUM> may further be used to inform the driver of the first vehicle <NUM>. Furthermore, safety margins may be adapted with respect to distances between, for example, the first vehicle <NUM> and the second vehicle <NUM>. The feedback module <NUM> may further provide motion control feedback data <NUM> which is transmitted to motion control module <NUM>. The motion control module <NUM> may change motion parameters of the first vehicle <NUM> in reaction to the reception of the motion control feedback data <NUM>. Current or planned movement of the first vehicle <NUM>, including its speed, trajectory and braking behavior may be changed in reaction to the motion control feedback data <NUM>.

The second vehicle <NUM> comprises an imaging system (not shown) which may be arranged in accordance with the description of the imaging system <NUM> comprised by the first vehicle <NUM> provided above.

<FIG> shows a principal sketch of a first autonomous vehicle <NUM> and a second autonomous vehicle <NUM>. The first vehicle comprises an imaging system <NUM> according to a fourth embodiment. The starting situation may be similar as discussed with respect to <FIG>. The imaging system <NUM> provides feedback data upon detection of light emitted by the second vehicle to overlap region <NUM>' such that a communication module of the first vehicle <NUM> opens a communication channel to a communication module of the second vehicle <NUM>. The first and the second vehicle <NUM>, <NUM> transmit data <NUM> via the communication channel. The first vehicle <NUM> or more precisely the imaging system <NUM> gets information with respect to the second field of detection <NUM> of the second vehicle <NUM> and information with respect to the motion of the second vehicle <NUM>. The imaging system <NUM> adapts the first field of detection <NUM> such that an overlap between the first field of detection and the second field of detection is minimized.

<FIG> shows a principal sketch of a first autonomous vehicle <NUM> and a second autonomous vehicle <NUM>, wherein the first vehicle comprises an imaging system <NUM> according to a fifth embodiment. The starting situation may be similar as discussed with respect to <FIG>. The imaging system <NUM> provides feedback data upon detection of light emitted by the second vehicle <NUM> to overlap region <NUM>' between the first field of detection <NUM> and the second field of detection <NUM> of the second vehicle <NUM>. The feedback data comprises motion control feedback data <NUM> as discussed with respect to <FIG> which is transferred to a guiding system <NUM>. The guiding system <NUM> changes a direction of movement of the first vehicle such that the overlap region <NUM>' is reduced without changing a size of the first field of detection <NUM>.

<FIG> shows a principal sketch of a first system according to a second embodiment comprising a first vehicle <NUM> and a second vehicle <NUM>. The first vehicle <NUM> and the second vehicle <NUM> each comprise an imaging system (not shown). Each imaging system is arranged to provide a first field of detection <NUM> or second field of detection <NUM>. The shape of the respective field of detection <NUM>, <NUM> is adapted based on spatial data available in the map database. The first vehicle <NUM> and the second vehicle <NUM> approach to a crossroad. The first field of detection <NUM> and the second field of detection <NUM> overlap in overlap region <NUM>'. The first vehicle <NUM> projects information signals which are comprised in the light emitted to the first field of detection <NUM>. The information signals comprise information with respect to the movement of the first vehicle <NUM>. The second vehicle detects the information which is visible in the overlap region <NUM>'. The second vehicle <NUM> projects a confirmation signal and additional information to the second field of detection <NUM>. The additional information may comprise information that the second vehicle <NUM> will stop before the second vehicle will reach the crossroad because passengers of the second vehicle <NUM> intend to leave the second vehicle <NUM>. The first vehicle <NUM> confirms reception and passes the crossroads without changing its velocity. The first vehicle <NUM> may optionally initiate communication with the second vehicle <NUM> via a separate wireless complication channel as discussed with respect to <FIG>.

<FIG> shows a principal sketch of a swarm of unmanned aerial vehicles <NUM>, <NUM>, <NUM>, <NUM> comprising imaging systems (not shown) according to a seventh embodiment. The light source and the light sensor form a time-of-flight based imaging system. The imaging system of a second unmanned aerial vehicle <NUM> sends out a light pulse to the ground to a second field of detection <NUM>, which then reflects and is captured by the corresponding light sensor. The captured light pulse is used, for example, to measure the distance-to-ground of the second unmanned aerial vehicle <NUM> to inspect the underlying terrain or vegetation, etc. Each of the unmanned aerial vehicles <NUM>, <NUM>, <NUM>, <NUM> comprises a corresponding field of detection <NUM>, <NUM>, <NUM>, <NUM>. The light sensors of or unmanned aerial vehicles <NUM>, <NUM>, <NUM>, <NUM> are characterized by a wide field-of-view to capture the light pulse reflections that are emitted by neighboring unmanned aerial vehicles. The light sensor of the second unmanned aerial vehicle <NUM> receives, for example, reflected light <NUM> originating from its own light source (second field of detection <NUM>) and from a first field of detection <NUM> of a first unmanned aerial vehicle <NUM> and a third field of detection <NUM> of a third unmanned aerial vehicle <NUM>. The capturing of the reflected light pulses emitted by the second unmanned aerial vehicle <NUM> may be used for various purposes, for example:.

The above use cases may especially be of interest in the following scenarios:.

<FIG> shows a principal sketch of a method of guiding an autonomous movable object. A first vehicle <NUM> emits light from its first light source in a predetermined pattern to the first field of detection <NUM> following the imaging parameters <NUM> set by the imaging parameters control module <NUM> (see <FIG>) in step <NUM>. The light illuminates the first field of detection <NUM> and is reflected from various surfaces at different spatial locations around the first vehicle <NUM>. In a nearby location, a second vehicle <NUM> is also emitting light at particular scanning settings. A light sensor <NUM> detects the light sensor data <NUM>, comprising the self-induced illumination data <NUM> (the reflected light emissions of the first vehicle <NUM>) and the externally-induced illumination data <NUM> (the light emitted by the light source of the second vehicle <NUM>) in step <NUM>. In a single light sensor system, the self-induced and externally-induced illumination data <NUM>, <NUM> are detected as a single information stream, to be extracted individually later in the process. In a two light sensor system, the self-induced and externally-induced illumination data <NUM>, <NUM> are detected separately as two distinct information streams. The light sensor <NUM> submits the light sensor data <NUM> to the illumination analysis module <NUM>, which identifies and extracts the self-induced illumination data <NUM> in step <NUM> and the externally-induced illumination data <NUM> in step <NUM>. The illumination analysis module <NUM> may determine various parameters of the received light sensor data <NUM>, such as direction, pulse frequency and light intensity. These parameters are then compared to the known imaging parameters <NUM> as set by the imaging parameters control module <NUM>. The light sensor data <NUM> is split into two datasets, where the first set has a high correlation (self-induced illumination data <NUM>) and the second a low correlation (externally-induced illumination data <NUM>) with the imaging parameters <NUM>. The illumination analysis module <NUM> sends the self-induced illumination data <NUM> to the mapping module <NUM>. The illumination analysis module <NUM> sends the externally-induced illumination data <NUM> to the feedback module <NUM>. The mapping module <NUM> analyses in step <NUM> the time-of-flight information contained in the self-induced illumination data <NUM>. The mapping module <NUM> uses the depth measurements described by the time-of-flight data to produce a depth map of the surrounding area that indicates environmental features associated with various spatial locations. The depth map is sent to the map database <NUM>, where it is combined and stored with any existing data on the scanned area. The feedback module <NUM> analyses in step <NUM> the externally-induced illumination data <NUM> to extract information that may be used to affect or enhance the behavior of the first vehicle <NUM>. The feedback module <NUM> uses the extracted information to trigger a desired action, which produces an output that may include performance optimization within vehicles and collaborative behavior between vehicles with regards to imaging, scanning, mapping, route planning, navigation and safety.

In the near future, LIDAR will overcome the cost-size-performance trade-off that is currently affecting its widespread integration especially into road vehicles. At this point, the number of LIDAR-equipped vehicles on our roads will increase, presenting a new problem: a larger number of LIDAR-emitting vehicles increases the probability of crosstalk affecting the ability of those vehicles to navigate accurately and safely.

At the same time, with the development of increased sensing capabilities of vehicles, other time-of-flight based sensing and imaging systems are expected to experience increased adaption in automotive applications.

By actively monitoring and reacting to the time-of-flight based sensing, ranging and imaging behaviors of other vehicles, the present invention enables, for example, a vehicle to modify its own active imaging settings to optimize information gathering for both itself and other vehicles. The real-time information obtained can also be combined with self-generated mapping data and used to autonomously trigger certain actions within the vehicle that can enhance its safety and performance.

The invention provides the following advantages:.

Claim 1:
A guiding system (<NUM>) for guiding an autonomous movable object (<NUM>), wherein the guiding system (<NUM>) comprises
a time-of-flight imaging system (<NUM>) comprising a first light source (<NUM>), wherein the first light source (<NUM>) is arranged to illuminate a first field of detection (<NUM>), wherein the imaging system (<NUM>) comprises at least one light sensor (<NUM>), wherein the light sensor (<NUM>) is arranged to detect reflected light (<NUM>), wherein the detected reflected light comprises first reflected light and second reflected light, wherein the first reflected light comprises light emitted by the first light source (<NUM>) reflected at the first field of detection (<NUM>), wherein the second reflected light originates from a second field of detection (<NUM>) illuminated by a second light source, wherein the second light source is independent from the first light source (<NUM>), wherein the second light source is a light source coupled to a different movable object (<NUM>), wherein the imaging system (<NUM>) is arranged to differentiate between the first reflected light and the second reflected light, wherein the imaging system (<NUM>) is arranged to determine a depth map of the first field of detection (<NUM>) based on the detected first reflected light, and wherein the imaging system (<NUM>) is arranged to generate a feedback signal for triggering a feedback action based on the detected second reflected light;
characterized in that
the guiding system further comprises a motion control module (<NUM>), wherein the motion control module (<NUM>) is arranged to receive the feedback signal, and wherein the motion control module (<NUM>) is arranged to modify a motion of the autonomous movable object based on the feedback signal.