WO2022167362A1 - Détection d'un changement de luminosité dans l'environnement d'un véhicule automobile - Google Patents

Détection d'un changement de luminosité dans l'environnement d'un véhicule automobile Download PDF

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Publication number
WO2022167362A1
WO2022167362A1 PCT/EP2022/052188 EP2022052188W WO2022167362A1 WO 2022167362 A1 WO2022167362 A1 WO 2022167362A1 EP 2022052188 W EP2022052188 W EP 2022052188W WO 2022167362 A1 WO2022167362 A1 WO 2022167362A1
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WO
WIPO (PCT)
Prior art keywords
detector
change
control unit
brightness
sensor system
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PCT/EP2022/052188
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German (de)
English (en)
Inventor
Marc Huber
Original Assignee
Valeo Schalter Und Sensoren Gmbh
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Publication of WO2022167362A1 publication Critical patent/WO2022167362A1/fr

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J1/00—Photometry, e.g. photographic exposure meter
    • G01J1/42—Photometry, e.g. photographic exposure meter using electric radiation detectors
    • G01J1/4204—Photometry, e.g. photographic exposure meter using electric radiation detectors with determination of ambient light
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
    • G01S17/02—Systems using the reflection of electromagnetic waves other than radio waves
    • G01S17/06—Systems determining position data of a target
    • G01S17/42—Simultaneous measurement of distance and other co-ordinates
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
    • G01S17/88—Lidar systems specially adapted for specific applications
    • G01S17/93—Lidar systems specially adapted for specific applications for anti-collision purposes
    • G01S17/931—Lidar systems specially adapted for specific applications for anti-collision purposes of land vehicles
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
    • G01S7/483—Details of pulse systems
    • G01S7/486—Receivers
    • G01S7/4861—Circuits for detection, sampling, integration or read-out
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
    • G01S7/483—Details of pulse systems
    • G01S7/486—Receivers
    • G01S7/4868—Controlling received signal intensity or exposure of sensor
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
    • G01S7/497—Means for monitoring or calibrating
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J1/00—Photometry, e.g. photographic exposure meter
    • G01J1/42—Photometry, e.g. photographic exposure meter using electric radiation detectors
    • G01J1/44—Electric circuits
    • G01J2001/4406—Plural ranges in circuit, e.g. switchable ranges; Adjusting sensitivity selecting gain values

Definitions

  • the present invention relates to a method for detecting an abrupt change in brightness in the area surrounding a motor vehicle, light from the area being detected by means of an optical detector and a detector signal being generated as a function of the detected light.
  • the invention also relates to a corresponding environment sensor system for a motor vehicle and a computer program product.
  • the document DE 10 2012 021 830 A1 describes a laser scanner for a motor vehicle that uses an avalanche photodetector as the optical detector.
  • a control device can regulate an electrical bias voltage of the avalanche photodetector during operation in such a way that the level of the noise remains constant. In this way it can be achieved that the laser scanner has the highest possible detector sensitivity under different environmental conditions.
  • the improved concept is based on the idea of determining the rate of change of the detector sensitivity and, depending on this, determining the presence of the abrupt change in brightness.
  • a method for detecting a change in brightness, in particular an abrupt change in brightness, in the surroundings of a motor vehicle is specified.
  • light from the environment is detected by means of an optical detector, in particular of the motor vehicle, or an environment sensor system of the motor vehicle, and a detector signal is generated as a function of the detected light.
  • a detector sensitivity of the detector is adjusted by means of a control unit, in particular of the environment sensor system, as a function of the detector signal, and a rate of change of the detector sensitivity is determined by means of the control unit.
  • the presence of the abrupt change in brightness as a function of the rate of change is determined by means of the control unit.
  • the determination of the abrupt change in brightness can include, for example, the control unit generating at least one output signal which indicates whether or not the change in brightness has taken place.
  • the at least one output signal can also indicate whether the change in brightness corresponds to a change from a dark to a light environment or vice versa.
  • An environment sensor system can generally be understood to mean a sensor system that is able to generate sensor data or sensor signals that depict, represent or reproduce an environment of the environment sensor system.
  • cameras, radar systems, lidar systems or ultrasonic sensor systems for example, can therefore be understood as environment sensor systems.
  • an optical detector is used.
  • Optical surroundings sensor systems are therefore possible as surroundings sensor systems, in particular lidar systems such as laser scanners.
  • the term “light” can be understood in such a way that it includes electromagnetic waves in the visible range, in the infrared range and/or in the ultraviolet range. Accordingly, the term “optical” can also be understood as referring to light according to this understanding.
  • the light which is detected from the environment by means of the optical detector is preferably infrared light, ie the optical detector is designed as an infrared-sensitive optical detector.
  • the light from the surroundings of the motor vehicle and thus the surroundings sensor system and the optical detector falls from the surroundings onto an active optical surface of the optical detector, so that it can be detected by the optical detector.
  • the detector signal can, for example, be proportional to the radiant power that impinges on the active optical surface.
  • the optical detector can be designed as a photodiode, in particular as an avalanche photodiode, also referred to as an APD. If the APD is operated in the reverse direction below its breakdown voltage, it represents an optical detector which has an output voltage proportional to the radiation power.
  • the detector signal is therefore generally a time-dependent signal. Accordingly, detector sensitivity, and ultimately the rate of change in detector sensitivity, can also be time dependent.
  • the detector sensitivity can be set as a function of the detector signal be designed differently.
  • the setting can be designed as a control or regulation.
  • the control unit can also have regulation functionality, that is to say represent or contain a regulation unit.
  • the adjustment can therefore include a regulation, for example in order to keep a noise level, a signal-to-noise ratio, SNR, or the like constant or within a certain predefined range.
  • the control unit can contain one or more sub-units, which may be spatially separate from one another.
  • part of the control unit can be implemented in an electronic control unit of the motor vehicle and another part of the control unit can be part of the surroundings sensor system.
  • the detector sensitivity is adjusted as a function of the detector signal and the detector signal in turn depends on the detected light, the detector sensitivity and thus the rate of change of the detector sensitivity are also dependent on the radiant power received from the environment by means of the optical detector. Accordingly, the rate of change in detector sensitivity indirectly represents a measure of the rate of change in ambient brightness.
  • an abrupt change in brightness for example, when the magnitude of the rate of change is greater than or equal to a predetermined limit value. For example, by comparing the rate of change or the amount of the rate of change with one or more such limit values, it can be determined whether or not there is an abrupt change in brightness defined in this way.
  • the sign of the rate of change also makes it possible to determine whether the brightness change takes place from a dark environment to a light environment, e.g. corresponds to exiting a tunnel, or from a light environment to a dark environment, e.g. corresponds to entering the tunnel .
  • component-dependent fluctuations can be partially compensated for by focusing on the rate of change of the detector sensitivity and not directly on the detector sensitivity.
  • the rate of change in detector sensitivity provides a more universal measure of change in ambient brightness than the absolute value of detector sensitivity.
  • the detector sensitivity can increase sharply, for example, to keep the SNR at a sufficiently high value and, depending on the design of the optical detector and the environment sensor system, reach a saturation value. The increase in detector sensitivity takes place within a number of seconds, for example.
  • the associated increase in the rate of change can already be seen after a shorter time, so that by taking into account the rate of change for determining the abrupt change in brightness, the presence of the abrupt change in brightness can be concluded more quickly than would be the case with the analysis of the detector sensitivity itself or the detector signal itself .
  • the rate of change is compared by the control unit in at least one comparison with at least one predefined limit value and the presence of the abrupt change in brightness is determined as a function of at least one result of the at least one comparison.
  • the rate of change can be compared in a first comparison using the control unit with a predefined positive first limit value and the presence of the abrupt change in brightness can be determined as a function of a result of the first comparison.
  • the rate of change can be compared in a second comparison by means of the control unit with a predetermined negative second limit value and the presence of the abrupt change in brightness can be determined depending on a result of the second comparison.
  • the presence of the abrupt change in brightness can be concluded if the rate of change is greater than or equal to the positive first limit value or if the rate of change is less than or equal to the negative second limit value.
  • the lower the ambient brightness the greater the detector sensitivity can be set in a specific value range. If the rate of change of the detector sensitivity is then greater than or equal to the first limit value, the detected change in brightness corresponds to a change from a bright environment to a dark environment. Conversely, the brightness change correspond to a change from a dark environment to a light environment if the rate of change is less than or equal to the negative second threshold.
  • the respective absolute values of the first and second limit values can be the same or different from one another.
  • the abrupt change in brightness is classified by the control unit as the motor vehicle entering a tunnel, depending on the result of the first comparison.
  • the abrupt change in brightness is classified by the control unit as entering a tunnel if, according to the first comparison, it is established that the rate of change is greater than or equal to the first limit value.
  • the abrupt change in brightness is classified by the control unit depending on the result of the second comparison as the motor vehicle exiting a tunnel.
  • the abrupt change in brightness is classified by the control unit as the motor vehicle exiting the tunnel if the rate of change according to the second comparison is less than or equal to the second limit value.
  • the output signal can be set accordingly or a corresponding flag can be set or the like.
  • an actual value for a parameter that relates to noise of the optical detector is determined by the control unit as a function of the detector signal, and the detector sensitivity is set, in particular by means of the control unit, as a function of the actual value, for example within the limits a regulation of the parameter.
  • the parameter relating to the noise of the optical detector can be regulated, for example, to a predetermined target value or target range in order to set the detector sensitivity.
  • the detector sensitivity depends on a manipulated variable for the regulation or corresponds to the manipulated variable. In other words, the detector sensitivity can be equal to the manipulated variable, the detector sensitivity can be a function of the manipulated variable, or the manipulated variable can be a function of the detector sensitivity.
  • the optical detector can contain a photodiode that can be operated in the reverse direction, for example an APD, and the manipulated variable can correspond to the blocking voltage or bias voltage for operating the photodiode in the reverse direction.
  • a photodiode that can be operated in the reverse direction
  • the manipulated variable can correspond to the blocking voltage or bias voltage for operating the photodiode in the reverse direction.
  • the parameter for setting the detector sensitivity is taken into account, it can be ensured in particular that the parameter, ie for example the SNR, is always at a desired value or in a desired range.
  • the characteristic value for the noise which can also be referred to as the noise level, can in principle be measured in any way.
  • the detector signal can be converted into a digital detector signal by means of an analog/digital converter, and the characteristic value can be measured on the basis of the digital detector signal.
  • the detector signal or the digital detector signal can be compared with one or more predefined threshold values, for example.
  • the control unit can then be used to determine how often the detector signal or the digital detector signal exceeds the threshold value or values within a predetermined period of time. These measurements can be carried out, for example, when it can be ruled out that light is incident on the optical detector, so that the influence of a dark current can be taken into account.
  • the number of times the threshold value is exceeded can also be determined for phases during which ambient light is detected by the optical detector, but no light that was emitted by the surroundings sensor system itself. Further details on the measurement of the noise characteristic can be found in the prior art document mentioned in the opening paragraph.
  • an angle of incidence of the detected light is determined, in particular by means of the control unit.
  • the rate of change of the detector sensitivity is not taken into account by the control unit in determining the presence of the abrupt change in brightness if the angle of incidence is within a predetermined angular range.
  • the angle of incidence can correspond to a horizontal angle of incidence, for example.
  • the angle of incidence can correspond, for example, to an angle in the xy plane, for example an azimuthal angle or, in other words, an angle that the incident light makes with the x-axis includes, wherein the x-axis is oriented parallel to a longitudinal axis of the motor vehicle.
  • the angle of incidence can be inferred, for example, via a current position of a deflection device for deflecting or deflecting the emitted and/or received laser pulses.
  • certain time periods are disregarded, for example.
  • Such specific embodiments prevent external interference, for example other motor vehicles driving ahead or oncoming, or their lighting, from affecting the reliability of the detection of the abrupt change in brightness.
  • This can be achieved in particular by selecting the predefined angular range, which is accordingly not taken into account, around the direction of travel or around the x-axis of the sensor coordinate system.
  • the control unit can still set the detector sensitivity as a function of the detector signal.
  • the angular range includes an interval [ -Wo , Wo], where Wo is a positive value for the angle of incidence and zero angle of incidence corresponds to light propagating in the opposite direction to a direction of travel of the motor vehicle.
  • the angular range is not necessarily identical to the interval [ ⁇ W o , W o ] and can in particular be larger than the interval and can also be asymmetrical if necessary.
  • the angular range is given by the interval [-W o - Di, W o + D 2 ], where Di and D 2 are both positive. Di and D 2 can be the same or different from one another.
  • an area of interest is defined that lies outside the specified angular range.
  • the area of interest corresponds to this in particular the part of the field of view of the environment sensor system or of the optical detector that does not overlap with the predetermined angular range.
  • the abrupt change in brightness when driving into or out of the tunnel becomes noticeable in a reliable manner, since, for example, light from other oncoming motor vehicles is not taken into account.
  • a disruptive influence of lighting devices on the ceiling of the tunnel can also be reduced by the selection of the area of interest.
  • an environment sensor system for a motor vehicle having an optical detector which is set up to detect light from an environment of the environment sensor system, in particular the motor vehicle, and to generate a detector signal based on the detected light.
  • the environment sensor system also has a control unit that is set up to set a detector sensitivity of the detector as a function of the detector signal.
  • the control unit is set up to determine a rate of change in the detector sensitivity and to determine the presence of an abrupt change in brightness as a function of the rate of change.
  • the environment sensor system is designed as a lidar system, in particular as a laser scanner.
  • the lidar system represents an active optical sensor system that has a transmission unit with a light source, in particular for the transmission of light or light pulses.
  • the light source can be designed in particular as a laser diode, for example as an infrared laser diode.
  • the lidar system has a receiving unit that contains the optical detector and optionally one or more further optical detectors. The optical detector is set up and designed to detect reflected portions of the emitted light.
  • the light can contain infrared light, for example with a wavelength of 905 nm, approximately 905 nm, 1200 nm or approximately 1200 nm.
  • the wavelength information can in each case designate a wavelength range with a broader distribution, which is typical for the corresponding light source.
  • the light source can be a laser light source, for example.
  • the wavelengths mentioned can correspond, for example, to peak wavelengths of the laser spectrum.
  • the lidar system can contain a deflection device, for example, which can contain a movable or rotatably mounted mirror, for example. Light pulses generated by the transmission unit can be deflected in a controlled manner by means of the deflection device.
  • the deflection device can have a mirror element that can be tilted and/or pivoted about one or about two axes for deflecting the light in the transmission plane.
  • the mirror element can be configured as a microelectromechanical system, MEMS, for example.
  • the longitudinal axis of the lidar system which defines an x-axis of the sensor coordinate system, for example, corresponds to an emission direction of the light beams at an emission angle of 0 degrees, ie for example when the deflection device is in a neutral position.
  • the deflection device can assume positions that deviate from the neutral position in order to deflect the light pulses so that the light pulses emerge from the sensor system within the transmission plane.
  • a transverse axis of the lidar system which, for example, defines a y-axis of the sensor coordinate system, lies within the transmission plane and is, for example, perpendicular to the longitudinal axis, which by design also lies within the transmission plane.
  • a normal axis of the lidar system is perpendicular to the longitudinal axis and to the transverse axis of the lidar system.
  • the normal axis of the lidar system defines a z-axis of the sensor coordinate system.
  • a viewing direction or transmission direction of the lidar system when the deflection device is in the neutral position is equal to the x-axis of the sensor coordinate system.
  • the transmit plane is given by the x-y plane of the sensor coordinate system.
  • the lidar system can emit the light with different emission angles within the transmission plane.
  • a longitudinal axis of the motor vehicle which in particular defines an x-axis of a vehicle coordinate system, is given, for example, by a direction of travel of the motor vehicle when a steering system of the motor vehicle is in the neutral position or at a steering angle, in particular a wheel angle or a steering wheel angle, of the motor vehicle of 0 degrees.
  • a transverse axis of the motor vehicle is perpendicular to the longitudinal axis of the motor vehicle and lies in a plane that is parallel to the roadway or parallel to a plane within which Support points of the wheels of the motor vehicle are on the road.
  • the transverse axis defines a y-axis of the vehicle coordinate system.
  • a normal axis of the motor vehicle which in particular defines a z-axis of the vehicle coordinate system, is perpendicular to the longitudinal axis and the transverse axis of the motor vehicle.
  • the coordinate axes of the sensor coordinate system can deviate from those of the vehicle coordinate system.
  • the axes of the sensor coordinate system are parallel to the axes of the vehicle coordinate system. If necessary, this can be effectively ensured by a corresponding calibration of the lidar system.
  • a distance measurement can be carried out by determining the light propagation time of a light pulse which is emitted, reflected in the area surrounding the lidar system and detected by the optical detector.
  • a direction of incidence of the detected light can be determined in particular from a position and/or orientation of the optical detector within the lidar system and a current position of the deflection device, in particular a rotational position of the mirror.
  • the rotational position of the mirror can be detected, for example, by means of a rotary encoder that is coupled to a shaft that rotates about the axis of rotation of the mirror together with the mirror.
  • the deflection device can be used, for example, not only to deflect the emitted light pulse within the transmission plane, but also to deflect the reflected light pulse in such a way that it is directed onto the optical detector.
  • the position of the optical detector defines a vertical angle of incidence or polar angle, and the position of the deflection device defines a horizontal angle of incidence or azimuthal angle.
  • a further deflection device can be provided, which is designed analogously to the deflection device, for example, in order to deflect the reflected light pulse and direct it onto the optical detector.
  • the optical detector has a photodiode that can be operated in the reverse direction.
  • the control unit is arranged to provide a blocking voltage for reverse bias operation of the photodiode and the detector sensitivity depends on the blocking voltage or corresponds to the blocking voltage.
  • the photodiode can be configured as an APD, for example.
  • the APD is operated in the reverse direction, in particular below its breakdown voltage. Accordingly, the gain of the APD is dependent on the blocking voltage and possibly dependent on the temperature. The blocking voltage thus affects the detector sensitivity directly.
  • the detector signal is approximately directly proportional to the optical radiation incident on the active surface of the APD.
  • control unit is set up to determine an actual value for a parameter relating to noise of the optical detector as a function of the detector signal and to set the detector sensitivity as a function of the actual value.
  • control unit is set up to regulate the parameter to a predetermined target value or target range, with the detector sensitivity depending on a manipulated variable for the regulation and in particular the blocking voltage serving as a manipulated variable for the regulation.
  • control unit is set up to compare the rate of change in at least one comparison with at least one predefined limit value and to determine the presence of the abrupt change in brightness depending on at least one result of the at least one comparison.
  • an environment sensor system according to the improved concept can be set up to carry out a method according to the improved concept or it carries out such a method.
  • a computer program with instructions is also provided according to the improved concept.
  • the commands are executed by a surroundings sensor system according to the improved concept, in particular by the control unit of the surroundings sensor system, the commands cause the surroundings sensor system to carry out a method according to the improved concept.
  • a computer-readable storage medium is also specified, which stores a computer program according to the improved concept.
  • the computer program and the computer-readable storage medium can each be regarded as computer program products with the instructions.
  • FIG. 1 shows a schematic representation of a motor vehicle with an exemplary embodiment of a surroundings sensor system according to the improved concept
  • FIG. 2 shows a schematic representation of a transmission unit of a further exemplary embodiment of a surroundings sensor system according to the improved concept
  • 3 shows a schematic representation of a receiving unit of a further exemplary embodiment of a surroundings sensor system according to the improved concept; 4 schematically shows the course of a blocking voltage as a function of temperature;
  • FIG. 6 shows a diagram of a rate of change in detector sensitivity as a function of time
  • FIG. 7 shows a schematic representation of a motor vehicle with a further exemplary embodiment of a surroundings sensor system according to the improved concept in a tunnel.
  • FIG. 1 shows a motor vehicle 1 with an exemplary embodiment of a surroundings sensor system 2 according to the improved concept.
  • the environment sensor system 2 is designed as a lidar system, in particular as a laser scanner.
  • Surroundings sensor system 2 has a transmission unit 5 with one or more laser light sources, in particular infrared laser diodes, in order to emit light pulses 7 at different emission angles within a transmission plane of surroundings sensor system 2 .
  • the transmission plane is defined in particular by the plane which is spanned by the longitudinal axis and a transverse axis of surroundings sensor system 2, ie in the present example of FIG. 1 is approximately parallel to the plane of the drawing.
  • the transverse axis and the longitudinal axis of the environment sensor system 2 can be viewed as parallel to the longitudinal axis or transverse axis of the motor vehicle 1 without loss of generality.
  • Surroundings sensor system 2 also has a control unit 3 and a receiving unit 4 with at least one optical detector 4a, 4b, 4c (see FIG. 3).
  • the control unit 3 is connected to the receiving unit 4 and to the transmitting unit 5, for example.
  • the control unit 3 can control the transmission unit 5 in order to emit the light pulses 7 .
  • the receiving unit 4 can detect reflected portions 7 ′ of the light pulses 7 , in particular reflected by an object 6 in the vicinity of the surroundings sensor system 2 , and based on this, generate at least one detector signal and transmit it to the control unit 3 .
  • the transmission unit 5 of the environment sensor system 2 is shown schematically. The upper image in Fig.
  • FIG. 2 corresponds, for example, to a viewing direction parallel to the transverse axis of environment sensor system 2 onto transmitter unit 5.
  • the lower image in Fig. 2 corresponds, for example, to a viewing direction parallel to the normal axis of environment sensor system 2 to transmitter unit 5.
  • a respective beam expansion of the light pulse 7 can turn out differently in different planes.
  • the receiving unit 4 contains the optical detectors 4a, 4b, 4c, which are in particular arranged linearly next to one another along an axis parallel to the normal axis of the surroundings sensor system 2 and are designed, for example, as avalanche photodiodes, APDs.
  • the deflection unit also has a shaft 10 which is rotatably mounted and connected to the mirror 9 so that the mirror 9 can be rotated about the corresponding axis of rotation.
  • the view in FIG. 3 can be understood, for example, as a plan view, that is to say according to a viewing direction parallel to the normal axis of the surroundings sensor system 2 , onto the receiving unit 4 .
  • the optical detectors 4a, 4b, 4c are shown in distorted perspective for the purpose of clarity. In fact, the optical detectors 4a, 4b, 4c would lie one above the other and, in particular, cover one another.
  • the transmission unit 5 is not shown in FIG. 3, but can be arranged with respect to the mirror 9 in such a way that when the mirror 9 rotates about the axis of rotation, the angle of emission of the light pulses 7 can be varied.
  • the axis of rotation and the shaft 10 are therefore aligned, in particular, perpendicular to the transmission plane.
  • the reflected light pulse 7' is then detected by one of the detectors 4a, 4b, 4c detected. Due to the rotation of the mirror 9 about the axis of rotation, each of the detectors 4a, 4b, 4c can detect incident reflected portions of the light pulse 7' from different directions, ie with different horizontal angles of incidence.
  • the current position of the mirror 9 can be determined, for example, via a rotary encoder (not shown) coupled to the shaft 10 .
  • a number of scanning points can be generated via the time sequence of the detected light beams.
  • a subset of the scanning points is generated by means of each detector 4a, 4b, 4c.
  • a subset of scanning points, which is generated for different angular positions of the mirror 9 by means of one of the detectors 4a, 4b, 4c, is also referred to as the position of scanning points.
  • the horizontal angle of incidence of the reflected portions 7' i.e. an angle of incidence in the transmission plane or a plane parallel to the transmission plane, which is also referred to as the azimuthal angle, and a vertical or polar angle in a plane perpendicular to the plane of transmission.
  • the vertical angle of incidence is therefore constant for each position of scanning points.
  • the radial distance of the corresponding reflection point, for example on the object 6, from the surroundings sensor system 2 or from the receiving unit 4 is determined by means of the control unit 3 by a time-of-flight measurement. In this way, three-dimensional scanning points can be generated.
  • the control unit 3 is set up to set a blocking voltage of the optical detectors 4a, 4b, 4c depending on the respective detector signals in order to set the respective detector sensitivity of the corresponding detector 4a, 4b, 4c.
  • the reverse voltage can also be referred to as the bias voltage for operating the APDs in the reverse direction.
  • the control unit 3 can regulate, for example, a noise level of the optical detectors 4a, 4b, 4c by correspondingly changing the blocking voltage and thus the detector sensitivity in order to keep a signal-to-noise ratio, SNR, of the detectors 4a, 4b, 4c as constant as possible on a maintain the specified value. Control methods known per se can be used for this purpose, for example.
  • the detector sensitivity can also be referred to as an amplification factor, gain or multiplication factor.
  • the detector sensitivity quantifies how high the respective output voltage of the optical detector 4a, 4b, 4c is for a given radiation power impinging on the active surface of the corresponding detector 4a, 4b, 4c.
  • the control unit 3 is also set up to determine a rate of change in the detector sensitivity and, based thereon, to determine whether there is an abrupt change in brightness in the area surrounding the motor vehicle 1 . Such an abrupt change in brightness can then be identified as entry into or exit from a tunnel 14 (see FIG. 7) by means of the control unit 3, for example taking into account the sign of the rate of change of the detector sensitivity.
  • the control can be designed, for example, in such a way that the highest possible SNR is achieved under different environmental conditions, for example with regard to the brightness in the environment and/or the temperature in the environment.
  • the optical detectors 4a, 4b, 4c can be calibrated in dark ambient conditions to determine the reverse voltage required to obtain the optimum SNR at a given ambient temperature. It can be assumed that the required blocking voltage increases approximately linearly as a function of the ambient temperature, as shown schematically in FIG. 4, the ambient temperature being denoted by T and the blocking voltage by V.
  • the blocking voltage determined in this way which can also be referred to as the dark voltage, can be used for regulation as an upper limit for the blocking voltage of the APDs.
  • the control unit can take the ambient brightness into account in order to adjust the blocking voltage accordingly.
  • the control unit 3 can, for example, evaluate the detector signals at corresponding points in time at which the transmission unit 5 does not emit any light.
  • FIG. 5 shows the detector sensitivity as a gain factor G as a function of time t.
  • the curve shown can correspond, for example, to an averaged detector sensitivity or to a smoothed detector sensitivity.
  • the detector sensitivity is approximately temperature-invariant, since the temperature-dependent dark voltage is taken into account.
  • the rate of change G' of the detector sensitivity ie the time derivative of the detector sensitivity G, is shown schematically in FIG.
  • the control unit 3 can compare the rate of change G' with a positive limit value S1, for example. As can be seen in FIG. 6, the rate of change G' exceeds the limit value S1 at a time ti.
  • the control unit 3 can change the rate of change G', for example with a further negative limit value S2 to compare. As shown in FIG. 6, the rate of change G′ falls below the further limit value S2 at a point in time t2. In this way, the abrupt change in brightness associated with driving into or out of the tunnel 14 can be detected at an early stage. If one compares the corresponding rise and fall in detector sensitivity G from FIG. 5 with the course of the rate of change G' from FIG an abrupt change in brightness in terms of an entry into or exit from the tunnel 14 could be closed.
  • Motor vehicle 1 with surroundings sensor system 2 is shown schematically in tunnel 14 in FIG. 7 . Furthermore, the longitudinal axis of the motor vehicle 1 and the environment sensor system 2 is shown schematically as a dashed line 11 .
  • the field of view 12 of the environment sensor system 2 is limited in the direction of the horizontal angle of incidence.
  • a predefined angular range 13 for the horizontal angle of incidence is not taken into account for the detection of the abrupt change in brightness or the entry into or exit from the tunnel 14 .
  • this predetermined angular range 13 is arranged symmetrically about the longitudinal axis 11, for example.
  • asymmetrical angular ranges around the longitudinal axis 11 can also be useful.
  • the field of view 12 without the angular range 13 therefore corresponds to a range of interest for detecting the abrupt change in brightness.
  • the detector sensitivity G is correspondingly reduced in the area of interest due to the ambient brightness through the regulation described.
  • the walls of the tunnel 14 are, for example, in the area of interest, so that only minor disruptions are to be expected due to overhead lighting in the tunnel 14 or due to rear lights or headlights of other road users. In this way, the reliability of the detection of the abrupt change in brightness can be further improved.
  • the improved concept allows abrupt changes in brightness to be detected more quickly even at higher speeds of the motor vehicle and thus in particular to quickly and reliably detect entering a tunnel or exiting a tunnel.
  • the corresponding information can be used to advantage for controlling the surroundings sensor system in order to increase the reliability of the corresponding measured values.
  • a corresponding confidence value for the measurements can be determined depending on the position of the motor vehicle in or outside the tunnel.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Electromagnetism (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Sustainable Development (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Optical Radar Systems And Details Thereof (AREA)

Abstract

La présente invention concerne un procédé de détection d'un changement brusque de luminosité dans l'environnement d'un véhicule automobile (1). Selon l'invention, la lumière (7') de l'environnement est détectée au moyen d'un détecteur optique (4a, 4b, 4c), et un signal de détecteur est généré sur la base de celle-ci. La sensibilité du détecteur est réglée au moyen d'une unité de commande (3) sur la base du signal de détecteur, et le taux de variation de la sensibilité du détecteur est déterminé. La présence d'un changement brusque de luminosité est déterminée au moyen de l'unité de commande (3) sur la base du taux de variation.
PCT/EP2022/052188 2021-02-03 2022-01-31 Détection d'un changement de luminosité dans l'environnement d'un véhicule automobile WO2022167362A1 (fr)

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DE102021102425.0A DE102021102425A1 (de) 2021-02-03 2021-02-03 Erkennung einer Helligkeitsänderung in der Umgebung eines Kraftfahrzeugs
DE102021102425.0 2021-02-03

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20110062057A (ko) * 2009-12-02 2011-06-10 현대자동차주식회사 엘시디 미러 장치
DE102012021830A1 (de) 2012-11-08 2014-05-08 Valeo Schalter Und Sensoren Gmbh Optoelektronische Detektionseinrichtung mit einstellbarer Biasspannung eines Avalanche-Photodetektors für ein Kraftfahrzeug, Kraftfahrzeug und entsprechendes Verfahren
WO2018055449A2 (fr) * 2016-09-20 2018-03-29 Innoviz Technologies Ltd. Systèmes et procédés lidar

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP5797884B2 (ja) 2010-08-04 2015-10-21 株式会社日立ハイテクノロジーズ 光量検出方法及びその装置

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20110062057A (ko) * 2009-12-02 2011-06-10 현대자동차주식회사 엘시디 미러 장치
DE102012021830A1 (de) 2012-11-08 2014-05-08 Valeo Schalter Und Sensoren Gmbh Optoelektronische Detektionseinrichtung mit einstellbarer Biasspannung eines Avalanche-Photodetektors für ein Kraftfahrzeug, Kraftfahrzeug und entsprechendes Verfahren
WO2018055449A2 (fr) * 2016-09-20 2018-03-29 Innoviz Technologies Ltd. Systèmes et procédés lidar

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