Computer-implemented method and system for testing a lidar sensor

Abstract

The invention relates to a computer-implemented method for testing a LiDAR sensor, comprising the steps of: receiving (S1), by means of a trigger detector (12), a trigger signal (TS), in particular a laser pulse, generated by a LiDAR sensor (10); providing (S2) a signal generator (14) which is connected to the trigger detector (12) and comprises a display surface (14b) having a plurality of pixels (14a); driving (S3) the signal generator (14) by means of the trigger detector (12) such that a signal-processing unit (16) of the signal generator (14) receives a predetermined, synthetically generated trigger-reflection signal (RTS) from a simulation unit (18); and at least partially displaying the synthetically generated trigger-reflection signal (RTS) by dynamically switching pixels of the display surface (14b) of the signal generator (14) depending on at least one photosensitive component (12a) of the trigger detector (12) which is activated in response to reception of the trigger signal (TS). The invention also relates to a system for testing a LiDAR sensor.

Description

[0001] Description

[0002] title

[0003] Computer-implemented method and system for testing a LiDAR sensor

[0004] The present invention relates to a computer-implemented method for testing a LiDAR sensor.

[0005] Furthermore, the invention relates to a system for testing a LiDAR sensor.

[0006] The invention also relates to a computer program with program code for carrying out the method according to the invention, and to a computer-readable data carrier with program code of a computer program for carrying out the method according to the invention when the computer program is executed on a computer.

[0007] State of the art

[0008] LiDAR light measurement systems are used for optical distance and speed measurement, among other applications. LiDAR light measurement systems emit light and measure the travel time it takes for the light to return to the system after reflecting off an object. The distance of the object from the LiDAR light measurement system can then be determined from the known speed of light.

[0009] Examples of LiDAR applications

[0010] Light measurement systems are mobile instruments for optical distance measurement and LiDAR light measurement systems for the application field of automotive, namely driver assistance systems and autonomous driving, as well as for aerospace applications.

[0011] LiDAR Time-of-Flight (ToF) simulations are used to test LiDAR sensors, in which a simulator generates response signals based on trigger signals from the LiDAR sensor.

[0012] Trigger signals from LiDAR ToF sensors correspond to the sensor's actual measurement signal. This means that the sensor uses these signals to measure its environment by measuring distances to objects. One or more measurement signals (triggers) are emitted sequentially or simultaneously in different directions, and the travel time of the reflected light signals is evaluated and converted into distance information.

[0013] According to the corresponding spatial direction, this distance information is entered into a data matrix and ultimately a pixel-shaped image of the sensor environment is created and successively updated.

[0014] With the help of the LiDAR ToF simulator, synthetic distance and intensity values ​​are transmitted to the sensor as reflected measurement signals, depending on the trigger signals, which represent both the start of measurement and the spatial direction.

[0015] DE 102007057372 Al of fenbart a test system for lidar sensors with a trigger unit, by which, in response to the reception of a signal from a lidar sensor to be tested, a signal generator is controlled in such a way that a predetermined synthetically generated or drawn optical signal is output by a signal generation unit of the signal generator.

[0016] DE 102017110790 A simulation device for a LiDAR light measurement system with a LiDAR light receiving sensor, wherein a light transmitter is present in the plane of the LiDAR light receiving sensor, wherein a further light transmitter is arranged next to the light transmitter in the plane of the LiDAR light receiving sensor, and wherein a computer monitors the activation of the LiDAR light receiving sensor and the time span for emitting a light signal via the light transmitter and / or the further light transmitter and registers the signal input of the light signal from the light transmitter or the further light transmitter.

[0017] A fundamental problem with LiDAR ToF simulation is that neither the number of simultaneously emitted measurement signals from the sensor nor their spatial direction sequence can be assumed to be known. Consequently, a high-resolution trigger detector is necessary. This high-resolution trigger detector consists, for example, of photodiodes and provides information about the start of a measurement (trigger edge) and the spatial direction of a measurement (diode ID).

[0018] Any signal from the high-resolution system will be used for this purpose.

[0019] Trigger detectors are connected to the LiDAR ToF simulator to transmit the corresponding synthetic measurement signal to the sensor, depending on the trigger edge and spatial direction. A key limitation is the number of available signal inputs on the LiDAR ToF simulator, or on each digital processing element (e.g., FPGA).

[0020] To circumvent the problem of the limited number of signal inputs on the LiDAR simulator, it was previously necessary either to drastically reduce the simulator's displayable resolution (i.e., the number of spatial directions that can be mapped) or to increase the displayable resolution by scaling the number of processing logic units in a complex and costly manner. In this process, each simulator processes a portion of the sensor environment.

[0021] Against this background, the object of the invention is therefore to provide an improved method and system for testing a LiDAR sensor, which enables a reduction in the required signal inputs at the LiDAR ToF simulator or any digital processing element.

[0022] Disclosure of the invention

[0023] The problem is solved according to the invention by a computer-implemented method for testing a LiDAR sensor with the features of claim 1.

[0024] Furthermore, the problem is solved according to the invention by a system for testing a LiDAR sensor with the features of claim 11. The problem is further solved according to the invention by a computer program with the features of claim 14 and a computer-readable data carrier with the features of claim 15.

[0025] The invention relates to a computer-implemented method for testing a LiDAR sensor.

[0026] The method comprises receiving a trigger signal generated by a LiDAR sensor, in particular a laser pulse, by a trigger detector, and providing a signal generator connected to the trigger detector, which includes a display area having a number of pixels.

[0027] Furthermore, the method includes controlling the signal generator by the trigger detector in such a way that a signal processing unit of the signal generator receives a predetermined, synthetically generated trigger reflection signal from a simulation unit, and at least partially displaying the synthetically generated trigger reflection signal by dynamically pixel-switching the display area of ​​the signal generator depending on at least one photosensitive component of the trigger detector activated in response to the reception of the trigger signal.

[0028] The invention further relates to a system for testing a LiDAR sensor.

[0029] The system includes a trigger detector which is configured to receive a trigger signal generated by a LiDAR sensor, in particular a laser pulse.

[0030] Furthermore, the system comprises a signal generator connected to the trigger detector, which includes a display area having a predetermined number of pixels, wherein the trigger detector is configured to control the signal generator in response to the reception of the trigger signal such that a signal processing unit of the signal generator receives a synthetically generated trigger reflection signal from a simulation unit, and wherein the display area of ​​the signal generator is configured to at least partially display the synthetically generated trigger reflection signal by dynamically switching pixels of the display area of ​​the signal generator depending on at least one photosensitive component of the trigger detector activated in response to the reception of the trigger signal.

[0031] The invention further relates to a computer program with program code to carry out the inventive method for testing a LiDAR sensor when the computer program is executed on a computer, and to a computer-readable data carrier with program code of a computer program to carry out the inventive method when the computer program is executed on a computer.

[0032] One idea of ​​the present invention is to significantly reduce, or to freely adjust, the number of required signal inputs on the LiDAR ToF simulator by at least partially displaying the synthetically generated trigger reflection signal through dynamic pixel switching of the display area of ​​the signal generator depending on at least one photosensitive component of the trigger detector activated in response to the reception of the trigger signal.

[0033] This can be achieved by using dynamic pixel gating or pixel switching to perform a preliminary selection of the synthetic measurement signals transmitted to the sensor, independent of the number of simulator inputs.

[0034] To control the LiDAR simulator, depending on the configuration, some (e.g., rows or columns) or all of the outgoing trigger signals are logically combined (e.g., as a logical OR). The resulting small number of trigger signals is then sent to the LiDAR simulator as combined trigger signals.

[0035] Unlike before, the LiDAR simulator now outputs all, or for example, rows or columns of synthetic measurement signals simultaneously, depending on the configuration. This includes signals that, due to incorrect spatial direction information in the trigger signal, should not be transmitted to the sensor.

[0036] To prevent incorrect, synthetic

[0037] Measurement signals are transmitted to the sensor;

[0038] Signal outputs of the LiDAR simulator are now upstream - and depending on the high-resolution trigger detection - switched on or off (gating).

[0039] The temporal sequence of the processing chain is advantageous, leading to a reduction in the gating process time. Typical delay times from sensor trigger input to synthetic data output are approximately 30 ns.

[0040] This means that the control of the gating elements by the high-resolution trigger detector must be set after approximately 10 ns and maintained for the duration of a sensor measurement process. The duration of a measurement process is sensor-dependent and based on the maximum resolvable object distance of the sensor (e.g., ~2 microseconds at 300 m).

[0041] Further embodiments of the present invention are the subject of the further dependent claims and the following description with reference to the figures.

[0042] According to a preferred embodiment of the invention, the triggering of the signal generator by the trigger detector in response to the receipt of the trigger signal is carried out using an electronic circuit for implementing a Boolean function, in particular at least one digital logic gate, and more preferably an OR gate, the output of which is activated upon receipt of the trigger signal. Thus, the interface between the trigger detector or trigger detector panel and the test system or signal generator can be kept very small. For example, if the trigger detector panel comprises 100 photodiodes, but only one of them is illuminated by the sensor, then only that one is transmitted to the signal generator.

[0043] According to a further preferred embodiment of the invention, the display surface or an electronic circuit upstream of the display surface is configured to switch the synthetically generated trigger reflection signal to specific pixels of the display surface of the signal generator, which are assigned to at least one photosensitive component, in particular photodiodes, of the trigger detector that is activated in response to the reception of the trigger signal.

[0044] Only the specific light sources for which the sensor's light signal is received on the trigger detector panel are switched on on the emitter panel; that is, not all pixels that the simulator would conventionally send to the emitter panel are switched on on the emitter panel or the display area of ​​the signal generator, but only the specific pixels that are currently illuminated by the sensor.

[0045] According to a further preferred embodiment of the invention, the display surface or the electronic circuitry upstream of the display surface is configured to deactivate a total number of remaining pixels of the signal generator's display surface, in particular to switch off the current to the light elements illuminating the pixels or to the pixels themselves. Thus, only the pixels actually required for the trigger reflection signal need to be switched on.

[0046] According to a further preferred embodiment of the invention, it is provided that the pixels of the display area of ​​the signal generator assigned to the activated at least one photosensitive component, in particular the activated photodiodes, of the trigger detector are assigned in such a way that the reflection signal generated by the pixels of the display area of ​​the signal generator is received in a specific detection area of ​​the LiDAR sensor.

[0047] The pixels of the signal generator's display surface are thus assigned to the activated photodiodes of the trigger detector in such a way that a spatial direction of reflection is taken into account.

[0048] According to a further preferred embodiment of the invention, it is provided that an angle of incidence of the trigger signal on a panel of the trigger detector corresponds to a radiation angle of the reflection signal emitted from the display surface of the signal generator.

[0049] This advantageously allows the spatial direction of the reflection signal to be mapped exactly to the trigger signal. According to a further preferred embodiment of the invention, the trigger signal generated by the LiDAR sensor and the reflection signal emitted by the display surface of the signal generator are parallel to each other. Thus, the position of the reflection object is displayed precisely.

[0050] According to a further preferred embodiment of the invention, it is provided that, for controlling the signal generator, at least a subset, in particular rows or columns, or all of the received trigger signals are logically linked together and fed to the signal generator as combined trigger signals.

[0051] The small number of trigger signals obtained in this way are then fed as combined trigger signals to the LiDAR simulator or signal generator.

[0052] According to a further preferred embodiment of the invention, the method comprises a time-of-flight simulation of an added signal propagation time of the trigger signal and the synthetically generated trigger reflection signal.

[0053] The time required by the simulator to generate an output can advantageously be used in parallel to switch the emitter panel according to the input pixels of the trigger detector panel.

[0054] According to a further preferred further education of the

[0055] The invention provides that the brightness of at least one synthetically generated trigger reflection signal displayed by the display surface of the signal generator represents an intensity of the reflection signal.

[0056] The intensity measurement is directly proportional to the strength of the reflected measurement signal and can, for example, provide an indication of the material of an object.

[0057] According to a further preferred embodiment of the invention, a receiving surface of the trigger detector and the display surface of the signal generator are designed as separate units or integrated in a single panel. This allows for flexibility in the arrangement and / or construction of the test system.

[0058] According to a further preferred embodiment of the invention, an electronic circuit upstream of the display surface comprises a flip-flop circuit for each luminaire element of the display surface. By using the flip-flop circuit, the current state of each luminaire element can be maintained and information can be stored.

[0059] The features of the computer-implemented method for testing a LiDAR sensor described herein are also applicable to the system for testing a LiDAR sensor and vice versa.

[0060] Brief description of the drawings For a better understanding of the present invention and its advantages, reference is now made to the following description in conjunction with the associated drawings.

[0061] The invention will now be explained in more detail with reference to exemplary embodiments shown in the schematic illustrations of the drawings.

[0062] They show:

[0063] Fig. 1 shows a flowchart of a computer-implemented method for testing a LiDAR sensor according to a preferred embodiment of the invention; and

[0064] Fig. 2 shows a schematic representation of a system for testing a LiDAR sensor according to the preferred embodiment of the invention.

[0065] Unless otherwise specified, the same reference symbols denote the same elements of the drawings.

[0066] Detailed description of the embodiments

[0067] The computer-implemented method for testing a LiDAR sensor shown in Fig. l comprises receiving S 1 of a trigger signal TS, in particular a laser pulse, generated by a LiDAR sensor 10 by a trigger detector 12 and providing S2 of a signal generator 14 connected to the trigger detector 12, which comprises a display area 14b having a number of pixels 14a.

[0068] Furthermore, the method comprises controlling S3 of the signal generator 14 by the trigger detector 12 such that a signal processing unit 16 of the signal generator 14 receives a predetermined, synthetically generated trigger reflection signal RTS from a simulation unit 18, and at least partially displaying the synthetically generated trigger reflection signal RTS by dynamically pixel-switching the display area 14b of the signal generator 14 depending on at least one photosensitive component 12a of the trigger detector 12 activated in response to the reception of the trigger signal TS.

[0069] The activation of S3 of the signal generator 14 by the trigger detector 12 is carried out in response to the reception of the trigger signal TS using an electronic circuit 20 to implement a Boolean function, in particular at least one digital logic gate, in particular preferably an OR gate, the output of which is activated upon receipt of the trigger signal TS.

[0070] The display area 14b or an electronic circuit upstream of the display area 14b is further configured to switch the synthetically generated trigger reflection signal RTS through to specific pixels 14a of the display area 14b of the signal generator 14, which are assigned to the at least one photosensitive component 12a, in particular photodiodes, of the trigger detector 12 activated in response to the reception of the trigger signal TS.

[0071] Furthermore, the display area 14b or the electronic circuit upstream of the display area 14b is configured to deactivate a total number of remaining pixels 14a of the display area 14b of the signal generator 14, in particular to switch off the power to the light elements illuminating the pixels 14a or to switch off the power to the pixels 14a themselves.

[0072] The pixels 14a of the display area 14b of the signal generator 14, which are assigned to the activated at least one photosensitive component 12a, in particular the activated photodiodes, of the trigger detector 12, are further assigned in such a way that the reflection signal RTS generated by the pixels 14a of the display area 14b of the signal generator 14 is received in a specific detection area of ​​the LiDAR sensor 12.

[0073] The angle of incidence of the trigger signal TS on a panel of the trigger detector 12 corresponds to a radiation angle of the reflection signal RTS emitted by the display surface 14b of the signal generator 14. Furthermore, the trigger signal TS generated by the LiDAR sensor 10 and the reflection signal RTS emitted by the display surface 14b of the signal generator 14 are parallel to each other.

[0074] To control the signal generator 14, at least a subset, in particular rows or columns, or all of the received trigger signals TS, are logically combined and fed to the signal generator 14 as combined trigger signals TS. The method is a time-of-f-light simulation of the added signal propagation time of the trigger signal and the synthetically generated trigger reflection signal RTS.

[0075] The brightness of at least one synthetically generated trigger reflection signal RTS displayed by the display surface 14b of the signal generator 14 represents an intensity of the reflection signal RTS .

[0076] Fig. 2 shows a schematic representation of a system for testing a LiDAR sensor according to the preferred embodiment of the invention.

[0077] The system includes a trigger detector 12, which is configured to receive a trigger signal TS generated by a LiDAR sensor 10, in particular a laser pulse.

[0078] Furthermore, the system comprises a signal generator 14 connected to the trigger detector 12, which includes a display area 14b having a predetermined number of pixels 14a, wherein the trigger detector 12 is configured to control the signal generator 14 in response to the reception of the trigger signal TS such that a signal processing unit 16 of the signal generator 14 receives a synthetically generated trigger reflection signal RTS from a simulation unit 18.

[0079] The display area 14b of the signal generator 14 is further configured to at least partially display the synthetically generated trigger reflection signal RTS by dynamically pixel switching of the display area 14b of the signal generator 14 depending on at least one photosensitive component 12a of the trigger detector 12 activated in response to the reception of the trigger signal TS.

[0080] A receiving surface of the trigger detector 12 and the display surface 14b of the signal generator 14 are designed as separate units or integrated in a single panel. An electronic circuit upstream of the display surface 14b includes a flip-flop circuit for each luminaire element of the display surface 14b.

[0081] Although specific implementation forms have been illustrated and described herein, it is understandable to those skilled in the art that a multitude of alternative and / or equivalent implementations exist. It should be noted that the exemplary implementation form or forms are merely examples and are not intended to limit the scope, applicability, or configuration in any way.

[0082] Rather, the aforementioned summary and detailed description provide the person skilled in the art with convenient guidance for implementing at least one exemplary embodiment, whereby it is understood that various modifications to the scope of functions and the arrangement of elements can be made without deviating from the scope of the appended claims and their legal equivalents. In general, this application intends to cover modifications, adaptations, or variations of the embodiments presented herein. For example, the sequence of process steps can be changed. Furthermore, the methods according to the invention can be carried out at least sectionally sequentially or in parallel.

[0083] Reference character list

[0084] 1 system

[0085] 10 LiDAR sensor 12 Trigger detector

[0086] 12a photosensitive component

[0087] 14 Signal generator

[0088] 14a pixels

[0089] 14b Display area 16 Signal processing unit

[0090] 18 simulation units

[0091] 20 electronic circuits

[0092] TS trigger signal

[0093] RTS trigger reflection signal S1-S4 process steps

Claims

Claims 1. Computer-implemented method for testing a LiDAR sensor, comprising the following steps: Receiving (S1) a trigger signal (TS) generated by a LiDAR sensor (10), in particular a laser pulse, by a trigger detector (12); providing (S2) a signal generator (14) connected to the trigger detector (12), which comprises a display area (14b) having a number of pixels (14a); controlling (S3) the signal generator (14) by the trigger detector (12) such that a signal processing unit (16) of the signal generator (14) receives a predetermined, synthetically generated trigger reflection signal (RTS) from a simulation unit (18); and at least partial display (S4) of the synthetically generated trigger reflection signal (RTS) by dynamically pixel switching of the display area (14b) of the signal generator (14) depending on at least one photosensitive component (12a) of the trigger detector (12) activated in response to the reception of the trigger signal (TS).

2. Computer-implemented method according to claim 1, wherein the control (S3) of the signal generator (14) by the trigger detector (12) in response to the reception of the trigger signal (TS) is carried out using an electronic circuit (20) to implement a Boolean function, in particular at least one digital logic gate, in particular preferably an OR gate, whose output is activated upon receipt of the trigger signal (TS).

3. Computer-implemented method according to claim 1 or 2, wherein the display area (14b) or an electronic circuit upstream of the display area (14b) is configured to switch the synthetically generated trigger reflection signal (RTS) to specific pixels (14a) of the display area (14b) of the signal generator (14), which are assigned to the at least one photosensitive component (12a), in particular photodiodes, of the trigger detector (12) activated in response to the reception of the trigger signal (TS).

4. Computer-implemented method according to claim 3, wherein the display area (14b) or the electronic circuit upstream of the display area (14b) is configured to deactivate a total number of remaining pixels (14a) of the display area (14b) of the signal generator (14), in particular to switch off the light elements illuminating the pixels (14a) or the pixels (14a) themselves.

5. Computer-implemented method according to claim 3 or 4, wherein the pixels (14a) of the display area (14b) of the signal generator (14) assigned to the activated at least one photosensitive component (12a), in particular the activated photodiodes, of the trigger detector (12) are assigned such that the pixels (14a) of the display area (14b) reflection signal generated by the signal generator (14) (RTS) is received in a specific detection area of ​​the LiDAR sensor (12).

6. Computer-implemented method according to one of the preceding claims, wherein an angle of incidence of the trigger signal (TS) on a panel of the trigger detector (12) corresponds to a beam angle of the reflection signal (RTS) emitted from the display surface (14b) of the signal generator (14).

7. Computer-implemented method according to claim 6, wherein the trigger signal (TS) generated by the LiDAR sensor (10) and the reflection signal (RTS) emitted by the display surface (14b) of the signal generator (14) are parallel to each other.

8. Computer-implemented method according to one of the preceding claims, wherein, for controlling the signal generator (14), at least a subset, in particular rows or columns, or all of the received trigger signals (TS) are logically combined and fed to the signal generator (14) as combined trigger signals (TS).

9. Computer-implemented method according to one of the preceding claims, wherein the method comprises a time-of-f light simulation of an added signal propagation time of the trigger signal and the synthetically generated trigger reflection signal (RTS).

10. Computer-implemented method according to one of the preceding claims, wherein the brightness of the at least one synthetically generated trigger reflection signal (RTS) displayed by the display surface (14b) of the signal generator (14) represents an intensity of the reflection signal (RTS).

11. System (1) for testing a LiDAR sensor, comprising: a trigger detector (12) configured to receive a trigger signal (TS), in particular a laser pulse, generated by a LiDAR sensor (10); and a signal generator (14) connected to the trigger detector (12), which displays a display area having a predetermined number of pixels (14a). (14b) comprises, wherein the trigger detector (12) is configured to drive the signal generator (14) in response to the reception of the trigger signal (TS) such that a signal processing unit (16) of the signal generator (14) receives a synthetically generated trigger reflection signal (RTS) from a simulation unit (18), and wherein the display area (14b) of the signal generator (14) is configured to display the synthetically generated trigger reflection signal (RTS) by dynamically pixel-switching the display area (14b) of the signal generator (14) depending on at least one photosensitive sensor activated in response to the reception of the trigger signal (TS). to at least partially indicate the component (12a) of the trigger detector (12).

12. System according to claim 11, wherein a receiving area of ​​the trigger detector (12) and the display area (14b) of the signal generator (14) are designed as separate units or integrated in a single panel.

13. System according to claim 11 or 12, wherein an electronic circuit upstream of the display area (14b) comprises a flip-flop circuit for each luminaire element of the display area (14b).

14. Computer program product comprising a computer program comprising software means for carrying out a method according to any one of claims 1 to 10, wherein the computer program is executed on a computer.

15. Computer-readable data carrier containing program code of a computer program for executing at least parts of a method according to any one of claims 1 to 10 when the computer program is executed on a computer.

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