DE102019109396A1 - LIDAR device for a vehicle, application system with such a LIDAR device and method for setting at least one performance index of such an application system - Google Patents

Abstract

The invention relates to a LIDAR device (10) for a vehicle with a transmitting unit (12) for transmitting a light beam (18) into an area in the vicinity of the LIDAR device (10), a receiving unit (14) with an optical sensor ( 26) for receiving light (28) reflected in the area, a control unit (24) for controlling at least one component of the transmitting unit (12) and / or the receiving unit (14) and an evaluation unit (30) for evaluating the signal from the optical sensor (26). The LIDAR device (10) is set up to receive specifications that are related to at least one operating parameter of the LIDAR device (10) from the outside and to set the operating parameters accordingly. The invention also relates to an application system with such a LIDAR- Device (10) which is connected via a signal transmission path to an application unit (34) using a detection signal from the LIDAR device (10), a corresponding method for setting at least one performance index of such an application system and a corresponding computer program product.

Description

The invention relates to a LIDAR device for a vehicle with a transmitting unit for emitting a light beam into an area in the vicinity of the LIDAR device, (i) a receiving unit with an optical sensor for receiving light reflected in the area, (ii) a Control unit for controlling at least one component of the transmitting unit and / or the receiving unit and (iii) an evaluation unit for evaluating the signal of the optical sensor.

The invention also relates to an application system with such a LIDAR device, which is connected to an application unit via a signal transmission path using a detection signal from the LIDAR device, a corresponding method for setting at least one performance index of such an application system and a corresponding computer program product (LIDAR: Light Detection and Ranging).

The document DE 10 2015 100910 A1 describes a LIDAR device for a vehicle with (i) a transmitting unit for emitting a laser beam that scans an area in the vicinity of the LIDAR device, the transmitting unit having a laser light source and a scanning unit, and (ii) a receiving unit for receiving reflected light, the receiving unit having an optical sensor and an evaluation unit for evaluating the sensor signal of the optical sensor. The optical sensor is based on at least one diode. In this document, the LIDAR device for motor vehicles is referred to more generally as “device for detecting objects for a motor vehicle”.

The document DE 10 2018 120845 A1 describes a spatial monitoring system for monitoring and characterizing a spatial environment of an autonomous vehicle, the system using spatial sensor devices such as LIDAR devices for object detection in the spatial environment of the vehicle, a GPS tracking device and a perception module for determining an actual spatial environment for the driving scenario based on corresponding data frames from the various devices. Various performance indices are defined for the perception module or the spatial monitoring system. A first performance index is determined based on correctly detected objects, objects not detected, and objects detected incorrectly. Such performance or performance indices are sometimes referred to as KPIs, Key Performance Indices.

In order to provide a selected compromise between various performance indices (or performance indices KPIs) of an application system with a LIDAR device, the internal operating parameters of the LIDAR device are usually selected by the corresponding LIDAR manufacturer. In practice, however, applications often require different tradeoffs which, depending on the application, can be permanent or even vary with the scene / situation in a single application.

The invention is based on the object of specifying means for improving the performance of an application system with a LIDAR device and an application unit using the detection signal of the LIDAR device.

This object is achieved by a LIDAR device, a corresponding application system, a corresponding method and a corresponding computer program product with the features of the respective independent claims. Advantageous embodiments of the invention are the subject matter of the subclaims, the description and the figures.

According to several aspects of the LIDAR device according to the invention for a vehicle with (i) a transmitting unit for emitting a light beam into an area in the vicinity of the LIDAR device, (ii) a receiving unit with an optical sensor for receiving light reflected in the area, (iii) a control unit for controlling at least one component of the transmitting unit and / or the receiving unit and (iv) an evaluation unit for evaluating the signal of the optical sensor, the LIDAR device is set up to specify specifications that match at least one operating parameter of the LIDAR device are related to receiving from the outside and to set the operating parameters accordingly. That is, the LIDAR device enables external control of internal operating parameters, in particular during the operation of the LIDAR device.

The lidar device can be any type of lidar device, i. a LIDAR device with at least one light beam that scans the area in the vicinity of the LIDAR device, or with at least one light beam that illuminates the entire area at once.

The LIDAR device is preferably set up to receive the specifications related to the at least one operating parameter from an application unit, in particular from an application unit related to a vehicle. An application unit of a corresponding Application system using a detection signal of the lidar device may transmit a signal having specifications related to such internal operating parameters of the lidar device to adjust the performance indices of the application system. The application system is preferably a vehicle-related application system, such as a driver assistance system. The driver assistance system can be an ADAS system (Advanced Driver Assistance System) or a driver assistance system of an autonomous vehicle.

Typically, a change in one or more lidar operating parameters affects multiple performance indexes.

1. (a) ein Betriebsparameter einer Lichtquelle der Sendeeinheit, der insbesondere die Leistung, die Pulslänge, die Wiederholungsrate der Impulse usw. betrifft;
2. (b) ein Betriebsparameter einer Scaneinheit der Sendeeinheit, der insbesondere Scanparameter wie den Scanbereich, die Scangeschwindigkeit usw. betrifft;
3. (c) ein Betriebsparameter eines optischen Sensors der Empfangseinheit, wie beispielsweise die Auslesezeit; und
4. (d) ein Betriebsparameter einer Auswerteeinheit der Empfangseinheit.

According to a further preferred embodiment of the invention, the at least one operating parameter of the LIDAR device is an operating parameter from the following parameter list:

1. (a) an operating parameter of a light source of the transmission unit, which in particular relates to the power, the pulse length, the repetition rate of the pulses, etc.;
2. (b) an operating parameter of a scanning unit of the transmitting unit, which in particular relates to scanning parameters such as the scanning area, the scanning speed, etc.;
3. (c) an operating parameter of an optical sensor of the receiving unit, such as the readout time; and
4. (d) an operating parameter of an evaluation unit of the receiving unit.

According to a further preferred embodiment of the invention, the LIDAR device also has an interface for receiving a signal with the external specifications.

According to yet another preferred embodiment of the invention, the LIDAR device further comprises a control unit of a higher level for assigning the specifications, which are related to the at least one operating parameter, to the at least one corresponding component of the LIDAR device. Due to this measure, the specification must not be hardware-related.

According to various aspects of the application system which has an aforementioned LIDAR device which is connected via a signal transmission path to an application unit for using a detection signal of the LIDAR device, the application unit is set up to transmit a signal with specifications that correspond to the at least one operating parameter of the lidar device to set at least one performance index of the application system.

1. (a) eine Erfassungsrate, die insbesondere durch das Verhältnis von True Positive zu False Positive (TP/FP) gegeben ist;
2. (b) eine Sigma-Grenze einer Entfernungsschätzung; und
3. (c) eine Rate von Betriebsrahmen pro Sekunde (fps).

The at least one performance index is preferably a performance index from the following list of performance indexes:

1. (a) a detection rate, which is given in particular by the ratio of true positive to false positive (TP / FP);
2. (b) a sigma limit of a range estimate; and
3. (c) a rate of operating frames per second (fps).

According to various aspects of the method for setting at least one performance index of an application system, which has a LIDAR device and an application unit, using a detection signal of the LIDAR device, the LIDAR device having: (i) a transmission unit for emitting a light beam into a Area in the vicinity of the LIDAR device, (ii) a receiving unit for receiving light reflected in the area, wherein the receiving unit has an optical sensor, (iii) a control unit for controlling at least one component of the transmitting unit and / or the receiving unit and ( iv) an evaluation unit for evaluating the signal of the optical sensor, the LIDAR device receives a specification from the application unit which is related to at least one operating parameter of the LIDAR device, and sets the at least one operating parameter to the at least one performance index of the application system G set according to the requirement of the application unit. In other words: the application unit transmits a specification which is related to at least one operating parameter of the LIDAR device in order to set the at least one performance index of the application system.

1. (a) eine Erfassungsrate, die insbesondere durch das Verhältnis von True Positive zu False Positive (TP/FP) gegeben ist;
2. (b) eine Sigma-Grenze einer Entfernungsschätzung; und
3. (c) eine Rate von Betriebsrahmen pro Sekunde (fps).

According to a preferred embodiment of the method according to the invention, the at least one performance index is a performance index from the following list of performance indices:

1. (a) a detection rate, which is given in particular by the ratio of true positive to false positive (TP / FP);
2. (b) a sigma limit of a range estimate; and
3. (c) a rate of operating frames per second (fps).

1. (a) ein Betriebsparameter einer Lichtquelle der Sendeeinheit;
2. (b) ein Betriebsparameter einer Scaneinheit der Sendeeinheit;
3. (c) ein Betriebsparameter eines optischen Sensors der Empfangseinheit; und
4. (d) ein Betriebsparameter einer Auswerteeinheit der Empfangseinheit.

According to a further preferred embodiment of the method according to the invention is the at least one operating parameter of the LIDAR device is an operating parameter from the following list of operating parameters:

1. (a) an operating parameter of a light source of the transmitting unit;
2. (b) an operating parameter of a scanning unit of the transmitting unit;
3. (c) an operating parameter of an optical sensor of the receiving unit; and
4. (d) an operating parameter of an evaluation unit of the receiving unit.

The computer program product according to the invention has program code sections which can be executed by a computer and which have program code instructions which are configured to execute the above-mentioned method when they are loaded into a processor of a computer-based device / unit of the application system.

Further features of the invention emerge from the claims, the figures and the description of the figures. All of the features and combinations of features mentioned above in the description and the features and combinations of features shown on their own in the description of the figures and / or in the figures can be used not only in the specified combination, but also in other combinations or on their own.

The invention is explained in more detail below using a preferred embodiment and with reference to the accompanying drawings.

• 1 ein System mit einer LIDAR-Vorrichtung für ein Kraftfahrzeug und einer Anwendungseinheit gemäß einer bevorzugten Ausführungsform der Erfindung;
• 2 ein Beispiel einer Empfängerbetriebskennlinie (ROC), die mögliche Systemzustände darstellt, die mit der Erfassung von True-Ereignissen und False-Ereignissen in Beziehung stehen;
• 3 ein Diagramm, in dem der Entfernungsschätzfehler und die Erfassungsrate gegen die Energie aufgetragen sind; und
• 4 Erfassungsentfernungskonturen in einem Diagramm, in dem eine Rahmenrate pro Sekunde gegen die Geschwindigkeit aufgetragen ist.

Show it:

• 1 a system with a LIDAR device for a motor vehicle and an application unit according to a preferred embodiment of the invention;
• 2 an example of a receiver operating curve (ROC) depicting possible system conditions related to the detection of true events and false events;
• 3 a diagram in which the distance estimation error and the detection rate are plotted against the energy; and
• 4th Detection distance contours on a graph of frame rate per second versus speed.

1 Figure 3 shows an example of a lidar device 10 especially for a vehicle. The LIDAR device 10 has a laser scanning device acting as a transmitting unit 12 (short: transmitter) works, and a receiving unit 14th (short: receiver).

The transmitter unit 12 has a light source 16 on that a ray of light 18th generated. The light source 16 is a laser light source and transmits the generated (laser) light beam 18th to one called a micromirror 22nd trained scanning unit 20th to generate a scanning movement of the light beam. For this purpose is the light source 16 at a predefined angle to the scanning unit 20th arranged. According to the so-called MEMS technology (MEMS: Micro-Electro-Mechanical System), the micromirror exists 22nd made of small individual elements, each with a reflective surface and therefore referred to below as MEMS micromirrors 22nd are designated.

The MEMS micromirror 22nd is like that at the light source 16 arranged that the light beam 18th directly onto the MEMS micromirror 22nd hits; according to further configuration examples, one or more deflecting mirrors are between the laser light source 16 and the MEMS micromirror 22nd arranged so that the light beam 18th via the deflecting mirror to the MEMS micromirror 22nd is distracted.

The MEMS micromirror 22nd can be moved around a first axis parallel to the plane of the drawing and possibly around a second axis perpendicular to the plane of the drawing. The ray of light 18th is made by the MEMS micromirror 22nd deflected in at least one direction of the environment. This direction can also be referred to as the scan angle.

It becomes a control unit 24 used the MEMS micromirror 22nd to move. The control unit 24 controls the MEMS micromirror 22nd such that it can be tilted in at least one direction (double arrow).

The light source 16 in the example has one or more laser diodes. The light source 16 is with the control unit 24 so connected that the light source 16 through the control unit 24 is controlled and a pulsed light beam 18th as an emitted light beam with a frequency of eg 100 kHz by the control unit 24 is emitted. The control unit 24 can also use the laser light source 16 turn off.

The receiving unit 14th has a receiving lens (not shown) and an optical sensor 26th which, in the example shown, is a photodiode based sensor. The optical sensor 26th receives light 28 that is the laser light beam reflected or backscattered by the environment, in particular from objects in the vicinity 18th corresponds. The received light 28 is through the optical sensor 26th and its circuit converted into an electrical signal. The electrical signal is then sent to an evaluation unit 30th the LIDAR device 10 supplied, wherein the evaluation unit is computer-based.

The LIDAR device 10 measures the distances to detected objects using a transit time measurement, ie a measurement based on the ToF principle (ToF: Time of Flight). When this scanning unit 20th a MEMS micromirror 22nd it oscillates almost cosine-shaped, usually with a natural frequency of several kHz. Such a "oscillating mirror" for beam deflection must be operated at its resonance frequency. Since this is in the kHz range, there are several oscillations of the MEMS micromirror 22nd required to meet every position in a scan area, which among other things makes higher demands on the quality of the mirror 22nd represents.

The LIDAR device 10 furthermore has an interface for transmitting and / or receiving signals via a corresponding signal path and a control unit 32 a higher level, the signal lines between the interface and the control unit 24 or between the interface and the evaluation unit 30th is interposed.

The LIDAR device 10 is via the signal transmission path with an application unit 34 with a user application using a detection signal of the LIDAR device 10 connected. The application unit 34 is set up to transmit a signal with specifications that correspond to at least one operating parameter of the LIDAR device 10 are related to at least one performance index (also referred to as KPI: Key Performance Index) of an application system that the LIDAR device 10 as well as the application unit 34 having. On the other hand is the LIDAR device 10 set up to receive these specifications with at least one operating parameter of the LIDAR device 10 are related, and adjust the operating parameters accordingly.

Possible operating parameters of the LIDAR device 10 could be: (a) an operating parameter of the light source 16 ; (b) an operating parameter of the scanning unit 20th ; (c) an operating parameter of the optical sensor 26th ; and (d) an operating parameter of the evaluation unit 30th .

Regardless of the specific embodiment of the LIDAR device 10 , as in 1 shown, the LIDAR device 10 generally any type of lidar device 10 be, ie a LIDAR device 10 with at least one light beam 18th , which is the area around the lidar device 10 scans, or a lidar device 10 with at least one light beam 18th that illuminates the entire area at the same time / at once.

• (i) eine Erfassungsrate, die insbesondere durch das Verhältnis von True Positive zu False Positive (TP/FP) gegeben ist;
• (ii) eine Sigma-Grenze einer Entfernungsschätzung; und
• (ii) eine Rate von Betriebsrahmen pro Sekunde (fps-Rate).

Possible performance indices could be:

• (i) a detection rate, which is given in particular by the ratio of true positive to false positive (TP / FP);
• (ii) a sigma limit of a range estimate; and
• (ii) a rate of operating frames per second (fps rate).

The control unit 32 the higher level is, in particular, a unit for assigning the specifications that are related to the at least one operating parameter to the at least one corresponding component 16 , 20th , 26th , 30th the LIDAR device 10 .

Physical measurement principles link the TP (True Positive) and the FP (False Positive) rate with each other, so that there is always a compromise between the number of true events and the number of false events. That means there is a receiver operating characteristic (ROC curve) 36 , which represents possible system states.

2 shows an example of such an ROC curve 36 in a graph showing the true positive rate ( TPR ) against the false positive rate ( FPR ) is applied. The system parameter (s) allows the selection of a point on the curve 36 , and such parameterization should be available to the end-user application.

1. (A) Abbildung „Anwendungssystem/Anwendung A“, die sehr empfindlich bezüglich einer False-Erfassung ist und gleichzeitig bezüglich ausbleibenden Erfassungen robust ist, da ausreichend Zeit für mehrere Beobachtungen zur Verfügung steht, bevor eine Entscheidung getroffen wird. Ein solches System würde von einem Punkt auf der ROC-Kurve 36 mit (FP = 10^-4, TPR = 0,3) profitieren.
2. (B) Im Gegensatz dazu ist eine Abbildung „Anwendungssystem/Anwendung B“ bezüglich einer ausbleibenden Erfassung sehr empfindlich, sie kann jedoch eine relativ große Anzahl sporadischer False-Erfassungen herausfiltern. Der beste Betrieb würde durch (FP = 3·10^-2:, TP = 0,82) bereitgestellt.

In Fig. In 2 the following two examples are shown:

1. (A) Figure “Application system / Application A”, which is very sensitive to false detection and at the same time is robust to lack of detection, since there is sufficient time for several observations before a decision is made. Such a system would start from one point on the ROC curve 36 with (FP = 10 ^-4 , TPR = 0.3) benefit.
2. (B) In contrast to this, an “application system / application B” mapping is very sensitive to a lack of detection, but it can filter out a relatively large number of sporadic false detections. The best operation would be provided by (FP = 3 * 10 ^-2 :, TP = 0.82).

Another important performance index (KPI) for LIDAR is an error in distance estimation. Such an error is usually found in mutual dependency with the acquisition rate ( DR ). 3 shows an example of such interdependence. The curves 38 , 40 refer to a graph showing the distance estimation error ( DEE ) against the energy ( No ) and the curves 42 , 44 refer to a graph showing the capture rate ( DR ) against the energy ( No ) is applied. The curves 38 , 32 represent system parameters that result in a 0.6 m 3 sigma error at a maximum detection distance with an associated detection rate in the vicinity of 0.2. This means that only 20% of events are recorded. The other two curves 40 , 44 represent a system that has a double fault but provides a 95% detection rate.

• etwas „sehen“, aber im Falle einer Erfassung wird ein kleiner Fehler in der Entfernungsschätzung vorhanden sein, oder fast alles „sehen“, aber mit größerem Entfernungsfehler.

Therefore, when such a compromise application layer is made available, the following options can be selected:

• “see” something, but in the case of a detection there will be a small error in the distance estimate, or “see” almost everything, but with a larger distance error.

A more important system parameter is the number of measurement cycles per second or frames per second (fps).

4th shows the detection distance contours (n = 5), in a diagram in which the frame rate per second (fps) is plotted against the speed in km / h (kilometers per hour).

• - die verfügbare Laserleistung der Laserlichtquelle 16, um in die Klasse 1 eingeteilt zu werden,
• - feste Konfigurationsentscheidungen, wie beispielsweise die Größe einer Empfangslinse (nicht dargestellt),
• - elektronisches Rauschen im System
• - usw.

The maximum detection distance of the LIDAR devices 10 is usually limited by:

• - the available laser power of the laser light source 16 to get into class 1 to be classified
• Fixed configuration decisions, such as the size of a receiving lens (not shown),
• - electronic noise in the system
• - etc.

To some extent, when estimating laser power, a compromise can be made between the detection distance and the frequency of the environment observation. However, the maximum distance is proportional to the square of the energy, while the repetition of the measurement is linear.

At the same time, a particular application can benefit more from a higher frame rate fps than from a larger detection area. The standard model of the system response time usually consists of the sum of several observations and a fixed time: sys _{reaction time} = N · cycle _time + 250ms.

The example in 4th shows a case of two imaginary systems with the same detection range of 70 m and different frame rates fps, namely fps = 20 and fps = 30.

As can be seen, a system with a frame rate fps = 30 is able to operate at a speed of up to 170 km / h, as opposed to 140 km / h of the system with a frame rate fps = 20. Therefore, it could be advantageous be to provide the possibility at the application level to choose a suitable compromise between frame rate fps and detection area.

List of reference symbols

10

LIDAR device

12

Sending unit

14th

Receiving unit

16

Light source

18th

Beam of light

20th

Scanning unit

22nd

Micromirrors

24

Control unit

26th

optical sensor

28

reflected light

30th

Evaluation unit

32

Higher level control unit

34

Application unit

36

Curve

38

Curve

40

Curve

42

Curve

44

Curve

TPR

TP rate

FPR

FP rate

No

Number of electrons

DEE

error

DR

Acquisition rate

fps

Frames per second

v [km / h]

Speed in kilometers per hour

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 102015100910 A1 [0003]
• DE 102018120845 A1 [0004]

Claims (10)

LIDAR device (10) for a vehicle, comprising: a transmission unit (12) for emitting a light beam (18) into an area in the vicinity of the LIDAR device (10); a receiving unit (14) having an optical sensor (26) for receiving light (28) reflected in the area; a control unit (24) for controlling at least one component of the transmitting unit (12) and / or the receiving unit (14); and an evaluation unit (30) for evaluating the signal from the optical sensor (26), characterized in that the LIDAR device (10) is set up to provide specifications that are related to at least one operating parameter of the LIDAR device (10) from the outside to receive and to set the operating parameters accordingly. LIDAR device Claim 1 , characterized in that the LIDAR device (10) is set up to receive the specifications that are related to the at least one operating parameter from an application unit (34), in particular from an application unit (34) related to a vehicle, to recieve. LIDAR device Claim 1 or 2 , characterized in that the at least one operating parameter of the LIDAR device (10) is an operating parameter from the following parameter list: an operating parameter of a light source (16) of the transmitting unit (12); an operating parameter of a scanning unit (20) of the transmitting unit (12); an operating parameter of an optical sensor (26) of the receiving unit (14); and an operating parameter of an evaluation unit (30) of the receiving unit (14). LIDAR device according to one of the Claims 1 to 3 characterized by an interface for receiving a signal having the external specifications; and / or a control unit (32) of a higher level for assigning the specifications, which are related to the at least one operating parameter, to the at least one corresponding component (16, 20, 26, 30) of the LIDAR device (10). Application system (10, 34), in particular a driver assistance system, with a LIDAR device (10) according to one of the Claims 1 to 4th which is connected via a signal transmission path to an application unit (34) using a detection signal of the LIDAR device (10), the application unit (34) being set up to transmit a signal with specifications that are related to the at least one operating parameter of the LIDAR device ( 10) are related, to set at least one performance index of the application system (10, 34). System according to Claim 5 , characterized in that the at least one performance index is a performance index from the following list of performance indices: a detection rate which is given in particular by the ratio of true positive to false positive (TP / FP); a sigma limit of a range estimate; and a rate of operating frames per second (fps). A method for setting at least one performance index of an application system, the system comprising a lidar device (10) and an application unit (34) using a detection signal of the lidar device (10), the lidar device (10) comprising: a Transmitting unit (12) for transmitting a light beam (18) into an area in the vicinity of the LIDAR device (10); a receiving unit (14) for receiving light (28) reflected in the area, the receiving unit having an optical sensor (26); a control unit (24) for controlling at least one component of the transmitting unit (12) and / or the receiving unit (14); and an evaluation unit (30) for evaluating the signal of the optical sensor (26), characterized in that the LIDAR device (10) receives a specification from the application unit (34) which corresponds to at least one operating parameter of the LIDAR device (10) is related, and sets the operating parameter to set the at least one performance index of the application system (10, 34). Procedure according to Claim 7 , characterized in that the at least one performance index is a performance index from the following list of performance indices: a detection rate which is given in particular by the ratio of true positive to false positive (TP / FP); a sigma limit of a range estimate; and a rate of operating frames per second (fps). Procedure according to Claim 7 or 8th . characterized in that the at least one operating parameter of the LIDAR device (10) is an operating parameter from the following parameter list: an operating parameter of a light source (16) of the transmitting unit (12); an operating parameter of a scanning unit (20) of the transmitting unit (12); an operating parameter of an optical sensor (26) of the receiving unit (14); and an operating parameter of an evaluation unit (30) of the receiving unit (14). A computer program product comprising computer-executable program code sections with program code instructions which are configured to carry out the method according to any one of Claims 7 to 9 when loaded into a processor of a computer based application unit (34).

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