DE102018216707A1 - Environment detection system and method for an environment detection system - Google Patents

Abstract

The present invention relates to an environment detection system. The environment detection system comprises a first environment sensor with a variable viewing angle, which is set up to provide first information about a first spatial area. The first area of the room depends on an instantaneous viewing angle of the first environment sensor. The environment detection system further comprises a second environment sensor, which is set up to provide second information about a second spatial area. The first room area is a partial area of the second room area. Furthermore, the environment detection system comprises an evaluation element, which is set up to determine the current viewing angle of the first environment sensor based on a comparison of the first information and the second information.

Description

The present invention relates to systems for recognizing the environment e.g. of a vehicle. The invention further relates to a method for an environment detection system.

To detect the vehicle environment, e.g. LIDAR (English Light Detection And Ranging) measuring systems used. A LIDAR measuring system can have one or more LIDAR sensors. Each LIDAR sensor preferably comprises a LIDAR transmitter unit and a LIDAR receiver unit.

A LIDAR sensor resolves a spatial area with a predetermined resolution at a given viewing angle. In order to recognize small objects even at great distances (for example a tire with a height of approx. 20 cm at a distance of 100 m), a higher resolution of the LIDAR image is sometimes required. The same LIDAR sensor can be used for this if its viewing angle is reduced by appropriate optics and thus its resolution is increased with the same number of pixels. So that the LIDAR sensor can cover the same image area with a narrowed viewing angle as before, the viewing angle of the LIDAR sensor is deflected (i.e. varies). This can be done, for example, by tilting the sensor (e.g. by ± 5 °) or by tilting a mirror or prism (e.g. by ± 10 °).

To derive the reaction of a system processing the LIDAR measurements (e.g. a vehicle), the viewing angle of the LIDAR sensor, i.e. the angle of the tilt can be sensed very precisely (e.g. with an accuracy of ± 0.05 °). A rotation angle sensor is usually used for sensing.

The high safety requirements for the LIDAR sensors also apply to the rotation angle sensor. To monitor the LIDAR sensor, therefore, a rotation angle sensor with high accuracy must be used. Rotation angle sensors that offer the required accuracy are hardly available on the market or are very expensive.

The publication DE 10 2013 211 648 A1 suggests for the calibration of two cameras attached to a vehicle to determine an image element that occurs in the respective individual images of the two cameras. The relative position of the first camera to the second camera is determined based on an orientation of the image element in the individual image of the first camera relative to the orientation of the image element in the individual image of the second camera. Depending on the relative position determined, the two individual images are now combined to form an overall image.

In block letters DE 10 2008 004 370 A1 proposes a method for calibrating a camera of a night vision system that is attached to a vehicle. The video image of the camera is measured using a reference object in order to determine a relative angle of rotation of the video image relative to the reference object. The reference object can be the video image of a second camera, for example. A shear for the video image is determined by means of the determined rotation angle in order to enable mechanically free rotation of the video image.

In contrast to optical cameras, environment sensors such as LIDAR sensors or radar sensors do not provide optical images in the classic sense. Rather, this provides information such as a distance, a speed or an elevation angle relative to an object scanned by the environment sensor. In addition, concern those in the publication DE 10 2013 211 648 A1 and DE 10 2008 004 370 A1 proposed method only the calibration of two cameras relative to each other. The absolute viewing angle of one of the cameras cannot be determined using this method.

Against this background, it is an object of the present invention to provide an improved and less expensive possibility for determining the viewing angle of a surroundings sensor.

The object according to the invention is achieved by an environment detection system and a method for an environment detection system according to the independent claims. Further aspects and developments of the invention are described in the dependent claims, the following description and in the figures.

According to a first aspect, the invention relates to an environment detection system. The environment detection system comprises a first environment sensor with a variable viewing angle, which is set up to provide first information about a first spatial area. The first area of the room depends on an instantaneous viewing angle of the first environment sensor. The environment detection system further comprises a second environment sensor, which is set up to provide second information about a second spatial area. The first room area is a partial area of the second room area. Both the first environment sensor and the second environment sensor are sensors which scan or sense their environment in order to receive information about objects in the environment (for example position, distance, relative movement to the environment sensor, etc.). Because of the changing perspective of the first Environment sensor, the first room area is adjustable. Accordingly, the first environment sensor can scan different areas of the room. The second environment sensor can have a fixed, unchangeable viewing angle, for example, so that it always scans the same spatial area. Alternatively, the second environment sensor can also have a variable viewing angle.

The combination of the first environment sensor with a variable viewing angle and the second environment sensor can now be used to determine the current viewing angle of the first environment sensor. For this purpose, the environment detection system comprises an evaluation element, which is set up to determine the current viewing angle of the first environment sensor based on a comparison of the first information and the second information. The second environment sensor scans the first room area as part of the second room area, so that the second information contains information corresponding to the first information. This subset of the second information corresponding to the first information is assigned to a specific partial area of the second spatial area scanned by the second environment sensor. From the position of this partial area within the known second room area, it is thus possible to infer the first room area scanned by the first environment sensor and thus its viewing angle.

The inventive comparison of the information provided by a first environment sensor with a variable viewing angle and a second environment sensor can thus enable the viewing angle of the first environment sensor to be determined without the use of a rotation angle sensor. In other words: The solution according to the invention can make it possible to save the rotation angle sensor. The evaluation element can e.g. a programmable hardware component already present in the environment detection system, such as a processor, a processor core, an application-specific integrated circuit (ASIC = Application-Specific Integrated Circuit) or an integrated circuit (IC = Integrated Circuit) on which software for the Control of the environment detection system expires. Accordingly, the determination of the viewing angle of the first environment sensor can be integrated into the existing software with only one effort. No additional hardware is then required. In addition to the simplified structure of the environment detection system, this also results in a cost advantage.

According to some exemplary embodiments, at least the second information can be arranged in a two-dimensional matrix (likewise the first information) in order to provide a flat representation of the surroundings. The evaluation element is then set up to determine a subset of the second information corresponding to the first information. For example, the evaluation element can check whether an object described in distance information provided by the first environment sensor is also described in distance information provided by the second environment sensor. Similar comparisons can e.g. can also be carried out by means of speed or elevation angle information provided by the two surroundings sensors. Information from different categories (e.g. distance and speed) provided by the two environment sensors can also be evaluated together. Based on a position of the subset of the second information in the two-dimensional matrix, the evaluation element is also set up to determine the instantaneous viewing angle of the first environment sensor.

The first environment sensor can, for example, be set up to provide the first information based on received reflections of a signal emitted by the first environment sensor. The signal emitted by the first environment sensor can e.g. be a radio frequency signal or a light signal. From the reflections received by objects in the environment of the first environment sensor, e.g. a distance or a speed can be calculated relative to the object. The second environment sensor can be designed accordingly.

In some embodiments, the first environment sensor is a LIDAR sensor. To adjust the viewing angle of the LIDAR sensor e.g. the entire LIDAR sensor or individual elements of the LIDAR sensor (e.g. its receiving unit and its receiving optics or an optical element such as a mirror or a prism) can be tilted about a respective tilt axis.

In other exemplary embodiments, the first environment sensor can also be a radar sensor, which provides the first information based on received reflections of a high-frequency signal emitted by the radar sensor. Accordingly, the viewing angle of the radar sensor can be determined or calculated by means of the comparison according to the invention of the information provided by the environment sensors.

According to exemplary embodiments, the first environment sensor can also be a camera with a variable viewing angle, for example, which records the environment.

The second environment sensor can be of the same type as the first environment sensor or a Environment sensor of different types. For example, both environment sensors can be LIDAR sensors. A LIDAR image can also be compared with a camera and / or a radar image. In other words: in some exemplary embodiments, the second environment sensor can be a LIDAR sensor, a radar sensor or a camera.

As already indicated above, one of the two environment sensors can be used to scan a sub-area of the spatial area scanned by the other environment sensor with greater accuracy. Accordingly, in some exemplary embodiments, the first spatial area can have a higher resolution in the first information than in the second information. In other words: the first environment sensor can be set up to sense the first room area with a higher resolution than the second environment sensor.

In a further aspect, the present invention also relates to a method for an environment detection system comprising a first environment sensor with a variable viewing angle and a second environment sensor. The method comprises providing first information about a first spatial area by the first environment sensor. The first area of the room depends on an instantaneous viewing angle of the first environment sensor. Furthermore, the method comprises providing second information about a second spatial area by the second environment sensor. The first room area is a partial area of the second room area. The method further includes determining the instantaneous viewing angle of the first environment sensor based on a comparison of the first information and the second information.

As already described above in connection with the environment detection system according to the invention, the method according to the invention can also enable an improved and more cost-effective determination of the viewing angle of the environment sensor with a variable viewing angle.

Possible further refinements of the method are described above in connection with the environment detection system according to the invention.

Another aspect of the present invention also relates to a program with a program code for carrying out the method described here when the program code runs on a processor or a programmable hardware component or is executed there.

According to a further aspect, the present invention also relates to a vehicle. Generally, a vehicle can be thought of as a device that includes one or more motor-driven wheels (and optionally, a powertrain system). For example, a vehicle can be a passenger car, a truck, a motorcycle, or a tractor. The vehicle includes at least one environment detection system in accordance with the present invention to detect an environment of the vehicle. In addition, the vehicle comprises a control element which is set up to derive a reaction of the vehicle to the first information as a function of the determined instantaneous viewing angle of the first environment sensor.

The vehicle according to the invention can enable an improved and more cost-effective determination of the viewing angle of the environment sensor with a variable viewing angle due to the environment detection system according to the invention, so that the manufacture of the vehicle can be reduced and the derivation of the vehicle reaction can be improved.

• 1 schematisch ein Ausführungsbeispiel eines Umfelderkennungssystems;
• 2 schematisch ein Ausführungsbeispiel eines Umfelderkennungssystems in Form eines LIDAR-Messsystems;
• 3 schematisch einen Schnitt durch den in 2 gezeigten LIDAR-Sensor; und
• 4 Vergleiche der Aufnahmen zweier LIDAR-Sensoren.

Exemplary embodiments of the present invention are explained in more detail below with reference to the attached figures. Show it:

• 1 schematically an embodiment of an environment detection system;
• 2nd schematically an embodiment of an environment detection system in the form of a LIDAR measurement system;
• 3rd schematically a section through the in 2nd shown LIDAR sensor; and
• 4th Compare the images of two LIDAR sensors.

1 schematically shows an environment detection system 100 . The environment detection system 100 includes a first environment sensor 110 that is set up first information 111 to provide over a first area. The environment detection system also includes 100 a second environment sensor 120 that is set up second information 121 to provide over a second room area. As in 1 indicated, both the first environment sensor 110 as well as the second environment sensor 120 eg one object at a time 140 by means of signals 112 respectively. 122 which of the object 140 to the environment sensors 110 and 120 be reflected back (indicated by reflections 142 and 143 ), scan.

To the point of view of the first environment sensor 110 to determine, includes the LIDAR measuring system 100 also an evaluation element 130 .

The evaluation element 130 is set up, the current point of view of the first environment sensor 110 based on a comparison of the first information 111 and the second information 121 to determine. The second environment sensor 120 scans the first room area as part of the second room area so that the second information 121 contain information corresponding to the first information. This is the first information 111 corresponding subset of the second information 121 is a certain sub-area of that of the second environment sensor 120 assigned to the scanned first room area. From the position of this partial area within the known second room area, it is therefore possible to refer to that of the first environment sensor 110 scanned first area and thus its perspective are closed.

An example of a LIDAR measurement system 200 with a first LIDAR sensor 210 and a second LIDAR sensor 220 , which represents a possible implementation of the environment detection system according to the invention is in 2nd shown. A sectional view of the first LIDAR sensor 210 is in 3rd shown. The second LIDAR sensor 220 can be like the first lidar sensor 210 be designed. The LIDAR measuring system 200 is in its basic structure according to the statements on the prior art ( WO 2017/081294 A1 ) educated.

The first LIDAR sensor 210 and the second LIDAR sensor 220 are in one housing 230 of the LIDAR measuring system 200 arranged. The second LIDAR sensor 220 is immovable, ie its viewing angle is fixed. The second LIDAR sensor 220 includes a LIDAR transmitter and a LIDAR receiver.

The first LIDAR sensor 210 includes a LIDAR transmitter and a LIDAR receiver. The LIDAR receiver unit forms together with the LIDAR transmitter unit, the receiving optics 213 , the transmission optics 214 and one around a tilt axis 215 tiltable mirror 216 a movable lidar unit with one by tilting the mirror 216 changing perspective.

The LIDAR receiving unit and / or the LIDAR transmitting unit are advantageously designed in a focal plane array configuration, as in 3rd indicated. The elements of the respective unit are essentially arranged in one plane, advantageously on a chip. The respective unit is on the LIDAR sensor 210 preferably in a focal point of a corresponding optics - transmission optics 214 or receiving optics 213 - arranged. In particular, the sensor elements 211 or the emitter elements 212 in the focus of the receiving optics 213 or the transmission optics 214 arranged. Such optics can be formed, for example, by an optical lens system.

The LIDAR receiver unit has several sensor elements 211 , which are preferably designed as SPAD, single photon avalanche diode. The LIDAR transmitter unit has several emitter elements 212 for emitting, for example, laser light, advantageously laser pulses. The emitter elements 212 are favorably designed as VCSEL, Vertical Cavity Surface Emitting Laser.

The transmitter unit has emitter elements 212 which are distributed over an area of the transmitter chip. The receiving unit has sensor elements 211 which are distributed over an area of the receiving chip. The transmission chip is a transmission optics 214 assigned and the receiving chip is the receiving optics 213 assigned. The optics represent a light arriving from a room area on the respective chip. The area corresponds to the field of view of the measuring system 200 who is examined or sensed for objects.

The spatial area of the transmitting unit and the receiving unit are essentially identical. The transmission optics form an emitter element 212 on a solid angle, which represents a partial area of the spatial area. The emitter element 212 accordingly emits laser light in this solid angle. The emitter elements 212 cover the entire room together.

The receiving optics 213 forms a sensor element 211 on a solid angle, which represents a partial area of the spatial area. The number of all sensor elements 211 covers the entire room area. Emitter elements 212 and sensor elements 211 , which consider the same solid angle, map to each other and are accordingly assigned to each other. A laser light from an emitter element 212 normally forms on the associated sensor element 211 from. If necessary, there are several sensor elements 211 within the solid angle of an emitter element 212 arranged.

The measuring system leads to the determination of objects within the room area 200 a measurement process. Such a measuring process comprises one or more measuring cycles, depending on the design of the measuring system 200 and its electronics.

The Time Correlated Single Photon Counting method, TCSPC, is preferably used. Here individual incoming photons are detected, in particular by SPAD, and the time at which the sensor element is triggered 211 , also the time of detection, are stored in a storage element. The time of detection is related to a reference time at which the laser light is emitted. From the difference, the Determine the transit time of the laser light, from which the distance of the object can be determined.

A sensor element 211 can be triggered on the one hand by the laser light and on the other hand by the ambient radiation. A laser light always arrives at a certain distance from the object at the same time, whereas the ambient radiation always provides the same probability of triggering a sensor element. When a measurement is carried out several times, in particular several measurement cycles, the triggering of the sensor element add up 211 at the time of detection that corresponds to the transit time of the laser light with respect to the distance of the object, whereas the triggers by the ambient radiation are distributed uniformly over the measurement duration of a measurement cycle. A measurement corresponds to the emission and subsequent detection of the laser light. The data of the individual measurement cycles of a measurement process stored in the memory element enable the multiple times of detection to be evaluated in order to infer the distance of the object.

A sensor element 211 is conveniently connected to a Time to Digital Converter, TDC, which stores the point in time at which the sensor unit is triggered in the memory element. Such a memory element can be designed, for example, as a short-term memory or as a long-term memory. For a measuring process, the TDC fills a storage element with the times at which the sensor elements detected an incoming photon. This can be graphically represented by a histogram, which is based on the data of the storage element. In the case of a histogram, the duration of a measurement cycle is divided into short periods of time, so-called bins. Becomes a sensor element 211 triggered, the TDC increases the value of a bin by one. The bin that corresponds to the transit time of the laser pulse, that is the difference between the detection time and the reference time, is filled.

An evaluation element according to the invention is shown in FIGS 2nd and 3rd not shown for reasons of clarity. According to embodiments, the tiltable mirror 216 to be dispensed with. The first LIDAR sensor can then accordingly 210 be tiltable as a whole or at least partially about a tilt axis. Also the second LIDAR sensor 220 can be tiltable about a further tilt axis.

Exemplary information of a LIDAR sensor with a variable viewing angle compared to information of a LIDAR sensor with an unchanging viewing angle are shown in 4th shown. For better comprehensibility, the information provided by the LIDAR sensors on the area covered by them is shown as a graphic image in 4th shown. It should be noted that this representation is chosen purely for educational reasons and the information as described above is of a different type. In particular, a LIDAR measuring system determines individual reflections, which are also referred to as detections. Each detection can include information such as distance, elevation angle, azimuth angle, speed, intensity and / or other variables.

As in 4th indicated, the two LIDAR sensors can, for example, in a vehicle 400 be installed to capture the surroundings of the vehicle. The picture 410 shows the area covered by the LIDAR sensor with an unchangeable viewing angle. The picture 420 shows the area covered by the LIDAR sensor with a variable viewing angle at a first viewing angle of the LIDAR sensor. The picture also shows 430 the area covered by the LIDAR sensor with a variable viewing angle at a second viewing angle of the LIDAR sensor.

At the in 4th the example shown represent the pictures 420 and 430 of the LIDAR sensor with a variable viewing angle each represent a small image section of the image taken by the LIDAR sensor with an unchanging viewing angle. The images 420 and 430 show the respective image section with increased resolution. From the comparison of the pictures 420 and 430 with the picture 410 can now the position of the respective image section in the image 410 determined and from this the angle of view of the LIDAR sensor can be calculated with a variable angle of view.

Reference list

100

Environment detection system

110

first environment sensor

111

Information about a first room area

112

signal emitted by the first environment sensor

120

second environment sensor

121

Information about a second room area

122

signal emitted by the second environment sensor

130

Evaluation element

140

object

142

Reflections of the signal emitted by the first environment sensor

143

Reflections of the signal emitted by the second environment sensor

200

LIDAR measuring system

210

first LIDAR sensor

211

Sensor element

212

Emitter element

213

Receiving optics

214

Receiving optics

215

Tilt axis

216

mirror

220

second LIDAR sensor

230

casing

400

vehicle

410

Image of a LIDAR sensor with a fixed viewing angle

420

Image of a LIDAR sensor with a variable viewing angle

430

Image of a LIDAR sensor with a variable viewing angle

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included 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 102013211648 A1 [0006, 0008]
• DE 102008004370 A1 [0007, 0008]
• WO 2017/081294 A1 [0031]

Claims (10)

An environment detection system (100), comprising: a first environment sensor (110) with a variable viewing angle, which is configured to provide first information (111) about a first spatial area, the first spatial area being dependent on a current viewing angle of the first environmental sensor (110); and a second environment sensor (120) which is set up to provide second information (121) about a second room area, the first room area being a partial area of the second room area, characterized by an evaluation element which is set up to determine the instantaneous viewing angle of the first environment sensor ( 110) based on a comparison of the first (111) information and the second information (121). Environment detection system according to Claim 1 , characterized in that at least the second information (121) is arranged in a two-dimensional matrix, the evaluation element being set up: to determine a subset of the second information (121) corresponding to the first information (111); and to determine the current viewing angle of the first environment sensor (110) based on a position of the subset of the second information (121) in the two-dimensional matrix. Environment detection system according to Claim 1 or Claim 2 , characterized in that the first environment sensor (110) is set up to provide the first information based on received reflections of a signal emitted by the first environment sensor (110). Environment detection system according to Claim 3 , characterized in that the first environment sensor (110) is a LIDAR sensor (210). Environment detection system according to Claim 3 , characterized in that the first environment sensor (110) is a radar sensor. Environment detection system according to one of the Claims 1 to 5 , characterized in that the second environment sensor (120) is a LIDAR sensor, a radar sensor or a camera. Environment detection system according to one of the Claims 1 to 6 , characterized in that the first spatial area has a higher resolution in the first information than in the second information. Vehicle (400), characterized by : at least one environment detection system according to one of the Claims 1 to 7 to detect an environment of the vehicle; and a control element that is set up to derive a reaction of the vehicle to the first information as a function of the determined instantaneous viewing angle of the first surroundings sensor. A method for an environment detection system comprising a first environment sensor (110) with a variable angle of view and a second environment sensor (120), the method comprising: providing first information (111) about a first spatial area by the first environment sensor (110), the first Area is dependent on an instantaneous viewing angle of the first environment sensor (110); and providing second information (121) about a second room area by the second environment sensor (120), the first room area being a partial area of the second room area, characterized by determining the instantaneous viewing angle of the first environment sensor (110) based on a comparison of the first information (111) and the second information (121). Procedure according to Claim 9 , characterized in that at least the second information (121) is arranged in a two-dimensional matrix, the determination of the instantaneous viewing angle of the first environment sensor (110) comprising: determination of a subset of the second information (121) corresponding to the first information (111) ; and determining the instantaneous viewing angle of the first environment sensor (110) based on a position of the subset of the second information (121) in the two-dimensional matrix.

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