Vehicle surroundings detection system with variable field of view

Abstract

The present invention relates to a vehicle surroundings detection system with a variable field of view, which has a surroundings detection device and a control device for operating the same, wherein the surroundings detection device has: a transmitting device for radiating electromagnetic waves into a region to be detected; and a sensing unit for receiving reflected electromagnetic waves, wherein the transmitting device is used to alternately irradiate a first field of view in the form of a near field in a near-field operation and a second field of view in the form of a far field in a far-field operation, wherein the far field is reduced by at least 50% relative to the near field with respect to the detected solid angle, wherein the transmitting device has an average first transmitting power that can be preconfigured by the control device, wherein the transmitting device emits the first transmitting power when irradiating the near field and emits a transmitting power at least at the magnitude of the first transmitting power when irradiating the far field and increases the radiation intensity when illuminating the far field relative to the illumination of the near field, and wherein the control device is used to control the conversion between irradiating the near field and the far field.

Description

Technical Field

[0001] The present invention relates to a vehicle surroundings detection system with a variable field of view, the vehicle surroundings detection system having a surroundings detection device and a control device for operating the surroundings detection device, wherein the surroundings detection device has: a transmitting device for radiating electromagnetic waves into an area to be detected in the vehicle surroundings; and a sensor unit for receiving electromagnetic waves reflected by the vehicle surroundings, wherein the transmitting device is configured to alternately irradiate a first field of view in the form of a near field in a near-field operation and a second field of view in the form of a far field in a far-field operation, wherein the far field is reduced by at least 50% relative to the near field with respect to the detected solid angle.

[0002] The invention further relates to a vehicle headlight comprising the vehicle surroundings detection system according to the invention, and a vehicle comprising the vehicle surroundings detection system according to the invention or the vehicle headlight according to the invention. Background Art

[0003] The prior art discloses vehicle surroundings detection systems that have a plurality of sensors with which the vehicle surroundings are to be detected as completely and reliably as possible. Even though the use of a plurality of mutually independent sensors is in principle welcome, there are usually limitations in terms of the spatial arrangement of the sensors and the costs of being able to use them economically.

[0004] Depending on the respective driving situation, the requirements placed on the vehicle surroundings detection system can vary significantly. For example, a sensor configuration optimized for parking procedures at low driving speeds generally provides little information that can be used for high-speed applications, such as driver assistance systems for driving at higher speeds on highways. Therefore, it has been necessary to equip the vehicle surroundings detection system with a plurality of sensors. Summary of the invention

[0005] Therefore, the object of the present invention is to eliminate the disadvantages of the prior art.

[0006] This object is achieved with a vehicle surroundings detection system of the type mentioned at the outset, in that, according to the invention, the transmitting device has an average first transmitting power which can be preconfigured by a control device, and the transmitting device is designed to emit the first transmitting power when irradiating a near field and to emit a transmitting power at least at the magnitude of the first transmitting power when irradiating a far field, and thus to increase the radiation intensity when illuminating the far field relative to illuminating the near field, wherein the control device is designed to control the changeover between irradiating the near field and the far field.

[0007] In this way, the sensor unit can detect both near-field information and far-field information, wherein the intensity of the signal reflected from the far-field is hardly reduced relative to the signal from the near-field, because the transmitting device now concentrates the transmission power that was previously radiated to the larger solid angle of the near-field on the reduced solid angle of the far-field. As a result, the radiation intensity measured in units of power per solid angle (e.g., Watt / sr) is increased in the case of far-field applications, thereby compensating for the usually significantly larger measuring distance and the signal loss associated therewith. Thus, the present invention makes use of the knowledge that in many cases, simultaneous near-field and far-field measurements can be omitted. Thus, through the present invention, the sensor device can be optimally used not only for far-field detection but also for near-field detection, in that the sensor device is controlled in a situation-specific manner. Thus, the number of sensors to be used can be reduced. In addition, the transmission power of the existing system can be optimally utilized, in that the existing system power is used in an application-specific manner. Thus, a local increase in radiation intensity does not presuppose an increase in the transmission power of the entire system. Thus, no more powerful components are required.

[0008] In particular, it can be provided that the transmitting device is additionally configured to radiate a higher average second transmission power that exceeds the average first transmission power, wherein the control device causes the transmitting device to emit the second transmission power when irradiating the far field. The second transmission power can be, for example, twice the first transmission power. By increasing the second transmission power relative to the first transmission power, the signal quality during far-field measurement can be additionally improved. This improvement in signal quality can be used, for example, to increase the detected resolution or also to increase the range of the measurement.

[0009] It can further be provided that the control device has an interface for transmitting vehicle data to the control device for the purpose of controlling the surroundings detection device, wherein these data include the current driving speed, and the control device is designed to define a switch between near-field operation and far-field operation as a function of the driving speed. In this way, the switch between near-field detection and far-field detection can be automated. In particular, it can be provided that the control device is designed to put the transmitting device into near-field operation when a minimum speed is detected and to put the transmitting device into far-field operation when a minimum speed is exceeded.

[0010] It can further be provided that the transmitting device comprises a laser light source, an infrared light source or an LED light source. The emitted and / or detected spectrum can include not only visible light but also invisible light, for example invisible light in the UV radiation range. In principle, lidar technology, NIR / FIR / MS / SWiR, camera technology, etc. can be used in the context of the present invention.

[0011] In particular, it can be provided that the surroundings detection device is set up to illuminate and detect the corresponding illuminated field of view at a refresh rate of at least 10 Hz, preferably at least 20 Hz, particularly preferably at least 40 Hz. In this case, the transmission rate of the transmitting unit is usually implemented at a significantly higher frequency, for example, a frequency in the kilohertz or megahertz range. On the other hand, in order to reduce the signal-to-noise ratio to a minimum, the sampling rate reception is low-frequency, thereby significantly improving the detection accuracy. The refresh rate can be, for example, a maximum of 500 Hz. In principle, a high frame rate is advantageous because it allows changes in the surroundings to be detected quickly, but as the refresh rate increases, the signal-to-noise ratio deteriorates, so for each application, an attempt is made to select the optimal relationship between the signal-to-noise ratio and the refresh rate.

[0012] It can further be provided that the surroundings detection device is set up so that the refresh rate in far-field operation is reduced, in particular at least halved, relative to the refresh rate in near-field operation. In this way, the signal-to-noise ratio can be significantly reduced due to the increased number of signal pulses entering within the duration of the adjustment image. The increased duration of the adjustment image is generally not a problem when detecting the near field, in particular when the detection is carried out at low driving speeds.

[0013] In particular, it can be provided that the solid angle of the far field is reduced in the horizontal direction relative to the solid angle of the near field. The specification of the direction always depends on the installation position of the vehicle surroundings detection system. The reduction can be, for example, 50%, in particular 75%.

[0014] It can further be provided that the solid angle of the far field is reduced in the vertical direction relative to the solid angle of the near field. This reduction can be, for example, 50%, in particular 75%.

[0015] By reducing the solid angle, the field of view of the sensor is effectively reduced. This reduction can be used to increase the resolution detected in this area or - as already mentioned - also to increase the sampling rate in the detected area.

[0016] The horizontal opening angle can be between -15° and +15°, ie a total of 30°, for example, in the case of far-field measurement, and can be between -90° and +30°, ie a total of 120°, for example, in the case of near-field measurement range.

[0017] In particular, it can be provided that the surroundings detection device is set up so that the transmission power when irradiating the far field varies within the far field in such a way that the radiation intensity at the center is increased and the radiation intensity at the edge area is reduced. This is advantageous, for example, when the road course of the highway is in the center. In this case, the area can be detected particularly accurately and with a good signal-to-noise ratio, while parts of the highway area surrounding, such as fields or woods separated by guardrails, are detected with a lower signal quality. It can further be provided that the radiation intensity is varied in the vertical direction in such a way that it increases from the edge area of ​​the far field towards the center, wherein the value of the radiation intensity at the center is at least twice the value of the radiation intensity at the edge area of ​​the far field.

[0018] In particular, it can be provided that the vehicle surroundings detection system also has a computing unit which is connected to the control device, wherein the computing unit is configured to execute a program code by means of which the radiation power of the transmitting device and / or the field of view to be illuminated can be adjusted. In this way, the vehicle surroundings detection system can be controlled simply by software.

[0019] It can further be provided that the vehicle surroundings detection system is configured to detect persons in the vehicle surroundings and to calculate the distance to the persons, wherein the radiation power of the transmitting device is limited to a safe value when a minimum distance is fallen below. In this way, since the far-field operation can be automatically adjusted when a person is present in the near field, it can be prevented, for example, that an increase in the radiation intensity during the far-field operation could lead to a hazard to persons in the near field.

[0020] The invention further relates to a vehicle headlight comprising the vehicle surroundings detection system according to the invention.

[0021] The present invention further relates to a vehicle comprising the vehicle surroundings detection system according to the present invention or the vehicle headlight according to the present invention.

[0022] Preferably, the vehicle surroundings detection system is used in the headlights, because there are good installation conditions here. In principle, the system may also be arranged in the radiator grille, the taillights, behind the windshield, in the bumper, etc.

[0023] The invention allows a compromise to be found between requirements with regard to costs, design, performance (range, field of view, angular resolution, beam divergence, refresh rate, signal-to-noise ratio) and eye safety.

[0024] In other words, the present invention can be described as follows:

[0025] The present invention makes it possible to provide a system that simultaneously performs the tasks of a short-range sensor and a long-range sensor. This allows the field of view and, in particular, the range of action to be adapted to the respective driving situation. Thus, the present invention makes it possible to achieve situation-based beam adaptation for active sensors.

[0026] By reducing the field of view, adapting the refresh rate or by changing the beam form, the range of action can be adapted according to the driving situation. This can be achieved by speed- and sensor-based authorization in order to maintain eye safety, in particular a safe distance.

[0027] To this end, the following features can be provided:

[0028] • Reduction of the field of view (ROI - Region Of Interest): In active systems this can be achieved by a time-dependent pattern change of the transmit signal to the beam deflector (rotating mirror, MEMS, OPA, oscillator unit), or a change of the angular range is also conceivable (e.g. + / - 15° or + / - 8° in the case of MEMS). Thus, by reducing the field of view from 120° to 30°, 4 times the number of pulses is provided. In the case of lasers, the system may be limited by the maximum permissible duty cycle of the laser (e.g. 0.1%).

[0029] • Adapting the update rate: By increasing the number of pulses, a further improvement in the range can be achieved by reducing the update rate. The signal-to-noise ratio is increased by averaging and the sensitivity of the sensor to interfering influences is thereby reduced.

[0030] • Beam shaping: By adapting the vertical radiation characteristics, the transmission power can be better utilized. This is achieved, among other things, for the areas that only need to be illuminated with less transmission power at short distances (upper and lower areas), so that more power is available in the center area. If a hybrid scanning concept is selected (see Figure 2 ) as the transmission signal (vertical line is scanned horizontally), the vertical components of the individual lasers can be selected to be different in size. As a result, the transmission power in the central area can be significantly increased without increasing the total power.

[0031] The field of view reduction, the adaptation of the refresh rate and the beam shaping can be adjusted and controlled via software. In addition, the exact orientation of the sensor can be adjusted and calibrated in a customer-specific manner via parameters. In addition, it is also conceivable to guide the beam cone similar to a turn signal in order to more precisely detect the area relevant to the driving situation.

[0032] A software-side security mechanism can be provided, which has the following functions:

[0033] • Permission to increase transmit power:

[0034] o From the speed to be limited, the safety distance can be increased (e.g. 10 cm at 0 km / h, 50 cm from 30 km / h, 200 cm from 80 km / h), so that the intensity can be increased by one of the three measures (see 2.6). As a permissible measure, the previously determined distance must not fall below the required new safety distance.

[0035] • Reduction of transmit power:

[0036] o If an object approaches a sensor that is critical with respect to the permitted safety distance, the transmission power should be reduced and this should be communicated to the higher-level control unit.

[0037] The following advantages can be achieved by the present invention:

[0038] • Active sensors, which can be used for short and long distances depending on the application;

[0039] • Significant performance gains in the form of increased range achieved at runtime via software (no mechanical systems required);

[0040] • Customer-specific changes to performance, orientation and calibration via software (using generics, keyword modules). BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In the following, the present invention is further described based on exemplary and non-limiting embodiments, which are illustrated in the accompanying drawings. In which:

[0042] Figure 1 A schematic diagram of a vehicle surrounding environment detection system according to the present invention is shown;

[0043] Figure 2 A diagram showing an application of the vehicle surroundings detection system according to the present invention built into a vehicle headlight; and

[0044] Figure 3 A diagram showing the spatial distribution of the radiation intensity of a transmitting device is shown.

[0045] In the following drawings, like reference numerals refer to like features unless otherwise specified. DETAILED DESCRIPTION

[0046] Figure 1A schematic diagram of a vehicle surroundings detection system 1 with a variable field of view according to the present invention is shown. The system 1 comprises a surroundings detection device 2 and a control device 3 for operating the surroundings detection device 2. The surroundings detection device 2 comprises: a transmitting device 2a for radiating electromagnetic waves into a region to be detected in the vehicle surroundings; and a sensing unit 2b for receiving electromagnetic waves reflected by the vehicle surroundings.

[0047] The transmitting device 2a is designed to alternately irradiate in the near-field operation with a near-field NF (see Figure 2 ) and in the case of far-field operation, a second field of view in the form of a far field FF. The far field FF is reduced by at least 50% relative to the near field NF with respect to the detected solid angle.

[0048] The transmitting device 2a has an average first transmitting power PNF which can be preconfigured by the control device 3, and the transmitting device is configured to emit the first transmitting power PNF when irradiating the near field NF. When irradiating the far field FF, a transmitting power at least as large as the first transmitting power PNF is emitted. As a result, the local radiation intensity when illuminating the far field FF is increased relative to the illumination of the near field NF.

[0049] The control device 3 is configured to control the changeover between irradiating the near field NF and the far field FF. It is preferably provided that the transmitting device 2a is additionally configured to radiate a higher average second transmission power PFF exceeding the average first transmission power PNF, wherein the control device 3 causes the transmitting device 2a to emit the second transmission power PFF when irradiating the far field. The transmitting device 2a can be realized, for example, by a laser, the laser beam of which can be deflected by means of a micromechanical mirror, such as Figure 1 as shown in .

[0050] exist Figure 1 It is also shown that the control device 3 has an interface for transmitting vehicle data D to the control device 3 for controlling the surroundings detection device 2, wherein these data include the current driving speed, and the control device 3 is set up to define the change between near-field operation and far-field operation as a function of the driving speed.

[0051] The control device 3 is also configured to place the transmitting device 2a in near-field operation when a minimum speed is detected and to place the transmitting device 2a in far-field operation when a minimum speed is exceeded. The vehicle surroundings detection system 1 also has a computing unit 4, which is connected to the control device 3, wherein the computing unit 4 is configured to execute a program code, by means of which the radiation power of the transmitting device 2a and / or the field of view to be illuminated can be adjusted.

[0052] Figure 2A scenario is shown in which a vehicle 7 has two vehicle headlights 6, wherein a vehicle surroundings detection system 1 is built into each of these vehicle headlights 6. For greater clarity, only the radiation characteristics of the vehicle surroundings detection system 1 on the left are shown. In the present example, the solid angle of the far field FF is reduced in the horizontal direction and in the vertical direction relative to the solid angle of the near field NF. In this case, the vehicle surroundings detection system 1 is set up to detect persons 5 in the vehicle surroundings and to calculate the distance to the persons 5, wherein the radiation power of the transmitting device is limited to a safe value when a minimum distance is exceeded.

[0053] Figure 3 Two exemplary spatial distributions of the radiation intensity of the emitting device 2a are shown, namely in the form of curves I1 and I2. The distribution of the radiation intensity I2 is constant over the entire solid angle α (or horizontal or vertical angle range). Figure 3 A straight line is obtained in the diagram of . The distribution of the radiation intensity I1 is formed so that the radiation intensity at the center (in the range near the 0° point) increases and the radiation intensity in the edge area decreases. In the current embodiment, the radiation intensity is increased stepwise in multiple steps. In this way, the surrounding environment detection can be further optimized by optimizing the radiation intensity within the distribution, for example, in the far field range, given the transmission power.

[0054] The present invention is not limited to the embodiments shown, but is defined by the entire scope of the claims. Various aspects of the present invention or embodiments may also be considered and combined with each other. Any reference numerals in the claims are exemplary and are only used to make the claims easier to read, but do not limit the claims.

Claims

1. A vehicle surrounding environment detection system (1) with a variable field of view, the vehicle surrounding environment detection system comprising: - Surrounding environment detection equipment (2); and - a control device (3) for operating the surrounding environment detection device (2), The surrounding environment detection device (2) comprises: A transmitting device (2a) for radiating electromagnetic waves into a region to be detected in the surroundings of the vehicle; and A sensing unit (2b) for receiving electromagnetic waves reflected by the surrounding environment of the vehicle, The transmitting device (2a) is configured to alternately illuminate a first field of view in the form of a near field (NF) in the case of near-field operation and a second field of view in the form of a far field (FF) in the case of far-field operation, wherein the far field (FF) is reduced by at least 50% with respect to the near field (NF) with respect to the detected solid angle, and is characterized in that The transmitting device (2a) has an average first transmitting power (PNF) which can be preconfigured by the control device (3), and the transmitting device is configured to emit the first transmitting power (PNF) when irradiating the near field (NF) and to emit a transmitting power at least equal to the first transmitting power (PNF) when irradiating the far field (FF), thereby increasing the radiation intensity when illuminating the far field (FF) relative to illuminating the near field (NF), wherein the control device (3) is configured to control the changeover between irradiating the near field (NF) and the far field (FF), The surroundings detection device (2) is configured to change the transmission power when irradiating the far field (FF) within the far field (FF) by increasing the radiation intensity in the center and reducing the radiation intensity in the edge area. The control device (3) has an interface for transmitting vehicle data (D) to the control device (3) for controlling the surroundings detection device (2), wherein the data include a current driving speed, and the control device (3) is configured to define a change between near-field operation and far-field operation as a function of the driving speed. wherein the control device (3) is configured to place the transmitting device (2a) in the near-field operation when a minimum speed is detected and to place the transmitting device (2a) in the far-field operation when the minimum speed is exceeded, wherein the solid angle of the far field (FF) decreases in the horizontal direction relative to the solid angle of the near field (NF), The solid angle of the far field (FF) decreases in the vertical direction relative to the solid angle of the near field (NF), wherein the vehicle surroundings detection system (1) is designed to detect a person (5) in the vehicle surroundings and to calculate the distance to the person, wherein the radiated power of the transmitting device is limited to a safe value when a minimum distance is fallen below. The magnitude of the transmission power when irradiating the far field (FF) is equal to the first transmission power (PNF) when irradiating the near field (NF).

2. The vehicle surrounding environment detection system (1) according to claim 1, wherein the transmitting device (2a) comprises a laser light source, an infrared light source or an LED light source.

3. The vehicle surroundings detection system (1) according to claim 1 or 2, wherein the surroundings detection device (2) is configured to illuminate and detect a corresponding illuminated field of view at a refresh rate of at least 10 Hz.

4. The vehicle surroundings detection system (1) according to claim 3, wherein the surroundings detection device (2) is configured to illuminate and detect a corresponding illuminated field of view at a refresh rate of at least 20 Hz.

5. The vehicle surroundings detection system (1) according to claim 4, wherein the surroundings detection device (2) is configured to illuminate and detect a corresponding illuminated field of view at a refresh rate of at least 40 Hz.

6. The vehicle surroundings detection system (1) according to claim 3, wherein the surroundings detection device (2) is configured to reduce a refresh rate during the far-field operation relative to a refresh rate during the near-field operation.

7. The vehicle surroundings detection system (1) according to claim 6, wherein the surroundings detection device (2) is configured to at least halve the refresh rate during the far-field operation relative to the refresh rate during the near-field operation.

8. A vehicle surroundings detection system (1) according to claim 1 or 2, wherein the radiation intensity is changed in the vertical direction in such a way that the radiation intensity increases from the edge area of ​​the far field toward the center, wherein the value of the radiation intensity at the center is at least twice the value of the radiation intensity at the edge area of ​​the far field.

9. A vehicle surroundings detection system (1) according to claim 1 or 2, wherein the vehicle surroundings detection system (1) also has a computing unit (4), which is connected to the control device (3), wherein the computing unit (4) is configured to execute a program code, with the aid of which the radiation power of the transmitting device (2a) and / or the field of view to be irradiated can be adjusted.

10. A vehicle headlamp (6), comprising the vehicle surroundings detection system (1) according to any one of claims 1 to 9.

11. A vehicle (7), comprising the vehicle surrounding environment detection system (1) according to any one of claims 1 to 9 or the vehicle headlight (6) according to claim 10.

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