Device and method for synchronizing a headlamp of a motor vehicle with a video camera

Abstract

The invention relates to a device for synchronizing a headlamp of a motor vehicle with a video camera, comprising: a headlamp having imaging elements for pixels for targeted production of a light distribution and being provided for individual driving of each imaging element via pulse-width modulation in order to predefine the luminous flux produced by the imaging element by the ratio of the on phase to the off phase of the pulse-width modulation; a video camera having an image sensor with a plurality of sensor elements which are sequentially readable in time in order to detect image information from different spatial angular regions illuminated by the headlamp in front of the motor vehicle; and a control unit for driving the headlamp and the video camera, which is provided for adjusting the temporal overlap between the on phase of the driving of the imaging element and the reading of at least one sensor element of the video camera onto which the luminous flux produced by the imaging element impinges, depending on the size of the luminous flux produced by the imaging element.

Description

Technical Field

[0001] The present invention relates to an apparatus for synchronizing the headlights of a motor vehicle with a camera and a method for synchronizing the headlights of a motor vehicle with a camera. Background Technology

[0002] Camera systems for detecting the environment around a motor vehicle are well known. Some of these systems have difficulty detecting the vehicle's environment in darkness. In principle, undesirable effects, such as interference or rolling shutter effects, may occur in headlight and camera systems utilizing pulse-width modulation (PWM) control. Furthermore, in the prior art, the headlight light is generally not fully utilized by the camera because the PWM off-phase (Aus-Phasen) also occurs.

[0003] A device and method of the same type is known from DE102016007591A1. The device described therein includes a matrix LED headlight, wherein light-emitting diodes (LEDs) are driven by pulse width modulation (PWM). The LEDs and a camera are driven synchronously such that the camera is specifically exposed when the LEDs produce a high luminous flux.

[0004] A disadvantage of this method and apparatus is that, in light distributions produced by headlights with very bright and very dark areas, such as in near-light distributions with clear light-dark boundaries, the image detected by the camera has a very large dynamic range. This can lead to underexposed and saturated areas, in which information is lost. Summary of the Invention

[0005] The problem upon which this invention is based is to provide an apparatus and a method of the type described at the beginning, wherein the dynamic range of an image detected by a camera is reduced. Furthermore, a motor vehicle having such an apparatus should also be provided.

[0006] According to the present invention, this is achieved by means of an apparatus for synchronizing the headlights of a motor vehicle with a camera according to the present invention, by means of a method for synchronizing the headlights of a motor vehicle with a camera according to the present invention, and by means of a motor vehicle according to the present invention.

[0007] According to the present invention, the image sensor of a camera has a plurality of sensor elements arranged in a matrix or array to detect image information from different spatial angular regions. The camera is configured to sequentially read each sensor element or group of sensor elements in time, and the control unit is configured to adjust the time overlap between the on-state phase of the driving control of the imaging element and the reading of at least one sensor element of the camera, based on the magnitude of the light flux generated by the imaging element, wherein the light generated by the imaging element is incident on the at least one sensor element. By such targeted phase matching of the driving control of each imaging element and the driving control of each sensor element, the dynamic range of the image detected by the camera can be reduced. Therefore, the camera is less sensitive to effects such as the light-dark boundary. Furthermore, the device can reduce or prevent interference effects or rolling shutter effects, and simultaneously improve the illumination efficiency of vehicle lighting for the camera.

[0008] The headlights and camera can be part of a system for generating glare-free high beam (ADB). Here, the phase of pulse width modulation of the individual imaging elements (whose light is emitted into different spatial angular regions) can vary with the angle depending on the magnitude of the luminous flux generated by the imaging elements. By synchronizing this phase variation with the camera's readout, a desired reduction in the dynamic range of the image detected by the camera is achieved.

[0009] It can be specified that the control unit is configured to adjust the time overlap between the on-state of the imaging element's drive and the reading of the camera's sensor element based on the magnitude of the luminous flux generated by the imaging element, such that the light distribution detected by the camera differs from the light distribution perceived by a human observer in front of the vehicle, and the light generated by the imaging element is incident on the sensor element. Therefore, the light distribution visible to the camera can be decoupled from the light distribution perceived by the human eye. Thus, the device can adjust the dynamic range of the image detected by the camera independently of the light distribution generated by the headlights.

[0010] A feasible solution exists as follows: the headlight is configured to drive a first imaging element via pulse width modulation (PWM) to generate a first luminous flux originating from the first imaging element, and to drive a second imaging element via PWM to generate a second luminous flux originating from the second imaging element, the second luminous flux being greater than the first luminous flux. Here, the control unit can be configured to drive the headlight and camera such that the time overlap between the on-state of the first imaging element's drive and the reading of at least one first sensor element of the camera (where light generated by the first imaging element is incident on the first sensor element) is at most 50%, particularly at most 20%, and preferably substantially the same, compared to the time overlap between the on-state of the second imaging element's drive and the reading of at least one second sensor element of the camera (where light generated by the second imaging element is incident on the second sensor element). These measures enable targeted reduction of the light intensity of portions of the image detected by the camera, thereby preventing overexposure or saturation. Furthermore, these measures enable targeted enhancement of the light intensity of other portions of the image detected by the camera, thereby also preventing underexposure.

[0011] It can be specified that the headlight is configured to generate a low-light distribution with light and dark boundaries, with light generated by a first imaging element emitted into a spatial angular region above the light and dark boundaries, and light generated by a second imaging element emitted into a spatial angular region below the light and dark boundaries. In this way, the dynamic range of the image detected by the camera is specifically reduced within the low-light distribution with light and dark boundaries.

[0012] The following feasible solution exists: the size and / or shape of the spatial angular region into which the light is emitted by one of the imaging elements is different from the size and / or shape of the spatial angular region into which image information is detected by a sensor element of the image sensor.

[0013] Alternatively, it can be specified that the size and / or shape of the spatial angular region into which light is emitted by one of the imaging elements corresponds to the size and / or shape of the spatial angular region from which image information is detected by a sensor element of the image sensor.

[0014] It can be specified that the camera is configured to read each sensor element row by row or column by column. When reading the sensor elements row by row or column by column, the time overlap between the activation phase of the imaging element's drive and the reading of the sensor elements can also be appropriately adjusted.

[0015] A feasible approach is to configure the imaging element on at least one active surface as a light-emitting diode or a laser diode, and in particular, the imaging element is a solid-state LED array. Here, the solid-state LED array can also be configured, for example, as an SSL|HD module.

[0016] Alternatively, the imaging element may be configured as a digital micromirror device or an LCoS or LC display, or the imaging element may include a digital micromirror device or an LCoS or LC display. In this case, the illumination device additionally includes at least one light source to illuminate the imaging element of the digital micromirror device or the LCoS or LC display.

[0017] According to the present invention, the image sensor of a camera has a plurality of sensor elements arranged in a matrix or array, each sensor element detecting image information from different spatial angular regions. The camera sequentially reads each sensor element or group of sensor elements in time, and adjusts the time overlap between the on-state of the imaging element's drive and the reading of at least one sensor element of the camera according to the magnitude of the light flux generated by the imaging element, wherein the light generated by the imaging element is incident on the at least one sensor element. Specifically, the method can be implemented using the apparatus according to the present invention.

[0018] The method may also specify that a first imaging element is driven by pulse width modulation (PWM) to generate a first luminous flux, and a second imaging element is driven by PWM to generate a second luminous flux, the second luminous flux being greater than the first luminous flux. Here, the headlight and camera can be driven such that the time overlap between the activation phase of driving the first imaging element and the reading of at least one first sensor element of the camera (where light generated by the first imaging element is incident on the first sensor element) is at most 50%, particularly at most 20%, and preferably substantially the same as the time overlap between the activation phase of driving the second imaging element and the reading of at least one second sensor element of the camera (where light generated by the second imaging element is incident on the second sensor element).

[0019] According to the present invention, the motor vehicle includes the device according to the present invention. Attached Figure Description

[0020] The invention will now be described in more detail with reference to the accompanying drawings. In the drawings:

[0021] Figure 1 A schematic side view of a portion of a motor vehicle having the device according to the invention is shown;

[0022] Figure 2 A schematic diagram showing the detection area of ​​the camera and the illumination area of ​​the headlight of the device according to the present invention;

[0023] Figure 3 A graph is shown, which schematically plots the amplitude of the drive signals for the camera and the headlights over time. Detailed Implementation

[0024] In the accompanying drawings, identical and functionally identical parts are given the same reference numerals.

[0025] exist Figure 1 The vehicle 1 shown includes two headlights 2 and a camera 3, the camera being positioned, for example, on the front end of the roof or in the upper region of the windshield of the vehicle 1. Furthermore, the device includes a control unit (not shown) for controlling the headlights 2 and the camera 3.

[0026] The headlight 2 can be, in particular, a high-resolution headlight with a solid-state LED array (not shown), which serves as an imaging element. The solid-state LED array comprises a plurality of light-emitting diodes (LEDs) arranged in a matrix, which function as imaging elements for producing pixels of targeted light distribution. Here, each pixel to be produced corresponds to a spatial angular region, and light from one of the LEDs corresponding to the respective pixel is emitted into said spatial angular region. Each LED can be individually driven via pulse width modulation (PWM) so that the luminous flux produced by the respective LED is pre-defined by the ratio of the on and off phases of the PWM.

[0027] A viable solution is to incorporate a digital micromirror device (DMD), an LCoS, or an LC display as the imaging element in the headlight, instead of a solid-state LED array. In this case, the headlight additionally includes at least one light source to illuminate the imaging element of the DMD, LCoS, or LC display.

[0028] Camera 3 includes an image sensor (not shown) having multiple sensor elements arranged in a matrix or array to detect image information from different spatial angular regions illuminated by headlight 2 in front of vehicle 1. The camera is configured to sequentially read individual sensor elements or groups of sensor elements in time. Here, the sensor elements can be read, for example, row-by-row or column-by-column. The reading of sensor elements can be performed using a pulse-width modulated signal, thereby reading the corresponding sensor element during the pulse-width modulation's on-phase and not reading the corresponding sensor element during the pulse-width modulation's off-phase.

[0029] Figure 1 and Figure 2The diagram schematically illustrates region 4 in front of vehicle 1, where the detection area of ​​the camera and the illumination area of ​​the headlight overlap. Specifically, the individual pixels of camera 3 overlap with the light-emitting diode pixels of headlight 2 in a defined manner. Here, the illumination area of ​​headlight 2 is divided into spatial angle regions by solid lines, into which light from the corresponding light-emitting diodes is emitted. Furthermore, the detection area of ​​camera 3 is divided into spatial angle regions by dashed lines, from which corresponding sensor elements of the image sensor detect image information.

[0030] The light distribution produced by the headlight 2 can be, for example, a low beam distribution with a light-dark boundary. In this case, for example, the light intensity produced by the headlight in the spatial angle regions RS1 and RS2 above the light-dark boundary is significantly less than the light intensity in the spatial angle region RS3 below the light-dark boundary.

[0031] As can be seen, in the division already performed, the spatial angle region of the illumination area of ​​the headlight 2 has a different shape and size than the spatial angle region of the detection area of ​​the camera 3. Therefore, the light emitted into the spatial angle region RS1 is divided into multiple spatial angle regions RK1, RK2, RK5, and RK6, and the corresponding sensor element of the image sensor detects image information from each of these spatial angle regions. The light emitted into the spatial angle region RS2 is also divided into multiple spatial angle regions RK3, RK4, RK7, and RK8, and the corresponding sensor element of the image sensor detects image information from each of these spatial angle regions. The light emitted into the spatial angle region RS3 is also divided into multiple spatial angle regions RK9, RK10, RK11, and RK12, and the corresponding sensor element of the image sensor acquires image information from each of these spatial angle regions.

[0032] Figure 3 The time-varying curves of the drive control for each LED and sensor element are shown. Here, the amplitude of the corresponding pulse-width modulation signal is plotted relative to time, particularly during the on-phase of the drive control signal. Figure 3 As can be seen, the camera pixel readout time period and the headlight pixel drive time period overlap with each other through appropriate phase shifting.

[0033] Here, the control time periods, or turn-on phases AS1, AS2, and AS3, are used to drive the following light-emitting diodes, whose light is emitted into spatial angle regions RS1, RS2, and RS3. Furthermore, the reading time periods, or turn-on phases AK1, AK2, AK3, AK4, and AK10, are used to read the following sensor elements, whose sensor elements detect image information from spatial angle regions RK1, RK2, RK3, RK4, and RK10.

[0034] It can be seen that the control time periods corresponding to the pulse width modulation (PWM) turn-on phases AS1 and AS2 (which allow light to radiate into spatial angle regions RS1 and RS2 located above the light-dark boundary) are significantly shorter than the control time period corresponding to the PWM turn-on phase AS3 (which allows light to radiate into spatial angle region RS3 located below the light-dark boundary). This results in a significantly lower luminous flux emitted from the corresponding LEDs during the shorter turn-on phases AS1 and AS2 compared to the longer turn-on phase AS3. Correspondingly, the light intensity in spatial angle region RS3, located below the light-dark boundary, is significantly greater than the light intensity in spatial angle regions RS1 and RS2. This is entirely desirable in near-light distribution.

[0035] Based on the light intensities in spatial angles RS1, RS2, and RS3, the control unit controls the headlight 2 and camera 3 such that the time overlaps U1 and U2 between the corresponding LED on-phase AS1 and AS2 and the corresponding sensor element on-phases AK1, AK2, AK3, and AK4 are approximately the same as the time overlap U3 between the corresponding LED on-phase AS3 and the corresponding sensor element on-phase AK10. Because the duration of on-phase AS3 is significantly longer than that of on-phases AS1 and AS2, on-phase AS3 is time-shifted relative to on-phase AK10 so that overlaps U1, U2, and U3 are equal (see...). Figure 3 ).

[0036] By using approximately the same amount of time overlap U1, U2, U3 between the corresponding LED turn-on phases AS1 and AS2 and the corresponding sensor element turn-on phases AK1, AK2, AK3, and AK4, and on the other hand between the corresponding LED turn-on phase AS3 and the corresponding sensor element turn-on phase AK10, the camera detects relatively uniform brightness in the spatial angle regions RS1, RS2, and RS3. In contrast, the human eye sees significantly stronger brightness in the spatial angle region RS3.

[0037] List of reference numerals

[0038] 1 motor vehicle

[0039] 2 headlights

[0040] 3 cameras

[0041] 4. In the area in front of the motor vehicle

[0042] The RS1-RS3 LEDs emit light into their spatial angular region.

[0043] The RK1-RK12 sensor elements detect spatial angular regions from which image information is obtained.

[0044] AS1-AS3 are used to control the turn-on phase of the LED.

[0045] AK1-AK4 and AK9 are used to read the on-state of sensor elements.

[0046] The time overlap between the turn-on phase for driving the LED and the turn-on phase for reading the sensor element in U1-U3

Claims

1. A device for synchronizing the headlights (2) of a motor vehicle (1) with a camera (3), said device comprising: - Headlamp (2), the headlamp having an imaging member with an active surface, on which imaging elements in the form of a matrix or array are arranged for targeted generation of light distribution pixels, each pixel to be generated corresponding to a spatial angle region, the light of the imaging element corresponding to the corresponding pixel being emitted into the spatial angle region, the headlamp being configured to drive each imaging element individually via pulse width modulation so as to pre-determine the luminous flux generated by the imaging element by means of the ratio of the on-state (AS1-AS3) and off-state of the pulse width modulation. - Camera (3), which has an image sensor to detect image information from a spatial angular region illuminated by the headlight (2) in front of the vehicle (1). - A control unit for driving the headlights (2) and the camera (3), The camera (3) is characterized in that its image sensor has a plurality of sensor elements arranged in a matrix or array to detect image information from different spatial angle regions. The camera (3) is configured to read each sensor element or group of sensor elements sequentially in time. The control unit is configured to adjust the time overlap (U1-U3) between the on-state of the driving control of the imaging element (AS1-AS3) and the reading of at least one sensor element of the camera (3) according to the magnitude of the light flux generated by the imaging element. The light generated by the imaging element is incident on the at least one sensor element.

2. The apparatus according to claim 1, characterized in that, The control unit is configured to adjust the time overlap (U1-U3) between the on-state of the driving control of the imaging element (AS1-AS3) and the reading of the sensor element of the camera (3) according to the magnitude of the light flux generated by the imaging element, so that the light distribution detected by the camera (3) is different from the light distribution that a human observer can perceive in front of the motor vehicle (1), and the light generated by the imaging element is incident on the sensor element.

3. The apparatus according to claim 1 or 2, characterized in that, The headlight is configured to: drive a first imaging element by pulse width modulation to generate a first luminous flux emanating from the first imaging element, and drive a second imaging element by pulse width modulation to generate a second luminous flux emanating from the second imaging element, wherein the second luminous flux is greater than the first luminous flux.

4. The apparatus according to claim 3, characterized in that, The control unit is configured to drive the headlight (2) and the camera (3) such that the time overlap between the turn-on phase of the drive of the first imaging element and the reading of at least one first sensor element of the camera (3) is at most 50% greater than the time overlap between the turn-on phase of the drive of the second imaging element and the reading of at least one second sensor element of the camera (3), wherein light generated by the first imaging element is incident on the first sensor element and light generated by the second imaging element is incident on the second sensor element.

5. The apparatus according to claim 3, characterized in that, The control unit is configured to drive the headlight (2) and the camera (3) such that the time overlap between the turn-on phase of the drive of the first imaging element and the reading of at least one first sensor element of the camera (3) is at most 20% greater than the time overlap between the turn-on phase of the drive of the second imaging element and the reading of at least one second sensor element of the camera (3), wherein light generated by the first imaging element is incident on the first sensor element and light generated by the second imaging element is incident on the second sensor element.

6. The apparatus according to claim 3, characterized in that, The control unit is configured to drive the headlight (2) and the camera (3) such that the time overlap between the turn-on phase of the drive of the first imaging element and the reading of at least one first sensor element of the camera (3) is the same as the time overlap between the turn-on phase of the drive of the second imaging element and the reading of at least one second sensor element of the camera (3), wherein light generated by the first imaging element is incident on the first sensor element and light generated by the second imaging element is incident on the second sensor element.

7. The apparatus according to claim 3, characterized in that, The headlight (2) is configured to generate a low beam distribution with a light-dark boundary, wherein light generated by the first imaging element is emitted into a spatial angle region (RS1, RS2) set above the light-dark boundary, and light generated by the second imaging element is emitted into a spatial angle region (RS3) set below the light-dark boundary.

8. The apparatus according to claim 1 or 2, characterized in that, The size and / or shape of the spatial angular region into which light is emitted by one of the imaging elements differs from the size and / or shape of the spatial angular region into which image information is detected by a sensor element of the image sensor.

9. The apparatus according to claim 1 or 2, characterized in that, The size and / or shape of the spatial angular region into which light is emitted by one of the imaging elements corresponds to the size and / or shape of the spatial angular region into which image information is detected by one of the sensor elements of the image sensor.

10. The apparatus according to claim 1 or 2, characterized in that, The camera (3) is configured to read each sensor element row by row or column by column.

11. The apparatus according to claim 1 or 2, characterized in that, The imaging element on at least one active surface is configured as a light-emitting diode or a laser diode.

12. The apparatus according to claim 11, characterized in that, The imaging component is a solid-state LED array.

13. The apparatus according to claim 1 or 2, characterized in that, The imaging component is configured as a digital micromirror device or an LCoS or an LC display, or the imaging component includes a digital micromirror device or an LCoS or an LC display.

14. A method for synchronizing the headlights (2) of a motor vehicle (1) with a camera (3), wherein, The headlight (2) has an imaging member with an active surface, on which imaging elements in the form of a matrix or array are arranged for the targeted generation of light distribution pixels. Each pixel to be generated corresponds to a spatial angle region. The light corresponding to the corresponding pixel of the imaging element is emitted into the spatial angle region. The headlight (2) drives each imaging element individually via pulse width modulation so that the light flux generated by the imaging element is pre-defined by the ratio of the on-state (AS1-AS3) and off-state of the pulse width modulation. The camera (3) has an image sensor so as to capture the light emitted by the headlight (2) from the vehicle (1) The camera (3) detects image information in a spatial angle region illuminated in front, characterized in that the image sensor of the camera (3) has a plurality of sensor elements arranged in the form of a matrix or array, each of the sensor elements detects image information from a different spatial angle region, the camera (3) reads each sensor element or group of sensor elements sequentially in time, and adjusts the time overlap (U1-U3) between the on-state of the driving control of the imaging element (AS1-AS3) and the reading of at least one sensor element of the camera (3) according to the magnitude of the light flux generated by the imaging element, and the light generated by the imaging element is incident on the at least one sensor element.

15. The method according to claim 14, characterized in that, The method is implemented using the apparatus according to any one of claims 1 to 13.

16. The method according to claim 14 or 15, characterized in that, The first imaging element is driven by pulse width modulation to generate a first luminous flux, and the second imaging element is driven by pulse width modulation to generate a second luminous flux, wherein the second luminous flux is greater than the first luminous flux.

17. The method according to claim 16, characterized in that, The headlights (2) and the camera (3) are driven such that the time overlap between the turn-on phase of the drive of the first imaging element and the reading of at least one first sensor element of the camera (3) is up to 50% greater than the time overlap between the turn-on phase of the drive of the second imaging element and the reading of at least one second sensor element of the camera (3), wherein light generated by the first imaging element is incident on the first sensor element and light generated by the second imaging element is incident on the second sensor element.

18. The method according to claim 16, characterized in that, The headlights (2) and the camera (3) are driven such that the time overlap between the turn-on phase of the drive of the first imaging element and the reading of at least one first sensor element of the camera (3) is up to 20% greater than the time overlap between the turn-on phase of the drive of the second imaging element and the reading of at least one second sensor element of the camera (3), wherein light generated by the first imaging element is incident on the first sensor element and light generated by the second imaging element is incident on the second sensor element.

19. The method according to claim 16, characterized in that, The headlights (2) and the camera (3) are driven such that the time overlap between the turn-on phase of the drive of the first imaging element and the reading of at least one first sensor element of the camera (3) is the same as the time overlap between the turn-on phase of the drive of the second imaging element and the reading of at least one second sensor element of the camera (3), wherein light generated by the first imaging element is incident on the first sensor element and light generated by the second imaging element is incident on the second sensor element.

20. A motor vehicle, said motor vehicle comprising the means according to any one of claims 1 to 13.

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