Method for the adaptive control of a high-resolution headlight system

Abstract

Method for the adaptive control of a high-resolution headlight system, comprising the following steps: - Dividing an area to be illuminated (1) into a plurality of sectors; - Illuminate the area (1) with at least one high-resolution spotlight; - Detecting the intensities of light in the individual sectors of the illuminated area (1) with at least one light sensor, wherein the light reflected from the individual sectors as well as the light generated in the individual sectors is detected; and - Reduction of the illumination of sectors whose detected light intensity exceeds an upper threshold value by appropriately controlling pixels of the high-resolution headlight until the respective detected light intensity of these sectors reaches a predetermined first target value, whereby, with a certain characteristic distribution of light intensities over different sectors and / or changes in light intensities over a period of time, the illumination of certain sectors is reduced or increased.

Description

[0001] The present invention relates to a method and a device for adaptive control of a high-resolution headlight system for illuminating an area to be illuminated.

[0002] Modern headlight systems feature control units that allow for freely programmable and modulated light output, enabling any desired light distribution. These systems utilize specialized headlights that incorporate, for example, an LCD display as a louvre, which is controlled by the control unit. By precisely controlling the louvre, virtually any desired illumination of areas in front of the headlight can be achieved. Individual sectors can be completely masked out or illuminated less intensely than others. Due to their precise controllability, these headlight systems are also known as high-resolution or HD headlight systems.

[0003] Known adaptive headlight systems can be configured to control the illumination of areas positioned in front of the high-definition headlights in such a way that certain areas, such as oncoming vehicles, are not illuminated to prevent dazzling the drivers of those vehicles. The higher the resolution of the headlights, the more precisely certain areas can be masked without negatively affecting the illumination of adjacent areas.

[0004] To determine the areas to be masked, known adaptive headlight systems equipped with a camera can identify objects that should not be illuminated. For this purpose, the camera records the surroundings within the headlight's illumination range and compares the recorded objects with known objects for identification. If an object to be masked is identified, the system sends a corresponding control signal to the LCD screen.

[0005] Various sensor-based headlight systems and methods for operating headlight systems of this type are known from documents DE 60 2005 004 544 T2, DE 10 2011 055 794 A1, DE 10 2010 049 215 A1 and DE 10 2005 061 590 A1.

[0006] Conventional adaptive headlight systems have the disadvantage that the adaptive control of the headlights is based solely on qualitative characteristics, often resulting in suboptimal illumination of the areas to be lit. Light-reflecting objects, in particular, pose a significant problem for these systems, as the reflected light can dazzle the driver and thus considerably impair road safety.

[0007] It is therefore the object of the present invention to provide a method and a device for the adaptive control of a high-resolution headlight system for illuminating an area to be illuminated, which do not have the aforementioned disadvantages.

[0008] The task is solved by a method for the adaptive control of a high-resolution headlight system, comprising the following steps: - Dividing an area to be illuminated into a plurality of sectors; - Illuminate the area with at least one high-resolution spotlight; - Detecting the intensities of light in the individual sectors of the illuminated area with at least one light sensor, detecting both the light reflected from the individual sectors and the light generated in the individual sectors; and - Reduction of the illumination of sectors whose detected light intensity exceeds an upper threshold value by appropriately controlling the pixels of the high-resolution headlight until the respective detected light intensity of these sectors reaches a first target value, whereby, with a certain characteristic distribution of light intensities over different sectors, the illumination of certain sectors is reduced or increased.

[0009] In this way, a sector of the illuminated area containing a highly reflective object or a strong light source is illuminated less intensely than a sector containing no reflective object, only a less reflective object, or a weak light source. Thus, for example, the intensities of the light rays reflected by the different sectors are limited to a maximum, so that a driver of a vehicle equipped with a headlight system according to the invention is not, or at least less, dazzled by such light reflections. Furthermore, a uniform illumination of the illuminated sectors is achieved.Using a method according to the invention, both qualitative and quantitative adjustment of the illumination can be achieved, thus further optimizing the illumination compared to conventional methods. Preferably, the upper threshold corresponds to the first setpoint. According to the invention, the first setpoint can also be below the upper threshold.

[0010] In an advantageous embodiment of the method, the illumination of sectors whose detected light intensity falls below a lower threshold is increased until the respective detected light intensity of these sectors reaches a predetermined second setpoint. In this way, sectors containing highly light-absorbing objects are illuminated more intensely than sectors containing less light-absorbing objects. Thus, the intensity of the reflected light in these sectors is adjusted to each other, giving the driver the impression of more uniform illumination of the illuminated area. Preferably, the lower threshold corresponds to the second setpoint. According to the invention, the second setpoint can also be above the lower threshold.

[0011] According to the invention, the illumination of certain sectors is reduced or enhanced based on a specific characteristic distribution of light intensities across different sectors. Such a characteristic distribution of light intensities could be, for example, the light from the headlights of an oncoming vehicle or the taillights of a preceding vehicle. The light intensities of the headlights or taillights, as well as their position within the illuminated area, are first detected. After successful identification of the oncoming or preceding vehicle based on this data, a control signal is sent to the high-definition headlight to mask a corresponding area of ​​the oncoming or preceding vehicle. Alternatively or additionally, the illumination of certain sectors can be controlled depending on a specific characteristic change in light intensities over a certain period of time. Such control is, for example,This is advantageous, for example, when environmental factors such as precipitation or fog need to be taken into account when controlling the lighting.

[0012] Preferably, the light sensor is designed as a camera. More preferably, the camera has a resolution corresponding to that of the HD spotlight, with each pixel of the HD spotlight preferably being assigned a pixel of the camera, so that a change in the emitted light intensity of a pixel of the HD spotlight causes a corresponding change in the light intensity detected by the corresponding pixel of the camera. Thus, by comparing the light intensities determined by the individual pixels of the camera with upper and lower threshold values, the pixels of the HD spotlight whose emitted light intensity is too high or too low can be uniquely identified.

[0013] Preferably, the upper threshold and / or lower threshold and / or first setpoint and / or second setpoint can be individually adjusted. Lowering the upper threshold reduces the maximum acceptable intensity of reflected light in a sector. This can be advantageous for drivers who are easily dazzled. Raising the lower threshold improves the illumination of areas where objects with low light reflection or high light absorption are located. This can be particularly beneficial for drivers with poor night vision. Thus, the inventive method for adaptively controlling a headlight system can be adapted to the individual needs of different drivers.

[0014] In an advantageous embodiment of the method, the sectors are assigned to corresponding pixels of the high-resolution headlight. In this way, it is possible to determine the sector whose light intensity will change most significantly when the intensity of emitted light from a pixel of the high-resolution headlight is altered. Thus, controlling the high-resolution headlight to achieve a specific illumination of the sectors is easily achievable.

[0015] It is particularly advantageous if the light sensor is designed to distinguish light intensities at intervals of at least 16 grayscale levels. Such light sensors are already commercially available and can be manufactured cost-effectively. Furthermore, 16 evenly spaced grayscale levels are well-suited to defining a sufficiently precise spectrum of different light intensities that meets the requirements for adaptive control of a high-resolution headlight system. White represents the highest light intensity, and black represents zero light intensity.

[0016] Preferably, the sectors are assigned to corresponding pixels of the light sensor. Thus, each pixel of the light sensor represents a sector of the area to be illuminated. This has the advantage that the light sensor can determine an accurate representation of the intensities of the light reflected by the sectors, and based on this representation, the high-resolution headlight can be controlled according to the threshold and target values.

[0017] Furthermore, the problem according to the invention is solved by a device for adaptive control of a high-resolution headlight system, comprising: - at least one high-resolution spotlight; - at least one light sensor to determine the distribution of intensities of reflected light in the area to be illuminated; - a storage unit for storing specific threshold values ​​and / or target values ​​of light intensities; - a computing unit for determining deviations between actual values ​​and threshold values, as well as between actual values ​​and target values ​​of reflected light intensities; - a control unit for controlling the high-resolution headlight; and - A control unit for adjusting the control of the high-resolution headlight based on the deviations in light intensity determined by the processing unit. The device is configured to implement a method according to the invention for the adaptive control of a high-resolution headlight system.

[0018] In an advantageous embodiment of the invention, at least one headlight comprises an LCD aperture, a digital micromirror device (DMD), or a scanning system, in particular a scanning laser system, for controlling the illumination of the sectors. It is important that the system for controlling the illumination of the sectors fulfills the functions of a high-resolution aperture (HD aperture). Such an aperture has the property that its light transmission, for example in the case of an LCD aperture by controlling the liquid crystals, can be varied almost arbitrarily across its effective aperture surface. By means of such an aperture, the light emission of each pixel of a high-resolution headlight can be selectively limited.

[0019] Further advantages, features, and details of the invention will become apparent from the following description, in which exemplary embodiments of the invention are described in detail with reference to the drawings. The features mentioned in the claims and in the description can each be essential to the invention individually or in any combination. The drawings show: Fig. 1 schematically depicts an illuminated area with a highly reflective object and a weakly reflective object arranged within it; Fig. 2 a schematic diagram of the recorded intensities of the reflected light of the illuminated area from Fig. 1, and Fig. 3 a schematic flowchart of a method according to the invention.

[0020] Fig. Figure 1 schematically shows an illuminated area 1 represented as a rectangle. The illuminated area 1 is a two-dimensional representation of a three-dimensional space, such as a central section of a vehicle's surroundings illuminated by a headlight, from the perspective of a camera mounted on the vehicle.

[0021] As from Fig. As can be seen in Figure 1, a highly reflective object 2 and a weakly reflective object 3 are arranged in the illuminated area 1. The highly reflective object 2 could be, for example, a road sign or a guidepost with a highly reflective surface. Light emitted from a headlight enters the illuminated area 1 and is reflected more strongly by the highly reflective object 2 than by the weakly reflective object 3. Therefore, the highly reflective object 2 is shown white and the weakly reflective object 3 is shown gray in this figure. The weaker an object reflects light, the darker it appears in this illustration. The hatched area 4 of the illuminated area 1 hardly reflects the light but essentially absorbs it. The hatched area 4 should therefore have been shown black, but this has been omitted in this view for the sake of clarity.

[0022] Fig. Figure 2 shows a schematic diagram illustrating the intensities of the reflected light from the illuminated area 1. The diagram has a vertical pixel axis 10 and a horizontal pixel axis 20, each with 300 pixels. The position of an object within the illuminated area 1 can be precisely determined using the vertical pixel axis 10 and the horizontal pixel axis. The intensity of the reflected light from the highly reflective object 2 is represented by the high light intensity 40, and the intensity from the weakly reflective object 3 by the low light intensity 50. In this example, the high light intensity 40 is assigned a value of approximately 1, and the low light intensity a value of approximately 0.4. With an upper threshold of, for example, 0.8, the system would selectively reduce the intensity of the illumination on the highly reflective object 2 until the high light intensity 40 is only approximately 0.8.With a lower threshold of 0.5, the system would selectively illuminate the weakly reflective object 3 more intensely until the weak light intensity 50 is approximately 0.5. Furthermore, the system would likely illuminate the hatched area 4 of the illuminated region 1 with the intensity of a predefined base light distribution, since no light with an intensity exceeding the lower threshold would be reflected from the hatched area 4 sector. Additionally, depending on the requirements, specific sectors of the illuminated region 1 can also be selectively illuminated less, for example, if illuminating these sectors is not practical.

[0023] In Fig.Figure 3 schematically illustrates the process of a method according to the invention. In the "Subdivide" step 100, an area 1 to be illuminated is subdivided into individual sectors, which preferably correspond to the pixels of a device for measuring light intensity, such as a suitable camera. Each sector is thus assigned a pixel of the camera. In the "Illuminate" step 200, the area 1 is illuminated by a high-resolution spotlight according to a predetermined illumination pattern. The illumination of the area 1 can be, for example, uniform or according to any desired pattern. Reflective objects arranged in the area 1 reflect the light, the intensity of which is measured for each pixel by the light intensity measuring device in the "Detect" step 300.This creates an accurate image of the light reflections, precisely reflecting the intensity and relative position of the light reflection to the device used to measure the light intensity.

[0024] The illumination of sectors reflecting light with an intensity above an upper threshold is reduced accordingly in process step "Reduce" 400 to achieve a first target value. The illumination of sectors reflecting light with an intensity below a lower threshold is increased accordingly in process step "Increase" 500 to achieve a second target value. The first target value is preferably less than or equal to the upper threshold, and the second target value is preferably greater than or equal to the lower threshold. In process step "Detect" 300, it is regularly checked whether further adjustments according to process step "Reduce" 400 or process step "Increase" 500 are necessary. Reference symbol list 1 area 2. Highly reflective object 3. Weakly reflective object 4 Hatched area 10 Vertical pixel axis 20 Horizontal pixel axis 30 Light intensity axis 40 High light intensity 50 Low light intensity 100 Process step “Subdivide” 200 Process step “Illuminate” 300 Process step “Capture” 400 Process step “Reduce” 500 Process step “Increase”

Claims

[1] Method for adaptive control of a high-resolution headlight system, comprising the steps: - dividing an area to be illuminated (1) into a plurality of sectors; - illuminating the area (1) with at least one high-resolution spotlight; - detecting the intensities of light of the individual sectors of the illuminated area (1) with at least one light sensor, whereby the light reflected by the individual sectors and the light generated in the individual sectors is detected; and - Reduction of the illumination of the sectors whose detected light intensity exceeds an upper threshold value by appropriately controlling pixels of the high-resolution headlight until the respective detected light intensity of these sectors reaches a predetermined first target value, whereby the illumination of certain sectors is reduced or increased given a certain characteristic distribution of the light intensities over different sectors and / or change in the light intensities over a period of time. [2] Method according to claim 1, characterized by that the illumination of sectors whose detected light intensity falls below a lower threshold is increased until the respective detected light intensity of these sectors reaches a predetermined second target value. [3] Method according to one of the preceding claims, characterized by that the light sensor is designed as a camera. [4] Method according to one of the preceding claims, characterized by that the level of the upper threshold and / or lower threshold and / or first setpoint and / or second setpoint can be individually changed. [5] Method according to one of the preceding claims, characterized by that the sectors are assigned to corresponding pixels of the high-resolution headlight. [6] Method according to one of the preceding claims, characterized by that the light sensor is designed to distinguish light intensities at intervals of at least 16 gray levels. [7] Method according to one of the preceding claims, characterized by , the sectors are assigned to corresponding pixels of the light sensor. [8] Device for adaptive control of a high-resolution headlight system, comprising: - at least one high-resolution headlight; - at least one light sensor for determining a distribution of intensities of reflected light of the area to be illuminated (1); - a memory unit for storing upper thresholds, lower thresholds and setpoint values ​​of light intensities; - a computing unit for determining deviations between actual values ​​and threshold values ​​as well as between actual values ​​and target values ​​of light intensities; - a control unit for controlling the high-resolution headlight; and - a control unit for adapting the control of the high-resolution headlight based on the deviations in light intensities determined by the computing unit; wherein the device is designed to carry out a method according to one of claims 1 to 7. [9] Device according to claim 8, characterized bythat at least one spotlight has an LCD aperture, a digital micromirror device or a scanning system to control the illumination of the sectors.

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