JP4523526B2 - Headlamp system - Google Patents

Description

  The present invention relates to a headlamp system for controlling lighting of a headlamp of a vehicle such as an automobile, and more particularly to control irradiation characteristics of a headlamp of the own vehicle in real time and to safely drive the own vehicle and other vehicles. It relates to the secured headlamp system.

  From the standpoint of safe driving of an automobile, an illumination characteristic in which the brightness of the headlamp is high and the illumination range is wide is preferable. However, such an illumination characteristic increases the risk of dazzling other vehicles such as an oncoming vehicle and a preceding vehicle. In recent years, in order to satisfy these conflicting requirements, a headlamp system has been proposed in which the irradiation characteristics during normal driving are enhanced while the irradiation characteristics are limited when another vehicle approaches. For example, in Patent Document 1, a bright area with high brightness corresponding to a headlamp or tail lamp of another vehicle is detected from an image obtained by imaging the front of the own vehicle with a camera, and the direction of the bright area is obtained to determine the direction of the bright area. Dazzling other vehicles is prevented by controlling the irradiation characteristics of the car headlamps. In the technique of this patent document 1, since it is not premised that the bright area in the image is a light source other than another vehicle such as a street lamp, the irradiation characteristic is limited even when the bright area by the street lamp is recognized. There are cases where the irradiation characteristics of the own vehicle are restricted more than necessary. On the other hand, Patent Document 2 performs signal processing on an image obtained by imaging, and performs a required calculation so that a bright area in the image is either a street light or a light source (lamp light) of another vehicle. A technique for determining whether or not the irradiation characteristics of the vehicle are not unnecessarily restricted has been proposed. As this signal processing, the captured image is binarized to extract a contour line, a pair having symmetry is extracted from the size of the bright region, and when this symmetry can be traced, these are extracted. This is a technology for obtaining the distance between vehicles as a light source of another vehicle and recognizing a preceding vehicle and an oncoming vehicle by a change in the distance between vehicles.

Patent Document 3 discloses a technique for determining whether a bright region in a captured image is a light source of another vehicle, or whether light from the light source of the own vehicle is reflected light reflected by a road sign or the like. Is described. In this technology, when a bright area is detected in an image, the light source of the own vehicle is dimmed, and when the brightness of the bright area decreases following the correlation, the correlation between the bright area and the light source of the own vehicle is established. And the bright area is determined as the reflected light of the own vehicle.
JP 2003-267125 A JP-A-8-166221 Japanese Patent No. 3568210

  In the technique of Patent Document 2, in order to determine a bright region of an image captured by a camera as a light source of another vehicle, it takes too much time for signal processing for performing the determination, and it is difficult to control real-time irradiation characteristics. In order to realize this, it is necessary to provide a high-accuracy camera and a high-speed CPU for performing processing at high speed, which causes high costs. On the other hand, in the technique of Patent Document 3, since it is only necessary to determine the correlation between the two by simply measuring the brightness of the bright area when the light source of the own vehicle is dimmed, real-time control is realized and the cost is reduced. It is effective in avoiding high. Actually, the light is greatly reduced to such an extent that a bright region cannot be confirmed in the image.

  However, since the technique of Patent Document 3 merely proposes a technique for determining whether or not the light source is the own vehicle, a problem may occur in the front illumination using the light source of the own vehicle. For example, when applied to an actual automobile, if the light source of the traveling vehicle is dimmed and it is determined that there is a correlation with a decrease in brightness of the bright region in the image, the bright region is reflected by the reflected light of the vehicle. The light source of the own vehicle is returned to the initial brightness again, but at that time, a bright area due to the reflected light of the own car appears again in the image, and this bright area is the same as the bright area due to the reflected light first. Since there is no technology for determining whether or not there is, the light source of the own vehicle is dimmed again for this bright region, and thereafter, this control is repeated, and as a result The light source of the car is in a blinking state, and it becomes impossible to properly illuminate the front of the host vehicle, which is not preferable in terms of safe driving. Also, even if the light source of the host vehicle is dimmed, the brightness of the bright area in the image does not decrease, and when it is determined that there is no correlation between the two, it is recognized as the light source of the other vehicle. In this case, the own vehicle travels with the light source dimmed, the front of the own vehicle becomes dark, and the own vehicle becomes difficult to recognize from other vehicles, which is not preferable in terms of safe driving.

  An object of the present invention is to provide a headlamp system that ensures safe driving by preventing the own vehicle from being dimmed more than necessary when preventing dazzling of other vehicles and controlling the irradiation characteristics of the own vehicle. It is.

The present invention includes a camera that captures the front of a vehicle, an image processing unit that detects a high-luminance portion in an image captured by the camera, a lamp control unit that controls the light intensity of a headlamp of the host vehicle, and the lamp control. And a processing device for determining whether the high luminance part is a light source of another vehicle or a reflected light of the light source of the own vehicle from the correlation between the control of the luminous intensity at the unit and the detected luminance of the high luminance part. In the determination by the processing device, the lamp control unit determines that the light intensity of the headlamp is a predetermined light intensity of 10% of the maximum light intensity and that the light source of the other vehicle is based on the determination result by the processing device . In some cases, the decrease in the light intensity is stopped, and when it is determined that the light is reflected from the host vehicle, the decrease in the light intensity is continued .

Here, in the present invention, when the brightness of the headlamp is decreased at the predetermined brightness described above, and the brightness of the high brightness portion is reduced following, the high brightness portion is determined to be reflected light of the headlamp of the own vehicle. When the luminance of the high luminance portion does not change following the determination, it is determined that the light source is the other vehicle. Also, the camera performs the imaging at every predetermined timing, the image processing unit performs the association of high luminance portion in the image captured, to be detected over time the brightness of the high luminance portion is determined that the identical object preferable.

According to the present invention, it is possible to determine whether the light source of another vehicle can be obtained simply by correlating the change in luminance of the high luminance portion in the image detected by the image processing unit with the change in luminous intensity of the headlamp of the own vehicle controlled by the lamp control unit. It is possible to easily determine whether the light is reflected from the light source of the host vehicle, the determination processing process by the CPU is small, determination in real time is possible, and lamp control based on the determination is possible. Further, when determining, the light intensity of the light source of the own vehicle is decreased by a predetermined light intensity of 10% of the maximum light intensity, and the determination is made based on whether or not the luminance of the high-luminance portion changes , and the light source of the other vehicle is determined When this happens, the light intensity continues to decrease, and when it is determined that the light is reflected from the own vehicle, the light intensity decrease is stopped. The vehicle is not darkened and safe driving is ensured. This eliminates the need for a high-accuracy camera and high-speed CPU, allows the system to be configured at low cost, and provides real-time control of appropriate irradiation characteristics that ensure safe driving of the vehicle even when dazzling other vehicles is prevented. Can be realized.

  Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a conceptual configuration diagram of an embodiment in which the present invention is applied to an automobile headlamp system. A lamp control unit 2 is connected to the left and right headlamps LL and RL of the automobile CAR, and the lamp control unit 2 controls the irradiation characteristics of the headlamps LL and RL, here the luminous intensity (brightness) of each headlamp. Configured to be dimmable. Here, the lamp control unit 2 is configured so that the light intensity can be gradually reduced in units of minute levels when the headlamps LL and RL are dimmed. The car CAR includes a camera 3 including a CCD image pickup device that picks up the front of the vehicle and an image processing unit 4 that processes an image picked up by the camera 3. As will be described later, the image processing unit 4 is capable of recognizing a bright area in a captured image and detecting the brightness (brightness) of the bright area. In addition, the lamp control unit 2 and the image processing unit 4 are connected to a CPU (Central Processing Unit) 1, and the CPU 1 controls the brightness of the lamp controlled by the lamp control unit 2 and the brightness recognized by the image processing unit 4. Based on the brightness of the area and its change, it is determined whether the bright area is a light source of another vehicle or a reflected light of the light source of the own vehicle. Based on the determination result, the headlamps LL, The light intensity of the RL is controlled.

  Control of the headlamp irradiation characteristics by the headlamp system having the above configuration will be described with reference to the main flowchart of FIG. First, the front of the vehicle is imaged by the camera 3 at a predetermined timing (S101). The image processing unit 4 determines whether or not the entire captured image is bright (S102). The image captured by the camera 3 during the daytime is a bright image as a whole. In this image, each light source such as the tail lamp of the preceding vehicle and the headlamp of the oncoming vehicle is rarely captured as a bright luminance portion. On the other hand, an image captured by the camera 3 at night is a dark image, and each light source such as a tail lamp of a preceding vehicle and a head lamp of an oncoming vehicle is captured as a bright luminance portion in the image. Therefore, when the image is bright, the lamp control of the headlamps LL and RL is not performed, the process returns to step S101, and the next imaging is executed at a timing after a predetermined time. If the image is dark, the image processing unit 4 detects a high-luminance portion that is a bright region in the image obtained by imaging (S103).

  The detection step S103 of the bright area in the image processing unit 4, that is, the high luminance part will be described. FIG. 3 is a flowchart thereof, and FIG. 4A is a schematic diagram of a captured image. In this high luminance portion detection step S103, as shown in FIG. 4A, the image processing unit 4 divides the entire image V captured by the camera 3 into a large number of blocks as a predetermined matrix configuration. Is detected (S201). In this example, it is assumed that the high-intensity part P1 by the light source of the preceding vehicle, the high-intensity part P2 by the light source of the oncoming vehicle, and the high-intensity part P3 of the road sign are captured in the image V. Then, the average luminance of all the blocks is calculated and set as a threshold value (S202), and the individual luminance of each block is compared with the threshold value (S203), thereby detecting a block in which a high luminance part exists. (S204). The brightness of each block can be detected at the light and dark levels in the image, and the high brightness portion can be detected by comparing the light and dark levels with each other. The detected block having the high luminance portion is recorded in the memory (S205). Next, when there is an image captured at the next timing (S206), the image processing unit 4 returns to step S201 and performs the same processing on the next image to determine a block in which the high luminance portion exists. Detect and record in memory.

  Next, as shown in the main flow of FIG. 2, the CPU 1 associates the high-intensity part (block) of the previous image detected by the image processing unit 4 with the high-intensity part (block) of the current image (S104). ). In this association, although a flowchart is omitted, a high-luminance portion whose position changes in the image as the automobile travels is obtained among the detected high-luminances. In general, a high-intensity part existing in an image is recognized by moving at a very small distance in an image sequentially captured as the vehicle travels, thereby recognizing the high-intensity part of the same target in each image. . For example, although details will be described later, each of the high-intensity portions P1, P2, and P3 in the image of FIG. 4A previously imaged is captured next in FIG. 4B and FIG. 4C. The high-intensity portion P1 in which the position of high-intensity in the image does not change much with respect to the image in FIG. In addition, the high luminance part P2 that gradually increases in brightness and moves at a high speed in the right direction in the image is likely to be a light source of an oncoming vehicle and is associated with the same object. Alternatively, the high-intensity part P3, which has substantially the same luminance but follows the vehicle speed of the own vehicle and moves to the right or left in the image at a relatively low speed, is reflected light from the vehicle by road signs or fixed objects. Associate with the same object. This association can be realized by a process of detecting high brightness and its position in an image and comparing them among a plurality of images. Therefore, the CPU 1 can be realized with a simple processing flow and does not require a high-speed CPU.

  In addition, about the high-intensity part which cannot be linked | related in step S104 and S105, it processes as follows. That is, when there is a high-luminance portion that is present in the current image but not present in the past image (S108), it is newly registered as initial data for associating with subsequent images. (S109). In this case, the association with the high luminance part in the subsequent images is performed. Further, the association processing is canceled for the high-luminance portion that was not present in the current image but was present in the past image (S110).

  Accordingly, the CPU 1 is present in the image, and whether the associated high-intensity part is the light source of the preceding vehicle or the oncoming vehicle, or the reflected light of the headlamp light of the vehicle by a road sign or a fixed object. A determination is made (S106). In this determination, as shown in the flow of FIG. 5, first, a dimming signal is sent from the CPU 1 to the lamp control unit 2 to diminish the luminous intensity of the headlamps LL and RL (S301). At this time, the light intensity reduction of the headlamp by the lamp control unit 2 is a minute light reduction amount. This light reduction is a light reduction within a range that cannot be identified with the naked eye by the driver. For example, a light intensity of about 10% of the maximum light intensity of the headlamp is set as a minute light reduction amount.

  After dimming the headlamp, the image processing unit 4 detects the luminance of the high luminance part in the image again (S302). The detection flow of the high-intensity part is almost the same as the flow shown in FIG. 3, but only for one captured image. In the CPU 1, based on the detected luminance, when the luminance of the high luminance portion associated with the same object does not change in step S104, the high luminance portion is determined as the light source of the oncoming vehicle or the preceding vehicle (S303, S304). . That is, when the high-intensity part existing in the image is a light source such as a tail lamp of a preceding vehicle, the distance between the host vehicle and the preceding vehicle is almost constant, so the position change of the high-intensity part in the image is small. The high-intensity part is determined to be the light source of the preceding vehicle. In addition, when the high-luminance portion present in the image is a light source such as a headlamp of an oncoming vehicle, the luminance of the high-luminance portion is at a remarkably high level, and the high-luminance portion is displayed on the right or left side of the screen at an extremely high speed. Since it moves to the lower right direction, the said brightness | luminance part determines with it being a light source of an oncoming vehicle. Further, when the luminance of the high luminance part associated with the same object is reduced (S303), the high luminance part is reflected light that is reflected from the road signs and fixed objects by the light emitted from the headlamps LL and RL of the own vehicle. It is determined that there is (S304).

After the determination is made in this way, the dimming control S107 is performed. As shown in the flow of FIG. 6, the dimming control S107 has no possibility of dazzling other vehicles when it is determined that the reflected light of the vehicle light source is a road sign or a fixed object (S401). The brightness of the headlamp of the host vehicle is increased (S402), and then a high-luminance portion of the image captured by the camera 3 is detected (S403). It is determined whether or not a high brightness portion has been detected (S404). When the high brightness portion is detected, the headlamp is dimmed again (S405), and the high brightness portion in the image captured by the camera 3 is detected again. (S406). It is determined whether or not the brightness of the high brightness portion is lowered (S407), and when the brightness is lowered, it can be confirmed that the light is reflected. Hereinafter, as long as the high brightness portion is detected (S408), the process returns to step S402 and the same flow is repeated. If there is no high luminance part in steps S404 and S408, and if the high luminance part does not follow the decrease in the luminous intensity of the headlamp of the host vehicle (S407), the flow ends. As a result, as shown in the solid line in FIG. 7A, the timing diagram of the luminous intensity control of the headlamps LL and RL, the dimming by the lamp control unit 2, the dimming is stopped, and the light is returned to the initial luminous intensity. The control will be repeated. Since the amount of light reduction in the vehicle light and the light reduction in the back light is so small that it cannot be identified with the naked eye, the driver does not feel bothersome, while the illumination in front of the vehicle is almost dark. This will ensure safe driving. Incidentally, the broken line in the figure is a characteristic of conventional control with a large amount of light reduction, and because the light intensity is dimmed by turning the headlamp on and off, the driver feels bothersome and the front is at the time of dimming It becomes dark and is not preferable in terms of safe driving.

  On the other hand, as a result of the determination in step S106, when it is determined that the high luminance part is a light source of another vehicle such as a preceding vehicle or an oncoming vehicle (S401), when the change in luminance is small as described above, The light source of the preceding vehicle is determined (S409). In this case, the headlamps LL and RL of the own vehicle are dimmed (S410), and this dimming is performed twice (S411), resulting in two stages. Only do dimming. As a result, as shown in the timing diagram with a solid line in FIG. 7B, the lamp controller 2 performs control so that the light reduction amount of the headlamps LL and RL does not fall below a predetermined light reduction amount. That is, in the case of a preceding vehicle, there is less glare due to the headlamps LL and RL of the own vehicle than in the case of an oncoming vehicle. Thereby, while reducing the luminous intensity of the headlamps LL and RL of the own vehicle to such an extent that the preceding vehicle is not dazzled, the illumination in front of the own vehicle can be maintained at the brightness required for safe driving. Incidentally, when the luminous intensity is lowered at a stroke as shown by the broken line in the drawing, the front illumination becomes dark, which is not preferable in terms of safe driving.

  If the brightness of the high brightness portion gradually increases as a result of the determination in step S106, it is determined that the light source is the oncoming vehicle approaching (S409). The lamps LL and RL are dimmed (S412), a high-luminance part in the image captured by the camera 3 is detected (S413), and if a high-luminance part is detected, the flow returns to step S412 again. Repeat as long as there is a part (S414). As a result, as shown in the timing diagram with a solid line in FIG. 7 (c), the amount of light reduction is increased step by step in correspondence with the increase in the brightness of the oncoming vehicle, and the light intensity of the headlamps LL and RL of the own vehicle is stepped. Decrease. Therefore, although the lighting in front of the host vehicle becomes darker, the other vehicle can be confirmed by the light source of the oncoming vehicle, and safe driving is ensured by the minimum brightness required. Is prevented. Incidentally, if the light intensity of the host vehicle is lowered at a stretch as shown by the broken line in the figure, the illumination in front of the host vehicle becomes dark, which is not preferable in terms of safe driving.

  When the own vehicle passes the oncoming vehicle and the target high luminance part disappears from the image or the luminance decreases, the association shown in step S104 is lost. In this case, the headlamp of the own vehicle is lost. Increasing the light intensity of LL and RL. At this time, the light intensity may be returned to the initial light intensity at once, or may be returned to the initial light intensity with a small number of steps. Of course, if there is a high brightness part of the next oncoming vehicle in the image, the increase in the luminous intensity of the headlamp of the vehicle corresponding to the next high brightness part is suppressed as described above, Alternatively, the light intensity once increased is decreased stepwise again.

  Depending on the driving conditions, the brightness of the high-intensity part in the image may be less than the reduced light amount of the host vehicle depending on the driving conditions, such as when driving oncoming vehicles or when driving on uneven roads or when driving on curved roads. In this case, it was determined that the reflected light was from the vehicle, but if the determination was corrected that it was the light source of the oncoming vehicle, What is necessary is just to make it reduce the light reduction amount of the own vehicle in steps from that time. On the other hand, if it was determined that the light source was an oncoming vehicle, but the determination was corrected that it was reflected light from the host vehicle, the brightness of the host vehicle was returned to the initial brightness at that point, and thereafter Control that repeats dimming and initial luminous intensity may be performed based on the luminance of the high luminance portion.

  As described above, the CPU 1 can detect other vehicles only by correlating the brightness of the high brightness portion in the image detected by the image processing unit 4 with the brightness of the headlamps LL and RL of the own vehicle controlled by the lamp control unit 2. Therefore, it is possible to easily determine whether the light source is the reflected light of the vehicle light source or the light source of the host vehicle, so that the determination process in the CPU 1 is small and determination in real time is possible, and lamp control based on the determination becomes possible. . In addition, since the light intensity of the headlamps LL and RL of the own vehicle is gradually reduced at a minute level in this determination, the illumination in front of the own vehicle does not become extremely and suddenly dark, and the own vehicle can be driven safely. Is secured. This eliminates the need for a high-accuracy camera and high-speed CPU, and can be configured at low cost. Also, even when the brightness of the headlamp of the vehicle is reduced to prevent dazzling other vehicles, the vehicle can be driven. Control of appropriate irradiation characteristics can be realized in real time.

  In the embodiment, the image processing unit divides the captured image into blocks and obtains the correlation and correlation in the high-luminance part. It is not limited to the example method. For example, the position change of the high-intensity part may be vector-calculated to determine the distance and direction of the movement, and the association may be performed. Even with such a method, the number of processing steps can be reduced and high-speed processing can be performed. No camera or high-speed CPU is required.

  In the embodiment, the light intensity of the headlamp of the own vehicle is lowered step by step, but if the irradiation characteristics are controlled in a direction to prevent dazzling with respect to other vehicles, the irradiation direction and irradiation range are controlled. It may be configured. For example, in the case of the irradiation direction, the irradiation direction is deflected stepwise to the left. In the case of the irradiation range, the irradiation range in the right direction may be narrowed stepwise. In such a case, the luminous intensity value on the vertical axis of the characteristic diagram shown in FIG. 7 may be read as the irradiation direction or irradiation range.

It is a conceptual diagram of the system of this invention. It is a main flowchart of control in the system of the present invention. It is a flowchart of a high-intensity detection step. It is a figure explaining the high-intensity part in the imaged image. It is a flowchart of a determination step. It is a flowchart of a dimming control step. It is a timing diagram of luminous intensity reduction control.

Explanation of symbols

1 CPU
2 Lamp control unit 3 Camera 4 Image processing unit LL, RL Headlamp CAR Car

Claims (3)

A camera that images the front of the vehicle, an image processing unit that detects a high-luminance part in an image captured by the camera, a lamp control unit that controls the luminous intensity of the headlamp of the host vehicle, and the luminous intensity in the lamp control unit And a processing device for determining whether the high brightness portion is a light source of another vehicle or a reflected light of a light source of the own vehicle from the correlation between the control of the high brightness portion and the detected brightness of the high brightness portion. In the determination, the lamp control unit reduces the luminous intensity of the headlamp at a predetermined luminous intensity of 10% of the maximum luminous intensity, and determines that it is a light source of another vehicle based on the determination result in the processing device. A headlamp system configured to stop the decrease in luminous intensity and to continue the decrease in luminous intensity when it is determined that the reflected light is from the own vehicle . The lamp control unit reduces the intensity of the headlamp at the predetermined intensity, the processor the high-intensity part is the reflected light of the vehicle headlamp when reduced by following the luminance of the high luminance portion 2. The headlamp system according to claim 1, wherein when the luminance of the high luminance portion does not change following the determination, the light source is determined to be a light source of another vehicle. The camera captures images at predetermined timings, the image processing unit associates high brightness portions in the captured images, and detects the brightness of the high brightness portions determined to be the same target over time. The headlamp system according to claim 1 or 2 .

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