JP5859896B2 - Vehicle detection device - Google Patents

Description

  The present invention relates to a vehicle detection device.

  In the case of vehicles, particularly automobiles, in order to ensure a good forward visibility during night driving, the headlight illumination state is usually set to a high beam, while there are forward vehicles such as oncoming vehicles and preceding vehicles. It is conceivable to automatically switch from a high beam to a low beam.

  In order to detect a vehicle ahead when traveling at night, Patent Document 1 and Patent Document 2 describe whether a light source is a headlight from a captured image by photographing the front of the vehicle with a camera. What is made to determine whether it is is disclosed.

JP 2008-40615 A JP 2008-293116 A

  By the way, the traveling road has a curved traveling road as represented by a mountain road. In this case, a forward vehicle such as an oncoming vehicle or a preceding vehicle is likely to cause a problem that the host vehicle suddenly appears while traveling on a curve, and the headlight of the host vehicle gives glare to the front vehicle. In particular, when the luminance of the light source in the captured image is equal to or higher than a predetermined luminance that can be considered to be the headlight or taillight of the vehicle ahead, whether or not this light source is the light source of the vehicle ahead is further detailed. In order to verify, since the determination based on the predetermined determination condition set in advance is performed, the timing of the low beam is delayed with respect to the preceding vehicle suddenly appearing during curve driving, and the driver of the preceding vehicle The problem of giving glare is likely to occur. In particular, even when the brightness of the light source is the same, it is easier to feel glare when the light source suddenly appears, compared to when the light source gradually approaches from a distance.

  The present invention has been made in consideration of the above-described circumstances, and an object of the present invention is to detect a light source suddenly appearing while driving on a curve as a light source of a preceding vehicle at an earlier timing. Is to provide.

In order to achieve the above object, the present invention is basically based on the knowledge that the light source of the forward vehicle that appears during running on a curve appears from the left end or the right end of the captured image. That is, the present invention is, as when the light source having a predetermined higher luminance from the left and right ends in the images appeared is different from the emerging light from other than the left and right ends, a light source of the forward vehicle at an earlier timing determination Ru Citea to.

Specifically, the following solution is adopted in the present invention . That is, as described in claim 1,
Imaging means for photographing the front of the vehicle;
Irradiating means for irradiating the front of the vehicle;
A light source present in front of the host vehicle and a light source detection unit for detecting the luminance of the light from the image captured by the imaging unit;
A determination unit that determines whether or not the light source is a light source of a preceding vehicle based on a predetermined determination condition when the luminance of the light source detected by the light source detection unit is greater than or equal to a predetermined value set in advance. When,
Light distribution control means for changing and controlling the light distribution by the irradiation means according to the determination result by the determination means;
With
The determination means determines whether or not the light source is a light source of a preceding vehicle when the light source appears from the left and right ends of the image picked up by the image pickup means compared to when it appears from other than the left and right ends. Set to do ,
A navigation device,
The determination means is set to perform the determination at the earlier timing on condition that the navigation device detects that the host vehicle is traveling on a mountain road.
It is like that. According to the above Kikai determined approach, by increasing the decision timing, and determines quickly that it is a source of the forward vehicle, by controlling the light distribution of the illumination means, glare to the driver of the forward vehicle It can prevent more reliably giving it.

In addition to the above, it is possible to confirm with the navigation device that a sharp curve with poor visibility often continues and is traveling on a mountain road, and the above effect can be ensured more reliably. Moreover, it is preferable also in reducing the chance of erroneously determining that the light source is the vehicle ahead.

A preferred mode based on the above solution is as described in claim 2 and the following. That is,
The determination means is when the host vehicle is traveling at a lower speed than the first vehicle speed set in advance or at a higher speed than the second vehicle speed that is set in advance and higher than the first vehicle speed. It is set so as not to perform the determination at the earlier timing (corresponding to claim 2 ). In this case, the need for a high beam is low during low-speed driving, and it is considered that the vehicle is not traveling on a sharp curve with poor visibility during high-speed driving. This is also preferable in reducing the chance of erroneously determining that the light source is the vehicle ahead.

The determination means determines that the light source emerging from the left and right ends of the image is an oncoming vehicle when the light source is approaching the host vehicle, and the preceding vehicle is a preceding vehicle when moving in a direction away from the host vehicle. Is set to be judged,
The light distribution control means makes the light distribution control different depending on whether the preceding vehicle is an oncoming vehicle or a preceding vehicle.
(Corresponding to claim 3 ). In this case, the light distribution of the irradiation unit can be made appropriate depending on whether the preceding vehicle is a preceding vehicle or an oncoming vehicle.

The determination at an early timing by the determination unit is set to determine that the light source is the light source of the preceding vehicle without performing the determination based on the determination condition when the luminance of the light source is equal to or higher than a predetermined value. (Corresponding to claim 4 ). In this case, it is only necessary to look at the luminance of the light source, which is preferable for shortening the time required to determine that the light source is the vehicle ahead.

  According to the present invention, it is possible to detect at an early timing that the light source is in front of the vehicle, particularly during curve driving.

BRIEF DESCRIPTION OF THE DRAWINGS The simple explanatory drawing which shows one Embodiment of this invention and shows a high beam state and a low beam state. The block diagram which shows the example of a control system of this invention. The figure which shows the example of the light source which has appeared in the image. Explanatory drawing which shows an example which the oncoming vehicle approaches during curve driving | running | working. Explanatory drawing which shows another example which the oncoming vehicle approaches during curve driving | running | working. The flowchart which shows the example of control of this invention. The flowchart which shows the 2nd example of control of this invention. The flowchart which shows the example of control in a reference example . The figure which shows the state which the brightness | luminance of the right end side in an image began to increase. The figure which shows the state after 1 frame from the state of FIG. The figure which shows the state after 1 frame from the state of FIG. The figure which shows an example of the fixed light source which appeared in the image.

  In FIG. 1, a vehicle V serving as a host vehicle is equipped with a camera 1 as an imaging means for photographing the front at a front portion (in the embodiment, a height of a front end portion of a roof portion in a vehicle interior). The camera 1 is a CCD camera, for example, and detects at least a light source in front of the vehicle and its luminance. Of course, the front end of the vehicle V is equipped with a headlight 2 as an irradiation means, and this headlight 2 can be switched between a high beam HB and a low beam LB. Of course, the shooting range (view angle) of the camera 1 is set so that at least the front end position (substantially irradiated light reachable distance) of the high beam HB can be shot.

  FIG. 2 shows an example of a control system installed in the vehicle V. In FIG. 2, U is a controller (control unit) configured using a microcomputer. In addition to signals from the camera 1, signals from various sensors or devices 3 to 7 are input to the controller U. Specifically, 3 is a vehicle speed sensor that detects the traveling speed of the vehicle V. Reference numeral 4 denotes a yaw rate sensor that detects the yaw rate of the vehicle V. Reference numeral 5 denotes a steering angle sensor that detects the steering angle of the vehicle V. Reference numeral 6 denotes an accelerator opening sensor that detects the accelerator opening. A navigation system 7 is equipped with GPS and map information.

  The controller U has a function of automatically switching from the high beam HB to the low beam LB when a preceding vehicle is present, and a function of automatically switching from the low beam LB to the high beam HB when no preceding vehicle is detected. In addition to this, as will be described later, the controller U determines that the light source in the image is the light source (headlight or taillight) of the vehicle ahead according to the difference in the appearance of the light source in the image captured by the camera 1. In accordance with the determination result, change control between the high beam HB and the low beam LB is performed.

  FIG. 3 shows an example of a light source in an image taken by the camera 1, and FIG. 3 shows two light sources α and β. In FIG. 3, R simply indicates an irradiation range in the high beam HB, and is set in consideration of the light distribution characteristics of the high beam HB. The light source α appears from the upper end of the image and is substantially at the center position of the irradiation range R. On the other hand, the light source β is in a state immediately after appearing from the right end of the image.

  The controller U determines whether or not the light source is the light source of the preceding vehicle. As a precondition for the determination, the light source is equal to or higher than a predetermined luminance corresponding to the headlight or taillight of the preceding vehicle. Is done. In the example of FIG. 3, it is assumed that the brightness of both the light sources α and β is set to be equal to or higher than a predetermined brightness and the possibility of being the light source of the preceding vehicle is considered.

  Various determination conditions can be set as to whether or not a light source having a luminance equal to or higher than a predetermined luminance is a light source of a preceding vehicle, and is set as follows, for example. First, it is assumed that the light source exists within the irradiation range R of the high beam HB in the image. Next, the condition is that the light source in the image is a moving object. When these two conditions are satisfied, it is determined that the light source in the image is the light source of the preceding vehicle, and the high beam HB is switched to the low beam LB.

  With respect to the light source α, a determination based on the above-described determination condition is performed. Therefore, there is a slight delay until it is determined whether the light source α is the light source of the preceding vehicle. On the other hand, the light source β is immediately determined to be the light source of the preceding vehicle by satisfying the condition that it is equal to or higher than the predetermined luminance without performing the determination based on the determination condition. In addition, when the light source appears from the left end of the image, the light source of the preceding vehicle is immediately determined by satisfying the condition that the light intensity is equal to or higher than the predetermined luminance, similarly to the case of appearing from the right end of the image. . As described above, the light source that appears from the left and right ends of the image is determined whether it is the light source of the preceding vehicle at an earlier timing than the light source that appears in the image from other than that.

  The meaning of performing determination at an early timing as to whether or not the light source that appears from the left and right ends of the image is the light source of the preceding vehicle will be described with reference to FIGS. First, FIG. 4 shows a case where the host vehicle V is traveling in a right-turn corner and there is an oncoming vehicle V2. In this case, the irradiation beam from the headlight of the oncoming vehicle is indicated by the symbol HB2. In the image taken by the camera 1 of the host vehicle V, the light source caused by the irradiation beam HB2 of the oncoming vehicle V2 appears from the right end side (when the curve is a left turn, it appears from the left end in the image. ).

  For the driver of the oncoming vehicle V2, the high beam HB of the own vehicle V suddenly appears, and even if it is the same brightness, it is easier to feel the glare than when approaching gradually from a distance. It becomes. In addition, the curve is an instant passing, and if the predetermined determination condition described above is performed, the timing for switching to the low beam LB is delayed, which may give glare to the driver of the oncoming vehicle V2. Extremely expensive. However, when a light source having a luminance higher than a predetermined luminance appears from the left and right ends in the image, it is immediately determined that the light source is the light source of the preceding vehicle and is switched to the low beam LB. Thus, it is possible to surely prevent a situation that gives glare.

  In FIG. 5, the host vehicle V is running on a right-turn curve, and the road then turns to the left and then turns to the right. In this case, even if the host vehicle V turns right and the oncoming vehicle V2 turns left, if the space between the host vehicle V and the oncoming vehicle V2 is open, the oncoming vehicle V2 is driven by the high beam HB of the own vehicle V. The driver may be dazzled. However, when a light source having a predetermined luminance or higher appears from the right end or the left end in the image, it is immediately determined to be the light source of the preceding vehicle and switched to the low beam LB. Thus, it is possible to reliably prevent the driver of the oncoming vehicle V2 from being dazzled. On the continuous curved road as shown in FIG. 5, the light source of the oncoming vehicle V2 appears from the right end in the image and temporarily disappears, but then appears in the image again in a short time. In this case, it is preferable to prevent glare from being given to the driver of the other vehicle V2.

  FIG. 6 is a flowchart showing a specific control example by the controller U. This flowchart will be described below. In the following description, Q indicates a step. First, at Q1, it is determined whether or not the vehicle is currently traveling on a curve. The determination in Q1 can be performed, for example, by detecting the steering angle or by detecting the position of the host vehicle V on the map by the navigation system 7.

  When the determination in Q1 is YES, it is determined whether or not the vehicle speed of the host vehicle V is equal to or higher than a predetermined vehicle speed (for example, a vehicle speed set in a range of 30 to 40 km / h). If the determination in Q2 is YES, it is determined in Q3 whether or not a light source has appeared from the left end or right end in the image taken by the camera 1 (for example, the light source β has appeared in FIG. 3). Whether or not). If the determination in Q4 is YES, it is determined in Q4 whether or not the luminance of the light source appearing from the left end or right end in the image is equal to or higher than a predetermined luminance. When the determination in Q4 is YES, it is determined in Q5 that the light source that appears from the left end or right end in the image is the light source of the preceding vehicle. Of course, when shifting to Q5, the high beam HB is switched to the low beam LB.

  When the determination in Q4 is NO, the movement of the light source is analyzed in Q6 (it is a monitoring target that may be the light source of the vehicle ahead). Further, when the determination at Q1 is NO, the determination at Q2 is NO, or the determination at Q3 is NO, the routine proceeds to Q7 and normal control is performed (as described in FIG. 3). Based on the determination condition, it is determined whether or not the light source is the light source of the preceding vehicle). When NO is determined in Q2, the vehicle speed is low. In this case, normal control (determination at a late timing) is performed in consideration of a large time margin until the vehicle approaches the vehicle ahead. To do. Note that the determination of Q2 may be omitted, and if the determination of Q1 is YES, the process may be unconditionally shifted to Q3. Further, when the vehicle encounters an oncoming vehicle while driving on a curve, the light source appears from the left or right end in the image. Therefore, the determination of Q1 may be omitted and the process may start from Q3.

  FIG. 7 shows a second control example by the controller U. In the present embodiment, a curve as shown in FIG. 4 is assumed, and it is also determined whether the preceding vehicle is an oncoming vehicle or a preceding vehicle. Based on the above, it is first determined at Q11 whether or not the vehicle is traveling on a curve. If YES in Q11, it is determined in Q12 whether the luminance of the light source that appears in the image from the same direction as the curve is equal to or higher than a predetermined luminance. If YES in Q12, it is determined in Q13 whether the speed vector of the light source is equal to or greater than a predetermined threshold value. If YES in Q13, it is determined in Q14 that the preceding vehicle is an oncoming vehicle.

  If the determination in Q13 is NO, it is determined in Q15 that the preceding vehicle is a preceding vehicle. When NO is determined in Q11 or NO in Q12, normal control is performed in Q16, respectively (execution of determination based on a predetermined determination condition as described in FIG. 3).

  In the case of the control in FIG. 7, the light distribution control of the headlight 2 is changed according to the difference from whether the preceding vehicle is an oncoming vehicle or a preceding vehicle. For example, in the case of an oncoming vehicle, the degree of glare is stronger than in the case of a preceding vehicle, so that, for example, when the light source is present in the irradiation range R shown in FIG. . On the other hand, in the case of a preceding vehicle, the low beam is switched only when the light source is located at the center of the irradiation range R and in the vicinity thereof.

8 to 11 show control examples in the reference example . That is, FIG. 9 to FIG. 11 show images for three frames when traveling on a right-turn curve. The order from FIG. 9, FIG. 10, FIG. It has become. And the brightness | luminance of the right end side of an image shows the state which changes so that it may become high gradually by irradiation based on the light source which exists ahead. That is, the luminance of the portion K1 with double hatching is the lowest, the portion K2 with single hatching is the intermediate luminance, and the portion K3 with dots is the highest.

  9 to 11, detection windows YL and YR are set on the left end side and the right end side in the image, and the average luminance in the detection windows YL and YR is detected. And when this average brightness | luminance becomes high gradually with progress of time, it determines with it being a time when the light source of a preceding vehicle is appearing, and switches to low beam LB immediately.

In this reference example , in the image, it is possible to determine that the light source of the preceding vehicle is the light source of the preceding vehicle at an early time point before the luminance of the light source of the preceding vehicle becomes equal to or higher than the predetermined luminance. Thus, it is possible to more reliably prevent the situation that gives glare.

  FIG. 8 is a flowchart showing an example of the case where the above-described control is performed, and this flowchart will be described below. First, in Q21, the average luminance of the left and right detection windows YL and YR in the image is calculated. Next, in Q22, it is determined whether or not the average luminance of the right window YR is higher than the average luminance in the previous frame. If the determination at Q22 is YES, the right counter is incremented by "1" at Q23. When the determination at Q22 is NO, the right counter is reset to zero.

  After Q23 or after Q24, in Q25, it is determined whether or not the average luminance of the left window YL is higher than the average luminance in the previous frame. If YES in Q25, the left counter is incremented by “1” in Q26. Further, when the determination in Q25 is NO, the left counter is reset to zero.

  After Q26 or Q27, it is determined in Q28 whether the count number of the right counter or the left counter is equal to or greater than a predetermined number (for example, 5). When the determination in Q28 is YES, it is determined that the oncoming vehicle is detected (front vehicle detection) (switched to the low beam LB based on this determination result). After Q29 or when NO in Q28, the process returns to Q21 (the counter count is gradually increased by repeating the process after Q21).

  As a predetermined determination condition at the normal timing as to whether or not the light source is a vehicle ahead, it is possible to include a noise removal process for removing a fixed light source or a reflecting object such as a reflector. FIG. 12 shows a pair of left and right street lamps GL and GR on the left and right of the road as fixed light sources. In the case of a fixed light source such as a streetlight, there is a possibility that it may be mistaken for the light source (headlight or taillight) of the vehicle ahead only by looking at its brightness. In order to remove the fixed light source as noise, for example, considering the vehicle speed of the host vehicle V, if the left light source has a velocity vector moving in the upper left direction, it is determined that the street light GL is on the left side. it can. Similarly, the right light source can be determined to be the right street lamp GL if it has a velocity vector that moves in the upper right direction. Further, since the light source caused by the reflector is caused by the irradiation from the own vehicle V, by temporarily changing the irradiation state from the own vehicle V (for example, temporarily switching to a low beam or temporarily When the luminance change is large by changing the light distribution direction of the high beam HB or reducing the illuminance thereof, it can be determined that the reflector is a reflector.

  Although the embodiment has been described above, the present invention is not limited to the embodiment, and can be appropriately changed within the scope described in the scope of claims. For example, the invention includes the following cases. . As the irradiation means for irradiating the front of the vehicle, in addition to the headlight 2, an auxiliary light having a large (high) illuminance provided separately from the headlight 2 may be used. The imaging means is not limited to a CCD camera, and any appropriate type can be used as long as it can detect the light source and its luminance at night.

  The light distribution control for preventing the driver of the vehicle ahead from being dazzled is not limited to switching to the low beam LB. For example, the illuminance of the high beam HB is reduced or the light distribution is changed and controlled in the lateral direction. Etc., which can be appropriately selected. Further, the predetermined determination condition as to whether or not the light source is the vehicle ahead is not limited to the case described in the embodiment, and can be set as appropriate. The determination result that is the light source of the preceding vehicle (that is, the detection result of the presence of the preceding vehicle) is not limited to use for switching control between the high beam HB and the low beam LB, and can be used for an appropriate application. .

  At high vehicle speeds higher than a predetermined high vehicle speed (for example, a predetermined vehicle speed set in the range of 60 to 70 km / h), it is considered that the vehicle is traveling on a highway, a motor vehicle exclusive road, or a road with good visibility. It is preferable not to perform the determination. When the navigation system 7 is traveling on a mountain road (especially a mountain road where a sharp curve continues), it is particularly preferable to make a determination at an early timing. Of course, the object of the present invention is not limited to what is explicitly stated, but also implicitly includes providing what is substantially preferred or expressed as an advantage.

  The present invention can detect the presence of a preceding vehicle earlier when traveling on a curve.

V: Vehicle (own vehicle)
V2: Oncoming vehicle U: Controller HB: High beam LB: Low beam α: Light source (appears from other than left and right edges of image)
β: Light source (appears from the right edge of the image)
K1: Low luminance portion K2: Brightness intermediate portion K3: High luminance portion YL: Left detection window YR: Right detection window 1: Camera (imaging means)
2: Headlight (irradiation means)
3: Vehicle speed sensor 5: Steering angle sensor 7: Navigation system

Claims (4)

Imaging means for photographing the front of the vehicle;
Irradiating means for irradiating the front of the vehicle;
A light source present in front of the host vehicle and a light source detection unit for detecting the luminance of the light from the image captured by the imaging unit;
A determination unit that determines whether or not the light source is a light source of a preceding vehicle based on a predetermined determination condition when the luminance of the light source detected by the light source detection unit is greater than or equal to a predetermined value set in advance. When,
Light distribution control means for changing and controlling the light distribution by the irradiation means according to the determination result by the determination means;
With
The determination means determines whether or not the light source is a light source of a preceding vehicle when the light source appears from the left and right ends of the image picked up by the image pickup means compared to when it appears from other than the left and right ends. Set to do ,
A navigation device,
The determination means is set to perform the determination at the earlier timing on condition that the navigation device detects that the host vehicle is traveling on a mountain road.
The vehicle detection apparatus characterized by the above-mentioned. Oite to claim 1,
The determination means is when the host vehicle is traveling at a lower speed than the first vehicle speed set in advance or at a higher speed than the second vehicle speed that is set in advance and higher than the first vehicle speed. The vehicle detection device is set so as not to perform the determination at the earlier timing. In claim 1 or claim 2 ,
The determination means determines that the light source emerging from the left and right ends of the image is an oncoming vehicle when the light source is approaching the host vehicle, and the preceding vehicle is a preceding vehicle when moving in a direction away from the host vehicle. Is set to be judged,
The said light distribution control means makes a light distribution control differ according to the difference whether a front vehicle is an oncoming vehicle or a preceding vehicle, The vehicle detection apparatus characterized by the above-mentioned. In any one of Claims 1 thru | or 3 ,
The determination at an early timing by the determination unit is set to determine that the light source is the light source of the preceding vehicle without performing the determination based on the determination condition when the luminance of the light source is equal to or higher than a predetermined value. The vehicle detection apparatus characterized by the above-mentioned.

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