JP5578145B2 - Headlight control device - Google Patents

Description

  The present invention relates to a headlamp control device.

Usually, a vehicle headlamp is configured to be switched between a high beam that distributes irradiation light upward (horizontal direction) and a low beam that directs irradiation light downward.
Since the high beam can secure a field of view far away by irradiating light far away, it is preferable to maintain the high beam as much as possible during traveling.
However, passing the oncoming vehicle with a high beam will cause illusion to the oncoming vehicle, so when passing the oncoming vehicle, the headlamp needs to be switched from the high beam to the low beam.
Therefore, an auto light device is provided that automatically switches between a high beam and a low beam of a headlamp when passing by an oncoming vehicle.
In addition, in such an autolight device, when the shape of the road on which the host vehicle is traveling is a curve having a predetermined radius of curvature or less, the road shape is switched to a high beam at an early stage so that the road shape can be seen from a distance. The technique to make is proposed (refer patent document 1).
In addition, on a road with poor visibility, a technique has been proposed in which an oncoming vehicle is prevented from being dazzled by switching to a low beam at an early stage (see Patent Document 2).

JP 2007-112280 A JP 2009-255639 A

By the way, if the headlight of the host vehicle is switched from the high beam to the low beam when passing the oncoming vehicle, returning from the low beam to the high beam as soon as possible is not necessary to ensure distant vision. In addition, it is advantageous for notifying other vehicles in the distance of the existence of the own vehicle.
However, in the above-described conventional technology, there is room for improvement because it is not sufficiently considered how to switch from a low beam to a high beam at an early stage when passing by an oncoming vehicle on a curved road.
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a headlight control device that is advantageous in securing a far field of view while preventing dazzling with respect to an oncoming vehicle.

  To achieve the above object, a headlamp control device according to the present invention includes a beam switching unit that switches between a low beam and a high beam of a headlamp of the host vehicle, an oncoming vehicle detection unit that detects an oncoming vehicle, and the host vehicle. Position detecting means for detecting the position in the width direction of the road on which the vehicle travels, estimation means for estimating the shape of the road on which the host vehicle travels, the traveling speed of the host vehicle or the relative speed between the host vehicle and the oncoming vehicle When the oncoming vehicle is detected by the oncoming vehicle detection means while the headlamp is in a high beam state, the beam switching means switches the headlamp to the low beam for the low beam maintenance period. The switching control means for returning to the high beam, the low beam maintenance period, the position of the host vehicle in the width direction of the road, and the estimated road shape , Characterized in that it comprises a period calculation means for calculating, based on said traveling speed or the relative speed.

According to the first aspect of the present invention, when an oncoming vehicle is detected, the headlamp is calculated based on the position of the host vehicle in the width direction of the road, the estimated road shape, and the traveling speed. Changed to low beam for the maintenance period and then returned to high beam. Therefore, depending on the position of the vehicle in the width direction of the road, the road shape, and the traveling speed, the headlamp can be switched from low beam to high beam at an early stage while preventing the oncoming vehicle from being dazzled. This is advantageous.
According to the second aspect of the present invention, the low beam maintenance period when the position of the own vehicle in the road width direction is a position inside the curve shape is such that the position of the own vehicle in the road width direction is outside the curve shape. The period is shorter than the low beam maintenance period at the position. Therefore, the headlamp can be switched accurately from low beam to high beam according to the situation where the host vehicle is traveling inside or outside the curve shape, so that it is possible to prevent distraction from oncoming vehicles at an early stage. It becomes more advantageous in securing.
According to the invention described in claim 3, since the position of the host vehicle in the width direction of the road is detected based on the image information, the position can be detected accurately.
According to the invention described in claim 4, since the road shape is estimated based on the image information and the detected steering angle, the road shape can be estimated accurately.
According to the fifth aspect of the present invention, since the oncoming vehicle is detected based on the image information, it is possible to accurately detect the oncoming vehicle.
According to the invention described in claim 6, in addition to the position of the host vehicle in the width direction of the road, the estimated road shape, and the traveling speed, based on whether the host vehicle is passing on the left side or on the right side. Since the low beam maintenance period is calculated, the low beam maintenance period can be calculated more accurately, which is more advantageous in securing a far field of view while preventing the dazzling of the oncoming vehicle.
According to the seventh aspect of the present invention, since the low beam maintenance period is calculated using the equation (1), the low beam maintenance period can be easily calculated and the control related to the switching operation of the headlamp can be simplified. This is advantageous in achieving this.

It is explanatory drawing which shows the structure of the headlamp control apparatus 10 of this Embodiment. It is explanatory drawing of the irradiation range of the headlamp of the own vehicle 2 and the oncoming vehicle 6 when the own vehicle 2 is passing on the left side, (A) is a case where the own vehicle 2 is traveling on a straight road. Explanatory drawing, (B) is explanatory drawing when the own vehicle 2 is traveling inside the curved road, (C) is explanatory drawing when the own vehicle 2 is traveling inside the curved road. It is. It is explanatory drawing of the irradiation range of the headlamp of the own vehicle 2 and the oncoming vehicle 6 when the own vehicle 2 is passing on the right side, (A) is a case where the own vehicle 2 is traveling on a straight road. Explanatory drawing, (B) is explanatory drawing when the own vehicle 2 is traveling inside the curved road, (C) is explanatory drawing when the own vehicle 2 is traveling inside the curved road. It is. It is a flowchart which shows operation | movement of the headlamp control apparatus 10 of this Embodiment. (A) is a low beam sustain period [Delta] T _LOW illustration of when the vehicle 2 travels the road linear shape, (B) a description of the low beam sustain period [Delta] T _LOW when the vehicle 2 is traveling inside the curve shape FIG. 4C is an explanatory diagram of the low beam maintenance period ΔT _LOW when the host vehicle 2 travels outside the curve shape.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
As shown in FIG. 1, the vehicle 2 includes a headlamp 4.
The headlamp 4 is provided at intervals in the left-right width direction of the front portion of the vehicle 2, and irradiates illumination light in front of the vehicle 2.
The headlamp 4 includes a high beam lamp that distributes irradiation light upward (horizontal direction) and a low beam lamp that directs irradiation light downward.
A switching unit 18 (to be described later) is configured to be switched between a high beam and a low beam by selectively supplying a current to either the high beam lamp or the low beam lamp.

The headlamp control device 10 according to the present embodiment is mounted on the vehicle 2.
The headlamp control device 10 includes a camera 12, a vehicle speed sensor 14, a steering angle sensor 16, a switching unit 18, and an ECU 20.
The camera 12 is attached to an appropriate location of the vehicle 2, for example, a location in the passenger compartment behind the windshield, images the front of the vehicle 2, generates image information, and supplies the image information to the ECU 20. It is.
As shown in FIG. 2A, the detection range 402 of the camera 12 is set so that the presence of the oncoming vehicle 6 that passes the vehicle 2 can be detected.
In the present embodiment, the camera 12 constitutes an imaging means.

The vehicle speed sensor 14 detects the traveling speed of the vehicle 2 and supplies the detection result to the ECU 20.
In this embodiment, the case where the speed detection means detects the “traveling speed” of the host vehicle 2 will be described. However, the speed detection means detects the “relative speed” between the host vehicle 2 and the oncoming vehicle 6. In the following configuration, “relative speed” may be used instead of “travel speed”.
The relative speed can be detected using various conventionally known detectors such as a radar sensor provided in the host vehicle 2.

The steering angle sensor 16 detects the steering angle of the steering (handle) of the vehicle 2 and supplies the detection result to the ECU 20.
In the present embodiment, the steering angle sensor 16 constitutes a steering angle detection means.

The switching unit 18 switches the low beam and the high beam of the headlamp 4 by supplying current to the headlamp 4 based on a control signal from the ECU 20.
In the present embodiment, the switching unit 18 constitutes a beam switching unit.

The ECU 20 includes a CPU, a ROM that stores and stores a control program, a RAM as an operation area of the control program, an interface unit that interfaces with peripheral circuits and the like.
The ECU 20 implements the oncoming vehicle detection means 20A, the position detection means 20B, the road shape estimation means 20C, the switching control means 20D, and the period calculation means 20E by executing the control program.

As shown in FIG. 2A, the oncoming vehicle detection means 20A detects an oncoming vehicle 6 that passes by the vehicle 2 (hereinafter referred to as the host vehicle 2).
In the present embodiment, the oncoming vehicle detection means 20 </ b> A detects the oncoming vehicle 6 based on image information in front of the host vehicle 2 captured by the camera 12.
In the present embodiment, the oncoming vehicle detection means 20A detects the oncoming vehicle 6 when it is determined that the headlamp of the oncoming vehicle 6 is lit in the detection range 402 shown in FIG. 2A based on the image information. To do.

As shown in FIG. 2 (A), the position detection means 20B detects the position in the width direction of the road L0 on which the host vehicle 2 travels.
In the present embodiment, the position detection unit 20B detects the position of the vehicle 2 in the width direction of the road L0 based on image information in front of the vehicle 2 captured by the camera 12.
FIG. 2A shows a case where the road L0 is a two-way round-trip lane composed of two lanes L _L and L _R and is left-hand traffic.
In this case, the position detection means 20B detects which lane of the two lanes L _L and L _R the host vehicle 2 is traveling on the basis of image information ahead of the host vehicle 2.
For example, the position detection unit 20B detects the position of the own vehicle 2 in the width direction of the road L0 based on whether the oncoming vehicle 6 that passes the own vehicle 2 is located on the right side or the left side of the own vehicle 2. can do.
In this case, whether the host vehicle 2 is traveling on the left side or the right side is specified depending on whether the oncoming vehicle 6 is located on the left or right side of the host vehicle 2.
Alternatively, the position detection unit 20B may detect the position of the vehicle 2 in the width direction of the road L0 based on the center line (center line) of the road L0 and the white line that divides the lane included in the image information.
In this case, whether the host vehicle 2 is passing on the left side or the right side is specified based on whether the detected position of the host vehicle 2 is on the left side or on the right side of the road L0.
In short, the position detection unit 20B only needs to be able to detect which lane of the two lanes L _L and L _R the vehicle 2 is traveling on the basis of image information ahead of the vehicle 2, Various conventionally known techniques can be used as detection algorithms.
The oncoming vehicle detection unit 20A and the position detection unit 20B can be realized by using various conventionally known image recognition processes.

The road shape estimating means 20C estimates the road shape on which the host vehicle 2 travels.
In the present embodiment, the road shape estimation means 20 </ b> C estimates the road shape based on the image information ahead of the host vehicle 2 captured by the camera 12 and the steering angle detected by the steering angle sensor 16.
Specifically, it is estimated whether the shape of the road L0 is a straight line (FIG. 2A), a left curve (FIG. 2B), or a right curve (FIG. 2C). .
Furthermore, the road shape estimation means 20C calculates the curvature radius R of the road L0 when the estimated road shape is curved.

When the headlamp 4 is in a high beam state and the oncoming vehicle 6 is detected by the oncoming vehicle detector 20A, the switching control unit 20D switches the headlamp 4 to the low beam for a low beam maintenance period ΔT _LOW described later by the switching unit 18. It will later return to the high beam.
The low beam maintenance period ΔT _LOW should be as short as possible without causing the oncoming vehicle 6 to be dazzled, so that the driver of the host vehicle 2 can secure a far field of view at an early stage, or the presence of the host vehicle 2 can This is advantageous for informing the vehicle.

The period calculation means 20E calculates the low beam maintenance period ΔT _{LOW based} on the position of the host vehicle in the width direction of the road L0, the estimated road shape, and the traveling speed.
Here, the relationship between the road shape and the low beam maintenance period ΔT _LOW will be described.
FIGS. 2A to 2C are explanatory diagrams of an irradiation range of the headlamp 4 (during high beam) when the host vehicle 2 passes the oncoming vehicle 6 while passing on the left side.
2A to 2C, all the distances between the host vehicle 2 and the oncoming vehicle 6 along the extending direction of the road L0 are the same. In the figure, reference numeral 202 indicates the irradiation range of the headlamp 4 of the host vehicle 2, and reference numeral 602 indicates the irradiation range of the headlamp of the oncoming vehicle 6.
In FIG. 2 (B), the oncoming vehicle 6 is outside the irradiation range 202 of the own vehicle 2, whereas in FIG. 2C, the oncoming vehicle 6 is located inside the irradiation range 202 of the own vehicle 2. Stays.
In FIG. 2A, the front part of the oncoming vehicle 6 remains inside the irradiation range 202 of the own vehicle 2, and the rear part of the oncoming vehicle 6 is outside the irradiation range 202 of the own vehicle 2.
Therefore, in order to as short as possible within a range not dazzle the low beam sustain period [Delta] T _LOW the oncoming vehicle 6, the low beam sustain period [Delta] T _LOW, and the shortest in the case of FIG. 2 (B), followed by FIG. 2 (A) The length may be increased in the order of FIG.

FIG. 5 shows a specific example of the low beam maintenance period ΔT _LOW . 5A, 5B, and 5C correspond to FIGS. 2A, 2B, and 2C, respectively.
That is, the period calculation means 20E determines that the low beam maintenance period ΔT _LOW when the host vehicle 2 is located inside the curve shape as shown in FIG. 2B is as shown in FIG. The low beam maintenance period ΔT _LOW is calculated so as to be shorter than the low beam maintenance period ΔT _LOW when 2 is located outside the curve shape.
In other words, when the estimated road shape is a curve shape, the period calculation means 20E determines that the low beam maintenance period ΔT _LOW when the position of the vehicle 2 in the width direction of the road is a position inside the curve shape is The low beam maintenance period is calculated so as to be shorter than the low beam maintenance period ΔT _LOW when the position of the host vehicle in the width direction is a position outside the curve shape.

In the present embodiment, the period calculation means 20E determines that the vehicle 2 specified as described above is on the left side in addition to the position of the vehicle 2 in the width direction of the road, the estimated road shape, and the traveling speed. The low beam maintenance period is calculated based on whether the vehicle is on the right side or on the right side.
That is, the low beam maintenance period ΔT _LOW is calculated by the period calculation means 20E using the following formula (1).
ΔT _LOW = Tc−R × α−V × β (1)
However,
Tc: a predetermined time constant R: a radius of curvature of the road shape calculated by the road shape estimation means 20C α: a predetermined curve coefficient V: a traveling speed detected by the vehicle speed sensor 14: a predetermined speed Coefficient The curve coefficient α is determined based on whether the host vehicle 2 is passing on the left side or on the right side, or on vehicle characteristics (such as a wheel base).
The curvature radius R takes a positive value when the host vehicle is located inside the curve shape, and takes a negative value when the host vehicle is located outside the curve shape. Further, when the road has a straight shape, R is infinite. When ΔT _LOW takes a negative value, it is regarded as zero.
Further, instead of the traveling speed, the relative speed between the host vehicle 2 and the oncoming vehicle 6 may be used. In this case, the speed of the oncoming vehicle 6 is reflected in addition to the speed of the own vehicle 2. This is advantageous in accurately calculating the low beam maintenance period ΔT _LOW .
When the relative speed is used, the speed coefficient β is also a value corresponding to the relative speed.

Although the case where the host vehicle 2 is passing on the left side has been described above, the same applies to the case where the host vehicle 2 is passing on the right side.
3A, 3B, and 3C illustrate the case of left-hand traffic, and correspond to FIGS. 2A, 2B, and 2C, respectively.
That is, in FIG. 3B, the oncoming vehicle 6 is outside the irradiation range 202 of the own vehicle 2, whereas in FIG. 3C, the oncoming vehicle 6 is within the irradiation range 202 of the own vehicle 2. Stays inside.
In FIG. 3A, the front part of the oncoming vehicle 6 stays inside the irradiation range 202 of the own vehicle 2, and the rear part of the oncoming vehicle 6 is outside the irradiation range 202 of the own vehicle 2.
Therefore, in order to as short as possible within a range not dazzle the low beam sustain period [Delta] T _LOW the oncoming vehicle 6, the low beam sustain period [Delta] T _LOW, and the shortest in the case of FIG. 3 (B), the then FIG 3 (A) In this case, the length may be increased in the order shown in FIG.
Therefore, even in the case of right-hand traffic, the period calculation means 20E has the low beam maintenance period ΔT _LOW when the host vehicle 2 is located inside the curve shape as shown in FIG. As shown in (C), the low beam maintenance period ΔT _LOW is calculated so as to be shorter than the low beam maintenance period ΔT _LOW when the host vehicle 2 is located outside the curve shape.
That is, even in the case of right-hand traffic, the period calculation means 20E determines that when the estimated road shape is a curve shape, the position of the host vehicle 2 in the road width direction is a position inside the curve shape. low beam sustain period [Delta] T _LOW calculates the low beam sustain period [Delta] T _LOW so that the position of the vehicle in the width direction of the road becomes low beam sustain period [Delta] T shorter than _LOW when a position outside of the curve shape.

Next, operation | movement of the headlamp control apparatus 10 is demonstrated with reference to the flowchart of FIG.
The ECU 20 determines whether or not the headlamp 4 is a high beam (step S10).
If the determination result of step S10 is negative, the process returns to step S10.
If the determination result of step S10 is affirmative, it is determined whether an oncoming vehicle 6 has been detected (step S12: oncoming vehicle detection means 20A).
If the determination result of step S12 is negative, the process returns to step S10.
If the determination result in step S12 is affirmative, the ECU 20 switches the headlamp 4 from the high beam to the low beam via the switching unit 18 (step S14: switching control means 20D). Here, the ECU 20 starts a timer and starts a time measuring operation.
Next, the ECU 20 detects the position of the host vehicle 2 in the width direction of the road L0 based on the image information of the camera 1212 (step S16: position detection means 20B).
Next, the ECU 20 estimates the road shape of the road L0 based on the image information of the camera 1212 and the steering angle detected by the steering angle sensor 16 (step S18: road shape estimation means 20C).
Next, the ECU 20 receives the traveling speed of the host vehicle 2 detected by the vehicle speed sensor 14 (step S20).

Next, the ECU 20 calculates the low beam maintenance period ΔT _LOW based on the detected position of the host vehicle 2, the estimated road shape, and the traveling speed of the host vehicle 2 (step S22: period calculation unit 20E). .
In the present embodiment, the low beam maintenance period ΔT _LOW is set based on the traveling speed, whether the host vehicle 2 is inside or outside the curve shape, and whether the host vehicle 2 is traveling on the left side or the right side. calculate. Therefore, even if the traveling speed of the host vehicle 2 is the same, different values are calculated for the low beam maintenance period ΔT _LOW depending on the following five types of situations.
1) Left-hand traffic or right-hand traffic road shape is straight 2) Left-hand traffic inside curve shape 3) Left-hand traffic outside curve shape 4) Right-hand traffic inside curve shape 5) Right-hand traffic inside curve shape

Next, the ECU 20 determines whether or not the low beam maintenance period ΔT _LOW has ended based on the timer measurement result (step S24: switching control means 20D).
If the determination result in step S24 is negative, the process returns to step S24. If the determination result in step S24 is affirmative, the ECU 20 returns the headlamp 4 from the low beam to the high beam via the switching unit 18 (step S24: switching control means 20D). ), The process returns to step S10.
The above process is repeatedly executed.

As described above, according to the present embodiment, when the oncoming vehicle 6 is detected, the headlamp 4 is moved to the position of the host vehicle 2 in the width direction of the road L0, the estimated road shape, and the traveling speed. After switching to the low beam for the low beam maintenance period ΔT _LOW calculated based on the above, the high beam is restored.
Therefore, the headlamp 4 can be switched from the low beam to the high beam at an early stage while preventing the oncoming vehicle 6 from being dazzled according to the position of the vehicle 2 in the width direction of the road L0, the road shape, and the traveling speed. This is advantageous for securing a far field of view.

Further, when the estimated road shape is a curve shape, the low beam maintenance period ΔT _LOW when the position of the host vehicle 2 in the width direction of the road L0 is a position inside the curve shape indicates that the host vehicle in the width direction of the road. The low beam maintenance period ΔT _LOW is calculated so as to be shorter than the low beam maintenance period ΔT _LOW when the position of 2 is a position outside the curve shape.
Accordingly, the headlamp 4 can be switched from the low beam to the high beam accurately according to the situation in which the host vehicle 2 is traveling inside or outside the curved shape, so that the oncoming vehicle 6 can be prevented from being dazzled at an early stage. This is more advantageous for securing a far field of view.

In addition, since the position of the host vehicle 2 in the width direction of the road is detected based on the image information captured by the camera 12, the position can be detected accurately.
Further, since the road shape is estimated based on the image information captured by the camera 12 and the detected steering angle, the road shape can be estimated accurately.
Moreover, since the oncoming vehicle 6 is detected based on the image information imaged by the camera 12, the oncoming vehicle can be accurately detected.
Further, in addition to the position of the host vehicle 2 in the width direction of the road L0, the estimated road shape, and the traveling speed, the low beam maintenance period ΔT _LOW is determined based on whether the host vehicle 2 is traveling on the left side or the right side. Therefore, the low beam maintenance period ΔT _LOW can be calculated more accurately, which is further advantageous in securing the far field of view at an early stage while preventing the oncoming vehicle 6 from being dazzled.
Further, since the calculation of the low beam maintenance period ΔT _LOW is performed using the above formula (1), the calculation of the low beam maintenance period ΔT _LOW can be easily performed and the control related to the switching operation of the headlamp 4 can be simplified. It is advantageous in planning.
In this embodiment, the low beam maintenance period ΔT _LOW is calculated in consideration of whether the host vehicle 2 is traveling on the left side or the right side. However, these left-hand traffic and right-hand traffic are not considered, and the road L0 The low beam maintenance period ΔT _LOW may be calculated based on the position of the host vehicle 2 in the width direction, the estimated road shape, and the traveling speed.
However, this embodiment is more advantageous in accurately calculating the low beam maintenance period ΔT _LOW .

  2 ... Vehicle (own vehicle), 4 ... Headlight, 6 ... Oncoming vehicle, 10 ... Headlight control device, 12 ... Camera, 14 ... Vehicle speed sensor, 16 ... Steering angle sensor, 18 ...... Switching unit, 20 ... ECU, 20A ... Oncoming vehicle detection means, 20B ... Position detection means, 20C ... Road shape estimation means, 20D ... Switch control means, 20E ... Period calculation means, 202, 602 ... irradiation range, A ... detection range.

Claims (7)

Beam switching means for switching between the low beam and high beam of the headlight of the own vehicle;
Oncoming vehicle detection means for detecting an oncoming vehicle;
Position detecting means for detecting a position in the width direction of the road on which the host vehicle travels; estimating means for estimating a road shape on which the host vehicle travels;
Speed detecting means for detecting a traveling speed of the host vehicle or a relative speed between the host vehicle and the oncoming vehicle;
A switching control unit that, when the oncoming vehicle is detected by the oncoming vehicle detection unit in a state where the headlamp is in a high beam, the beam switching unit switches the headlamp to a low beam for a low beam maintenance period and then returns to the high beam. ,
Period calculation means for calculating the low beam maintenance period based on the position of the host vehicle in the width direction of the road, the estimated road shape, and the traveling speed or the relative speed;
A headlamp control device comprising: When the estimated road shape is a curve shape, the period calculation means determines that the low beam maintenance period when the position of the host vehicle in the road width direction is a position inside the curve shape is the road width. Calculating the low beam maintenance period so as to be shorter than the low beam maintenance period when the position of the host vehicle in the direction is a position outside the curve shape;
The headlamp control apparatus according to claim 1, wherein Comprising imaging means for imaging the front of the host vehicle,
The position detection means detects the position of the host vehicle in the width direction of the road based on image information captured by the imaging means.
The headlamp control apparatus according to claim 1 or 2, wherein Steering angle detection means for detecting the steering angle of the host vehicle,
The estimating means estimates the road shape based on the image information and the steering angle;
The headlamp control device according to claim 3. The oncoming vehicle detection means detects the oncoming vehicle based on the image information.
The headlamp control device according to claim 3 or 4, In addition to the position of the host vehicle in the width direction of the road, the estimated road shape, and the traveling speed or the relative speed, the period calculation unit is configured to pass the host vehicle on the left side or on the right side. Calculating the low beam maintenance period based on whether
The headlamp control device according to any one of claims 1 to 5, wherein The calculation of the low beam maintenance period by the period calculation means is performed using the following formula (1).
The headlamp control device according to claim 6.
ΔT _LOW = Tc−R × α−V × β (1)
Where ΔT _LOW is the low beam maintenance period, Tc is a predetermined time constant, R is the radius of curvature of the road shape that differs depending on the road section, and α is whether the vehicle is traveling on the left side or on the right side. And a curve coefficient predetermined based on vehicle characteristics, V is the traveling speed or relative speed, and β is a predetermined speed coefficient.

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