JP6642886B2 - Vehicle driving support device - Google Patents

Description

  The present invention relates to a driving support device for a vehicle that recognizes the lighting of a brake lamp of a preceding vehicle traveling in front of the own vehicle and controls acceleration and deceleration of the own vehicle.

  In vehicles such as automobiles, the environment in front of the host vehicle is imaged by a camera or the like, and the system recognizes the preceding vehicle or obstacle traveling in front of the host vehicle and automatically runs to keep the distance between the host vehicle and the preceding vehicle safe. Driving assistance technology has been developed and put into practical use that assists the driver in driving, such as increasing or decreasing the speed or automatically applying a brake.

  For example, Patent Literature 1 discloses a method of performing a collision prevention control with a natural feeling by calculating the reliability of detecting an obstacle ahead and a collision prediction time, and switching the control type of the collision prevention control based on the calculated values. A possible vehicle driving assistance device is disclosed.

JP 2012-183868 A

  In such driving support control, when the traveling speed of the host vehicle is automatically adjusted, generally, two types of target accelerations are set, a normal target acceleration and a target acceleration that enables early deceleration. When the brake lamp lighting of the preceding vehicle is determined or when the deceleration determination is performed based on the acceleration of the preceding vehicle, the reference map is switched from the normal reference map to the reference map for deceleration, and the target acceleration of the own vehicle is set. By setting, the deceleration responsiveness when the preceding vehicle applies the brake is improved.

  This switching of the target acceleration is performed when the lighting state of the brake lamp is recognized with high reliability and it is determined that the brake lamp is on, so that unnecessary deceleration due to erroneous recognition can be avoided. Then, there are many “undetected” scenes in which it is determined that the brake lamp is lit but not lit. In such a scene, the running is controlled at the normal target acceleration, and the start of deceleration may be delayed.

  The present invention has been made in view of the above circumstances, and when controlling acceleration / deceleration of a host vehicle with respect to a host vehicle traveling ahead of the host vehicle, improves the deceleration responsiveness when the host vehicle applies a brake. In addition, it is an object of the present invention to provide a vehicle driving support device capable of optimizing the acceleration of the host vehicle in following the preceding vehicle.

  The driving assistance device for a vehicle according to one aspect of the present invention recognizes the lighting state of a brake lamp of a preceding vehicle traveling ahead of the host vehicle, determines whether the brake lamp is on, and turns on the brake lamp. A brake lamp lighting recognition unit that outputs a state recognition reliability, and a preceding vehicle deceleration determining unit that determines whether the preceding vehicle has decelerated based on the acceleration of the preceding vehicle, and the own vehicle and the preceding vehicle. A first target acceleration setting unit that sets a first target acceleration based on the traveling state of the vehicle, and a second target acceleration corresponding to a brake lamp lighting determination of the preceding vehicle or a deceleration determination of the preceding vehicle. A second target acceleration setting unit to be set, based on the deceleration determination result of the preceding vehicle, the determination result of the lighting of the brake lamp, and the recognition reliability of the lighting state of the brake lamp, An internal dividing point coefficient setting unit for setting an internal dividing point coefficient for calculating an internal dividing point between the first target acceleration and the second target acceleration; and the first internal dividing point coefficient using the internal dividing point coefficient. A target acceleration determination unit that calculates an internal dividing point between the target acceleration and the second target acceleration, and determines the calculated internal dividing point as the target acceleration of the host vehicle.

  According to the present invention, when controlling acceleration / deceleration of a host vehicle with respect to a host vehicle traveling in front of the host vehicle, the responsiveness of the host vehicle to deceleration when a brake is applied to the host vehicle is improved. This makes it possible to optimize the acceleration of the host vehicle in the following travel.

Overall configuration diagram of the driving support device Explanatory drawing showing a first target acceleration and a second target acceleration Explanatory drawing showing a setting example of an internal dividing point coefficient Flowchart of target acceleration determination processing Explanatory diagram showing deceleration due to differences in recognition reliability of brake lamp lighting Explanatory diagram showing deceleration when recognition reliability decreases

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In FIG. 1, reference numeral 1 denotes a driving support device for a vehicle, and executes driving support control including automatic driving based on a recognition result of an external environment of the own vehicle for a driving operation of a driver. The driving support device 1 includes a communication bus 100 in which an external environment monitoring device 20, an engine control device 30, a brake control device 40, a steering control device 50, an alarm control device 60, and the like form a vehicle-mounted network with a driving control device 10 as a center. Are connected so as to be capable of bidirectional communication with each other.

  The external environment monitoring device 20 is configured to include a device group capable of autonomously recognizing the external environment and a device group for acquiring information through communication with the outside. The former group of devices includes a camera unit 20A for processing an image of the external environment of the vehicle to recognize the external environment, and a radar unit (laser radar, millimeter radar) for receiving a reflected wave from a three-dimensional object existing around the vehicle. Wave radar, ultrasonic radar, etc.) 20B.

  The latter device group includes a vehicle position positioning unit 20C that measures the position of the vehicle (longitude, latitude, and altitude) using a GPS (Global Positioning System), and a vehicle position positioning unit. It is integrated with the 20C and displays the measured vehicle position on a map image to provide route guidance, and uses the fine map data held in the system to determine the shape of roads and the position of junctions (intersections). A navigation unit 20D that outputs coordinate data, road type (highway, highway, city road, etc.) data, data on facility information existing near a node point on a map, etc., road traffic by road-to-vehicle communication or vehicle-to-vehicle communication There is a road traffic information communication unit 20E for acquiring information.

  Here, in the present embodiment, the camera unit 20A is configured by integrating a stereo camera 21 that captures the same object from different viewpoints and an image processing unit 22. The stereo camera 21 is composed of a pair of left and right cameras using a solid-state imaging device such as a CCD or a CMOS. These one set of cameras are shutter-synchronous cameras capable of taking color images. For example, the cameras are mounted at a fixed interval in front of the ceiling in a vehicle interior, and perform stereo imaging of an object outside the vehicle at a predetermined cycle to convert the captured image into an image processing unit. 22.

  The image processing unit 22 performs stereo matching processing on a pair of left and right images captured by the stereo camera 21 in front of the own vehicle to obtain a pixel shift amount (parallax) at a corresponding position of the left and right images, and converts the pixel shift amount into luminance data. By doing so, a distance image having distance information is generated. The points on the distance image are converted into points on three-dimensional coordinates in the real space based on the principle of triangulation, and the white line (lane) of the road on which the vehicle travels, obstacles, and the preceding vehicle traveling ahead of the vehicle. A vehicle or the like is recognized three-dimensionally. Then, the inter-vehicle distance between the own vehicle and the preceding vehicle, the vehicle speed (relative speed) of the preceding vehicle with respect to the own vehicle, the acceleration (deceleration) of the preceding vehicle, and the like are calculated, and the three-dimensional information of the recognized object is sent to the travel control device 10. Is output.

  As described later, the camera unit 20A functions as a brake lamp lighting recognition unit that recognizes the lighting state of the brake lamp at the rear of the preceding vehicle and outputs the recognition result to the travel control device 10 together with the recognition reliability. Also have.

  The engine control device 30 is a well-known control device that controls an operation state of an engine (not shown) of the vehicle, and includes, for example, an intake air amount, a throttle opening, an engine water temperature, an intake air temperature, an air-fuel ratio, a crank angle, and an accelerator. Based on the opening degree and other vehicle information, main controls such as fuel injection control, ignition timing control, and electronic control throttle valve opening degree control are performed.

  The brake control device 40 controls the four-wheel brake device (not shown) independently of the driver's brake operation based on, for example, a brake switch, four-wheel speed, steering wheel angle, yaw rate, and other vehicle information. This is a well-known control device that performs a well-known antilock brake system, a yaw moment control for controlling a yaw moment applied to a vehicle such as a side slip prevention control, and the like. When the brake force of each wheel is input from the travel control device 10, the brake control device 40 calculates the brake fluid pressure of each wheel based on the brake force, and a brake driving unit (not shown) ) Is activated.

  The steering control device 50 controls an assist torque by an electric power steering motor (not shown) provided in a steering system of the vehicle based on, for example, a vehicle speed, a steering torque of a driver, a steering wheel angle, a yaw rate, and other vehicle information. It is a known control device. In addition, the steering control device 50 is capable of lane keeping control for keeping the vehicle in the lane for traveling control and lane departure preventing control for performing control for preventing departure from the traveling lane. The steering angle or the steering torque required for the departure prevention control is calculated by the traveling control device 10 and input to the steering control device 50, and the electric power steering motor is driven and controlled according to the input control amount.

  The alarm control device 60 is a device that appropriately generates an alarm when an abnormality occurs in various devices of the vehicle. For example, a visual output of a monitor, a display, an alarm lamp, and the like, and an audio output of a speaker, a buzzer, and the like. The warning / notification is performed using at least one of the outputs. Further, when the driving support control is stopped by the override operation of the driver, the current driving state is notified to the driver.

  The driving control device 10 which is the center of the driving support device 1 detects information from the devices 20, 30, 40, and 50 and various sensors such as a vehicle speed sensor, a steering angle sensor, a yaw rate sensor, and a lateral acceleration sensor. On the basis of the driving state information of the host vehicle, driving support control such as constant speed traveling control including following traveling while maintaining a constant inter-vehicle distance with respect to the preceding vehicle, lane keeping control, lane departure prevention control, and the like are performed. In addition, the traveling control device 10 forcibly applies the brake when the driver determines that there is a risk of collision because the driver cannot appropriately start the deceleration action because the driver cannot recognize the deceleration of the preceding vehicle or the appearance of the obstacle, and there is a possibility of collision. Activate an automatic emergency brake (pre-crash brake) to avoid collisions or reduce collision damage.

  In such driving support control, the traveling control device 10 controls the acceleration and deceleration of the own vehicle at a first target acceleration set based on the running state of the own vehicle and the preceding vehicle when following the preceding vehicle. I do. When it is determined that the preceding vehicle has decelerated or the brake lamp has been turned on based on information from the camera unit 20A, the second target acceleration in the deceleration direction is switched to decelerate the own vehicle. . In addition, even when the deceleration determination of the preceding vehicle and the determination of the lighting of the brake lamp are not performed, if there is a certain degree of certainty in the recognition of the lighting of the brake lamp, the second target is determined according to the reliability of the recognition. By controlling the acceleration / deceleration of the own vehicle with the target acceleration reflecting the acceleration component, early deceleration is enabled.

  For this reason, the driving support device 1 includes, in correspondence with the function as the brake lamp lighting recognition unit of the camera unit 20A, the traveling control device 10 includes various functional units related to the setting of the target acceleration. The function units related to the setting of these target accelerations include a preceding vehicle deceleration determination unit 11, a first target acceleration setting unit 12, a second target acceleration setting unit 13, an internal dividing point coefficient setting unit 14, and a target acceleration determination unit 15. Represented by

  Schematically, the target acceleration determining unit 15 calculates the first target acceleration set by the first target acceleration setting unit 12 and the second target acceleration set by the second target acceleration setting unit 13, The final target acceleration is determined using the internal dividing point coefficient set by the internal dividing point coefficient setting unit 14. The internal dividing point coefficient is set based on the deceleration state determined from the acceleration of the preceding vehicle, the determination result of the brake lamp lighting of the preceding vehicle, and the recognition reliability of the brake lamp lighting.

  The target acceleration determined by the target acceleration determination unit 15 is output to the acceleration / deceleration control unit 16, and a control command is transmitted from the acceleration / deceleration control unit 16 to the engine control device 30 or the brake control device 40 via the communication bus 100, Acceleration / deceleration of the host vehicle is controlled by increasing / decreasing a driving force, operating a brake, and the like. At this time, when the target acceleration of the own vehicle is switched from the first target acceleration to the second target acceleration in accordance with the deceleration state of the preceding vehicle, the second target is changed in accordance with the recognition reliability of the brake lamp lighting of the preceding vehicle. The target acceleration is controlled to reflect the acceleration component, and the deceleration can be started early.

  In detail, in this embodiment, the preceding vehicle deceleration determination unit 11 checks the acceleration of the preceding vehicle transmitted from the camera unit 20A, and when the change in the acceleration of the preceding vehicle is equal to or greater than the set value, the preceding vehicle decelerates. And turns on the deceleration determination flag FG (sets FG = 1). The deceleration of the preceding vehicle may be determined based on information from the radar unit 20B or information from inter-vehicle communication by the road traffic information communication unit 20E.

  The first target acceleration setting unit 12 sets a first target acceleration a1 based on the traveling state of the host vehicle and the preceding vehicle. The first target acceleration a1 is, for example, a normal acceleration for accelerating the own vehicle so that the inter-vehicle distance with the preceding vehicle quickly reaches a set value. As shown in FIG. As the speed V increases, the first target acceleration a1 increases. When the relative speed V is negative (the speed of the host vehicle> the preceding vehicle), the characteristic is set such that the first target acceleration a1 is negative. ing. The first target acceleration a1 is stored in the first acceleration map M1.

  The second target acceleration setting unit 13 determines whether or not the camera unit 20A determines that the brake lamp of the preceding vehicle is on (when a recognition flag FL described later is turned on) or the preceding vehicle deceleration determination unit 11 determines A second target acceleration a2 for decelerating the vehicle at an early stage is set in response to the case where the vehicle is determined to be decelerated (FG = 1). The second target acceleration a2 is set such that an acceleration is set in a direction more negative than the target acceleration a1 with respect to the relative speed V between the host vehicle and the preceding vehicle, and is equal to or lower than a predetermined speed even when the relative speed V is in a positive region. In this example, the vehicle is decelerated (a2 <0). The second target acceleration a2 is stored in the second acceleration map M2.

  The internal dividing point coefficient setting unit 14 sets the internal dividing point coefficient when the target acceleration determining unit 15 determines the internal dividing point between the first target acceleration a1 and the second target acceleration a2 as the final target acceleration a. m, n (m and n are positive numbers) are set. Here, the internally dividing point coefficients m and n are coefficients for internally dividing the distance between the first target acceleration a1 and the second target acceleration a2 into n: m. Based on the state of recognition of the lighting of the brake lamp of the vehicle, it is set by referring to the internally dividing point coefficient table Tmn having the characteristics as shown in FIG.

The target acceleration determination unit 15 calculates an internal dividing point between a first target acceleration a1 obtained by referring to the first acceleration map M1 and a second target acceleration a2 obtained by referring to the second acceleration map M2. Is calculated, and the calculated dividing point is determined as the final target acceleration a. The internal dividing point between the first target acceleration a1 and the second target acceleration a2 is obtained by dividing the internal dividing point coefficients m and n set by the internal dividing point coefficient setting unit 14 as shown in the following equation (1). It is calculated using
a = (n × a2 + m × a1) / (m + n) (1)

  Specifically, the internal dividing point coefficients m and n are set based on whether or not the preceding vehicle deceleration determining unit 11 determines whether the preceding vehicle has been decelerated, the determination result of the brake lamp lighting of the preceding vehicle by the camera unit 20A, and the recognition reliability. Is done. For example, the recognition reliability R of the lighting of the brake lamp is divided into a plurality of stages of 0, 1, 2, 3, and 4, and the recognition flag FL of the lighting of the brake lamp is OFF (FL = 0; "Brake lamp lighting not detected"). ), The recognition reliability R when the recognition flag FL is ON and the recognition flag FL is ON (FL = 1; the state where the recognition reliability is the highest and it is determined that the brake lamp is lit). Is set to R = 4, internally dividing point coefficients m and n as shown in FIG. 3 are set.

  In the internally dividing point coefficient table Tmn shown in FIG. 3, when the deceleration determination flag FG indicating that there is a deceleration determination of the preceding vehicle is FG = 1, or when the recognition flag FL indicating that there is a determination of turning on the brake lamp is FL = 1, n = 10, m = 0 is set, and the final target acceleration a is determined as the second target acceleration a2 (a = a2). Further, when FG = 0 and FL = 0, that is, when the deceleration determination of the preceding vehicle and the lighting determination of the brake lamp are not performed, when R = 0 (no detection), n = 0 and m = 10 are set; The final target acceleration a is determined as the first target acceleration a1 (a = a1). Further, in the state of FG = 0 and FL = 0, as the recognition reliability of the lighting of the brake lamp becomes higher, the internal dividing point coefficient m on the second target acceleration a2 side becomes higher than the internal dividing point coefficient m on the first target acceleration a1 side. n becomes large, and early deceleration becomes possible.

  Here, the reliability of lighting recognition of the brake lamp of the preceding vehicle by the camera unit 20A will be described. In the present embodiment, a region corresponding to the emission color of the brake lamp of the preceding vehicle is extracted from the color image captured by the camera unit 20A, and the brightness B of this region is compared with a plurality of brightness threshold values.

  The thresholds of a plurality of stages are set corresponding to the stage from the highest recognition reliability to the lowest, and in the present embodiment, the thresholds of H4, H3, H2, and H1 are set in descending order of the recognition reliability. ing. Then, as described below, the recognition reliability R is calculated according to the comparison result between the brightness B of the lighting area of the brake lamp and each of the thresholds H4, H3, H2, and H1.

B ≧ H4 → R = 4 (Brake lamp lighting judgment: FL = 1)
H3 ≦ B <H4 → R = 3 (FL = 0; brake lamp lighting almost recognized)
H2 ≦ B <H3 → R = 2 (FL = 0; brake lamp lighting slightly recognized)
H1 ≦ B <H2 → R = 1 (FL = 0; Brake lamp lighting slightly recognized)
B <H1 → R = 0 (FL = 0; brake lamp lighting not detected)

  Among the threshold values H1 to H4 of the plurality of stages, the threshold value H4 is a threshold value that is set based on the same standard as in the related art and is given in advance, and is a determination value for determining whether to turn on the brake lamp (turns the recognition flag FL on and off). Judgment value). With respect to the determination value H4, the thresholds H3, H2, and H1 are set as state values obtained by stepwise reducing the recognition reliability. Then, the judgment value H4 is learned and updated for each predetermined traveling distance and traveling time in order to correspond to individual differences and aging of the camera unit 20A for each vehicle. Each state value H3, H2, H1 is reset.

  Next, the program processing for determining the target acceleration by the travel control device 10 will be described with reference to the flowchart in FIG.

  In the target acceleration determination process, in the first step S1, information on the preceding vehicle is acquired from the external environment monitoring device 20 including the camera unit 20A, and it is determined in step S2 whether the preceding vehicle has decelerated. As a result, when it is determined that the preceding vehicle has decelerated, the deceleration determination flag FG is turned ON (FG = 1 is set) and the process proceeds to step S3. When it is determined that the preceding vehicle is not decelerating, the deceleration determination flag The FG is turned off (FG = 0 is cleared), and the process proceeds to step S4.

  When it is determined that the preceding vehicle has decelerated, in step S3, the deceleration determination flag FG is referred to, and under the condition of FG = 1 (recognition reliability R = 4), the internally dividing point coefficient table Tmn in FIG. 3 is referred to. The internally dividing point coefficients m and n are set to m = 0 and n = 10. On the other hand, if it is determined that the preceding vehicle is not decelerating, it is determined based on the recognition flag FL and the recognition reliability R whether or not it is determined in step S4 that the brake lamp of the preceding vehicle is on. I do.

  In step S4, when it is determined that FL = 1, that is, the brake lamp of the preceding vehicle is turned on (when the brake lamp lighting is recognized with high reliability of R = 4), the process proceeds from step S4 to step S5. Then, under the condition of FL = 1 (recognition reliability R = 4), the internal dividing point coefficients m and n are set with reference to the internal dividing point coefficient table Tmn of FIG. The internally dividing point coefficients m and n at this time are set to m = 0 and n = 10, as in step S3 when the deceleration determination is made, and the component of the first target acceleration a1 is set to 0.

  If FL = 0 in step S4 and it is not determined that the brake lamp is turned on, the process proceeds from step S4 to step S6, and based on the recognition reliability R of the lighting state of the brake lamp in FIG. The internal dividing point coefficients m and n are set with reference to the internal dividing point coefficient table Tmn. At this time, as the recognition reliability R decreases, the value of m on the first target acceleration a1 side increases and the value of n on the second target acceleration a2 side decreases as the recognition reliability R decreases.

  After setting the internally dividing point coefficients m and n in any of Steps S3, S5, and S6, the process proceeds to Step S7, where the first acceleration map M1 and the second acceleration map M2 are referred to, and the first acceleration map M1 and the second acceleration map M2 are referred to. And the second target acceleration a2 and the second target acceleration a1 based on the above-described equation (1) using the internally dividing point coefficients m and n in step S8. The target acceleration a is calculated by calculating the internal dividing point with the acceleration a2.

  By determining the target acceleration by such an internal dividing point calculation, as shown in FIG. 5, even in a scene where the recognition reliability R is 1, 2, 3 and the conventional brake lamp lighting is "not detected", as shown in FIG. The deceleration component due to the second target acceleration a2 can be taken in, and the deceleration can be made earlier than before.

  As shown in FIG. 6, the value of the threshold value H4 of the recognition flag FL is reduced, and the brake lamp is erroneously detected (erroneously determined) as being lit even though the brake lamp is not lit. 2 (dashed line in the figure) and the case where the internal dividing point is calculated with the recognition reliability of R = 1 (solid line in the figure), the conventional second map In the case where only the target acceleration a2 is used, since the deceleration component due to the second target acceleration a2 is reflected in accordance with the recognition reliability R, the influence of unnecessary deceleration due to “erroneous detection” can be reduced.

  As described above, in the present embodiment, when switching from the first target acceleration based on the traveling state of the host vehicle and the preceding vehicle to the second target acceleration corresponding to the determination of the lighting of the brake lamp of the preceding vehicle or the deceleration of the preceding vehicle. In addition, the internal dividing point between the first target acceleration and the second target acceleration is determined using an internal dividing point coefficient set based on the deceleration determination result of the preceding vehicle, the lighting determination result of the brake lamp, and the recognition reliability. After the calculation, the final target acceleration is determined. As a result, it is possible to improve the deceleration responsiveness when the preceding vehicle applies the brake, and to optimize the acceleration when following the preceding vehicle.

DESCRIPTION OF SYMBOLS 1 Driving assistance device 10 Driving control device 11 Leading vehicle deceleration determination unit 12 First target acceleration setting unit 13 Second target acceleration setting unit 14 Internal dividing point coefficient setting unit 15 Target acceleration determination unit 20 External environment monitoring device 20A Camera unit FG deceleration determination flag FL recognition flag R recognition reliability a target acceleration a1 first target acceleration a2 second target acceleration m, n

Claims (5)

Brake lamp lighting recognition that recognizes the lighting state of the brake lamp of the preceding vehicle running ahead of the host vehicle and outputs a determination result as to whether the brake lamp is on and the recognition reliability of the lighting state of the brake lamp. Department and
A preceding vehicle deceleration determining unit that determines whether the preceding vehicle has decelerated based on the acceleration of the preceding vehicle,
A first target acceleration setting unit that sets a first target acceleration based on a traveling state of the host vehicle and a preceding vehicle;
A second target acceleration setting unit that sets a second target acceleration in response to the brake lamp lighting determination of the preceding vehicle or the deceleration determination of the preceding vehicle;
An internal dividing point between the first target acceleration and the second target acceleration based on a deceleration determination result of the preceding vehicle, a determination result of lighting of the brake lamp, and a recognition reliability of a lighting state of the brake lamp. An internal dividing point coefficient setting unit for setting an internal dividing point coefficient for calculating
A target acceleration determining unit that calculates an internal dividing point between the first target acceleration and the second target acceleration using the internal dividing point coefficient, and determines the calculated internal dividing point as the target acceleration of the vehicle. A driving assistance device for a vehicle, comprising:   The second target acceleration is set in a deceleration direction than the first target acceleration, and as the recognition reliability increases, the internal dividing point coefficient is set so that the internal dividing point approaches the second target acceleration. The driving support device for a vehicle according to claim 1, wherein the setting is set.   The brake lamp lighting recognition unit divides the recognition reliability into a plurality of stages, and calculates the luminance of an area corresponding to the brake lamp lighting of the preceding vehicle in the image obtained by imaging the front of the own vehicle, to the recognition reliability at each stage. 3. The driving support apparatus for a vehicle according to claim 1, wherein the recognition reliability is calculated by comparing the recognition reliability with a corresponding threshold.   Brake lamp lighting recognition unit, the threshold value corresponding to the highest recognition reliability level, given as a determination value to determine whether the brake lamp is lit, the threshold value corresponding to other stages, 4. The driving support apparatus for a vehicle according to claim 3, wherein the recognition reliability is set as a state value obtained by gradually lowering the recognition reliability with respect to the determination value.   The vehicle driving support device according to claim 4, wherein the brake lamp lighting recognition unit updates the determination value in a learning manner and resets each of the state values according to the update of the determination value.

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