JP2018200593A - Brake determination method and brake determination device - Google Patents

Abstract

To allow an easy detection of a lighting of a brake lamp even in a driving situation where it is difficult to detect the lighting of the brake lamp at a tail light position.SOLUTION: A preceding vehicle detection part 41 detects a preceding vehicle 1 in front of an own vehicle. A search area setting part 42 sets a search area for searching for a presence/absence of a light source of the preceding vehicle 1 in the vicinity of the center of the lateral width of the preceding vehicle 1. A light source extraction part 43 extracts the light source from the set search area.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a brake determination method and a brake determination device.

  As a technique for detecting lighting of a brake lamp of a preceding vehicle, a technique for detecting lighting of a brake lamp based on a change in luminance or area of a tail lamp detection region is known (for example, Patent Document 1).

JP 11-39597 A

In the technique described in Patent Literature 1, lighting of the brake lamp is determined based on lamp detection in two left and right areas corresponding to the taillight position. For this reason, the lighting of the brake lamp may not be detected depending on the traveling condition of the area.
An object of the present invention is to make it easy to detect the lighting of a brake lamp even in a traveling situation in which it is difficult to detect the lighting of a brake lamp at a taillight position.

  In the brake determination method according to one aspect of the present invention, a preceding vehicle ahead of the host vehicle is detected, and a search area for searching for the presence or absence of a light source of the preceding vehicle is set near the center of the lateral width of the preceding vehicle and set. The lighting of the brake lamp is detected from the search area.

  According to one aspect of the present invention, it is easy to detect the lighting of the brake lamp even in a traveling situation in which it is difficult to detect the lighting of the brake lamp at the taillight position.

It is explanatory drawing of the example of arrangement | positioning of the brake lamp and tail lamp of the rear part of a vehicle. It is a figure which shows the example of schematic structure of a driving assistance device provided with the brake determination apparatus of embodiment. It is a figure used for description of the process which calculates a search area | region from the presence area | region of a preceding vehicle. It is explanatory drawing of the example of a setting of the search area | region when the preceding vehicle is drive | working the curve. It is a flowchart of the brake determination method of an embodiment. It is a flowchart of the search area | region determination process in FIG.5 S5. It is a flowchart of the brake determination process in step S6 of FIG.

  Embodiments of the present invention will be described below with reference to the drawings. The following embodiments of the present invention exemplify apparatuses and methods for embodying the technical idea of the present invention, and the technical idea of the present invention describes the structure and arrangement of components as follows. It is not something specific. The technical idea of the present invention can be variously modified within the technical scope defined by the claims described in the claims.

Please refer to FIG. The brake determination device of the embodiment determines whether or not the preceding vehicle 1 has applied a brake by detecting lighting of the brake lamp of the preceding vehicle 1 in front of the host vehicle. Here, it is assumed that the preceding vehicle 1 has brake lamps 2, 3 and 4.
The brake lamp 2 is provided slightly above the center of the lateral width of the rear portion of the preceding vehicle 1. Hereinafter, the brake lamp 2 is referred to as “high-mount stop lamp 2”.

The brake lamps 3 and 4 are provided at the same height at the rear, left end, and right end of the preceding vehicle 1. Hereinafter, the brake lamps 3 and 4 are referred to as “left brake lamp 3” and “right brake lamp 4”, respectively.
The left brake lamp 3 and the right brake lamp 4 are provided at positions near the tail lights 5 and 6, respectively. Here, the term tail lamp (so-called tail lamp) means a lamp that lights in accordance with the lighting of the headlamp in conjunction with the headlamp, and is distinguished from the left brake lamp 3 and the right brake lamp 4. use.

(Constitution)
Please refer to FIG. The driving support device 10 automatically controls the traveling speed of the host vehicle to a set vehicle speed, and controls the inter-vehicle distance from the preceding vehicle 1 detected using a sensor at a predetermined interval. (AAC: Adaptive Cruise Control) is performed.
In addition, the driving support device 10 detects that the preceding vehicle 1 has applied the brake and decelerates or automatically stops the own vehicle by an automatic brake that applies the brake of the own vehicle.

Further, the driving support device 10 may perform automatic steering for detecting that the preceding vehicle 1 has applied the brake and avoiding the preceding vehicle 1.
The driving assistance device 10 may perform automatic driving control that automatically operates the steering mechanism without depending on the driving operation of the driver. The driving support device 10 may detect that the preceding vehicle 1 has applied the brake during the automatic driving control, and perform automatic braking or automatic steering.

The driving support device 10 includes a brake determination device 11, a vehicle travel controller 12, and an actuator group 13.
The brake determination device 11 detects the preceding vehicle 1 ahead of the host vehicle and determines whether the preceding vehicle 1 has applied a brake, that is, whether the brake lamp of the preceding vehicle 1 has been lit. The brake determination device 11 outputs the brake determination result of the preceding vehicle 1 to the vehicle travel controller 12.

The vehicle travel controller 12 performs constant speed travel / inter-vehicle distance control, automatic braking, and automatic steering of the host vehicle by driving the actuator group 13.
The actuator group 13 includes a brake actuator 14, an accelerator opening actuator 15, and a steering actuator 16.
The brake actuator 14 operates the brake device of the host vehicle.

The accelerator opening actuator 15 changes the accelerator opening of the host vehicle.
The steering actuator 16 operates a steering mechanism of the host vehicle.
When the brake determination device 11 determines that the brake of the preceding vehicle 1 has been lit, the vehicle travel controller 12 outputs a command signal to the brake actuator 14 and drives the brake actuator 14 to automatically apply the brake. Alternatively, the vehicle travel controller 12 outputs a command signal to the steering actuator 16 and drives the steering actuator 16 to automatically operate the steering mechanism.

The brake determination device 11 includes a preceding vehicle detection sensor 20, a navigation device 30, and a controller 40.
The preceding vehicle detection sensor 20 is a sensor that detects the situation ahead of the host vehicle in order to detect the preceding vehicle 1. The preceding vehicle detection sensor 20 is a camera 21 that is mounted on the host vehicle and generates an image obtained by photographing the front of the host vehicle, or a radar (even a laser radar) that detects the position of an object in front of the host vehicle. Good) 22 may be provided.
The camera 21 outputs the generated image information ahead of the host vehicle to the controller 40. The radar 22 outputs the detection result of the object ahead of the host vehicle to the controller 40. An image generated by the camera 21 is simply referred to as a “captured image”.

  The navigation device 30 outputs map information ahead of the host vehicle to the controller 40. The navigation device 30 may include a map database 31 and a GPS (Global Positioning System) receiver 32. The navigation device 30 measures the current position of the host vehicle based on the positioning satellite signal received by the GPS receiver 32. The navigation device 30 acquires map information ahead of the host vehicle based on the current position of the host vehicle and the map information in the map database 31.

The controller 40 detects the preceding vehicle 1 based on the captured image of the camera 21 of the preceding vehicle detection sensor 20 and the detection result of the radar 22.
When the preceding vehicle 1 is detected, the controller 40 sets a search region for detecting the brake lamp of the preceding vehicle 1 in the captured image, and extracts the light source in the search region to extract the preceding vehicle 1 from the search region. The lighting of the brake lamp is detected and the lighting of the brake lamp is determined.

The controller 40 includes a preceding vehicle detection unit 41, a search region setting unit 42, a light source extraction unit 43, a lighting determination unit 44, a search region storage unit 45, and a tracking determination unit 46.
The controller 40 may include a processor and peripheral components of the storage device. The processor may be, for example, a CPU (Central Processing Unit) or an MPU (Micro-Processing Unit).

The storage device may include any one of a semiconductor storage device, a magnetic storage device, and an optical storage device. The storage device may include a register, a cache memory, and a memory such as a ROM (Read Only Memory) and a RAM (Random Access Memory) used as a main storage device.
In the storage device, the functions of the preceding vehicle detection unit 41, the search region setting unit 42, the light source extraction unit 43, the lighting determination unit 44, the search region storage unit 45, and the tracking determination unit 46 are executed on the processor. A computer program for realizing the above is stored.

  The controller 40 may be realized by a functional logic circuit set in a general-purpose semiconductor integrated circuit. For example, the controller 40 may include a programmable logic device (PLD) such as a field-programmable gate array (FPGA).

The preceding vehicle detection unit 41 detects the position in the three-dimensional real space of the preceding vehicle 1 ahead of the host vehicle based on the image processing of the captured image. Alternatively, the position of the preceding vehicle 1 in the three-dimensional real space is detected based on the detection result of the radar 22.
The preceding vehicle detection unit 41 specifies an existing area on the captured image of the preceding vehicle 1 based on the position information of the preceding vehicle 1. For example, the preceding vehicle detection unit 41 projects the detected position in the three-dimensional real space of the preceding vehicle 1 on a point on the captured image based on the mounting position of the camera 21, the optical axis direction, and the angle of view. The existence area of the car 1 may be specified.
The preceding vehicle detection unit 41 outputs information on the specified existence region to the search region setting unit 42.

The search area setting unit 42 sets search area candidates to be searched from the captured image using the high-mount stop lamp 2, the left brake lamp 3, and the right brake lamp 4 of the preceding vehicle 1 as the light source of the preceding vehicle 1.
Please refer to FIG. Ranges surrounded by broken lines 7, 8 and 9 indicate search area candidates for searching for the high-mount stop lamp 2, the left brake lamp 3, and the right brake lamp 4, respectively.

For example, the first region 7 may be set to a range Rh near the center of the width of the preceding vehicle 1 in the lateral direction. Further, the second region 8 and the third region 9 may be set as regions having the same height so as to form a pair from the left end and the right end in the lateral direction of the preceding vehicle 1 to a range Rt having a predetermined width.
Here, the term “lateral direction of the preceding vehicle 1” means the lateral direction (that is, the vehicle width direction) of the actual preceding vehicle 1 as shown in FIG. 3, and is used separately from the lateral direction of the captured image. To do.

Please refer to FIG. For example, the search region setting unit 42 may acquire the position of the rear surface 50 of the preceding vehicle 1 in the three-dimensional real space from the preceding vehicle detection unit 41 (note that the rear surface 50 is schematically shown in FIG. 3). ).
Based on the position of the rear surface 50 in the three-dimensional real space, the search region setting unit 42 sets the position of the first region 7 in the three-dimensional real space in the range Rh near the center of the lateral width of the preceding vehicle 1. You may decide. Similarly, the positions of the second region 8 and the third region 9 in the three-dimensional real space may be determined.
Then, the search area setting unit 42 projects the positions of the first to third areas 7 to 9 on the captured image of the first to third areas 7 to 9 by projecting the positions on the captured image. A range may be specified.

  Please refer to FIG. The high mount stop lamp 2 is installed above the tail lights 5 and 6 of the vehicle, the left brake lamp 3 and the right brake lamp 4. Therefore, the search area setting unit 42 may set the first area 7 of the high-mount stop lamp 2 above the tail lights 5 and 6 of the vehicle and above the left brake lamp 3 and the right brake lamp 4. For example, the search area setting unit 42 may set the first area 7 above the second area 8 and the third area 9.

  The high mount stop lamp 2 is installed between the tail lights 5 and 6 and the left brake lamp 3 and the right brake lamp 4 of the vehicle. Therefore, the search area setting unit 42 may set the first area 7 of the high-mount stop lamp 2 between the tail lights 5 and 6 of the vehicle or between the left brake lamp 3 and the right brake lamp 4. For example, the search area setting unit 42 may set the first area 7 between the second area 8 and the third area 9.

Further, for example, the search area setting unit 42 is located at the position of the light source lit at the rear part of the preceding vehicle 1, the first area 7 of the high-mount stop lamp 2, the second area 8 of the left brake lamp 3 and the right brake lamp 4, Three areas 9 may be set.
For example, the left brake lamp 3 and the right brake lamp 4 are provided at positions near the tail lights 5 and 6.

Therefore, the search area setting unit 42 may set the second area 8 and the third area 9 in a range including the positions of the tail lights 5 and 6 that are turned on when the headlamp of the preceding vehicle 1 is turned on.
Whether the taillight is turned on when the headlight of the preceding vehicle 1 is turned on depends on whether the ambient brightness is less than the threshold (for example, dusk) or the decrease in ambient brightness is greater than or equal to the threshold ( For example, the determination may be made based on whether or not lighting has started for a predetermined period of time after the lighting has started.

On the other hand, the high-mount stop lamp 2 is not lit even when the headlamp is lit. Therefore, the search area setting unit 42 may set the first area 7 at the position of the light source where there is no change in brightness when the headlamp is turned on. Whether or not the light source has no change in brightness when the headlamp is turned on may be determined as follows, for example.
First, the position of the light source at the rear of the preceding vehicle 1 in the captured image is specified and stored. And when the ambient brightness is less than the threshold, or when the amount of decrease in ambient brightness is greater than or equal to the threshold, there is no change in brightness when the headlamp is turned on according to the change in luminance at the stored position. You may determine whether it is a light source.

Next, the search area setting unit 42 selects a search area for searching for the light source of the preceding vehicle 1 from the captured image from the first to third areas 7 to 9.
At this time, the search area setting unit 42 detects the lighting of the light source at the rear of the preceding vehicle 1 from the existing area of the preceding vehicle 1 in the captured image. For example, the search area setting unit 42 may detect the lighting of the light source based on the temporal change of the luminance of the pixel of the captured image in which the rear portion of the preceding vehicle 1 is captured and the color of the pixel.

Then, the search area setting unit 42 determines whether the picked-up image in which the lighting of the light source is detected has a lot of noise, that is, the magnitude of the noise.
For example, when there is a disturbance such as reflected light of the vehicle body of the preceding vehicle 1, a red signal, or a red light of an emergency vehicle, a light source other than the brake lamp appears in the captured image.
For this reason, the search area setting unit 42 may detect pixels having a luminance equal to or higher than a threshold value, combine adjacent pixels among these pixels into one area by a labeling process, and detect each light source. The search area setting unit 42 has a large amount of noise in the captured image when the number of light sources appearing in the captured image is equal to or greater than the threshold, and a small amount of noise in the captured image when the number of light sources that appear in the captured image is less than the threshold. Is determined.

Next, the search area setting unit 42 determines the state of the preceding vehicle 1, that is, the traveling direction of the preceding vehicle 1, and the distance between the preceding vehicle 1 and the host vehicle. For example, the search area setting unit 42 determines whether the preceding vehicle 1 is traveling straight, is traveling on a left curved road, is traveling on a right curved road, is about to turn left at an intersection, or is about to make a right turn. It may be determined whether or not.
For example, the search area setting unit 42 obtains the travel locus of the preceding vehicle 1 based on the captured image and the detection result of the radar 22, and the preceding vehicle 1 is determined based on the travel locus of the preceding vehicle 1 and the map information ahead of the host vehicle. It may be determined whether the vehicle is traveling straight, traveling on a left curved road, traveling on a right curved road, whether it is going to make a left turn, or going to a right turn at an intersection.

The search area setting unit 42 sets the search area for searching for the light source of the preceding vehicle 1 from the captured image, that is, the search area for detecting the lighting of the brake lamp of the preceding vehicle 1 as follows.
(1) When it is determined that there is little noise in the captured image, only the first area 7 of the high-mount stop lamp 2 is set as the search area. Since the high-mount stop lamp 2 is away from the taillights 5 and 6, it is possible to prevent erroneous detection of the brake lamp lighting by the lighting of the taillights 5 and 6 accompanying the automatic lighting of the headlamp.

On the other hand, when it is determined that there is a lot of noise in the captured image, the search area setting unit 42 determines the first area 7 and the second areas of the left brake lamp 3 and the right brake lamp 4 according to the state of the preceding vehicle 1. A combination with at least one of 8 and the third area 9 is set as a search area.
Since the high-mount stop lamp 2 is located near the roof of the vehicle, a light source caused by disturbance such as reflected light, a red signal, and a red light of an emergency vehicle is likely to be erroneously detected as the lighting of the high-mount stop lamp 2.

For this reason, by detecting not only the high-mount stop lamp 2 but also the lighting of the left brake lamp 3 and the right brake lamp 4, it is possible to prevent erroneous detection due to these disturbances. That is, erroneous detection due to disturbance can be prevented by detecting that not only one brake lamp but also a plurality of brake lamps are lit simultaneously.
Further, not only the brake lights at the taillight positions such as the left brake lamp 3 and the right brake lamp 4, but also the lighting of the high-mount stop lamp 2 is detected together, so that the brake lamps at the taillight positions are out of bulb or mud dirt. Even in such a case, the lighting of the brake lamp can be detected.

For example, the search area setting unit 42 may classify the state of the preceding vehicle 1 into a first state, a second state, and a third state.
(2) When the state of the preceding vehicle 1 is the first state, all of the first to third areas 7 to 9 are set as search areas. That is, when the lighting of the brake lamp is simultaneously detected as the light source in all of the first to third areas 7 to 9, it is determined that the brake lamp of the preceding vehicle 1 is lit.
For example, when the preceding vehicle 1 is traveling straight, it is determined that the state of the preceding vehicle 1 is the first state.

(3) When the state of the preceding vehicle 1 is the second state, the first area 7 and the second area 8 are set as search areas. That is, when the lighting of the brake lamp is simultaneously detected as the light source in the first area 7 and the second area 8, it is determined that the brake lamp of the preceding vehicle 1 has been lit.
For example, when traveling on a left curve road, it is determined that the state of the preceding vehicle 1 is the second state. As shown in FIG. 4, the right brake lamp 4 is less likely to appear in the captured image when traveling on a left curve road. Therefore, by not using the third area 9 of the right brake lamp 4, it is possible to prevent the failure to detect the lighting of the brake lamp.

For the same reason, when the preceding vehicle 1 is turning left at the intersection and the distance between the preceding vehicle 1 and the host vehicle is equal to or greater than the threshold value, the state of the preceding vehicle 1 is determined to be the second state.
Also, when the preceding vehicle 1 is turning right at the intersection and the distance between the preceding vehicle 1 and the host vehicle is less than the threshold, the state of the preceding vehicle 1 is determined to be the second state.
When the preceding vehicle 1 makes a right turn near the host vehicle, the right brake lamp 4 may be out of frame from the angle of view of the camera 21. For this reason, by not using the third region 9 of the right brake lamp 4, it is possible to prevent the failure to detect the lighting of the brake lamp.

(4) When the state of the preceding vehicle 1 is the third state, the first area 7 and the third area 9 are set as search areas. That is, when the lighting of the brake lamp is simultaneously detected as the light source in the first area 7 and the third area 9, it is determined that the brake lamp of the preceding vehicle 1 has been lit.
For example, when traveling on a right curve road, it is determined that the state of the preceding vehicle 1 is the third state.
Further, when the preceding vehicle 1 is turning right at the intersection and the distance between the preceding vehicle 1 and the host vehicle is equal to or greater than the threshold value, the state of the preceding vehicle 1 is determined to be the third state.
Also, when the preceding vehicle 1 is turning left at the intersection and the distance between the preceding vehicle 1 and the host vehicle is less than the threshold, the state of the preceding vehicle 1 is determined to be the third state.

Please refer to FIG. The search area setting unit 42 outputs information on the set search area to the light source extraction unit 43.
The light source extraction unit 43 determines whether there is a lit light source in the search area in the captured image, and extracts the lit light source in the search area in the captured image. That is, the lighting of the brake lamp in the search area is detected. The light source extraction unit 43 outputs the extracted light source information, that is, the information of the lit brake lamp, to the lighting determination unit 44.

The lighting determination unit 44 detects the lighting of the brake lamp in all the search regions set by the search region setting unit 42 when light sources that are turned on in all the search regions set by the search region setting unit 42 are extracted simultaneously. In the case), it is determined that the brake lamp of the preceding vehicle 1 is lit. When a light source that is turned on in any of the search areas is not extracted, it is determined that the brake lamp of the preceding vehicle 1 is not turned on. The lighting determination unit 44 outputs a lighting determination result of the brake lamp to the vehicle travel controller 12.
When the lighting determination unit 44 determines that the brake lamp of the preceding vehicle 1 is lit, the lighting determination unit 44 stores the position information of the search region set by the search region setting unit 42 in the search region storage unit 45.
The lighting determination unit 44 may store all the position information of the first to third regions 7 to 9 in the search region storage unit 45. For example, when it is determined that there is a lot of noise in the captured image, the lighting determination unit 44 may store all position information of the first to third regions 7 to 9 in the search region storage unit 45.

The tracking determination unit 46 determines whether or not the preceding vehicle detection unit 41 continues to detect the same preceding vehicle 1 (that is, whether or not tracking is continued). In other words, when the light source extraction unit 43 previously determined whether there is a light source that is lit in the search region (that is, whether the lighting of the brake lamp has been detected in the search region), the preceding vehicle detection unit 41. It is determined whether or not the preceding vehicle 1 detected by is the same as the preceding vehicle 1 detected this time.
For example, the tracking determination unit 46 may determine that the same preceding vehicle 1 is continuously detected when the change in the position of the preceding vehicle 1 detected by the preceding vehicle detection unit 41 is less than the threshold value.

When it is determined that the preceding vehicle detection unit 41 continues to detect the same preceding vehicle 1, the search region setting unit 42 reads the position information of the search region stored in the search region storage unit 45. The search area setting unit 42 sets the read area as a search area.
That is, when it is determined that the brake lamp of the preceding vehicle 1 is turned on by detecting the lighting of the light source (that is, the lighting of the brake lamp) in a certain search area, the search area storage unit 45 stores the position information of the search area. The search area setting unit 42 stores the search area again. That is, lighting of the brake lamp is detected while maintaining the position of the search area.
The lighting determination unit 44 may store, in the search region storage unit 45, identification information indicating which search region it is instead of the position information of the search region. The search area setting unit 42 may read the identification information from the search area storage unit 45 and newly specify a range on the captured image of the search area indicated by the identification information and set it as the search area.

On the other hand, if it is determined that the preceding vehicle detection unit 41 does not continue to detect the same preceding vehicle 1, the search area setting unit 42 determines the entire range of the rear part of the preceding vehicle 1 that is newly detected. The first to third regions 7 to 9 are specified, and a new search region is set based on the magnitude of noise in the captured image and the state of the preceding vehicle 1.
In the present embodiment, the light source extraction unit 43 determines whether there is a light source that is turned on using a captured image generated by the camera 21, but the present invention is not limited to this. Whether or not there is a lit light source is determined depending on whether or not light from the light source is incident on the light receiving element directed to the search area for searching for the light source, using a light receiving element having directivity instead of the camera 21. You may judge.

(Operation)
Next, the operation of the brake determination device 11 will be described. Please refer to FIG. For example, the operation of the brake determination device 11 is started when an ignition switch (indicated as IGN in FIG. 5) of the host vehicle is turned on or when the automatic driving mode is turned on. In addition to or instead of this, the operation of the brake determination device 11 may be started when the constant speed traveling / inter-vehicle distance control or the automatic emergency brake control is turned on.
In step S <b> 1, the preceding vehicle detection unit 41 detects the preceding vehicle 1. The preceding vehicle detection unit 41 identifies an existing area of the preceding vehicle 1 in the captured image.
In step S <b> 2, the search area setting unit 42 determines the state of the preceding vehicle 1.

In step S <b> 3, the search area setting unit 42 detects lighting of the rear light source of the preceding vehicle 1 from the existing area of the preceding vehicle 1 in the captured image.
In step S4, the search area setting unit 42 determines noise in the captured image based on the captured image in which the lighting of the light source is detected.
In step S <b> 5, the search area setting unit 42 executes a search area determination process for determining a search area for searching for the light source of the preceding vehicle 1 from the captured image.

The search area determination process will be described with reference to FIG. In step S20, the search area setting unit 42 determines whether the preceding vehicle detection unit 41 has detected the preceding vehicle 1, that is, whether the preceding vehicle 1 exists. When the preceding vehicle 1 exists (step S20: Y), the process proceeds to step S22. If the preceding vehicle 1 does not exist (step S20: N), the process proceeds to step S21.
In step S <b> 21, the search area setting unit 42 resets the position information of the search area stored in the search area storage unit 45. Thereafter, the process returns to step S20.

In step S22, the search area setting unit 42 determines whether or not the preceding vehicle 1 is traveling straight ahead. If the preceding vehicle 1 is traveling straight (step S22: Y), the process proceeds to step S23. If the preceding vehicle 1 is not traveling straight (step S22: N), the process proceeds to step S24.
In step S23, the search area setting unit 42 determines that the state of the preceding vehicle 1 is the first state. Thereafter, the process proceeds to step S34.

In step S24, the search area setting unit 42 determines whether or not the preceding vehicle 1 is traveling on a left curve road. When the preceding vehicle 1 is traveling on the left curve road (step S24: Y), the process proceeds to step S25. If the preceding vehicle 1 is not traveling on the left curve road (step S24: N), the process proceeds to step S26.
In step S25, the search area setting unit 42 determines that the state of the preceding vehicle 1 is the second state. Thereafter, the process proceeds to step S34.

In step S26, the search area setting unit 42 determines whether or not the preceding vehicle 1 is traveling on a right curve road. When the preceding vehicle 1 is traveling on the right curve road (step S26: Y), the process proceeds to step S27. If the preceding vehicle 1 is not traveling on the right curve road (step S26: N), the process proceeds to step S28.
In step S27, the search area setting unit 42 determines that the state of the preceding vehicle 1 is the third state. Thereafter, the process proceeds to step S34.

In step S28, the search area setting unit 42 determines whether the preceding vehicle 1 is turning left at the intersection. If the preceding vehicle 1 is turning left at the intersection (step S28: Y), the process proceeds to step S29. When the preceding vehicle 1 is turning right instead of turning left at the intersection (step S28: N), the process proceeds to step S31.
In step S29, the search area setting unit 42 determines whether the inter-vehicle distance between the preceding vehicle 1 and the host vehicle is greater than or equal to a threshold Th. If the inter-vehicle distance is greater than or equal to the threshold Th (step S29: Y), the process proceeds to step S30. If the inter-vehicle distance is less than the threshold Th (step S29: N), the process proceeds to step S32.

In step S30, the search area setting unit 42 determines that the state of the preceding vehicle 1 is the second state. Thereafter, the process proceeds to step S34.
In step S31, the search area setting unit 42 determines whether the inter-vehicle distance between the preceding vehicle 1 and the host vehicle is greater than or equal to a threshold Th. If the inter-vehicle distance is greater than or equal to the threshold Th (step S31: Y), the process proceeds to step S32. If the inter-vehicle distance is less than the threshold Th (step S31: N), the process proceeds to step S33.

In step S32, the search area setting unit 42 determines that the state of the preceding vehicle 1 is the third state. Thereafter, the process proceeds to step S34.
In step S33, the search area setting unit 42 determines that the state of the preceding vehicle 1 is the second state. Thereafter, the process proceeds to step S34.

In step S34, the tracking determination unit 46 determines whether or not the preceding vehicle detection unit 41 continues to detect the same preceding vehicle 1. When the same preceding vehicle 1 is continuously detected (step S34: Y), the process proceeds to step S35. If the same preceding vehicle 1 has not been detected (step S34: N), the process proceeds to step S36.
In step S <b> 35, the search area setting unit 42 reads the position information of the search area stored in the search area storage unit 45. Thereafter, the process proceeds to step S37.

In step S <b> 36, the search area setting unit 42 specifies the first to third areas 7 to 9 from the entire range of the rear part of the newly detected preceding vehicle 1, and performs a new search based on the state of the preceding vehicle 1. Select as region. Thereafter, the process proceeds to step S37.
In step S37, the search area setting unit 42 sets the area read in step S35 or the area selected in step S36 as the search area. Thereafter, the process ends.

  Please refer to FIG. In step S <b> 6, the search area setting unit 42, the light source extraction unit 43, and the lighting determination unit 44 execute a brake determination process for determining whether or not the brake lamp of the preceding vehicle 1 is lit.

The brake determination process will be described with reference to FIG. In step S40, the light source extraction unit 43 determines whether or not lighting of the light source is detected in the captured image. If lighting of the light source is detected (step S40: Y), the process proceeds to step S41. If the lighting of the light source is not detected (step S40: N), the lighting determination unit 44 ends the process without determining that the brake lamp of the preceding vehicle 1 has been lit.
In step S41, the search area setting unit 42 determines whether or not there is little noise in the captured image. If there is little noise in the captured image (step S41: Y), the process proceeds to step S42. If there is a lot of noise in the captured image (step S41: N), the process proceeds to step S45.

In step S <b> 42, the light source extraction unit 43 determines whether or not a light source that has been turned on in the first region 7 that is a search region has been extracted. When the light source is extracted in the first region 7 (step S42: Y), the process proceeds to step S43. If the light source is not extracted in the first region 7 (step S42: N), the process proceeds to step S49.
In step S <b> 43, the lighting determination unit 44 stores the position information of the first region 7 in the search region storage unit 45. Thereafter, the process proceeds to step S44.
In step S44, the lighting determination unit 44 determines that the brake lamp of the preceding vehicle 1 has been lit. Thereafter, the process ends.

In step S45, when the state of the preceding vehicle 1 is the first state, the lighting determination unit 44 determines whether or not the light sources that have been turned on in the first to third areas 7 to 9 that are search areas have been extracted. That is, it is determined whether or not the lighting of the brake lamp is detected in the first to third regions 7 to 9. When the state of the preceding vehicle 1 is the first state and the light source is extracted in the first to third regions 7 to 9 (step S45: Y), the process proceeds to step S46. When the state of the preceding vehicle 1 is not the first state or when the light source is not extracted in any of the first to third regions 7 to 9 (step S45: N), the process proceeds to step S47.
In step S <b> 46, the lighting determination unit 44 stores the position information of the first to third regions 7 to 9 in the search region storage unit 45. Thereafter, the process proceeds to step S44.

  In step S47, when the state of the preceding vehicle 1 is the second state, the lighting determination unit 44 determines whether or not the light sources that have been turned on in the first region 7 and the second region 8 that are search regions have been extracted. That is, it is determined whether or not lighting of the brake lamp is detected in the first area 7 and the second area 8. When the state of the preceding vehicle 1 is the second state and the light source is extracted in the first region 7 and the second region 8 (step S47: Y), the process proceeds to step S46. If the state of the preceding vehicle 1 is not the second state or if the light source is not extracted in either the first region 7 or the second region 8 (step S47: N), the process proceeds to step S48.

In step S48, when the state of the preceding vehicle 1 is the third state, the lighting determination unit 44 determines whether or not the light sources that have been turned on in the first area 7 and the third area 9 that are search areas have been extracted. That is, it is determined whether or not lighting of the brake lamp is detected in the first area 7 and the third area 9. When the state of the preceding vehicle 1 is the third state and the light source is extracted in the first region 7 and the third region 9 (step S48: Y), the process proceeds to step S46. If the preceding vehicle 1 is not in the third state or if the light source is not extracted in any of the first region 7 and the third region 9 (step S48: N), the process proceeds to step S49.
In step S49, the lighting determination unit 44 determines that the taillight has been turned on. That is, it is determined that the brake lamp of the preceding vehicle 1 is not lit. Thereafter, the process ends.

Please refer to FIG. If it is determined that the brake lamp is lit (step S7: Y), the process proceeds to step S8. If it is not determined that the brake lamp is lit (step S7: N), the process proceeds to step S9.
In step S <b> 8, the vehicle travel controller 12 performs travel support control such as deceleration by automatic braking, automatic stop, and automatic steering to avoid the preceding vehicle 1. Thereafter, the process proceeds to step S9.

  In step S9, the driving assistance apparatus 10 determines whether the ignition switch is turned off or the automatic driving mode is turned off. When it is determined that the ignition switch is turned off or the automatic operation mode is turned off (step S9: Y), the process ends. If it is not determined that the ignition switch is turned off or the automatic operation mode is turned off (step S9: N), the process returns to step S1.

(Effect of embodiment)
(1) The preceding vehicle detection unit 41 detects the preceding vehicle 1 ahead of the host vehicle, and the search region setting unit 42 sets the search region for searching for the presence or absence of the light source of the preceding vehicle 1 in the lateral width of the preceding vehicle 1. Set near the center of. The light source extraction unit 43 detects lighting of the brake lamp from the set search area.
For this reason, even in a driving situation in which it is difficult to detect the brake lamp at the taillight position, the high-mount stop lamp 2 can be detected near the center of the lateral width of the preceding vehicle 1. Therefore, it becomes easy to detect lighting of the brake lamp.

  For example, if the brake lamp lighting is determined based on the change in brightness or area of the tail lamp detection area as in Patent Document 1, even if the taillight is turned on due to the headlamp lighting at tunnel or dusk, it is erroneously determined that the brake lamp is on. On the other hand, since the lighting of the brake lamp that is not at the taillight position is detected in this embodiment, it is possible to prevent misjudgment during a tunnel or dusk.

(2) The search area setting unit 42 sets the search area above the positions of the tail lights 5 and 6 of the preceding vehicle 1.
For this reason, since it becomes possible to detect the lighting of the brake lamp above the tail light position of the preceding vehicle 1 even in a traveling situation in which it is difficult to detect the brake lamp at the tail light position, it becomes easy to detect the lighting of the brake lamp. .

(3) The search area setting unit 42 sets the search area between the positions of the left and right tail lights 5 and 6 of the preceding vehicle 1.
For this reason, since it becomes possible to detect the lighting of the brake lamp between the left and right taillight positions of the preceding vehicle 1 even in a driving situation in which it is difficult to detect the brake lamp at the taillight position, it is easy to detect the lighting of the brake lamp. Become.

(4) The search area setting unit 42 further sets a search area at a taillight position that is turned on in accordance with the lighting of the headlamp among the light sources of the preceding vehicle 1.
In general, the brake lamp is disposed in the vicinity of a taillight position that lights in accordance with the lighting of the headlamp. For this reason, it becomes easy to detect lighting of a brake lamp by setting a search area | region to the taillight position which lights according to headlight lighting among the light sources of the preceding vehicle 1. FIG.

(5) The search area setting unit 42 sets the search area at the position of the light source that does not change in brightness when the headlamp is turned on, among the light sources of the preceding vehicle 1.
The high-mount stop lamp 2 is not lit even when the headlamp is lit. By setting the search area at the position of the light source where there is no change in brightness when the headlamp is turned on, it becomes easier to detect the lighting of the high-mount stop lamp 2.

(6) The search area setting unit 42 further sets a search area at the left and right taillight positions of the preceding vehicle 1. The light source extraction unit 43 detects lighting of a plurality of brake lamps from the search area. The lighting determination unit 44 determines that the brake lamp of the preceding vehicle 1 has been lit when detecting lighting of a plurality of brake lamps.
As described above, when lighting of a plurality of brake lamps is detected from a plurality of search areas, it is determined that the brake lamp is lit, so that the lighting of the brake lamp can be reliably detected.

(7) When it is determined that the lighting of the brake lamp is lit by detecting the lighting of the brake lamp in the search area, the search area setting unit 42 maintains the position of the search area and detects the lighting of the brake lamp.
Thereby, the detection of the brake lamp can be continued at a position where it can be reliably detected.

(8) The search area setting unit 42 determines the traveling direction of the preceding vehicle 1 and sets the search area according to the traveling direction.
Thus, for example, even when the preceding vehicle 1 travels on a curved road or makes a right or left turn at an intersection, even when it is difficult to detect the brake lamp at the taillight position, the search range can be set at an appropriate position. Therefore, it becomes easy to detect lighting of the brake lamp.

(9) The search area setting unit 42 determines the inter-vehicle distance from the preceding vehicle 1 and sets the search area according to the inter-vehicle distance.
Thereby, for example, when the inter-vehicle distance from the preceding vehicle 1 is large, it becomes difficult to detect the behavior of the brake lamp due to the minute behavior of the preceding vehicle 1, but even in this case, the brake lamp can be easily detected. Further, for example, when the distance between the preceding vehicle 1 is small, the brake lamp may not be within the detection range of the sensor for detecting the lighting of the brake lamp. Even in this case, the brake lamp is detected. It becomes easy to do.

  DESCRIPTION OF SYMBOLS 10 ... Driving assistance device, 11 ... Brake determination device, 12 ... Vehicle travel controller, 13 ... Actuator group, 14 ... Brake actuator, 15 ... Accelerator opening actuator, 16 ... Steering actuator, 20 ... Preceding vehicle detection sensor, 21 ... Camera , 22 ... radar, 30 ... navigation device, 31 ... map database, 32 ... GPS receiver, 32 ... receiver, 40 ... controller, 41 ... preceding vehicle detection unit, 42 ... search area setting unit, 43 ... light source extraction unit, 44 ... lighting determination unit, 45 ... search area storage unit, 46 ... tracking determination unit

Claims (10)

Detect the preceding vehicle ahead of your vehicle,
A search area for searching for the presence or absence of the light source of the preceding vehicle is set near the center of the lateral width of the preceding vehicle,
Detecting lighting of a brake lamp from the set search area,
A brake determination method characterized by the above.   The brake determination method according to claim 1, wherein the search area is set above the taillight position of the preceding vehicle.   The brake determination method according to claim 1 or 2, wherein the search area is set between left and right taillight positions of the preceding vehicle.   The brake determination method according to any one of claims 1 to 3, wherein the search area is further set to a taillight position that is turned on when a headlight is turned on, among light sources of the preceding vehicle. .   The brake according to any one of claims 1 to 4, wherein the search area is set to a position of a light source that does not change in brightness when a headlamp is lit among light sources of the preceding vehicle. Judgment method. The search area is further set to the left and right taillight positions of the preceding vehicle,
Detecting lighting of a plurality of brake lamps from the search area;
The brake determination method according to claim 1, wherein when the lighting of the plurality of brake lamps is detected, it is determined that the brake lamp of the preceding vehicle is turned on.   The brake lamp lighting is detected by maintaining the position of the search area when it is determined that the lighting of the brake lamp is lit by detecting the lighting of the brake lamp in the search area. The brake determination method according to claim 6. Determine the direction of travel of the preceding vehicle,
The brake determination method according to claim 1, wherein the search area is set according to the traveling direction. Determine the inter-vehicle distance from the preceding vehicle,
The brake determination method according to claim 8, wherein the search area is set according to the inter-vehicle distance. A sensor for detecting a preceding vehicle ahead of the host vehicle;
A search area for searching for the presence or absence of the light source of the preceding vehicle detected by the sensor is set near the center of the lateral width of the preceding vehicle, and a controller that detects lighting of a brake lamp from the set search area; ,
A brake determination device comprising:

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