Saddle-type vehicle FCW device and saddle-type vehicle FCW method

Abstract

Provided is a saddle-type vehicle forward collision warning (FCW) device that is used in a saddle-type vehicle, said saddle-type vehicle FCW device comprising: a warning unit that issues a warning to a driver; and one or a plurality of control units that execute host-vehicle course prediction for predicting the course of a host-vehicle and host-vehicle peripheral object position detection for detecting the position of an object around the host-vehicle, that calculate a collision possibility between the host-vehicle and the object using the result of the host-vehicle course prediction and the result of the host-vehicle peripheral object position detection, and that execute warning control for controlling the presence or absence of a warning by the warning unit on the basis of the collision possibility. The saddle-type vehicle FCW device is characterized by further comprising a monocular camera that is fixed to a vehicle body of the saddle-type vehicle and that images the periphery of the host-vehicle, and is characterized in that the control unit executes the host-vehicle peripheral object position detection on the basis of a captured image captured by the monocular camera, and by using the obtained results, executes the warning control as described in each of the following situations. Situation 1: When the host-vehicle is traveling straight on a horizontal road that lacks white lines and has an uphill portion ahead in the traveling direction of the host-vehicle, if a first preceding vehicle is traveling at a vehicle speed lower than the vehicle speed of the host-vehicle through a position that is in the uphill portion and is on an extension line obtained by extending a centerline in a vehicle width direction of the host-vehicle in the traveling direction of the host-vehicle, the control unit executes the warning control so that a warning is issued by the warning unit when the collision possibility between the host-vehicle and the first preceding vehicle becomes equal to or greater than a predetermined collision possibility. Situation 2: When the host-vehicle is traveling straight on a horizontal road that lacks white lines and that has an uphill portion ahead in the traveling direction of the host-vehicle, if a second preceding vehicle is traveling at the same vehicle speed as the host-vehicle through a position that is in the uphill portion and is on an extension line obtained by extending a centerline in a vehicle width direction of the host-vehicle in the traveling direction of the host-vehicle, and a third preceding vehicle is traveling in parallel to the second preceding vehicle at a vehicle speed lower than the vehicle speed of the host-vehicle, the control unit executes the warning control so that a warning is not issued by the warning unit.

Description

FCW device for saddle-riding type vehicle and FCW method for saddle-riding type vehicle

[0001] The present disclosure relates to a FCW device for a saddle-ride type vehicle and a FCW method for a saddle-ride type vehicle that issues a forward collision warning (FCW) to a driver of the saddle-ride type vehicle.

[0002] Conventionally, FCW devices are known that issue a warning to a driver of a saddle-riding vehicle based on the possibility of a collision with a surrounding object. An example of a saddle-riding vehicle is a motorcycle. For example, Patent Document 1 discloses a device that issues a warning based on the positional relationship between a saddle-riding vehicle and a preceding vehicle traveling in front of the saddle-riding vehicle when multiple saddle-riding vehicles are traveling together. Patent Document 2 discloses a system that captures an image of the front using a camera attached to the saddle-riding vehicle, detects surrounding vehicles using the captured image, and issues a warning.

[0003] International Publication No. 2021 / 060357 Special Publication No. 2021-526681

[0004] Saddle-ride type vehicles tend to be lighter and more compact than non-saddle-ride type four-wheel vehicles. Therefore, saddle-ride type vehicles are characterized by the fact that the posture of the vehicle body is more likely to change while traveling than non-saddle-ride type four-wheel vehicles. The technologies disclosed in Patent Documents 1 and 2 do not take into consideration FCW control that takes into account changes in the posture of the vehicle body while traveling.

[0005] An object of the present disclosure is to provide an FCW device for a saddle-riding type vehicle and an FCW method for a saddle-riding type vehicle that perform FCW control different from conventional methods.

[0006] Saddle-ride type vehicles tend to have shorter wheelbases and smaller masses than non-saddle-ride type four-wheel vehicles. The inventors realized that saddle-ride type vehicles are therefore more susceptible to disturbances such as uneven road surfaces and weight shifts caused by driver steering than four-wheel vehicles. Therefore, the inventors investigated FCW control that takes into account the effects of disturbances when a saddle-ride type vehicle is traveling.

[0007] Another feature of saddle-type vehicles is that the body of a saddle-type vehicle is smaller than that of a four-wheeled vehicle, limiting the space available for mounting devices. Therefore, it is necessary to reduce the processing load and increase the design flexibility of hardware resources. The FCW device detects objects ahead of the vehicle using images captured by an onboard camera, etc. The processing load can be reduced by limiting the object detection area. For example, when detecting objects in a captured image, it is possible to reduce the processing load by excluding from the detection processing area the sky area where there is no risk of collision.

[0008] For example, to reduce the processing load, a method can be considered in which the detection area is limited to the lower area of ​​the image captured by the vehicle-mounted camera, where the road is captured. The inventors of the present application have realized that with this method, an object ahead of the vehicle may fall outside the detection area when the vehicle body of the saddle-type vehicle leans forward due to road surface irregularities or the like. This phenomenon of an object falling outside the detection area can also occur in an image captured immediately before starting uphill. If the detection area is set below the captured image, a preceding vehicle traveling uphill may be located outside the detection area while the vehicle is traveling on a level road immediately before the uphill road.

[0009] Therefore, the inventors of the present application have studied an FCW device for a saddle-type vehicle that can detect objects in front of the vehicle even in the above-mentioned situations and that can increase the design freedom of hardware resources, and have come up with the present invention.

[0010] In order to address both of the conflicting issues described above, the FCW device for a saddle-ride type vehicle according to the present disclosure employs the following configuration.

[0011] An FCW device for a saddle-riding type vehicle according to one embodiment of the present disclosure includes an alarm unit that issues an alarm to a driver, and one or more control units that perform host vehicle path prediction to predict a path of the host vehicle and host vehicle peripheral object position detection to detect the positions of objects around the host vehicle, calculate a possibility of a collision between the host vehicle and an object using the results of the host vehicle path prediction and the results of the host vehicle peripheral object position detection, and perform alarm control that controls whether or not an alarm is issued by the alarm unit based on the possibility of collision, and the FCW device for a saddle-riding type vehicle used in a saddle-riding type vehicle further includes a monocular camera fixed to a body of the saddle-riding type vehicle for capturing images of the periphery of the host vehicle, and the control unit performs position detection of the host vehicle peripheral objects based on images captured by the monocular camera, and performs the alarm control using the obtained results as described in each of the following situations. Situation 1: When the host vehicle is traveling straight on a horizontal road that has no white lines and has an uphill portion ahead of the host vehicle in the direction of travel, and a first leading vehicle is traveling on the uphill portion on a position on an extension of the center line of the host vehicle in the width direction in the direction of travel at a speed slower than the host vehicle's speed, the control unit executes warning control so that the warning unit issues a warning when the possibility of a collision between the host vehicle and the first leading vehicle reaches a predetermined collision probability or higher. Situation 2: When the host vehicle is traveling straight on a horizontal road that has no white lines and has an uphill portion ahead of the host vehicle in the direction of travel, and a second leading vehicle is traveling on the uphill portion on a position on an extension of the center line of the host vehicle in the width direction in the direction of travel at the same speed as the host vehicle, and a third leading vehicle is traveling parallel to the second leading vehicle at a speed slower than the host vehicle's speed, the control unit executes warning control so that the warning unit does not issue a warning.

[0012] In the above configuration, the control unit may set an object detection area on the image captured by the monocular camera based on the result of the host vehicle path prediction using the method described below, and execute the warning control based on the detection area and the position of the object obtained by performing position detection of the object around the host vehicle based on the captured image.Method 1: If a straight line corresponding to a virtual horizon when the host vehicle is parked upright on a horizontal road is defined as a reference line on the image captured by the monocular camera, the detection area is set so that its width becomes narrower in the region below the reference line as it goes from a position closer to the host vehicle to a position farther away.Method 2: In the region above the reference line on the captured image, the detection area set in the region below the reference line is set so that it extends upward perpendicular to the reference line from the point where it intersects with the reference line.

[0013] An FCW method for a saddle-riding type vehicle according to one embodiment of the present disclosure includes an alarm unit that issues an alarm to a driver, and one or more control units that perform host vehicle path prediction to predict a path of the host vehicle and host vehicle peripheral object position detection to detect the positions of objects around the host vehicle, calculate a possibility of a collision between the host vehicle and an object using the results of the host vehicle path prediction and the results of the host vehicle peripheral object position detection, and perform alarm control that controls whether or not an alarm is issued by the alarm unit based on the possibility of collision. The FCW method for a saddle-riding type vehicle is performed by an FCW device used in a saddle-riding type vehicle, and includes the steps of: capturing an image of the surroundings of the host vehicle with a monocular camera fixed to a body of the saddle-riding type vehicle; detecting the positions of the objects around the host vehicle based on the captured image; and executing the alarm control using the results of the host vehicle peripheral object position detection as described in each of the following situations. Situation 1: When the host vehicle is traveling straight on a horizontal road that has no white lines and has an uphill portion ahead of the host vehicle in the direction of travel, and a first leading vehicle is traveling on the uphill portion on a position on an extension of the center line of the host vehicle in the width direction in the direction of travel at a speed slower than the host vehicle's speed, the control unit executes warning control so that the warning unit issues a warning when the possibility of a collision between the host vehicle and the first leading vehicle reaches a predetermined collision probability or higher. Situation 2: When the host vehicle is traveling straight on a horizontal road that has no white lines and has an uphill portion ahead of the host vehicle in the direction of travel, and a second leading vehicle is traveling on the uphill portion on a position on an extension of the center line of the host vehicle in the width direction in the direction of travel at the same speed as the host vehicle, and a third leading vehicle is traveling parallel to the second leading vehicle at a speed slower than the host vehicle's speed, the control unit executes warning control so that the warning unit does not issue a warning.

[0014] The above configuration may also include the steps of: setting an object detection area on an image captured by the monocular camera based on the result of the host vehicle path prediction using the method described below; and executing the warning control based on the detection area and the position of the object obtained by performing position detection of the object around the host vehicle based on the captured image.Method 1: If a straight line corresponding to a virtual horizon when the host vehicle is parked upright on a horizontal road is defined as a reference line on the image captured by the monocular camera, the detection area is set so that its width becomes narrower in the region below the reference line as it moves from a position closer to the host vehicle to a position farther away.Method 2: In the region above the reference line on the captured image, the detection area set in the region below the reference line is set so that it extends upward perpendicular to the reference line from the point where it intersects with the reference line.

[0015] According to the FCW device for a saddle-riding type vehicle and the FCW method for a saddle-riding type vehicle of the present disclosure, it is possible to provide an FCW device for a saddle-riding type vehicle and an FCW method for a saddle-riding type vehicle that perform FCW control different from conventional ones.

[0016] [Saddle-riding Vehicle] A saddle-riding vehicle according to the present disclosure generally refers to a vehicle on which a driver sits astride a saddle. In the present disclosure, the right side, left side, front, and rear, as viewed from the driver of the saddle-riding vehicle, are referred to as the right, the left, the front, and the rear, respectively. The term "host vehicle" used in the present disclosure refers to a saddle-riding vehicle. Saddle-riding vehicles include motorcycles. A saddle-riding vehicle includes at least one front wheel and at least one rear wheel. For example, a saddle-riding vehicle may have two front wheels and one or two rear wheels, or one front wheel and one or two rear wheels. A saddle-riding vehicle may have steered front wheels or steered rear wheels. A saddle-riding vehicle travels by driving drive wheels with a drive source. The drive source may be an internal combustion engine, an electric motor, or a hybrid drive source including an engine and an electric motor.

[0017] [FCW Device for Straddle-Type Vehicle] The FCW device for a saddle-type vehicle described in the present disclosure includes an alarm unit, one or more control units, and a monocular camera. The FCW device is mounted on a saddle-type vehicle for use.

[0018] [White Lines] The white lines described in this disclosure refer to lines drawn on roads to indicate the vehicle's travel lane, and are not intended to be limited to a specific color. For example, the lines may be drawn in other colors, such as yellow. Such road lines may also be called outer roadway lines, shoulder strips, diagonal boundary lines, or dividing lines. The FCW device can perform FCW control without detecting white lines. In this disclosure, when a description is made that the vehicle is traveling on a road without white lines, this indicates that FCW control can be performed even on roads without white lines, and is not intended to limit the roads on which saddle-type vehicles travel to roads without white lines.

[0019] [Situation] In this disclosure, situations described with numbers, such as "Situation 1," indicate examples of situations in which the operation of the FCW device can be confirmed. One of the characteristics of the FCW device is that it can perform processes such as detecting the position of objects around the vehicle and predicting the vehicle's path, and can execute different warning controls depending on the situation. Each situation described with a number indicates that the warning control executed by the FCW device can be confirmed by recreating this situation, and is not intended to limit the operation of the FCW device to the described situation.

[0020] [Reference Line] The reference line described in this disclosure is defined as a straight line corresponding to a virtual horizon on an image captured by a monocular camera when the saddle-type vehicle is assumed to be parked upright on a horizontal road. When the saddle-type vehicle is parked upright on a straight, horizontal road, the line on the captured image corresponding to the horizon beyond the horizontal road is the reference line. When the saddle-type vehicle is traveling on a non-level road, such as an uphill road, the reference line is a virtual horizon on the captured image corresponding to the horizon obtained by extending the road parallel to the road surface in the direction of straight travel. When the saddle-type vehicle is traveling on a curved road, the reference line is a virtual horizon on the captured image corresponding to the horizon obtained by extending the road surface at the time of image capture in a straight line parallel to the road surface in the direction of travel at the time of image capture. Because the reference line is a virtual horizon when the road surface on which the saddle-type vehicle is traveling is considered to be a horizontal road, it is not affected by the tilt of the vehicle body or the monocular camera. Even if the saddle riding type vehicle is stopped and the front or rear of the vehicle body is lowered, the reference line on the captured image will be in the same position. Note that the above description of the reference line does not limit the method for setting the reference line.

[0021] [Warning Unit] The warning unit described in the present disclosure is a warning device that issues a warning to at least the driver of a saddle-riding type vehicle. The warning unit issues a warning targeting at least one of the auditory, visual, and tactile senses. A warning targeting the auditory sense may be issued by emitting a voice or warning sound from a speaker. A warning targeting the visual sense may be issued by displaying information on a display device or illuminating a light-emitting device. Warning devices such as speakers, display devices, and light-emitting devices may be installed, for example, on or near the handlebars. If the driver wears a helmet, the warning device may be mounted on the helmet. Devices such as a speedometer and a navigation device provided in the saddle-riding type vehicle may be used as warning devices. A warning targeting the tactile sense may be issued by vibrating at least one of the handlebars, helmet, and seat.

[0022] [Control Unit] The control unit described in the present disclosure controls each unit constituting the FCW device. The control unit controls each unit to realize the functions and operations of the FCW device described in the present disclosure. The control unit is a control device that executes FCW control. FCW control includes host vehicle path prediction, host vehicle peripheral object position detection, and warning control. The FCW device may include multiple control units, and multiple processes may be executed in parallel by separate control units. For example, a process related to host vehicle path prediction and a process related to host vehicle peripheral object position detection may be executed in parallel simultaneously. The control unit calculates a numerical value indicating the likelihood of a collision between the host vehicle and the object based on the host vehicle path prediction result and the host vehicle peripheral object position detection result. For example, the time to collision (TTC) may be used as the numerical value indicating the likelihood of a collision. Furthermore, the numerical value indicating the likelihood of a collision may be, for example, the distance between the saddle-type vehicle and the object or the relative movement speed. The control unit determines whether an alarm is necessary and when to issue the alarm based on the possibility of a collision, and executes alarm control to issue an alarm from the alarm device based on the determination result. The control unit can execute alarm control continuously while the saddle-riding type vehicle is traveling, regardless of whether the saddle-riding type vehicle is traveling straight or turning. A program corresponding to the control unit is prepared in advance in a non-volatile storage device, and the function and operation of the control unit are realized by executing this program by predetermined hardware. The control unit may be realized by an ECU (Electronic Control Unit) for vehicle control, or the FCW device may have a dedicated control unit.

[0023] [Monocular Camera] The monocular camera described in the present disclosure is an imaging device that captures images of the periphery of a saddle-riding vehicle. The FCW device can perform FCW control using a single monocular camera, which is smaller than a stereo camera. The monocular camera is fixed to the saddle-riding vehicle and used. The monocular camera can capture images of the area ahead of the road on which the saddle-riding vehicle is traveling. The monocular camera captures images of preceding vehicles traveling ahead of the saddle-riding vehicle while the saddle-riding vehicle is traveling straight or turning, vehicles stopped or parked in front of the saddle-riding vehicle, and other obstacles. The preceding vehicles captured by the monocular camera include vehicles traveling on a predicted path obtained by predicting the vehicle's path and vehicles traveling at a position deviating from the predicted path. The monocular camera captures moving images or continuously captures still images, thereby continuously capturing images of objects around the saddle-riding vehicle.

[0024] [Vehicle Path Prediction] The vehicle path prediction described in the present disclosure is a process for predicting the path of the vehicle. Vehicle path prediction also includes predicting the path on an image captured by a monocular camera. Note that predicting the path on the captured image may be performed by mapping the vehicle path predicted in three-dimensional coordinates in the real world onto corresponding planar coordinates on the captured image. Planar coordinates on the captured image are, for example, an orthogonal coordinate system with the center of the captured image as the origin. When the saddle-riding vehicle is traveling straight, the FCW device can predict the path of the saddle-riding vehicle on the image captured by the monocular camera based on the mounting position, mounting angle, imaging direction, imaging range, etc. of the monocular camera on the saddle-riding vehicle. When the saddle-riding vehicle is turning, the FCW device can predict a curved path as the path of the turning saddle-riding vehicle based on the detection result by the turning state detection unit. When the saddle riding type vehicle is turning, the FCW device can also predict the path of the turning saddle riding type vehicle by curvature correcting the predicted path on the captured image, which is obtained assuming that the saddle riding type vehicle is traveling straight, based on the detection result by the turning state detection unit.The FCW device can predict the path of the turning saddle riding type vehicle in approximately real time after acquiring an image by the monocular camera while the saddle riding type vehicle is traveling.

[0025] [Position Detection of Objects Surrounding the Vehicle] The position detection of objects surrounding the vehicle described in the present disclosure is a process of detecting objects around the vehicle and identifying the position of each object. The position detection of objects around the vehicle is performed using images captured by a monocular camera. Here, the position of an object may be a position on the image captured by the monocular camera. By performing image analysis to detect objects on the image captured by the monocular camera, the objects appearing in the captured image and the positions of each object are detected. This type of image analysis is sometimes referred to as object detection, object recognition, or the like. Objects detected from the captured image include a preceding vehicle traveling ahead of the saddle-riding vehicle while the vehicle is traveling straight or turning, a stopped or parked vehicle ahead, and other obstacles. The preceding vehicle detected from the captured image includes a vehicle traveling on a predicted path obtained by vehicle path prediction and a vehicle traveling at a position deviating from the predicted path. When a detected vehicle is referred to as a "preceding vehicle," it refers to a vehicle traveling ahead of the saddle-riding vehicle in the same direction as the saddle-riding vehicle. The FCW device can detect the positions of objects around the vehicle in substantially real time after capturing an image using a monocular camera while the straddle-type vehicle is traveling.

[0026] [Collision Likelihood] The collision likelihood described in the present disclosure is a numerical value indicating the likelihood of a collision between the saddle-riding vehicle and a nearby object. For example, the collision likelihood can be determined based on the relative movement speed of the object relative to the saddle-riding vehicle, the distance between the saddle-riding vehicle and the object, the time until the saddle-riding vehicle collides with the object, and the like. The collision likelihood is calculated based on the predicted path of the host vehicle obtained by performing host-vehicle path prediction, the position of each object obtained by performing host-vehicle peripheral object position detection, and the relative movement between each detected object and the saddle-riding vehicle. For example, the position detection of the object's peripheral object determines the distance from the detected object to the saddle-riding vehicle in the captured image. The direction and movement speed of the detected object relative to the saddle-riding vehicle are determined by comparing multiple consecutively captured images. The time until collision is determined based on the distance from the object to the saddle-riding vehicle and the relative movement speed. Alarm control is performed to determine whether and when an alarm should be issued by the alarm unit based on the result of comparing the value indicating the collision likelihood with a threshold value prepared in advance according to the type of collision likelihood. For example, when the time to collision (TTC) is used as the collision probability, a predetermined time is set as a threshold, and when the time to collision reaches the threshold time, alarm control is performed to issue an alarm.

[0027] [Hardware Configuration] The FCW device according to the present disclosure is characterized in that it performs FCW control that has not been achieved in the past. A person skilled in the art can implement the hardware configuration of the FCW device according to the present disclosure and a saddle-riding type vehicle equipped with an FCW device using the hardware configurations of devices and saddle-riding type vehicles known in prior art documents, other publicly known documents, and conventional technology. Therefore, a detailed description of the hardware configuration of the FCW device and saddle-riding type vehicle will be omitted.

[0028] [Others] In this disclosure, when a process is described as being performed "based on A" or "taking A into consideration," the process is performed using A, but the information used is not limited to A, and information other than A may also be used. In this disclosure, when "at least one" is used in conjunction with an option, this means that all possible combinations of multiple options are included. In this disclosure, when "including," "comprising," "having," and their derivatives are used, this means that other content may be included in addition to the listed content. In this disclosure, when "may" or "may" is used, this means that this is a non-exclusive example and is not limited to the described example. In this disclosure, unless the number of components is clearly specified, the number of components may be one or more. Unless otherwise defined, the terms used in this disclosure have the general meaning understood by those skilled in the art of FCW control. The FCW device according to the present disclosure is not limited to the configurations described in the following embodiments or the configurations shown in the drawings. The FCW device according to the present disclosure can be implemented by combining multiple embodiments described below. The FCW device according to the present disclosure can also be implemented in forms other than the embodiments described below, or by modifying the embodiments described below.

[0029] Fig. 1 is a diagram for explaining an overview of an FCW device for a saddle-riding type vehicle according to a first embodiment of the present disclosure. Fig. 2 is a diagram for explaining an overview of an FCW device for a saddle-riding type vehicle according to a second embodiment of the present disclosure. Fig. 3 is a diagram for explaining an overview of an FCW device for a saddle-riding type vehicle according to a third embodiment of the present disclosure. Fig. 4 is a diagram for explaining an example in which pitching occurs.

[0030] In a saddle-ride type vehicle equipped with an FCW device for a saddle-ride type vehicle according to the present disclosure, if the front or rear of the vehicle moves up or down due to unevenness in the road, causing a change in the posture of the vehicle body due to so-called pitching, the on-board camera fixed to the vehicle body also tilts, changing the imaging range. One objective of the FCW device is to detect objects that may be in a collision with the saddle-ride type vehicle from an image within this imaging range, even if the imaging range of the on-board camera changes due to such disturbances.

[0031] For example, when the front of the saddle-type vehicle pitches downward, the onboard camera also faces downward, so that objects in front of the vehicle appear higher in the image than before the pitching (see Figure 4).If an image of a leading vehicle traveling uphill is captured while the saddle-type vehicle is traveling on a level road just before entering an uphill road, the leading vehicle traveling uphill will appear higher in the image than the leading vehicle traveling on the level road, just like in the pitching example (see Figure 3(b)).

[0032] Although there is no direct relationship between when pitching occurs and when the vehicle is traveling uphill, if the function and operation of the FCW device can be understood using the example of an uphill road, the function and operation of the FCW device when pitching occurs can also be easily understood. For this reason, the FCW device will be explained below using the example of a saddle-type vehicle traveling on a level road that leads to an uphill road.

[0033] [First embodiment] An FCW device for a saddle-riding type vehicle according to a first embodiment of the present disclosure will be described with reference to Fig. 1. As shown in Fig. 1, an FCW device for a saddle-riding type vehicle 2 is provided on a saddle-riding type vehicle 1.

[0034] The FCW device 2 includes an alarm unit 21 , one or more control units 22 , and a monocular camera 23 .

[0035] The warning unit 21 issues a warning to the driver of the saddle-ride type vehicle 1. The control unit 22 predicts the path of the saddle-ride type vehicle 1, i.e., the host vehicle, and detects the positions of objects around the host vehicle. The control unit 22 calculates the possibility of a collision using the results of the host vehicle path prediction and the results of the position detection of objects around the host vehicle. The control unit 22 executes warning control, which controls whether or not the warning unit 21 issues a warning and the timing of issuing the warning, based on the possibility of a collision.

[0036] As shown within the dashed line frame in FIG. 1, the FCW device 2 executes FCW control including position detection and warning control of objects around the vehicle.

[0037] A monocular camera 23 fixed to the body of the saddle riding type vehicle 1 captures images of the surroundings of the vehicle, including the area ahead of the saddle riding type vehicle 1. The control unit 22 acquires the captured image captured by the monocular camera 23 (A). The control unit 22 executes position detection of objects around the vehicle based on the captured image (B). Using the results obtained from executing position detection of objects around the vehicle, the control unit 22 executes warning control (C) so that a warning is issued in situation 1 shown in Fig. 1 and no warning is issued in situation 2.

[0038] Situations 1 and 2 shown in Figure 1 show the positional relationship between the saddle-type vehicle 1 while it is moving and the preceding vehicles 101 to 103 detected by position detection of objects around the vehicle, as viewed from the side, and the captured images 31 and 32 captured by the monocular camera 23.

[0039] In situation 1, the saddle-riding vehicle 1 is traveling straight on a road without white lines at a vehicle speed V1. This road is a horizontal road that leads to an uphill road on which the first leading vehicle 101 is traveling. The uphill road is a slope that continues from the horizontal road on which the saddle-riding vehicle 1 is traveling to an upward and forward direction of the saddle-riding vehicle 1. The first leading vehicle 101 is traveling (climbing) on ​​the uphill road at a vehicle speed V2 that is slower than the vehicle speed V1 of the saddle-riding vehicle 1 (V2<V1). The first leading vehicle 101 is traveling straight ahead of the saddle-riding vehicle 1. The first leading vehicle 101 is traveling straight in the same direction as the saddle-riding vehicle 1. The captured image 31 shows the uphill road that continues upward and the first leading vehicle 101 traveling on this uphill road.

[0040] The detection line 50 is a line obtained by extending the center line of the saddle riding vehicle 1 in the vehicle width direction in the traveling direction of the saddle riding vehicle 1 on the images 31, 32 captured by the monocular camera 23. The control unit 22 executes host vehicle path prediction to predict the path of the saddle riding vehicle 1. When the saddle riding vehicle 1 is traveling straight, the predicted path obtained by executing host vehicle path prediction coincides with the detection line 50. Therefore, the detection line 50 can also be described as the predicted path of the saddle riding vehicle 1. When the predicted path is a band-shaped area set to match the vehicle width of the saddle riding vehicle 1, the detection line 50 coincides with the center line of the band-shaped area in the width direction; an example of this will be described in the second embodiment.

[0041] In situation 1, the control unit 22 executes warning control so that the warning unit 21 issues a warning when the likelihood of a collision between the saddle riding type vehicle 1 and the first leading vehicle 101 reaches or exceeds a predetermined likelihood of collision. For example, the control unit 22 controls the warning unit 21 to issue a warning when the distance between the saddle riding type vehicle 1 and the first leading vehicle 101 reaches a predetermined distance. For example, the control unit 22 controls the warning unit 21 to issue a warning when the relative speed between the saddle riding type vehicle 1 and the first leading vehicle 101 reaches a predetermined speed. For example, the control unit 22 controls the warning unit 21 to issue a warning when the time to collision reaches a predetermined time.

[0042] In situation 2, the saddle-riding vehicle 1 is traveling straight on a road without white lines at a vehicle speed V1. This road is a horizontal road that connects to the uphill road on which the second leading vehicle 102 and the third leading vehicle 103 are traveling. The uphill road is a slope that continues from the road on which the saddle-riding vehicle 1 is traveling to an upper front of the saddle-riding vehicle 1. The second leading vehicle 102 is traveling on the uphill road (climbing) at the same vehicle speed V1 as the saddle-riding vehicle 1. The second leading vehicle 102 is traveling straight in the same direction as the saddle-riding vehicle 1. The third leading vehicle 103 is traveling on the uphill road (climbing) at a vehicle speed V2 that is slower than the vehicle speed V1 of the saddle-riding vehicle 1 (V2<V1). The third leading vehicle 103 is traveling straight in the same direction as the saddle-riding vehicle 1. The second leading vehicle 102 and the third leading vehicle 103 are traveling ahead of the saddle-riding vehicle 1. The third leading vehicle 103 is traveling on the right side of the second leading vehicle 102. The third leading vehicle 103 is traveling parallel to the second leading vehicle 102. The captured image 32 shows an uphill road continuing upward, and the second leading vehicle 102 and the third leading vehicle 103 traveling on this uphill road.

[0043] In the captured image 32 of situation 2, the second leading vehicle 102 is located on the detection line 50, i.e., overlaps with the detection line 50. On the other hand, the third leading vehicle 103 is located off the detection line 50.

[0044] In situation 2, the control unit 22 executes warning control so that the warning unit 21 does not issue a warning. Like the first leading vehicle 101 in situation 1, the third leading vehicle 103, which is traveling at a vehicle speed V2 that is slower than the vehicle speed V1 of the saddle riding type vehicle 1, moves relatively toward the saddle riding type vehicle 1, but the third leading vehicle 103 is located outside the detection line 50 that coincides with the predicted path of the saddle riding type vehicle 1. Therefore, the possibility of a collision between the saddle riding type vehicle 1 and the third leading vehicle 103 is below a predetermined collision possibility that requires a warning, and the control unit 22 controls the warning unit 21 so that a warning for the third leading vehicle 103 is not issued.

[0045] The second leading vehicle 102 is on the detection line 50 that coincides with the predicted path of the saddle riding type vehicle 1, but is traveling at the same vehicle speed V1 as the saddle riding type vehicle 1. The distance between the saddle riding type vehicle 1 and the second leading vehicle 102 is maintained, and the second leading vehicle 102 is not moving relative to the saddle riding type vehicle 1. Therefore, the possibility of a collision between the saddle riding type vehicle 1 and the second leading vehicle 1023 is also below a predetermined probability of collision that requires an alarm, and the control unit 22 controls the alarm unit 21 not to issue an alarm for the second leading vehicle 102.

[0046] The FCW device 2 can also detect objects located relatively higher than the vehicle, at least a portion of which overlaps the detection line 50, and issue an alarm when the likelihood of a collision with the detected object reaches a predetermined collision likelihood. Situations 1 and 2 are merely examples, and the alarm control by the FCW device 2 is not limited to situations 1 and 2. For example, when the first leading vehicle 101 is stopped on the road in situation 1, the alarm control is executed in the same manner as in situation 1 described above. For example, when the second leading vehicle 102 is traveling at a speed greater than the vehicle speed of the saddle riding type vehicle 1 in situation 2, or when the third leading vehicle 103 is stopped on the road, the alarm control is executed in the same manner as in situation 2 described above. The FCW device 2 can detect objects from images captured by the monocular camera 23 in various other situations as well, and can execute alarm control based on the relative movement between the object and the saddle riding type vehicle 1.

[0047] Second Embodiment A FCW device 2 for a saddle-riding type vehicle according to a second embodiment of the present disclosure will be described with reference to Fig. 2. Below, content that overlaps with the description of the first embodiment will be omitted, and only content necessary to describe the FCW device 2 of the second embodiment will be described.

[0048] The FCW device 2 according to the second embodiment has the same configuration as the FCW device 2 according to the first embodiment. As shown in FIG. 2A, the control unit 22 predicts the vehicle's path (S1). Based on the result of the vehicle's path prediction, the control unit 22 sets an object detection area on the image captured by the monocular camera 23 (S2). Based on the image captured by the monocular camera 23, the control unit 22 detects the position of an object around the vehicle (S3). The control unit 22 executes warning control based on the object detection area set based on the predicted path and the object position obtained by detecting the position of the object around the vehicle (S4).

[0049] A method for setting the detection area will now be described. As shown in Fig. 2(b), when the saddle-riding vehicle 1 is parked in an upright position on a horizontal road just before an uphill road, an image 30 captured by the monocular camera 23 is obtained as shown in Fig. 2(c). The control unit 22 sets a reference line 40 on the captured image 30. The reference line 40 is a straight line on the image 30 captured by the monocular camera 23 that corresponds to the imaginary horizon when the saddle-riding vehicle 1 is parked in an upright position on a horizontal road.

[0050] For example, suppose the captured image 30 was taken when the saddle-riding vehicle 1 was standing upright on a level road without tilting in any direction, including forward, backward, left, or right. In this case, the point at which the optical axis of the monocular camera 23, which is fixed horizontally to the body of the saddle-riding vehicle 1, intersects with the surface of the uphill road when extended horizontally as shown by the dashed line in Figure 2(b) is defined as point P1. In this case, as shown in Figure 2(c), the reference line 40 on the captured image 30 is a horizontal straight line passing through point P11 on the image that corresponds to point P1.

[0051] In reality, the road surface or the vehicle body may be tilted, so for example, using the monocular camera 23, a point P11 on the captured image 30 corresponding to a position parallel to the road surface on which the saddle-riding vehicle 1 is traveling and a sufficiently long distance (for example, 100 m) in front of the saddle-riding vehicle 1 can be identified, and the horizontal line passing through point P11 can be used as the reference line 40.

[0052] After setting the reference line 40, the control unit 22 sets a detection area 60a in the area below the reference line 40 on the captured image 30 based on a predicted path 70 obtained by predicting the vehicle's path.

[0053] 2(c) , a predicted path 70 obtained by executing the host vehicle path prediction is a band-like area of ​​equal width having the width of the saddle riding type vehicle 1. In the predicted path 70, a line 50 passing through the center position of the saddle riding type vehicle 1 in the vehicle width direction becomes the detection line 50 on the captured image 30.

[0054] The control unit 22 designates the area on the captured image 30 that corresponds to the predicted path 70 as the detection area 60a. While the predicted path 70 on the road is a strip-like area of ​​equal width, the predicted path on the captured image 30, i.e., the detection area 60a, becomes narrower from a position closer to the saddle-riding vehicle 1 to a position farther away. The detection area 60a is widest at the bottom end of the captured image 30 and becomes narrower as it approaches the reference line 40.

[0055] After setting the detection area 60a, the control unit 22 identifies intersections P12 and P13 between the detection area 60a and the reference line 40. Specifically, the intersections P12 and P13 are defined as the left and right boundary lines indicating the boundary between the detection area 60a and the outside of the area and the reference line 40.

[0056] Having identified intersections 12 and 13, control unit 22 sets detection area 60b by extending detection area 60a, which was set in the area above reference line 40 and below reference line 40 on captured image 30, upward from intersections P12 and P13 perpendicular to reference line 40. Specifically, detection area 60b is defined as the area between a line extending from point P12 on the left side to reference line 40 to the top of the image, and a line extending from point P13 on the right side perpendicular to reference line 40 to the top of the image.

[0057] In this way, as shown in the captured image 30 of Figure 2 (c), a detection area 60 (60a, 60b) is set, consisting of a detection area 60a below the reference line 40 and having a trapezoidal shape, and a detection area 60b above the reference line 40 and having a rectangular shape.

[0058] 3A, for example, two leading vehicles 201 and 202 are traveling uphill ahead of the saddle riding vehicle 1 while the saddle riding vehicle 1 is traveling straight on a level road. The leading vehicle 201 is traveling in the same direction as the saddle riding vehicle 1 (climbing the slope) along a predicted path 70 of the saddle riding vehicle 1 obtained by predicting the vehicle's path. Meanwhile, the leading vehicle 202 is traveling in the same direction as the leading vehicle 201 (climbing the slope) at a position off the predicted path 70, traveling parallel to the leading vehicle 201.

[0059] The control unit 22 sets a reference line 40 as shown in Figure 3(b) on the captured image 30 obtained by the monocular camera 23 in the situation shown in Figure 3(a), and sets the detection area 60 as described above based on the reference line 40 and the predicted course 70.

[0060] The control unit 22 detects the positions of objects around the vehicle based on the captured image 30, and detects the positions of the two preceding vehicles 201, 202. Because the preceding vehicle 201 is at a position where at least a portion of the preceding vehicle 201 overlaps with the detection area 60, the control unit 22 executes warning control for the preceding vehicle 201. While the preceding vehicle 201 is within the detection area 60, the control unit 22 monitors the relative movement between the saddle-type vehicle 1 and the preceding vehicle 201, and issues a warning when the likelihood of a collision reaches a predetermined level. On the other hand, because the preceding vehicle 202 is outside the detection area 60, the control unit 22 does not execute warning control for the preceding vehicle 202.

[0061] The FCW device 2 sets the detection area 60 based on the predicted path 70 obtained by executing the host vehicle path prediction. Therefore, for example, if the predicted path of the saddle riding type vehicle 1 that has started to turn is a curved band-shaped area indicating the turning path, the portion of the detection area 60 below the reference line 40 will have a curved shape corresponding to the predicted path, as shown in Figure 3(c).

[0062] 1 to 3 have been described as an example in which the saddle-riding vehicle 1 is traveling on a level road just before an uphill road, but the FCW device 2 also operates as described above when the posture of the saddle-riding vehicle 1 changes due to an external disturbance such as an uneven road.

[0063] For example, when the saddle riding type vehicle 1 is traveling straight on a horizontal road, the control unit 22 sets the detection area 60 based on the reference line 40 and the predicted path, as described above, on the image 30 captured by the monocular camera 23, as shown in Fig. 4(a) . In the example shown in Fig. 4(a) , the upper end of the horizontal road captured in the captured image 30 and the reference line 40 are in a positional relationship in which they substantially overlap.

[0064] If the saddle riding type vehicle 1 is in a posture with the front of the vehicle lowered or the rear of the vehicle raised when the captured image 30 is obtained, the control unit 22 sets the detection area 60 as shown in Fig. 4(b). In the example shown in Fig. 4(b), due to a change in the posture of the saddle riding type vehicle 1, the upper end of the horizontal road shown in the captured image 30 is above the reference line 40. In this case as well, the control unit 22 sets the detection area 60 by a trapezoidal area based on the predicted course below the reference line 40 and a rectangular area obtained by extending the upper side of the trapezoid upward perpendicular to the reference line 40.

[0065] If the saddle riding type vehicle 1 is in a posture where the front of the vehicle is raised or the rear of the vehicle is lowered when the captured image 30 is obtained, the control unit 22 sets the detection area 60 as shown in Fig. 4(c) . In the example shown in Fig. 4(c) , due to a change in the posture of the saddle riding type vehicle 1, the upper end of the horizontal road shown in the captured image 30 is below the reference line 40. In this case as well, the control unit 22 sets the detection area 60 by a trapezoidal area below the reference line 40 based on the predicted course, and a rectangular area above the reference line 40.

[0066] When the body of the saddle-ride type vehicle 1 pitches and tilts forward or backward, the monocular camera 23 also tilts, changing the imaging range. However, the position of the reference line 40 on the captured image 30 captured at the same position remains the same regardless of the forward or backward tilt. The control unit 22 sets the detection area 60 using the reference line 40, so that the same area can be set as the detection area 60 without being affected by pitching, as shown in FIGS. 4( a) to 4(c). For example, if the detection area is set only below the reference line 40 for the road portion shown in FIG. 4(a), when pitching causes the state shown in FIG. 4(b), the road above the reference line 40 will fall outside the detection area. By setting the detection area also above the reference line 40, the FCW device 2 can detect a preceding vehicle without being affected by pitching.

[0067] 1 saddle-ride type vehicle 2 FCW device 21 alarm unit 22 control unit 23 monocular camera

Claims

1. An FCW device for a saddle-riding type vehicle comprising: an alarm unit which issues an alarm to a driver; and one or more control units which execute a host vehicle path prediction which predicts a path of the host vehicle and a host vehicle peripheral object position detection which detects the positions of objects around the host vehicle, calculate a possibility of a collision between the host vehicle and the object using the results of the host vehicle path prediction and the results of the host vehicle peripheral object position detection, and execute an alarm control which controls whether or not an alarm is issued by the alarm unit based on the possibility of collision; the FCW device for a saddle-riding type vehicle is further provided with a monocular camera which is fixed to a body of the host vehicle and which images the surroundings of the host vehicle, wherein the control unit executes position detection of the objects around the host vehicle based on an image captured by the monocular camera, and executes the alarm control using the obtained result as described in each of the following situations. Situation 1: When the host vehicle is traveling straight on a horizontal road that has no white lines and has an uphill portion ahead of the host vehicle in the direction of travel, and a first preceding vehicle is traveling on the uphill portion at a position on an extension of the center line of the host vehicle in the width direction in the direction of travel of the host vehicle at a speed slower than the speed of the host vehicle, the control unit executes warning control so that the warning unit issues a warning when the possibility of a collision between the host vehicle and the first preceding vehicle reaches a predetermined collision possibility or greater. Situation 2: When the host vehicle is traveling straight on a horizontal road that has no white lines and has an uphill portion ahead of the host vehicle in the direction of travel, and a second leading vehicle is traveling at the same speed as the host vehicle on the uphill portion and on an extension of the center line of the host vehicle in the width direction in the direction of travel of the host vehicle, and a third leading vehicle is traveling parallel to the second leading vehicle at a speed slower than the speed of the host vehicle, the control unit executes warning control so that the warning unit does not issue a warning.

2. The FCW device for a saddle-type vehicle according to claim 1, characterized in that the control unit sets an object detection area on the image captured by the monocular camera based on the result of the host vehicle path prediction in the following manner, and executes the warning control based on the detection area and the object position obtained by executing position detection of the object around the host vehicle based on the captured image. Method 1: When a straight line corresponding to a virtual horizon when the host vehicle is parked upright on a horizontal road is defined as a reference line on the image captured by the monocular camera, the detection area is set so that the width becomes narrower from a position closer to the host vehicle to a position farther away. Method 2: In the region above the reference line on the captured image, the detection area is set so that the detection area set in the region below the reference line is extended upward perpendicular to the reference line from the intersection with the reference line.

3. An FCW method for a saddle-type vehicle executed by an FCW device used in a saddle-type vehicle, the FCW method comprising: an alarm unit that issues an alarm to a driver; and one or more control units that execute a host vehicle path prediction that predicts the path of the host vehicle and a host vehicle peripheral object position detection that detects the positions of objects around the host vehicle, calculate a possibility of a collision between the host vehicle and the object using the results of the host vehicle path prediction and the results of the host vehicle peripheral object position detection, and execute an alarm control that controls whether or not an alarm is issued by the alarm unit based on the possibility of collision, the FCW method for a saddle-type vehicle comprising: a step of capturing an image of the surroundings of the host vehicle with a monocular camera fixed to the body of the saddle-type vehicle; a step of detecting the positions of the objects around the host vehicle based on the captured image obtained by the monocular camera; and a step of executing the alarm control using the results of the host vehicle peripheral object position detection as described in each of the following situations. Situation 1: When the host vehicle is traveling straight on a horizontal road that has no white lines and has an uphill portion ahead of the host vehicle in the direction of travel, and a first preceding vehicle is traveling on the uphill portion at a position on an extension of the center line of the host vehicle in the width direction in the direction of travel of the host vehicle at a speed slower than the speed of the host vehicle, the control unit executes warning control so that the warning unit issues a warning when the possibility of a collision between the host vehicle and the first preceding vehicle reaches a predetermined collision possibility or greater. Situation 2: When the host vehicle is traveling straight on a horizontal road that has no white lines and has an uphill portion ahead of the host vehicle in the direction of travel, and a second leading vehicle is traveling at the same speed as the host vehicle on the uphill portion and on an extension of the center line of the host vehicle in the width direction in the direction of travel of the host vehicle, and a third leading vehicle is traveling parallel to the second leading vehicle at a speed slower than the speed of the host vehicle, the control unit executes warning control so that the warning unit does not issue a warning.

4. The FCW method for a saddle-type vehicle as described in claim 3, characterized in that it includes the steps of: setting an object detection area on an image captured by the monocular camera in a manner described below based on the result of the vehicle path prediction; and executing the warning control based on the detection area and the position of the object obtained by performing position detection of the object around the vehicle based on the captured image. Method 1: In the case where a straight line corresponding to a virtual horizon when the vehicle is parked upright on a horizontal road is defined as a reference line on the image captured by the monocular camera, the detection area is set so that the width becomes narrower from a position closer to the vehicle to a position farther away in the region below the reference line.Method 2: In the region above the reference line on the captured image, the detection area is set so that the detection area set in the region below the reference line is extended upward perpendicular to the reference line from the intersection with the reference line.

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