Patent ID: 12195009

DESCRIPTION OF EMBODIMENTS

An apparatus for displaying lane information that can present a section where a lane change is possible on a display in a manner appropriately recognizable by a driver will now be described in detail with reference to the attached drawings. The apparatus detects a lane change section from an image representing surroundings of a vehicle. The lane change section is a section in an adjoining lane adjoining a travel lane of the vehicle, has a length in a travel direction of the vehicle greater than a lane change threshold indicating a length required for a lane change, and includes no other vehicles. The apparatus presents the position of the lane change section on a display. Specifically, when an entry position is inside the lane change section, the apparatus presents the entry position on the display as a position indicating the lane change section. When the entry position is outside the lane change section, the apparatus presents an endpoint of the lane change section closest to a current position of the vehicle on the display as a position indicating the lane change section. The entry position is a position in a front-back direction at which the vehicle making a lane change from the current position enters the adjoining lane.

FIG.1schematically illustrates the configuration of a vehicle equipped with the apparatus for displaying lane information.

The vehicle1includes a camera2, a meter display3, a global navigation satellite system (GNSS) receiver4, a storage device5, and an electronic control unit (ECU)6. The ECU6is an example of the apparatus for displaying lane information. The camera2, the meter display3, the GNSS receiver4, and the storage device5are connected to the ECU6via an in-vehicle network conforming to a standard, such as a controller area network, so that they can communicate with each other.

The camera2is an example of a sensor for detecting the situation around the vehicle. The camera2includes a two-dimensional detector constructed from an array of optoelectronic transducers, such as CCD or C-MOS, having sensitivity to visible light and a focusing optical system that forms an image of a target region on the two-dimensional detector. The camera2is disposed, for example, in a front and upper area in the interior of the vehicle and oriented forward, takes a picture of the surroundings of the vehicle1through a windshield every predetermined capturing period (e.g., 1/30 to 1/10 seconds), and outputs images representing the surroundings.

The meter display3, which is an example of the display, includes, for example, a liquid crystal display. The meter display3presents information on the travel lane of the vehicle1so as to be visible to the driver, according to a signal received from the ECU6via the in-vehicle network.

The GNSS receiver4receives GNSS signals from GNSS satellites at predetermined intervals, and determines the position of the vehicle1, based on the received GNSS signals. The GNSS receiver4outputs positioning signals each indicating the result of determination of the position of the vehicle1based on the GNSS signals to the ECU6via the in-vehicle network at predetermined intervals.

The storage device5, which is an example of a storage unit, includes, for example, a hard disk drive or a nonvolatile semiconductor memory. The storage device5contains map data including information on features, such as lane lines, in association with their positions.

The ECU6generates a trajectory, based on information on features in map data around the position corresponding to a positioning signal outputted by the GNSS receiver4and information on features represented in an image of the surroundings generated by the camera2. The ECU6then operates a travel mechanism including an engine or a motor, brakes, and steering so that the vehicle1will travel along the trajectory. The ECU6presents information on lanes around the trajectory on the meter display3.

FIG.2schematically illustrates the hardware of the ECU6. The ECU6includes a communication interface61, a memory62, and a processor63.

The communication interface61, which is an example of a communication unit, includes a communication interface circuit for connecting the ECU6to the in-vehicle network. The communication interface61provides received data for the processor63, and outputs data provided from the processor63to an external device.

The memory62includes volatile and nonvolatile semiconductor memories. The memory62contains various types of data used for processing by the processor63, e.g., a margin length to be kept from a vehicle for determining the length of an interval in a lane including no other vehicles and a lane change threshold for determining whether an interval including no other vehicles is enough for a lane change. The memory62also contains various application programs, such as a program for displaying lane information to execute a process therefor.

The processor63, which is an example of a control unit, includes one or more processors and a peripheral circuit thereof. The processor63may further include another operating circuit, such as a logic-arithmetic unit, an arithmetic unit, or a graphics processing unit.

FIG.3is a functional block diagram of the processor63included in the ECU6.

As its functional blocks, the processor63of the ECU6includes a detection unit631and a presentation unit632. These units included in the processor63are functional modules implemented by a computer program stored in the memory62and executed on the processor63. The computer program for achieving the functions of the units of the processor63may be provided in a form recorded on a computer-readable and portable medium, such as a semiconductor memory, a magnetic recording medium, or an optical recording medium. Alternatively, the units included in the processor63may be implemented in the ECU6as separate integrated circuits, microprocessors, or firmware.

The detection unit631detects a lane change section from an image representing the surroundings of the vehicle.

First, the detection unit631inputs an image of the surroundings outputted by the camera2into a classifier that has been trained to detect vehicles and lane lines, thereby detecting two or more vehicles and lane lines.

The classifier may be, for example, a convolutional neural network (CNN) including convolution layers connected in series from the input toward the output. A CNN that has been trained using inputted images including vehicles and lane lines as training data operates as a classifier to determine the positions of vehicles and lane lines.

The detection unit631then identifies a lane travelable without straddling a lane line as the travel lane of the vehicle1, using lane lines detected from an image of the surroundings. The detection unit631also identifies a lane adjoining the travel lane with a lane line in between as an adjoining line.

The detection unit631determines the positions of two or more vehicles detected in the adjoining lane and the length in the travel direction of a section between a pair of lengthwise adjacent vehicles of the two or more vehicles. The detection unit631then detects a lane change section having a length in the travel direction greater than the lane change threshold stored in the memory62.

FIG.4is a first diagram for explaining the lane change section.

The road being traveled by the vehicle1includes lane lines LL11, LL12, and LL13, and the vehicle1is traveling on a lane L11demarcated by the lane lines LL11and LL12.

The detection unit631detects lengthwise adjacent vehicles11and12in an adjoining lane L12demarcated by the lane lines LL12and LL13. The detection unit631determines the length BL1in the travel direction from a position a margin length M11ahead of the front end of the vehicle11to a position a margin length M12behind the rear end of the vehicle12. The detection unit631then determines whether the length BL1is greater than the lane change threshold LCT stored in the memory62, and, if so, detects a lane change section LCS1corresponding to the length BL1. When changing lanes from the current position, the vehicle1enters the adjoining lane L12at a position1′. The entry position EP1is the position of the front end of the vehicle1at the position1′. The detection unit631determines the entry position EP1by referring to an entry position table stored in the memory62that associates the current vehicle speed with the distance in the front-back direction from the current position to the entry position. The detection unit631may determine the entry position EP1by generating a trajectory for a lane change from the current position.

The presentation unit632presents the position of the lane change section LCS1on the meter display3. In the example ofFIG.4, the entry position EP1is outside the lane change section LCS1. In this case, the presentation unit632presents an endpoint LCS1aof the lane change section LCS1closest to the current position of the vehicle1as a position indicating the lane change section LCS1. If the vehicle12does not exist in the example ofFIG.4, the lane change section LCS1does not have a front end in the travel direction. In this case, the rear end LCS1ain the travel direction of the lane change section LCS1corresponds to the endpoint closest to the current position of the vehicle1. Thus the presentation unit632presents the endpoint LCS1aon the meter display3as a position indicating the lane change section LCS1.

FIG.5illustrates a first example of display of lane information. The presentation unit632displays a lane information screen31indicating the position of the lane change section LCS1illustrated inFIG.4, on the meter display3.

The lane information screen31represents the travel lane L11and the adjoining lane L12. In the travel lane L11are represented the vehicle1and a trajectory P1along which the vehicle1will be controlled to travel. In the adjoining lane L12is represented afigure LCM1indicating the lane change section LCS1. Thefigure LCM1indicates the endpoint LCS1aof the lane change section LCS1closest to the current position of the vehicle1. Thefigure LCM1is longer in the width direction than in the travel direction. InFIG.5, thefigure LCM1has a line segment in the width direction of the adjoining lane L12and two triangles separated from the respective ends of the line segment with their vertexes oriented to the center of the line segment. Such presentation of the lane change section LCS1with a figure longer in the width direction than in the travel direction enables the ECU6to make the driver appropriately grasp the position in the front-back direction of the lane change section LCS1.

FIG.6is a second diagram for explaining the lane change section.

The road being traveled by the vehicle1includes lane lines LL21, LL22, and LL23, and the vehicle1is traveling on a lane L21demarcated by the lane lines LL21and LL22. The detection unit631detects a lane change section LCS2having a length BL2and located between lengthwise adjacent vehicles21and22in an adjoining lane L22demarcated by the lane lines LL22and LL23.

The entry position EP2at which the vehicle1changes lanes from the current position is inside the lane change section LCS2. In this case, the presentation unit632presents the entry position EP2as the position of the lane change section LCS2.

FIG.7illustrates a second example of display of lane information. The presentation unit632displays a lane information screen32indicating the position of the lane change section LCS2illustrated inFIG.6, on the meter display3.

The lane information screen32represents the travel lane L21and the adjoining lane L22. In the travel lane L21are represented the vehicle1and a trajectory P2along which the vehicle1will be controlled to travel. In the adjoining lane L22is represented a figure LCM2indicating the position of the lane change section LCS2. The figure LCM2indicates the entry position EP2.

When control of the lane change to the lane change section starts, the presentation unit632finishes presentation of the position indicating the lane change section. The presentation unit632then presents a trajectory for the lane change leading from the travel lane to an adjoining lane under the lane change control, instead of the lane change section, on the meter display3. The entry position in a trajectory used for lane change control may differ from the actual entry position into an adjoining lane. The ECU6finishes presentation of the position indicating the lane change section at the start of lane change control, and thereby prevents presentation of a location that is not used for travel control, so that it will not look unnatural to the driver.

FIG.8is a flowchart of a process for displaying lane information. The ECU6repeats this process at predetermined intervals (e.g., intervals of 1 second) during travel of the vehicle1under autonomous driving control.

First, the detection unit631detects a lane change section in an adjoining lane adjoining the travel lane from an image of the surroundings outputted by the camera2(step S1). The lane change section has a length in the travel direction of the vehicle1greater than the lane change threshold and includes no other vehicles.

The presentation unit632determines whether the position in the adjoining lane corresponding to the current position of the vehicle1is inside the lane change section (step S2).

When it is determined that the position in the adjoining lane corresponding to the current position of the vehicle1is inside the lane change section (Yes in step S2), the presentation unit632presents the position in the adjoining lane corresponding to the current position of the vehicle on the meter display3as the position of the lane change section (step S3) and terminates the process.

When it is determined that the position in the adjoining lane corresponding to the current position of the vehicle1is outside the lane change section (No in step S2), the presentation unit632presents an endpoint of the lane change section near the position in the adjoining lane corresponding to the current position of the vehicle1on the meter display3as the position of the lane change section (step S4) and terminates the process.

Such a process for displaying lane information enables the ECU6to present a section where a lane change is possible on a display in a manner appropriately recognizable by the driver.

Note that those skilled in the art can apply various changes, substitutions, and modifications without departing from the spirit and scope of the present disclosure.