JP4882761B2 - Route guidance device for vehicles - Google Patents

Description

  The present invention generally relates to a vehicular route guidance device that is mounted on a vehicle and guides a route to a driver, and more particularly, to a vehicular route guidance device that improves the vehicle position estimation accuracy.

  2. Description of the Related Art Conventionally, an apparatus that determines whether or not the own vehicle is turning right or left at an intersection is known (see, for example, Patent Document 1).

Patent Document 1 discloses an apparatus for determining whether a right / left turn is being performed based on the steering angle and the output of a yaw rate sensor in a car navigation system.
JP 2000-233699 A

  However, according to the conventional device described in Patent Document 1, when steering is performed in a very low speed traveling state, for example, when the vehicle is almost stopped due to waiting for a pedestrian to cross, the steering operation amount is reduced. The change in the yaw rate is small, and as a result, the right / left turn determination may be delayed.

  As a result, a difference may occur between the actual vehicle position when passing the intersection and the vehicle position recognized by the navigation system on the map data. In other words, the navigation system still recognizes that the vehicle is turning right or left at the intersection or turning on the curved road, even though the vehicle has already passed the intersection or curved road and is going straight ahead. A situation can occur.

  As described above, when the followability of the own vehicle position recognized by the navigation system with respect to the actual own vehicle position is deteriorated, the own vehicle position displayed on the navigation screen is deviated from the actual own vehicle position, so that the driver feels uncomfortable. In addition to giving, there is a delay in providing guidance after turning right / left / turning (for example, guidance on features, guidance on right / left turns, etc.).

  The present invention has been made to solve such problems, and it is a main object of the present invention to provide a vehicular route guidance apparatus with improved self-vehicle position estimation accuracy.

One aspect of the present invention for achieving the above object is a vehicle route guidance device that is mounted on a vehicle and guides a route to a driver, and the vehicle is an intersection, branch, or curved road based on map information. Road discriminating means for discriminating whether or not the vehicle has reached a predetermined distance from the vehicle, imaging means for imaging a scene outside the host vehicle, and the host vehicle is turning or traveling straight from the image captured by the imaging unit After determining that the own vehicle has reached a predetermined distance from an intersection, branch, or curve road by the determining means for determining whether or not there is an intersection, the own vehicle is an intersection based on the determination result by the determining means. A vehicle path guidance device comprising: a passage discriminating unit that discriminates whether or not the vehicle has passed a branch or a curved road .

  In the one aspect, the determination unit determines, for example, whether the host vehicle is turning or traveling straight based on an optical flow of an image captured by the imaging unit. In this case, the determination unit, for example, when the optical flow in the image captured by the imaging unit has a rotation vector equal to or higher than a predetermined ratio (preferably changed according to the road shape) It is determined that the host vehicle is turning. In this case, the determination unit can determine the turning direction of the host vehicle from the rotation direction of the rotation vector and the imaging direction of the imaging unit.

  Moreover, in the above aspect, the imaging unit images, for example, a road surface around the host vehicle (for example, behind the host vehicle).

  According to the above aspect, since it is possible to determine whether the host vehicle is turning or going straight from the captured image, it is possible to appropriately detect that the vehicle has returned straight after turning right / left / turning. The accuracy of the vehicle position estimation can be improved.

  ADVANTAGE OF THE INVENTION According to this invention, the route guidance apparatus for vehicles which improved the own vehicle position estimation precision can be provided.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to the accompanying drawings. The basic concept, main hardware configuration, operating principle, basic control method, and the like of a general car navigation system are known to those skilled in the art, and thus detailed description thereof is omitted.

  Hereinafter, a vehicle route guidance apparatus according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2.

  FIG. 1 is a schematic configuration diagram of a vehicle route guidance apparatus 100 according to the present embodiment.

  The route guidance apparatus 100 includes an imaging unit 101 that images a scene outside the host vehicle. The imaging unit 101 is typically a camera such as a CCD (Charge Coupled Device) camera or a CMOS (Complementary Metal-Oxide Semiconductor) camera.

  The imaging unit 101 is also used with other in-vehicle system cameras (for example, an obstacle detection camera, a white line detection camera, a rear monitoring camera for parking assistance, etc.) installed in the host vehicle. It may be.

  In this embodiment, as an example, it is assumed that the imaging unit 101 determines the installation position and imaging angle on the vehicle so as to mainly image the road surface behind the host vehicle.

  The route guidance apparatus 100 further includes an image recognition unit 102 that performs image recognition processing on the image captured by the imaging unit 101. The image recognition unit 102 is typically an ECU (Electronic Control Unit) designed for image recognition processing.

  The route guidance device 100 further includes a car navigation system 103 as route guidance means. The car navigation system 103 according to the present embodiment may have a function equivalent to that of a general car navigation system. The route to the destination set by the user is displayed on the screen with the vehicle position superimposed on the map information. It is assumed that it has various functions such as calculating and displaying on the screen, and guiding a feature existing near the current position of the host vehicle.

  Here, for the sake of convenience, only the own vehicle position estimation unit 104 and the determination register 105 necessary for the description to be described later are illustrated as components of the car navigation system 103. The host vehicle position estimation unit 104 has a function of determining whether or not the host vehicle is turning, and the determination result by the host vehicle position estimation unit 104 is stored in the determination register 105.

  Next, the flow of the turning / straight ahead determination process by the vehicle route guidance apparatus 100 having the above configuration will be described with reference to the flowchart of FIG.

  First, the car navigation system 103 obtains information related to the road shape ahead of the host vehicle by referring to the map information on the position and traveling direction of the host vehicle at that time (S201).

  When an intersection, a branch, or a curve road exists within a predetermined range ahead of the host vehicle, in other words, when the host vehicle reaches a predetermined distance before the intersection, branch, or curve path (“YES” in S202) The car navigation system 103 causes the imaging unit 101 to start imaging (S203).

  Next, the car navigation system 103 initializes the determination register 105 (S204). Here, it is assumed that the initialized state of the determination register 105 indicates that the host vehicle is traveling straight ahead.

  Next, the car navigation system 103 reads the road shape (for example, curvature) of the intersection, branch, or curved road detected ahead of the host vehicle from the map information, and based on the road shape, is the host vehicle turning? A determination threshold value is set (S205). This determination threshold will be described in detail later.

  In this way, when imaging by the imaging unit 101 is started, the determination register 105 is initialized, and the determination threshold is set, the car navigation system 103 is then imaged by the image recognition unit 102 by the imaging unit 101. Start the image recognition process for the selected image.

  More specifically, the car navigation system 103 extracts the optical flow from the image captured by the image recognition unit 102 and outputs the optical flow to the car navigation system 103 (S206).

  Here, the optical flow is a movement vector indicating to which position each pixel in the image captured at time t has moved in the image captured at time t + Δt.

  When matching the images captured at different times by the image capturing unit 101 while the host vehicle is traveling straight, a uniform linear optical flow toward the vanishing point is extracted from fixed objects such as scenes, features, and road surface paint. Will be. On the other hand, when matching the images captured at different times by the imaging unit 101 while the host vehicle is turning, a non-linear optical flow having a uniform rotation vector is extracted in a predetermined ratio or more according to the vehicle turning direction. become.

  Therefore, if the optical flow is extracted and the flow having a rotation component occupies a predetermined ratio or more in all pixels, it can be determined that the host vehicle is turning. The predetermined ratio mentioned here is the determination threshold value set according to the road shape in S205. Since the ratio of the pixels whose optical flow is the rotation vector while the vehicle is turning to all pixels may vary depending on the road shape such as the curvature, in this embodiment, the determination threshold is set according to the road shape as a more preferable embodiment. To change. However, as will be apparent to those skilled in the art, it is naturally possible to always use the same determination threshold regardless of the road shape.

  Returning to FIG. When the optical flow is extracted in this way, the vehicle position estimation unit 104 of the car navigation system 103 determines whether or not there is a flow having a rotation component equal to or greater than the threshold ratio set in S205 as part of the turning determination function. Is determined (S207).

  When it is determined that there is a flow having a rotation component equal to or greater than the threshold (predetermined ratio) (“YES” in S207), the host vehicle position estimation unit 104 determines that the host vehicle is turning (S209). Next, in order to determine the turning direction, it is determined whether the optical flow having the detected rotation component is a right rotation or a left rotation (S211).

  In this embodiment, since the imaging unit 101 is arranged to capture the rear of the host vehicle, when it is determined that the extracted optical flow having the rotation component is a right rotation flow (" YES ”), the host vehicle position estimating unit 104 determines that the host vehicle is turning left, writes“ turning left ”into the determination register 105 (S215), and returns to S206.

  On the other hand, when it is determined that the optical flow having the extracted rotation component is a left rotation flow (“NO” in S211), the vehicle position estimation unit 104 determines that the vehicle is turning right. Judgment is made, “turning right” is written in the judgment register 105 (S216), and the process returns to S206.

  Return to S207. When it is determined that there is no flow having a rotation component equal to or greater than the threshold (predetermined ratio) (“NO” in S207), the host vehicle position estimation unit 104 determines that the host vehicle is traveling straight ahead (S208).

  Next, the host vehicle position estimation unit 104 determines whether or not the content of the determination register 105 is “straight ahead” (S210).

  If “straight ahead” is written in the determination register 105 at that time (“YES” in S210), the determination register 105 has not been rewritten yet after the initialization, and the vehicle has detected the intersection or branch detected in S202. Alternatively, it is determined that the vehicle is still traveling straight ahead of the curve road, and the contents of the determination register 105 remain unchanged, and the process returns to S206.

  On the other hand, if “straight ahead” is not written in the determination register 105 (“NO” in S210), then whether the contents of the determination register 105 are “turning right” or “turning left” Is determined (S212).

  If “left turning” is written in the determination register 105 at that time (“NO” in S212), the host vehicle position estimation unit 104 makes a left turn and then goes straight ahead. In other words, it is determined that the vehicle has made a left turn at the intersection or has passed the left curve road (S213).

  On the other hand, if “turning right” is written in the determination register 105 at that time (“YES” in S212), the host vehicle position estimation unit 104 makes a right turn once and then It is determined that the vehicle is traveling straight, that is, the vehicle has finished a right turn at the intersection or has passed the right curve road (S214).

  When it is determined that the vehicle has made a right or left turn or a turn and has now returned to the straight-ahead state, the car navigation system 103 ends imaging by the imaging unit 101 (S217), and ends one routine of this flow. To do.

  As described above, according to the present embodiment, it is possible to appropriately determine whether or not the host vehicle is turning based on an image around the host vehicle captured from the host vehicle. Even when the vehicle is turning so that the change in yaw rate is small, the vehicle position recognized by the navigation system can be made to follow the actual vehicle position appropriately and displayed on the navigation screen. The occurrence of inconveniences such as giving the driver a sense of incongruity due to the position of the host vehicle being deviated from the actual host vehicle position or delay in providing guidance after turning right / left / turning is avoided.

  In the above embodiment, as an example, the imaging unit that captures the scene around the host vehicle is provided to capture the rear of the host vehicle. However, as will be apparent to those skilled in the art, The imaging direction may be arbitrary as long as a scene around the host vehicle capable of extracting an optical flow can be captured.

  In the above-described embodiment, as an example, the imaging unit that captures the scene around the host vehicle is provided so as to mainly capture the road surface, but this may be road paint or road surface rather than a feature such as a building. This is based on the viewpoint that the image itself is a fixed object that can be imaged more reliably, and as will be apparent to those skilled in the art, the road surface does not necessarily have to be the main imaging object when implementing the present invention.

  INDUSTRIAL APPLICABILITY The present invention can be used for a vehicle route guidance device that guides a route to a driver. The power source type, fuel type, appearance design, weight, size, running performance, etc. of the vehicle to be mounted are all unquestioned.

1 is a schematic configuration diagram of a vehicle route guidance apparatus according to an embodiment of the present invention. It is a flowchart which shows the flow of the turning / straight-forward determination process by the vehicle route guidance apparatus which concerns on one Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Route guidance apparatus for vehicles 101 Imaging part 102 Image recognition part 103 Car navigation system 104 Own vehicle position estimation part 105 Determination register

Claims (7)

A vehicle route guidance device mounted on a vehicle for guiding a route to a driver,
Road discriminating means for discriminating whether or not the vehicle has reached a predetermined distance before the intersection, branch or curve road based on the map information;
Imaging means for imaging a scene outside the host vehicle;
Determining means for determining whether the host vehicle is turning or traveling straight from the image captured by the imaging means;
Vehicle intersection by the road determination unit, branched, or after it is judged to have reached a predetermined distance before the curved road, the host vehicle based on the determination result by the determining means is operable to pass an intersection, branching, or the curved road Passage determination means for determining whether or not the vehicle has been finished, and a vehicle route guidance device. The vehicle route guidance device according to claim 1,
The vehicle route guidance apparatus according to claim 1, wherein the determination unit determines whether the host vehicle is turning or traveling straight based on an optical flow of an image captured by the imaging unit. The vehicle route guidance device according to claim 2,
The determining means, when those with a rotation vector of the optical flow in the image captured by the imaging means is a predetermined ratio or more, own-vehicle, characterized in the determining, it is turning Route guidance device. The vehicle route guidance device according to claim 3,
It said determining means, when the vehicle is determined to be turning further from the imaging direction of the rotational direction and the imaging means of the rotating vector to determine the constant a turning direction of the vehicle, and characterized in that A vehicle route guidance device. The vehicle route guidance device according to claim 3 or 4,
A vehicular route guidance apparatus, comprising: a ratio changing means for changing the predetermined ratio according to a road curvature of the intersection, branch, or curve road read from map information . A vehicle route guidance apparatus according to any one of claims 1 to 5,
The route guide device for a vehicle, wherein the imaging means images a road surface around the host vehicle. The vehicle route guidance device according to claim 6,
The route guide device for a vehicle, wherein the imaging means images a road surface behind the host vehicle.

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