JP2008101985A - On-vehicle device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technique capable of determining quickly a branch. <P>SOLUTION: A dotted line drawn on a road face of a main line is detected based on respective frame images photographed by a camera when a vehicle travels on the main line branched in an advancing direction of the vehicle, a current position is determined to be on a branch line when the dotted line detected in each frame image is positioned in a diagonal direction in a frame image photographed thereafter, and the calculated current position is corrected in response to the determination. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an in-vehicle device that calculates a current position.

  Conventionally, a navigation apparatus calculates a cost from a two-dimensional position and direction using a direction sensor, a distance sensor, GPS (Global Positioning System), and map data, and the position having the lowest cost is calculated on a map. The current position above. Therefore, for example, when the main line and the branch line form an angle in the vicinity of the branch part at a branch of an expressway or the like, and thereafter the branch line and the main line are parallel, an accurate current position is obtained. Was difficult.

  In order to solve this, there is a technique of Patent Document 1. Patent Document 1 describes a technique for determining whether a road is a branch line or a main line depending on whether the road after the branch has a gradient and the change in the height direction is equal to or greater than a threshold value.

JP 2005-274187 PR

  The technique described in Patent Document 1 cannot determine whether the current position is on the branch line or on the main line unless the change in the height direction becomes equal to or greater than the threshold value. That is, with the technique described in Patent Document 1, a quick branch determination cannot be made with a branch having no inclination, a branch line with a gentle inclination, or the like.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a technique capable of quickly performing branch determination even with a branch having no inclination or a branch line with a gentle inclination.

  The present invention has been made to achieve the above-mentioned object. Whether the vehicle has entered the branch line or is traveling on the main line depending on whether or not the vehicle has passed on the dotted line drawn on the road surface to show the branch. It is characterized by determining.

  In addition, the present invention is an in-vehicle device mounted on a vehicle, which calculates a current position of the vehicle, a camera that captures a road surface of a road on which the vehicle travels, map data storage means that stores map data, and the like. When the current position calculating means and the vehicle are on the main line branched in the traveling direction of the vehicle, a dotted line drawn on the road surface of the main line is detected from the frame image taken by the camera, When the detected dotted line is located in a diagonal direction in a frame image captured thereafter, a determination unit that determines that the current position is on the branch line, and the calculated current position is corrected according to the determination. Correction means.

  According to the technique of the present invention, it is possible to make a branch determination based on whether or not the vehicle has passed on a dotted line drawn on the road surface to indicate a branch. Therefore, it is possible to quickly make a branch determination even for a branch having no inclination or a branch line having a gentle inclination.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

  In the present embodiment, it is determined whether the vehicle has entered the branch line or is traveling on the main line depending on whether or not the vehicle has passed a dotted line drawn on the road surface to show the branch. Here, it is assumed that a conventional navigation system has this function.

  First, with reference to FIG. 1, the structural example of the navigation system 1 of this embodiment is demonstrated. The navigation system 1 is mounted on a vehicle (not shown). In FIG. 1, the navigation system 1 includes an angular velocity sensor 101, a vehicle speed sensor 102, a calculation unit 103, a GPS receiver 104, a storage device 105, an input device 106, a display 107, an audio output device 108, a communication interface 109, a camera 110, and the like. Have.

  The angular velocity sensor 101 detects a change in the direction of the vehicle on which the navigation system 1 is mounted by detecting the yaw rate of the vehicle. The vehicle speed sensor 102 outputs pulses output at time intervals proportional to the rotation of the output shaft of the vehicle transmission to the counter 122 described later.

  The GPS receiver 104 is equipped with the navigation system 1 by receiving a signal from a GPS satellite and measuring the distance between the vehicle on which the navigation system 1 is installed and the GPS satellite and the rate of change of the distance. Measure vehicle position, heading direction, speed, etc.

  The storage device 105 is, for example, a storage medium such as a CD-R (Compact Disc-Recordable) or a DVD-RAM (Digital Versatile Disk-Random Access Memory), a drive device for the storage medium, an HDD (Hard Disk Drive), or the like. Stores map data and the like.

  The input device 106 is, for example, a remote control and a remote control receiving unit, a touch panel, a switch, or the like.

  The display 107 displays a map, and synthesizes and displays the current position, route, and the like on the displayed map. The voice output device 108 is, for example, a speaker and outputs a voice for guidance and the like.

  The camera 110 is, for example, a camera that captures the front of the vehicle or a camera that captures the rear of the vehicle. This camera 110 may be provided for travel distance correction described below, or may be provided for other functions such as for lane keeping and for back view monitoring. Here, description will be made assuming that the camera 110 is for the back view monitor.

  The arithmetic unit 103 is for controlling the operation of each peripheral device described above, and includes an AD converter 121, a counter 122, a RAM 123, a ROM 124, a CPU (Central Processing Unit) 125, and the like.

  The AD converter 121 converts the signal (analog) of the angular velocity sensor 101 into a digital signal. The counter 122 counts the number of pulses output from the vehicle speed sensor 102, for example, every 0.1 second. The RAM 123 stores calculation data by the CPU 125, data read from the storage device 105, and the like. The ROM 124 stores programs, data, and the like.

  The CPU 125 implements a current position calculation unit 141, an activation determination unit 142, a camera control unit 143, a branch determination unit 144, a current position correction unit 145, and the like by executing a program (not shown) in the ROM 124. The current position calculation unit 141 calculates the current position of the vehicle on which the navigation system 1 is mounted. The current position calculation process of the current position calculation unit 141 is the same as that of the conventional technique. The activation determination unit 142 determines whether or not to perform subsequent processing depending on whether or not there is a branch within a predetermined distance from the traveling direction of the vehicle. The camera control unit 143 controls shooting by the camera 110. The branch determination unit 144 performs image processing on the frame image taken by the camera 110, detects a dotted line indicating the boundary between the branch line and the main line, and determines whether the dotted line moves in a predetermined direction in the frame image. Then, it is determined whether or not the vehicle has passed on the dotted line indicating the boundary between the branch line and the main line. The technology for the branch determination unit 144 to detect a dotted line by image processing is the same as the conventional technology. The current position correction unit 145 determines that the vehicle has passed the dotted line indicating the boundary between the branch line and the main line by the branch determination unit 144, and the current position calculation unit 141 has the current position of the vehicle on the main line. If it is calculated, the vehicle position is corrected on the branch line.

  Although not shown, the navigation system 1 executes a program read out from the ROM 124 by the CPU 125, thereby searching for a route search function by a Dijkstra method, a recommended route guidance function, an address, a telephone number, a place name, a landmark, and the like. It may have functions such as functions that the navigation system of the prior art has. Here, the search function indicates, for example, the address data indicating the address and the location of the address, the phone book data indicating the location of the phone number and the phone number, and the location name and the location of the location name in advance in the storage device 105. Stores place name data, names of major buildings and places, and detailed information and landmark data that indicates the location, etc., and the search function applies from the input address, telephone number, place name, landmark, etc. The position and detailed information to be searched are displayed and displayed.

  Next, map data and the like stored in the storage device 105 will be described.

  In the present embodiment, the map data includes a plurality of meshes uniquely determined by latitude and longitude, and XY coordinates indicating positions in each mesh. Each mesh is indicated by a mesh ID. The map data includes a mesh ID, image data of a plurality of maps including XY coordinates in the mesh ID, road data, address data, place name data, and the like. The position on the map data is uniquely indicated by the mesh ID and XY coordinates.

  The road data is approximated by one or more line segments connecting two points, and these line segments are indicated by XY coordinates of the start point and the end point. Hereinafter, this line segment is called a link, and points at both ends of the link are called nodes.

  FIG. 2 is an example of map data stored in the storage device 105. In FIG. 2, the map data has a plurality of map information tables 201. Each map information table 201 includes one mesh ID 202, one or more link information 203, and the like. The mesh ID 202, the link information 203, and the like are associated with each other. The mesh ID 202 is a mesh identification code. The link information 203 is information related to each link constituting the road included in the mesh with the corresponding mesh ID 202.

  The link information 203 includes a link ID 211, start node coordinates 212, end node coordinates 213, road type 214, link length information 215, regulated speed information 216, start connection link 217, end connection link 218, and the like. Link ID 211, start node coordinates 212, end node coordinates 213, road type 214, link length information 215, regulated speed information 216, start connection link 217, end connection link 218, and the like are associated with each other. The link ID 211 is a link identification code. The start node coordinates 212 and the end node coordinates 213 are the latitude and longitude of two nodes (start node and end node) constituting the link with the corresponding link ID 211. The road type 214 is a type of road including the link with the corresponding link ID 211. In the example of FIG. 2, the road type 214 includes “general road”, “highway”, and the like. The link length information 215 indicates the link length of the corresponding link ID 211. The restriction speed information 216 indicates the restriction speed (limit speed) of the link with the corresponding link ID 211. The start connection link 217 and the end connection link 218 are link IDs of links to which two nodes of the corresponding link ID 211 link are respectively connected. Here, by distinguishing the start node and the end node for the two nodes constituting the link, the upward direction and the downward direction of the same road are managed as different links. Although not shown, the map information table 201 includes information on map components other than roads (address, telephone number, name, XY coordinates, etc.) included in the mesh indicated by the mesh ID 202, and map images. Information etc. may also be included.

  2 is stored in advance in the storage device 105 of the navigation system 1.

  Next, an operation example will be described.

  First, an operation example for calculating the current position will be described.

  The operation illustrated in FIG. 3 is an operation performed by the current position calculation unit 141 at a constant cycle, for example, every 100 mS.

  First, the current position calculation unit 141 reads the output value of the angular velocity sensor 101 from the AD converter 121 (S301). Next, the current position calculation unit 141 calculates the traveling direction of the vehicle from the output value of the angular velocity sensor 101 (S302).

  The current position calculation unit 141 counts the number of pulses output from the vehicle speed sensor 102 by the counter 122 every predetermined time such as every 0.1 second, and reads the count value (S303). The current position calculation unit 141 calculates a distance traveled during a predetermined time of 0.1 seconds by multiplying the read value by a distance coefficient (S304). Specifically, for example, when the measured value by the counter 122 is “Cp” and the distance coefficient is “R”, the distance “lu” that has advanced for 0.1 seconds is expressed by the following equation.

lu = Cp × R
The current position calculation unit 141 sequentially stores the travel direction and distance for each predetermined time acquired in this manner in the RAM 123.

  Next, the current position calculation unit 141 adds the distance value traveled by the vehicle on which the navigation system 1 is mounted within the predetermined time calculated in S304 to the distance value until the previous time, and the added distance is predetermined. It is determined whether or not the distance (for example, 20 m) is exceeded (S305).

  If the result of determination in S305 is that the distance is less than the predetermined distance, the current position calculation unit 141 ends the current process, and performs the above process again after a certain period.

  If the result of determination in S305 is that the distance is equal to or greater than the predetermined distance, the current position calculation unit 141 stores the traveling direction and distance at that time in the RAM 123, and executes map matching processing described later (S306). The distance stored in the RAM 123 by the current position calculation unit 141 is the predetermined distance used for the determination in the process of S305, and is 20 m, for example.

  Next, an example of map match operation will be described with reference to FIG.

  First, the current position calculation unit 141 reads the traveling direction, distance, and the like from the RAM 123 (S401). Next, the current position calculation unit 141 calculates the movement amount of the vehicle on which the navigation system 1 is mounted separately for the latitude direction and the longitude direction based on the read traveling direction and distance. Furthermore, the current position calculation unit 141 adds the calculated movement amount in each direction to the position of the candidate point obtained in the previous map match process, and is the virtual current position that is currently estimated to be present. The position is calculated (S402).

  Next, the current position calculation unit 141 calculates one or more candidate points from the calculated virtual current position and the road data included in the map data (S403), and further calculates the reliability of each candidate point. (S404).

  Here, candidate points and reliability will be described. The current position calculation unit 141 reads a map around the virtual current position from the storage device 105, selects road data (line segments) within a preset distance D centered on the virtual current position, and selects these Take out. In the present embodiment, a map included in an area corresponding to a square having a length L1 centered on the virtual current position is read from the storage device 105.

  Next, the current position calculation unit 141 selects and selects only the line segment in which the direction of the line segment is within the predetermined value from the extracted direction from the extracted line segment. With respect to all the n line segments, a perpendicular line is dropped from the virtual current position, and the length of the perpendicular line L (n) is obtained. Next, based on the lengths of these perpendicular lines, an error cost value ec (n) defined by the following equation is calculated for each selected line segment.

ec (n) = α × | θcar−θ (n) | + β | L (n) |
Here, θcar is the vehicle direction at the virtual current position, θ (n) is the direction of the line segment, L (n) is the distance from the virtual current position to the line segment, that is, the length of the perpendicular, α and β are , A weighting factor. The values of these weighting factors may be changed depending on whether the shift in the traveling direction or the direction of the road or the shift in the current position or the road is important in selecting a road on which the current position is located.

  Next, the current position calculation unit 141 is defined by the following equation according to the calculated error cost ec (n) and the accumulated error cost es related to the candidate point calculated in the previous process. The accumulated error cost es (n) in the current process is calculated.

es (n) = (1-k) × es + k × ec (n)
Here, k is a weight coefficient larger than 0 and smaller than 1. Next, the current position calculation unit 141 calculates a reliability trst (n) defined by the following equation based on the calculated accumulated error cost es (n).

trst (n) = 100 / (1 + es (n))
Next, based on the calculated reliability trst (n), the current position calculation unit 141 sets a point advanced from a certain candidate point by a length corresponding to the distance R traveled by the vehicle along the corresponding line segment. And a new candidate point C (n). Therefore, when the number of line segments that are within a predetermined range D from the current position A with respect to a candidate point and the difference between the direction and the vehicle direction is equal to or less than a predetermined value is n, n pieces A new candidate point C (n) will be generated.

  When the candidate point and the reliability of each candidate point are calculated, the current position calculation unit 141 selects a candidate point having the highest reliability value among the candidate points, and sets the candidate point as a display candidate point ( S405). This display candidate point becomes information indicating the current position displayed on the display 107. The current position calculation unit 141 stores information indicating the position of the display candidate point in the RAM 123.

  Next, the current position calculation unit 141 positions the display candidate points read from the predetermined area of the RAM 123 on the map and displays them on the display 107 (S406).

  The current position may be calculated from the traveling direction, distance, map data, etc. acquired by the sensor as described above, or from the position, traveling direction, traveling direction, etc. received by the GPS receiver 104. May be. In addition, the current position calculated from the traveling direction, distance, map data, and the like acquired by the above-described sensor may be corrected by the position received by the GPS receiver 104. Such calculation processing of the current position is the same as that of the conventional navigation system.

  Next, an operation example for determining whether or not the vehicle has entered the branch line will be described.

  First, branch line entry determination in the present embodiment will be described with reference to FIGS. 5 and 6.

  In FIG. 5, the main line 501 branches off from the branch line 502. Here, an example in which the vehicle 511 travels on the main line 501 and enters the branch line 502 will be described.

  FIG. 6 shows an example of a frame image taken by the back view camera mounted on the vehicle 511 when the vehicle 511 enters the branch line 502 and is at each of the position 521, the position 522, and the position 523.

  In FIG. 6, an image 601 shown in (a) is taken when the user is at the position 521 in FIG. 5. An image 611 shown in (b) is taken when the user is at the position 522 in FIG. An image 621 shown in (c) was taken when at the position 523 in FIG.

  In the image 601 in FIG. 6A, a dotted line 602 is shown at the upper left. This dotted line 602 forms an angle α1 with the vertical direction (or horizontal direction) of the image 601. In the image 611 in FIG. 6B, a dotted line 612 is shown at a position in the lower right direction with respect to the position of the dotted line 602 shown in the previously captured image 601. This dotted line 612 forms an angle α2 with the vertical direction (or horizontal direction) of the image 611. In the image 621 in FIG. 6C, a dotted line 622 is shown at a position in the lower right direction with respect to the position of the dotted line 612 shown in the previously captured image 611. The dotted line 622 forms an angle α3 with the vertical direction (or horizontal direction) of the image 621.

  In the branch line entry determination in the present embodiment, as described above, a continuously shot image has a dotted line that forms a predetermined angle with the vertical direction (or horizontal direction) of the image, and is taken after that. When there is a dotted line in the lower right position of the dotted line detected in the previous image, it is determined that the image has passed the dotted line that distinguishes the main line from the branch line.

  A specific operation example will be described with reference to FIG. FIG. 7 shows an example of an operation that is activated every predetermined time or every predetermined distance.

  In FIG. 7, the activation determination unit 142 refers to the map information in the storage device 105 and branches within a predetermined distance with respect to the traveling direction of the vehicle with the current position of the vehicle calculated by the current position calculation unit 141 as a base point. It is determined whether or not there is (S701). This predetermined distance may be an arbitrary distance, may be determined in advance, or may be set by a user or the like. The predetermined distance may change according to the traveling speed of the vehicle.

  If the result of determination in S <b> 701 is that there is no branch within the predetermined distance, the activation determination unit 142 ends the current process.

  If the result of determination in S <b> 701 is that there is a branch within a predetermined distance, the camera control unit 143 outputs a predetermined command to the camera 110 to turn on the power and start shooting (S <b> 702). The camera 110 sequentially outputs the captured frame images to the navigation system 1.

  The branch determination unit 144 performs image processing on continuously captured frame images while the vehicle travels a predetermined distance, and has a dotted line that forms a predetermined angle with the vertical direction (or horizontal direction) of the image, Then, it is determined whether or not there is a dotted line at a position in the lower right direction with respect to the previously detected dotted line in the image photographed thereafter (S703). Although this determination process is not particularly limited, for example, a dotted line may be detected by performing a process such as pattern matching on each captured image.

  Specifically, for example, the branch determination unit 144 sequentially refers to consecutively captured images, and a first image including a video that matches the dotted line of the reference pattern in a predetermined area on the upper left of each image. To detect. Next, the branch determination unit 144 refers to images taken after that image, and in the lower right direction from the region where the reference pattern has been previously detected, a second image including a video that matches the dotted line of the reference pattern. To detect. When the first image and the second image are detected, the branch determination unit 144 performs image processing on continuously captured images in the above-described determination in S703, and performs vertical processing (or horizontal processing) on the images. It is determined that there is a dotted line that forms a predetermined angle with the (direction), and that there is a dotted line at a position in the lower right direction with respect to the previously detected dotted line in the image captured thereafter.

  Note that the first image and the second image may be, for example, an “n” th image (n is a positive integer) and an “n + 1” th image. Alternatively, the “n” th image and the “n + m” th image (m is an integer of 2 or more) may be used. The value of “m” may be a predetermined value, or may be changed according to the vehicle speed, such as a smaller value as the vehicle traveling speed is faster.

  Further, the number of frame images to be detected may be arbitrary. For example, when not only the first image and the second image are detected but also a third image is further detected, the determination in S703 described above is performed continuously. Then, the captured image is subjected to image processing, and there is a dotted line that forms a predetermined angle with the vertical direction (or horizontal direction) of the image, and from the previously detected dotted line of the frame image captured thereafter It may be determined that there is a dotted line at a position in the lower right direction. Since the third image detection determination condition is the same as the second image detection condition described above, the description thereof is omitted.

  As a result of the determination in S703, there is a dotted line that forms a predetermined angle with the vertical direction (or horizontal direction) of the frame image obtained by performing image processing on the continuously captured frame images in the determination in S703, and If there is no dotted line at a position in the lower right direction from the previously detected dotted line in the frame image taken thereafter, the branch determination unit 144 performs the process of S706 described later.

  As a result of the determination in S703, there is a dotted line that forms a predetermined angle with the vertical direction (or horizontal direction) of the frame image obtained by performing image processing on the continuously captured frame images in the determination in S703, and If there is a dotted line at a position in the lower right direction from the previously detected dotted line in the frame image taken after that, the branch determination unit 144 determines that the vehicle has entered the branch line (S704), and corrects the current position. The unit 145 is instructed to correct the current position. When the current position calculated by the current position calculation unit 141 is on the main line, the current position correction unit 145 corrects the current position to be on the branch line (S705). This correction process may be arbitrary. For example, the weighting factor described above may be temporarily changed so as to increase the reliability of the current position on the branch line, or an arbitrary value may be added. Also good.

  Here, FIG. 8 shows a screen example when the current position is not corrected and a screen example when the current position is corrected. A screen 801 in FIG. 8A is a screen example when the current position is not corrected. On the screen 801, a car mark 802 indicates the current position of the vehicle. A screen 811 in FIG. 8B is a screen example when the current position is corrected. On the screen 811, a car mark 812 indicates the current position of the vehicle. As described above, the technique according to the present embodiment can determine whether the vehicle is on the branch line or the main line immediately after the branch, and can correct the current position.

  In FIG. 7, the activation determination unit 142 outputs a predetermined command to the camera 110, turns off the power, etc., and terminates the photographing (S706). The camera 110 finishes shooting.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes design changes and the like within a scope not departing from the gist of the present invention.

  For example, in the above-described determination in S703, the frame images captured continuously are subjected to image processing, and there is a dotted line that forms a predetermined angle with the vertical direction (or horizontal direction) of the frame image, and is captured after that. If there is no dotted line at a position in the lower right direction from the previously detected dotted line in the frame image, that is, if it can be determined that the vehicle is traveling back on the main line, the current position correcting unit 145 If the current position calculated by 141 is on the branch line, the current position may be corrected to be on the main line. The specific processing of this correction may be arbitrary as described above.

  The process shown in FIG. 7 as an example may be performed when a recommended route is set and guided along the recommended route, or may not be guided.

  Further, in the present embodiment, since the branch line is assumed to branch leftward, in the determination of S703 described above, the frame images continuously shot are subjected to image processing, and the vertical direction ( It is determined whether there is a dotted line that forms a predetermined angle with the horizontal direction) and a frame image that is taken after that, and whether there is a dotted line at a position in the lower right direction from the previously detected dotted line. Is branched to the right, in step S703, continuous frame images are subjected to image processing, and there is a dotted line that forms a predetermined angle with the vertical direction (or horizontal direction) of the frame image, and Then, it is preferable to determine whether or not there is a dotted line at a position in the lower left direction with respect to the previously detected dotted line in the frame image taken thereafter. The branch determination unit 144 may determine whether to branch rightward or leftward from the current position calculated by the current position calculation unit 141 and the map information.

  That is, in the determination of S703, if the dotted line shown in the previously captured frame image is reflected in the diagonally moved area in the later captured frame image, the branch has entered the main line or the main line. You may determine that you have entered.

In one Embodiment of this invention, it is a figure which shows the structural example of a navigation system. In the embodiment, it is a figure for demonstrating an example of map data. In the same embodiment, it is an operation example which shows the outline | summary in which a navigation system calculates a present position. In the embodiment, it is an operation example for calculating a current position. It is a figure explaining the image image | photographed with a camera, when a vehicle enters into a branch line. It is a figure explaining the image image | photographed with a camera, when a vehicle enters into a branch line. In the embodiment, it is an operation example for determining whether or not a branch line has been entered. In the embodiment, it is an example of a screen that displays a current position.

Explanation of symbols

  1: navigation system, 101: angular velocity sensor, 102: vehicle speed sensor, 103: arithmetic unit, 104: GPS receiver, 105: secondary storage device, 106: input device, 107: display, 108: audio output device, 109: Communication interface, 110: camera, 121: AD converter, 122: counter, 123: RAM, 124: ROM, 125: CPU, 141: current position calculation unit, 142: activation determination unit, 143: camera control unit, 144: Branch determination unit, 145: current position correction unit

Claims (2)

An in-vehicle device mounted on a vehicle,
A camera for photographing the road surface on which the vehicle travels;
Map data storage means for storing map data;
A current position calculating means for calculating a current position of the vehicle;
When the vehicle is on the main line branched in the traveling direction of the vehicle, a dotted line drawn on the road surface of the main line is detected from the frame image taken by the camera, and the detected dotted line is A determination unit that determines that the current position is on a branch line when the frame image is captured in a diagonal direction in a frame image captured thereafter;
An in-vehicle device, comprising: a correction unit that corrects the calculated current position according to the determination. The in-vehicle device according to claim 1,
The correction device, when it is determined by the determination that the current position is on the branch line, sets the current position on the branch line.

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