Patent Publication Number: US-2018045516-A1

Title: Information processing device and vehicle position detecting method

Description:
TECHNICAL FIELD 
     The present invention relates to a technique for detecting a position of a vehicle. 
     BACKGROUND ART 
     As background art of the present technical field, Patent Literature 1 recites: “by detecting a current location of a vehicle using dead reckoning navigation to manage current location information about the vehicle, integrating an amount of movement in left and right directions using the dead reckoning navigation, and comparing the amount of movement with a lane width of a road to detect lane movement of the current location information, a current location of the vehicle is detected using the dead reckoning navigation by current location detecting means, and by detecting lane movement by lane movement detecting means to manage the current location information about the vehicle including a lane position by current location information managing means.” 
     CITATION LIST 
     Patent Literature 
     Patent Literature 1 
     Japanese Patent Laid-Open No. 2006-189325 
     SUMMARY OF INVENTION 
     Technical Problem 
     The technique described in Patent Literature 1, however, has a problem that, since a current position of a vehicle is detected by using an integrated amount of movement of the vehicle, an error between the detected position of the vehicle and an actual position of the vehicle increases when a vehicle traveling distance increases. 
     The present invention has been made in view of the situation described above, and an object is to calculate a position of a vehicle on a road with a higher accuracy. 
     Solution to Problem 
     In order to achieve the above object, the present invention is an information processing device mounted in a vehicle, characterized by comprising a control portion acquiring photographed image data obtained by photographing an outside of the vehicle, calculating, when object image data that is image data of a predetermined object is included in the photographed image data, a relative position of the vehicle relative to the object on the basis of the object image data, and detecting a position of the vehicle on a road on the basis of the calculated relative position. 
     Further, the information processing device of the present invention is characterized in that the control portion judges whether the object image data is included in the photographed image data or not on the basis of a result of comparison between stored image data corresponding to the object image data and the photographed image data. 
     Further, the information processing device of the present invention is characterized by comprising a storage portion storing road information including information showing a position of the object and information showing a relationship between the object and a road; wherein the control portion calculates the position of the vehicle on the road on the basis of the calculated relative position and the road information stored in the storage portion. 
     Further, the information processing device of the present invention is characterized in that the control portion calculates a right angle direction separation distance that is a separation distance between the vehicle and the object in a direction crossing a traveling direction of the vehicle, as the relative position, and calculates the position of the vehicle on the road on the basis of the calculated right angle direction separation distance and the road information stored in the storage portion. 
     Further, the information processing device of the present invention is characterized in that the road information includes information about widths of lanes that the road has and information about a separation distance between the object and the road; and the control portion identifies a lane in which the vehicle is traveling on the basis of the calculated right angle direction separation distance and the road information stored in the storage portion. 
     Further, the information processing device of the present invention is characterized in that the object includes a road sign. 
     Further, the information processing device of the present invention is characterized by comprising an interface to which a photographing device having a photographing function is connectable; wherein the control portion receives and acquires the photographed image data from the photographing device via the interface. 
     In order to achieve the above object, a vehicle position detecting method of the present invention is characterized by comprising: acquiring photographed image data obtained by photographing an outside of a vehicle, by a control portion; when object image data that is image data of a predetermined object is included in the photographed image data, calculating a relative position of the vehicle relative to the object on the basis of the object image data, by the control portion; and detecting a position of the vehicle on a road on the basis of the calculated relative position, by the control portion. 
     Further, the vehicle position detecting method of the present invention is characterized by comprising: storing image data corresponding to the object image data; and judging whether the object image data is included in the photographed image data or not on the basis of a result of comparison between stored image data corresponding to the object image data and the photographed image data. 
     Further, the vehicle position detecting method of the present invention is characterized by comprising calculating the position of the vehicle on the road on the basis of the calculated relative position and road information including information showing a position of the object and information showing a relationship between the object and the road. 
     Further, the vehicle position detecting method of the present invention is characterized by comprising: calculating a right angle direction separation distance that is a separation distance between the vehicle and the object in a direction crossing a traveling direction of the vehicle, as the relative position; and calculating the position of the vehicle on the road on the basis of the calculated right angle direction separation distance and the road information stored in the storage portion. 
     Further, the vehicle position detecting method of the present invention is characterized by comprising: identifying a lane in which the vehicle is traveling on the basis of the calculated right angle direction separation distance and the road information including information about widths of lanes that the road and information about a separation distance between the object and the road. 
     Further, in order to achieve the above object, the present invention is an information processing device communicably connected to an in-vehicle device mounted in a vehicle via a network, the information processing device being characterized by comprising a control portion acquiring photographed image data obtained by photographing an outside of the vehicle, from the in-vehicle device, calculating, when object image data that is image data of a predetermined object is included in the photographed image data, a relative position of the vehicle relative to the object on the basis of the object image data, detecting a position of the vehicle on a road on the basis of the calculated relative position and notifying the in-vehicle device of a detection result. 
     Advantageous Effect of Invention 
     According to the present invention, it is possible to calculate a position of a vehicle on a road with a higher accuracy. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a block diagram showing a functional configuration of an in-vehicle navigation device according to a first embodiment. 
         FIG. 2  is a diagram showing a relationship among a travel lane, a vehicle and a road sign. 
         FIG. 3  is a flowchart showing operation of the in-vehicle navigation device. 
         FIG. 4  is a diagram showing an example of photographed image data. 
         FIG. 5  is a diagram showing a data structure of road information data. 
         FIG. 6  is a flowchart showing operation of an in-vehicle navigation device according to a second embodiment. 
         FIG. 7  is a diagram showing a relationship among a travel lane, a vehicle and a road sign. 
         FIG. 8  is a flowchart showing operation of an in-vehicle navigation device according to a third embodiment. 
         FIG. 9  is a diagram showing a relationship among a travel lane, a vehicle and a road sign. 
         FIG. 10  is a diagram showing a configuration of a vehicle position detection system according to a fourth embodiment. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Embodiments of the present invention will be described below with reference to drawings. 
     First Embodiment 
       FIG. 1  is a block diagram showing a functional configuration of an in-vehicle navigation device  1  (an information processing device) according to a first embodiment. 
     The in-vehicle navigation device  1  is a device mounted in a vehicle and is provided with a function of performing own vehicle position detection of detecting a current position of the vehicle, a function of displaying a map and performing map display of displaying the current position of the vehicle on a displayed map, a function of performing route search of searching for a route to a destination, and a function of performing route guidance of displaying a map, displaying a route to a destination on the map and guiding a route to the destination. 
     Hereinafter, a vehicle mounted with the in-vehicle navigation device  1  will be expressed as an “own vehicle”. 
     As shown in  FIG. 1 , the in-vehicle navigation device  1  is provided with a control portion  10 , a touch panel  11 , a storage portion  12 , a GPS unit  13 , a relative bearing detecting unit  14 , an interface  15  and a vehicle speed acquiring portion  16 . 
     The control portion  10  is provided with a CPU, a ROM, a RAM, other peripheral circuits and the like and controls each portion of the in-vehicle navigation device  1 . The control portion  10  controls each portion of the in-vehicle navigation device  1  by cooperation between hardware and software, for example, the CPU reading and executing a control program stored in the ROM. 
     The touch panel  11  is provided with a display panel  111  and a touch sensor  112 . The display panel  111  is provided with a display device such as a liquid crystal display panel and an organic EL panel and displays various images in accordance with control of the control portion  10 . The touch sensor  112  is arranged being overlapped on the display panel  111 , and the touch sensor  112  detects a user&#39;s touch operation and outputs a signal indicating the touch operation to the control portion  10 . The control portion  10  executes a process corresponding to the user&#39;s touch operation on the basis of the signal inputted from the touch sensor  112 . 
     The storage portion  12  is provided with a nonvolatile memory and stores various data. 
     The storage portion  12  stores map data  121 . 
     The map data  121  includes parcel data. The parcel data is data used in the map display and route guidance described above, and includes depiction data for display of a map such as road depiction data for depiction of shapes of roads, background depiction data for depiction of backgrounds such as landforms, and character string depiction data for depiction of character strings for administrative districts and the like. The road depiction data further includes node information having information about nodes corresponding to connection points in a road network, such as intersections, link information having information about links corresponding to roads formed among nodes, and information required for the route guidance. 
     Further, the map data  121  includes region data. The region data is data used in the route search described above, and includes information required for the route search, such as the node information having information about nodes corresponding to connection points in a road network, such as intersections, and the link information having information about links corresponding to roads formed among nodes. 
     Further, the map data  121  includes road information data  1211 . The road information data  1211  will be described later. 
     The GPS unit  13  receives a GPS radio wave from a GPS satellite via a GPS antenna not shown and acquires a current position and a traveling direction of the own vehicle from a GPS signal superimposed on the GPS radio wave by calculation. The GPS unit  13  outputs an acquisition result to the control portion  10 . 
     The relative bearing detecting unit  14  is provided with a gyro sensor and an acceleration sensor. The gyro sensor is configured, for example, with a vibration gyro and detects a relative orientation of the own vehicle (for example, an amount of turning in a yaw axis direction). The acceleration sensor detects acceleration acting on the own vehicle (for example, inclination of the own vehicle relative to the traveling direction). The relative bearing detecting unit  14  outputs detection results of the gyro sensor and the acceleration sensor to the control portion  10 . 
     The vehicle speed acquiring portion  16  is connected, for example, to a sensor for detecting a vehicle speed pulse, detects vehicle speed of the own vehicle on the basis of a vehicle speed pulse inputted from the sensor. Further, for example, by communicating with an ECU (Engine Control Unit), the vehicle speed acquiring portion  16  acquires information about vehicle speed from the ECU to detect the vehicle speed of the own vehicle. The vehicle speed acquiring portion  16  outputs a detection result to the control portion  10 . The control portion  10  detects the vehicle speed of the own vehicle on the basis of the input from the vehicle speed acquiring portion  16 . 
     In the case of performing the own vehicle position detection, the control portion  10  estimates a current position of the own vehicle on the basis of the inputs from the GPS unit  13  and the relative bearing detecting unit  14 , the state of the own vehicle, such as the vehicle speed of the own vehicle detected on the basis of the input from the vehicle speed acquiring portion  16 , and the map data  121 , and appropriately corrects the estimated current position by a method to be described later to detect the current position of the own vehicle. 
     Further, in the case of performing the map display, the control portion  10  displays the detected current position of the own vehicle on a map displayed on the touch panel  11 . 
     Further, in the case of performing the route search, the control portion  10  searches for a route from the detected current position to a destination set by the user on the basis of the map data  121 . 
     Further, in the case of performing the route guidance, the control portion  10  displays the appeared current position of the own vehicle on the map while showing the route to the destination on the map to guide the route. 
     An external device is connected to the interface  15 , and the interface  15  communicates with the connected external device in accordance with a predetermined protocol, in accordance with control of the control portion  10 . In the present embodiment, an in-vehicle camera  20  (a photographing device) is connected to the interface  15  as the external device. 
     The in-vehicle camera  20  is a stereo camera having two photographing portions for photographing a forward direction of the own vehicle. Lens mechanisms of the two photographing portions are arranged being separated from each other in a left-right direction, which is a direction orthogonal to a front-back direction of the own vehicle, on the inner side of front glass of the own vehicle. The two photographing portions synchronously execute photographing in a predetermined cycle. The in-vehicle camera  20  generates two pieces of photographed image data on the basis of photographing results of the two photographing portions and outputs the generated two pieces of photographed image data to the control portion  10  via the interface  15 . 
     By the way, as described above, the in-vehicle navigation device  1  according to the present embodiment has the function of performing the own vehicle position detection of detecting a current position of the own vehicle. 
     As for the own vehicle position detection, there is a need for detecting a current position of an own vehicle on a road where the own vehicle is traveling with as high accuracy as possible. Especially, as for the own vehicle position detection, there is a need for, in a case where a road on which an own vehicle is traveling has a plurality of lanes, detecting in which lane the own vehicle is traveling among the plurality of lanes with as high accuracy as possible. By detecting the lane in which the own vehicle is traveling (hereinafter referred to as a “traveling lane”) with as high accuracy as possible, it is possible to accurately inform the user of the lane in which the own vehicle is traveling at the time of performing the map display and accurately inform the user of change of the lane for smoothly traveling on a retrieved route at the time of performing the route guidance, and, thereby, user convenience is improved. On the basis of the above, the in-vehicle navigation device  1  detects a lane in which the own vehicle is traveling by the following method. 
       FIG. 2  is a diagram showing an example of, when the own vehicle is traveling on a predetermined travel lane, a relationship among the travel lane, a position P 1  which is a current position of the own vehicle, and a position P 2  which is a position of a road sign (hereinafter referred to as “road sign”) to be used for detection of a position of the own vehicle in a process to be described later. 
     Further,  FIG. 3  is a flowchart showing operation of the in-vehicle navigation device  1  at the time of detecting a lane in which the own vehicle is traveling. 
     The process described below using the flowchart of  FIG. 3  is on the assumption that the shape of a travel lane is similar to the shape of the travel lane illustrated in  FIG. 2 , and that a relationship among the travel lane, a current position of the own vehicle and a position of a road sign is similar to the relationship illustrated in  FIG. 2 . 
     That is, it is assumed that the travel lane has a plurality of lanes (in the example of  FIG. 2 , five lanes of a first lane S 1  to a fifth lane S 5 ). 
     Further, it is assumed that the travel lane linearly extends without bending at least up to the position of the road sign (in the example of  FIG. 2 , the position P 2 ) from the current position of the own vehicle (in the example of  FIG. 2 , the position P 1 ) in a traveling direction, that the number of lanes does not change, and that a width of each lane substantially does not change. 
     Further, it is assumed that, on the left side of the leftmost lane relative to the traveling direction (in the example of  FIG. 2 , the first lane S 1 ) among the lanes included in the travel lane, a side strip (in the example of  FIG. 2 , a side strip R 1 ) extends along the lane. 
     Further, it is assumed that the position of the road sign (in the example of  FIG. 2 , the position P 2 ) is a position in a diagonally left forward direction relative to the traveling direction from the position of the own vehicle (in the example of  FIG. 2 , the position P 1 ), which can be photographed by the in-vehicle camera  20  mounted in the own vehicle. 
     In the description below, a direction crossing the traveling direction of the own vehicle will be referred to as a “right angle direction” (in the example of  FIG. 2 , a right angle direction Y 1 ). 
     As shown in  FIG. 3 , the control portion  10  of the in-vehicle navigation device  1  acquires photographed image data outputted by the in-vehicle camera  20  (step SA 1 ). 
     As described above, the in-vehicle camera  20  synchronously photographs the forward direction of the own vehicle in a predetermined cycle by the two photographing portions and outputs the photographed image data based on a result of the photographing to the control portion  10 . Therefore, the control portion  10  executes the processing of step SA 1  in a cycle corresponding to the cycle of the in-vehicle camera  20  outputting the photographed image data, and executes the pieces of processing at and after step SA 2  with execution of the processing of step SA 1  (acquisition of the photographed image data) as a trigger. 
     Next, the control portion  10  analyzes the photographed image data acquired at step SA 1 , and judges whether object image data, which is image data of an image of a road sign showing maximum speed (speed limit, regulatory speed) (hereinafter, referred to as a “maximum speed road sign”), is included in the photographed image data or not (step SA 2 ). The processing of step SA 2  will be described below in detail. 
     The control portion  10  executes the processing of step SA 2  using any one of the pieces of photographed image data that are synchronously inputted from the two stereo cameras. 
       FIG. 4  is a diagram schematically showing an example of the photographed image data in an aspect suitable for description. 
     In the present embodiment, the photographed image data is image data in which dots having information about colors (for example, information about color components of each of RGB colors represented by gradation values of a predetermined gradation) are arranged in a form of a dot matrix according to predetermined resolution. 
     Here, the map data  121  has image data to be used as a template in pattern matching for each of maximum speed road signs for maximum speeds (hereinafter referred to as “template image data”). The template image data corresponds to “image data corresponding to stored object image data”. At step SA 2 , the control portion  10  performs pattern matching using the template image data the map data  121  has, and judges whether object image data is included in the photographed image data or not. 
     In the example of  FIG. 4 , an area A 1  is image data of an image of a maximum speed road sign showing that the maximum speed is 50 km/h, and the image data corresponding to the area A 1  corresponds to the object image data. Therefore, when acquiring the photographed image data of  FIG. 4  at step SA 1 , the control portion  10  judges that object image data is included in the photographed image data by pattern matching using template image data of a template of the image of the maximum speed road sign showing that the maximum speed is 50 km/h at step SA 2 . 
     At step SA 2 , in order to improve accuracy of the judgment about whether object image data is included in photographed image data or not and accuracy of calculation of a sign/vehicle distance to be described later, the control portion  10  may judge that object image data is included in photographed image data when the size of the object image data included in the photographed image data is equal to or larger than a predetermined threshold. 
     The method for judging whether object image data is included in photographed image data or not is not limited to the method using pattern matching but may be any method. 
     If it is judged at step SA 2  that object image data is not included in the photographed image data (step SA 2 : NO), the control portion  10  ends the process. 
     If it is judged at step SA 2  that object image data is included in the photographed image data (step SA 2 : YES), the control portion  10  recognizes a photographed road sign (the maximum speed road sign) on the basis of the object image data (step SA 3 ). 
     Specifically, at step SA 3 , the control portion  10  analyzes the object image data and acquires the type of a road sign corresponding to the object image data. For example, the control portion  10  identifies a character string and a figure included in the road sign corresponding to the object image data. Here, for each type of road sign, the map data  121  has information associating a character string and a figure included in the road sign with the type of the road sign. The control portion  10  acquires the type of the road sign corresponding to the identified character string and figure, on the basis of the information. 
     The method for identifying the type of a road sign is not limited to the method based on a character string and a figured included in the road sign but may be any method. For example, the method for identifying the type of a road sign may be a method of identifying the type of the road sign by reflecting the shape, color and the like of the road sign. 
     At the next step SA 4 , the control portion  10  calculates a separation distance between the road sign corresponding to the object image data and the own vehicle (hereinafter referred to as a “sign/vehicle distance”; in the example of  FIG. 2 , a sign/vehicle distance A). 
     For example, the control portion  10  calculates the sign/vehicle distance by existing image processing utilizing a difference between positions of the pieces of object image data in the two pieces of photographed image data of the two photographing portions inputted from the in-vehicle camera  20  (a parallax). 
     The method for calculating the sign/vehicle distance is not limited to the exemplified method but may be any method. For example, the control portion  10  may calculate the sign/vehicle distance by predetermined means based on sizes of the pieces of object image data in the pieces of photographed image data. 
     At the next step SA 5 , the control portion  10  calculates an angle between a virtual straight line extending in the traveling direction of the own vehicle (in the example of  FIG. 2 , a virtual straight line KT 1 ) and a virtual straight line connecting the own vehicle and the road sign (in the example of  FIG. 2 , a virtual straight line KT 2 ) (hereinafter referred to as a “sign/vehicle angle”; in the example of  FIG. 2 , an angle θ). 
     For example, the control portion  10  calculates the sign/vehicle angle by existing image processing based on the sign/vehicle distance calculated at step SA 4 , positions of the pieces of object image data in the two pieces of photographed image data of the two photographing portions inputted from the in-vehicle camera  20 , and a direction of white lines indicating boundaries among lanes in the pieces of photographed image data. 
     The method for calculating the sign/vehicle angle is not limited to the exemplified method but may be any method. 
     At the next step SA 6 , the control portion  10  calculates a distance between a current position of the own vehicle (in the example of  FIG. 2 , the position P 1 ) and a position of a road sign (in the example of  FIG. 2 , the position P 2 ) in a right angle direction (in the example of  FIG. 4 , the right angle direction Y 1 ) (hereinafter referred to as a “right angle direction separation distance”; in the example of  FIG. 4 , a right angle direction separation distance B). The processing of step SA 6  will be described below in detail. 
     The control portion  10  calculates the right angle direction separation distance by the following formula M1 on the basis of the sign/vehicle distance calculated at step SA 4  and the sign/vehicle angle calculated at step SA 5 . 
       Right angle direction separation distance=Sign/vehicle distance·sin(Sign/vehicle angle)  (Formula M1):
 
     Next, the control portion  10  detects a current position of the own vehicle on the basis of the inputs from the GPS unit  13 , the relative bearing detecting unit  14  and the vehicle speed acquiring portion  16  (step SA 7 ). 
     In the description below, the current position of the own vehicle detected on the basis of the inputs from the GPS unit  13  and the relative bearing detecting unit  14  will be expressed as an “estimated current position”. Since the estimated current position is calculated using the input from the GPS unit  13 , an error due to the GPS may occur, and it is not appropriate to detect a traveling lane on the basis of the estimated current position. Further, the estimated current position indicates a current position of the own vehicle by longitude and latitude. 
     Next, the control portion  10  refers to the road information data  1211  (step SA 8 ). 
     The road information data  1211  is a database having a record for each of road signs displayed on a map based on the map data  121  (road signs managed in the map data  121 ). 
       FIG. 5  is a diagram showing a data structure of one record of the road information data  1211 . 
     As shown in  FIG. 5 , the one record of the road information data  1211  has sign information J 1  and corresponding road information J 2 . 
     The sign information J 1  is information about a road sign and has a sign ID J 11  for uniquely identifying the road sign, sign type information J 12  showing the type of the road sign, and sign position information J 13  showing a position of the road sign (a position indicated by longitude and latitude). 
     The corresponding road information J 2  is information about a road on which the road sign is provided. Note that the road on which the road sign is provided means a one-side road on which traveling in conformity with a rule shown by the road sign is required. 
     The corresponding road information J 2  has a link ID J 21  of the road (identification information assigned for each link in the link information of the region data or parcel data described above), number-of-lanes information J 22  showing the number of lanes of the road, road separation information J 23  showing a separation distance between the left end of the leftmost lane in the traveling direction among lanes of the road on which the road sign is provided and the position of the road sign (hereinafter referred to as a “sign/road separation distance). Further, the corresponding road information J 2  has first lane width information J 241  to n-th lane width information J 24   n  showing widths of the lane for n lanes (n is an integer equal to or larger than “1”) that the road has, respectively. In the description below, the n lanes are expressed as a first lane, a second lane, . . . , an n-th lane in order from the leftmost lane in the traveling direction. 
     Information that each record of the road information data  1211  has corresponds to “road information”. 
     Further, the road separation information J 23  corresponds to “information about a separation distance between an object and a road”. 
     At the next step SA 9 , the control portion  10  identifies a record of a road sign corresponding to the object image data among the records that the road information data  1211  has. The processing of step SA 9  will be described below in detail. 
     At step SA 9 , the control portion  10  extracts a record in which a position shown by the sign position information J 13  of the road information data  1211  and the estimated current position detected at step SA 7  are in a predetermined relationship, among the records that the road information data  1211  has. 
     That the position shown by the sign position information J 13  of the road information data  1211  and the estimated current position detected at step SA 7  are in a predetermined relationship means that the position shown by the sign position information J 13  is within a photographing range of the in-vehicle camera  20  with the estimated current position as a starting point. 
     When one record is extracted, the control portion  10  identifies the extracted record as the record of the road sign corresponding to the object image data. 
     On the other hand, a case may occur where a plurality of records are extracted. In this case, the control portion  10  identifies such a record that the type of a road sign shown by the sign type information J 12  corresponds to the type of the road sign corresponding to the object image data acquired at step SA 3 , among the extracted plurality of records, as the record of the road sign corresponding to the object image data. 
     Here, in general, road signs of the same type are arranged being separated by a predetermined distance or more. Therefore, by identifying a corresponding record by the above method, it is possible to appropriately identify a record of a road sign corresponding to object image data. 
     At the next step SA 10 , the control portion  10  acquires road separation information J 23  and first lane width information J 241  to n-th lane width information J 24   n  on the basis of the record identified at step SA 9 . 
     Next, the control portion  10  identifies a lane in which the own vehicle is traveling (a traveling lane) on the basis of the right angle direction separation distance calculated at step SA 6 , and the road separation information J 23  and the first lane width information J 241  to n-th lane width information J 24   n  acquired at step SA 10  (step SA 11 ). The processing of step SA 11  will be described below in detail. 
     Here, the lane in which the own vehicle is traveling can be identified by a relationship among the right angle direction separation distance, the sign/road separation distance and widths of the lanes that the road has. 
     That is, the right angle direction separation distance, the sign/road separation distance and the widths of the first lane to n-th lane that the road (the travel lane) has are in the following relationship: “Sign/road separation distance+Width of first lane+ . . . +Width of (m−1)th lane&lt;Right angle direction separation distance&lt;Sign/road separation distance+Width of first lane+ . . . +Width of m-th lane” (m is an integer equal to or larger than “1”). In this case, the lane in which the own vehicle is traveling (the traveling lane) is the m-th lane. 
     For example, in the case of  FIG. 2 , a right angle direction separation distance C, a sign/road separation distance H 1  and a width L 1  to a width L 5  of the first lane S 1  to the fifth lane S 5  that the road (the travel lane) has are in the following relationship: “Sign/road separation distance H 1 +Width L 1 +Width L 2 &lt;Right angle direction separation distance C&lt;Sign/road separation distance H 1 +Width L 1 +Width L 2 +Width L 3 ”. In this case, the lane in which the own vehicle is traveling is the third lane S 3 . 
     On the basis of the above, at step SA 11 , the control portion  10  identifies the lane in which the own vehicle is traveling (the traveling lane), on the basis of the relationship among the right angle direction separation distance, the sign/road separation distance and the width of each lane that the road has. 
     The operation of the in-vehicle navigation device  1  at the time of detecting (identifying) the lane in which the own vehicle is traveling has been described above. 
     Here, in the above description, the control portion  10  calculates a sign/vehicle angle, a sign/vehicle distance and a right angle direction separation distance. 
     If the sign/vehicle angle and the sign/vehicle distance are decided, a position of the own vehicle relative to a road sign is decided. Therefore, the sign/vehicle angle and the sign/vehicle distance correspond to a “relative position of an own vehicle (a vehicle) relative to a road sign (an object)”. 
     Similarly, if the right angle direction separation distance is decided, a position of the own vehicle in a right angle direction relative to the road sign is decided. Therefore, the right angle direction separation distance corresponds to the “relative position of an own vehicle (a vehicle) relative to a road sign (an object)”. 
     Further, in the embodiment described above, the control portion  10  detects a lane in which the own vehicle is traveling, using the calculated sign/vehicle angle, sign/vehicle distance and right angle direction separation distance. These relative positions, however, can be used in other methods at the time of detecting the own vehicle. 
     For example, the control portion  10  can detect a relative position of the own vehicle relative to a road sign based on the sign/vehicle angle and the sign/vehicle distance. Therefore, the control portion  10  can detect a position of the own vehicle on a map by acquiring a position of a road sign on the map. Then, for example, by correcting an estimated current position detected from an input from the GPS unit  13  or the like by the position of the own vehicle on the map detected on the basis of the sign/vehicle angle and sign/vehicle distance, the position of the own vehicle can be detected with a higher accuracy. 
     Further, though, in a self-driving system (including not only a complete self-driving system but also a system supporting self-driving in a predetermined case), it is required to detect a position of the own vehicle with a high accuracy, it is possible to detect the position of the own vehicle with a higher accuracy by using a calculated sign/vehicle angle, sign/vehicle distance and right angle direction separation distance at the time of detecting the position of the own vehicle. 
     As described above, the in-vehicle navigation device  1  (the information processing device) according to the present embodiment is provided with the control portion  10  that acquires photographed image data obtained by photographing an outside of the own vehicle (the vehicle), and, when object image data, which is image data of a road sign (a predetermined object), is included in the photographed image data, calculates a relative position of the vehicle relative to the road sign (a combination of a sign/vehicle angle and a sign/vehicle distance, or a right angle direction separation distance) on the basis of the object image data, and detects a position of the vehicle on a road on the basis of the calculated relative position. 
     According to this configuration, a relative position of the own vehicle relative to a road sign is calculated on the basis of object image data included in photographed image data, and a position of the own vehicle on the road is detected on the basis of the calculated relative position. Therefore, for example, in comparison with the case of detecting a current position of a vehicle using an integrated amount of movement of the vehicle, an error of position detection accompanying increase in a traveling distance of the vehicle does not occur, and it is possible to calculate a position of the vehicle on a road with a high accuracy. 
     Further, in the present embodiment, the in-vehicle navigation device  1  is provided with the storage portion  12  that stores the road information data  1211  having road information including information showing positions of road signs and information showing relationships between the road signs and roads. 
     The control portion  10  calculates a position of the own vehicle on a road on the basis of the calculated relative position (the combination of the sign/vehicle angle and the sign/vehicle distance, or the right angle direction separation distance) and the road information data  1211  stored in the storage portion  12 . 
     According to this configuration, the control portion  10  can detect a position of the own vehicle on a road with a high accuracy on the basis of a calculated relative position using the road information that the road information data  1211  has. 
     Further, in the present embodiment, the control portion  10  calculates a right angle direction separation distance, which is a separation distance between the own vehicle and a road sign in the right angle direction (a direction crossing a traveling direction of the own vehicle) as the relative position, and calculates a position of the own vehicle on a road on the basis of the calculated right angle direction separation distance and the road information data  1211 . 
     According to this configuration, the control portion  10  detects a position of the own vehicle on a road with a high accuracy on the basis of a calculated right angle direction separation distance using the road information that the road information data  1211  has. 
     Further, in the present embodiment, the road information of the road information data  1211  includes the first lane width information J 241  to the n-th lane width information J 24   n  (information about widths of lanes a road has) and the road separation information J 23  (information about a separation distance between an object and a road). 
     The control portion  10  identifies a lane in which the own vehicle is traveling on the basis of the calculated right angle direction separation distance and the road information data  1211 . 
     According to this configuration, a position of the own vehicle on a road is detected with a high accuracy on the basis of the calculated right angle direction separation distance using the road information that the road information data  1211  has. 
     Second Embodiment 
     Next, a second embodiment will be described. 
     In the description below, the same components as the components described in the first embodiment will be given the same reference numerals, and detailed description thereof will be omitted. 
     Further, in the second embodiment, as for a shape of a travel lane and a relationship among the travel lane, a current position of the own vehicle and a position of a road sign, they are assumed to be similar to those according to the first embodiment. 
       FIG. 6  is a flowchart showing operation at the time of the in-vehicle navigation device  1  according to the present embodiment detecting a lane in which the own vehicle is traveling. 
       FIG. 7  is a diagram showing a relationship among a travel lane, a position of a road sign and a position of the own vehicle to illustrate a process of the in-vehicle navigation device  1  according to the present embodiment. 
     As for the pieces of processing of steps SA 4  to SA 6  among the pieces of processing described using the flowchart of  FIG. 3  in the first embodiment, the in-vehicle device according to the present embodiment performs different pieces of processing. On the basis of this, steps at which the same pieces of processing as pieces of processing in  FIG. 3  are performed will be given the same reference signs in the flowchart of  FIG. 6 , and description of the steps will be omitted. Pieces of processing of steps SB 1  to SB 5  performed instead of the pieces of processing of steps SA 4  to SA 6  in  FIG. 3  will be described below. 
     As shown in  FIG. 6 , at step SB 1 , the control portion  10  calculates a sign/vehicle angle in a method similar to the method described in the first embodiment. 
     In the example of  FIG. 7 , the position of the own vehicle at the timing of executing the processing of step SB 1  is a position Q 1 ; the position of the road sign is a position Q 2 ; and the control portion  10  calculates an angle θ 1  as the sign/vehicle angle at step SB 1 . 
     Next, the control portion  10  monitors whether or not the own vehicle has traveled a predetermined distance or more after the timing of executing the processing of step SB 1  (step SB 2 ). The detection of step SB 2  about whether the own vehicle has traveled a predetermined distance or more does not have to be strict detection. For example, in a situation that there is a strong possibility that the own vehicle has traveled the predetermined distance or more, from a relationship between vehicle speed and traveling time, a judgment that the own vehicle has traveled the predetermined distance or more may be made. 
     If the own vehicle has traveled the predetermined distance or more after the timing of executing the processing of step SB 1  (step SB 2 : YES), the control portion  10  calculates a second sign/vehicle angle based on a current position of the own vehicle at that time point (hereinafter referred to as a “second current position”; in the example of  FIG. 7 , a position Q 3 ) (step SB 3 ). 
     The second sign/vehicle angle is an angle between a virtual straight line extending in a traveling direction of the own vehicle (in the example of  FIG. 7 , a virtual straight line KT 3 ) and a virtual straight line connecting the second current position of the own vehicle (in the example of  FIG. 7 , the position Q 3 ) and the position of the road sign (in the example of  FIG. 7 , the position Q 2 ) (in the example of  FIG. 2 , a virtual straight line KT 4 ). In the example of  FIG. 7 , the second sign/vehicle angle is an angle θ 2 . 
     At step SB 3 , the control portion  10  calculates the second sign/vehicle angle in a method similar to the method for calculating a sign/vehicle angle described in the first embodiment. 
     Next, the control portion  10  calculates a distance between the position of the own vehicle at the timing of executing the processing of step SB 1  (in the example of  FIG. 7 , the position Q 1 ) and the position of the own vehicle at the timing of executing the processing of step SB 3  (in the example of  FIG. 7 , the position Q 3 ) (hereinafter referred to as a “vehicle traveling distance”; in the example of  FIG. 7 , a vehicle traveling distance E) (step SB 4 ). 
     At step SB 4 , for example, the control portion  10  detects an estimated current position of the own vehicle at the timing of executing the processing of step SB 1  and an estimated current position of the own vehicle at the time of executing the processing of step SB 3  on the basis of inputs from the GPS unit  13  and the relative bearing detecting unit  14 , and appropriately performs correction on which the situation of vehicle speed during traveling and the like are reflected to calculate a vehicle traveling distance. Further, for example, the control portion  10  calculates the vehicle traveling distance on the basis of an aspect of a change between an image of a predetermined object (which may be a road sign) in photographed image data based on photographing performed by the in-vehicle camera  20  at the timing of executing the processing of step SB 1  and an image of the predetermined object in photographed image data based on photographing performed by the in-vehicle camera  20  at the timing of executing the processing of step SB 3 . 
     The method for calculating the vehicle traveling distance is not limited to the exemplified method but may be any method. 
     Next, the control portion  10  calculates a right angle direction separation distance (in the example of  FIG. 7 , a right angle direction separation distance C) on the basis of the sign/vehicle angle calculated at step SB 1  (in the example of  FIG. 7 , the angle θ 1 ), the second sign/vehicle angle calculated at step SB 3  (in the example of  FIG. 7 , the angle θ 2 ) and the vehicle traveling distance calculated at step SB 4  (in the example of  FIG. 7 , the vehicle traveling distance E) (step SB 5 ). 
     Here, when a distance between the second current position (in the example of  FIG. 7 , the position Q 3 ) and an intersection point between a virtual straight line passing through the second current position and extending in the traveling direction of the own vehicle (in the example of  FIG. 7 , the virtual straight line KT 3 ) and a virtual straight line passing through the position of the road sign (in the example of  FIG. 7 , the position Q 2 ) and extending in a right angle direction (in the example of  FIG. 7 , a virtual straight line KT 5 ) is regarded as a “corresponding distance” (in the example of  FIG. 7 , a corresponding distance x), the following formulas are satisfied. 
       tan(Sign/vehicle angle)=Right angle direction separation distance/(Vehicle traveling distance+Corresponding distance)  (Formula M2):
 
       tan(Second sign/vehicle angle)=Right angle direction separation distance/Corresponding distance  (Formula M3):
 
     Therefore, the right angle direction separation distance can be calculated by the following formula M4: 
       Right angle direction separation distance=(Vehicle traveling distance·tan(Sign/vehicle angle)·tan(Second sign/vehicle angle))/(tan(Second sign/vehicle angle)−tan(Sign/vehicle angle))  (Formula M4):
 
     On the basis of the above, the following formulas are satisfied in the case of the example of  FIG. 7 : 
       tan θ1=Right angle direction separation distance  C /(Vehicle traveling distance  E +Corresponding distance  x )  (Formula M2′):
 
       tan θ2=Right angle direction separation distance  C /Corresponding distance  x   (Formula M3′):
 
     The right angle direction separation distance C can be calculated by the following formula M4′: 
       Right angle direction separation distance  C =(Vehicle traveling distance  E ·tan θ1·tan θ2)/(tan θ2−tan θ1)  (Formula M4′):
 
     At step SB 5 , the control portion  10  calculates the right angle direction separation distance using the formula M4 described above. 
     The operation performed at the time of the control portion  10  of the in-vehicle navigation device  1  according to the present embodiment detecting a position of the own vehicle (a lane in which the own vehicle is traveling) has been described above. By performing the process described in the present embodiment, it is possible to detect a position of the own vehicle with a higher accuracy similarly to the first embodiment. 
     Though calculation of angles with a current position of the own vehicle as a vertex (the sign/vehicle angle and the second sign/vehicle angle) is performed twice in the present embodiment, a configuration is also possible in which the calculation is executed three or more times according to travel of the own vehicle, and a relative position of the own vehicle relative to a road sign (the right angle direction separation distance) is calculated in a method corresponding to the method described above on the basis of each of the calculated angles. According to this configuration, it is possible to calculate the relative position with a higher accuracy. 
     Further, in the embodiment described above, the in-vehicle camera  20  photographs a forward direction of the own vehicle, and the control portion  10  calculates a relative position of the own vehicle relative to a road sign on the basis of photographed image data based on a result of the photographing of the forward direction of the own vehicle. On the other hand, if the in-vehicle camera  20  is provided at a position capable of photographing a side direction or backward direction of the own vehicle, the control portion  10  can calculate the relative position of the own vehicle relative to a road sign on the basis of photographed image data based on a result of the photographing of the side direction or backward direction of the own vehicle in the method described above. 
     Third Embodiment 
     Next, a third embodiment will be described. 
     In the description below, the same components as the components described in the first embodiments will be the same reference numerals, and detailed description of the components will be omitted. 
     In the first and second embodiments described above, it is assumed that a road (a travel lane) does not bend at least from a current position of the own vehicle to a road sign. On the other hand, in the present embodiment, operation of the in-vehicle navigation device  1  when a road (a travel lane) from a current position of the own vehicle to a road sign bends will be described. 
       FIG. 8  is a flowchart showing the operation of the in-vehicle navigation device  1  according to the present embodiment. 
       FIG. 9  is a diagram showing an example of, when the own vehicle is traveling on a predetermined travel lane, a relationship among the travel lane, a position Z 1  which is a current position of the own vehicle, and a position Z 2  which is a position of a road sign used for detection of the position of the own vehicle. 
     The in-vehicle navigation device  1  executes the process of the flowchart shown in  FIG. 8  in the following case. That is, when object image data of an image of a road sign is included in photographed image data, the control portion  10  of the in-vehicle navigation device  1  judges whether the road between a current position of the own vehicle and a road sign bends or not by predetermined means. For example, the control portion  10  acquires link information about the road (the travel lane) on which the own vehicle is traveling, and judges whether the road between the current position of the own vehicle and the road sign bends or not on the basis of a relationship among the link information, the position of the own vehicle and the position of the road sign. The method for judging whether a road bends or not is not limited to the exemplified method but may be any method. 
     If judging that the road bends between the current position of the own vehicle and the road sign bends, the control portion  10  executes the process of the flowchart of  FIG. 8 . 
     It is assumed that, at the starting point of the flowchart of  FIG. 8  below, the control portion  10  has executed the pieces of processing corresponding to steps SA 1  and SA 3  of the flowchart of  FIG. 3 . 
     As shown in  FIG. 8 , the control portion  10  of the in-vehicle navigation device  1  calculates a sign/vehicle distance (in the example of  FIG. 9 , a sign/vehicle distance F) and a sign/vehicle angle (in the example of  FIG. 9 , an angle θ 3 ) on the basis of object image data of an image of the road sign included in photographed image data in a method similar to the method described in the first embodiment (step SC 1 ). 
     Next, the control portion  10  refers to the road information data  1211  to identify a record of a road sign corresponding to the aspect image data in a method similar to the method described in the first embodiment described above, and acquires sign position information J 13  that the identified record has (step SC 2 ). As described above, the sign position information J 13  is information showing the position of the road sign (a position indicated by longitude and latitude; coordinates in a predetermined coordinate system on which a map based on the map data  121  is developed is also possible). 
     Next, the control portion  10  calculates a current position of the own vehicle (in the example of  FIG. 9 , the position Z 1 ) on the basis of a position of the road sign shown by the sign position information J 13  acquired at step SC 2  (in the example of  FIG. 9 , the position Z 2 ), the sign/vehicle distance calculated at step SC 1  (in the example of  FIG. 9 , the sign/vehicle distance F) and the sign/vehicle angle (in the example of  FIG. 9 , θ 3 ) (step SC 3 ). 
     By the sign/vehicle distance and the sign/vehicle angle being decided, a relative position of the own vehicle relative to the road sign is decided. Therefore, by the position of the road sign being decided, the current position of the own vehicle is decided. 
     Next, the control portion  10  refers to the map data  121  to acquire information about a center line of the road (the travel lane) on which the own vehicle is traveling (hereinafter referred to as “center line information”) (step SC 4 ). 
     In the present embodiment, a center line of a road refers to a line following the center of a roadway in a right angle direction relative to the overall road width including travel lanes in opposite traveling directions, and is a center line TS in the example of  FIG. 9 . In the map data  121 , a center line on a map is managed as a set of straight lines along the center line (hereinafter referred to as “unit straight lines”). For example, in the example of  FIG. 9 , the center line TS is managed as a unit straight line TS 1  and a unit straight line TS 2 . For each of the unit straight lines, the map data  121  has unit straight line information including a position of one end on a map and a position of the other end on the map. 
     At step SC 4 , the control portion  10  acquires unit straight line information about a unit straight line positioned in a side direction of the position of the own vehicle (in the example of  FIG. 9 , the unit straight line TS 1 ) as the center line information. 
     Next, the control portion  10  calculates, in a case of drawing a perpendicular line down from the current position of the own vehicle to the unit straight line shown by the unit straight line information acquired at step SC 4 , a length between the current position of the own vehicle and an intersection point between the perpendicular line and the unit straight line (in the example of  FIG. 9 , a length N 2 ) (step SC 5 ). 
     Next, the control portion  10  refers to the road information data  1211  to acquire first lane width information J 241  to n-th lane width information J 24   n  about the road on which the own vehicle is traveling (step SC 6 ). 
     Next, the control portion  10  identifies a lane in which the own vehicle is traveling on the basis of the center line information (the unit straight line information) acquired at step SC 4 , the length of the perpendicular line calculated at step SC 5  and the first lane width information J 241  to the n-th lane width information J 24   n  acquired at step SC 6  (step SC 7 ). 
     Here, on a road, lanes are provided side by side in a left direction relative to a traveling direction from a center line. Therefore, if a width of each lane provided on the road and a distance between the center line and a current position of the own vehicle are decided, a lane in which the own vehicle is positioned is decided. 
     On the basis of the above, at step SC 7 , the control portion  10  calculates a position of the intersection point between the perpendicular line and the center line on the map, and identifies the lane in which the own vehicle is traveling on the basis of a relationship among the position, the length of the perpendicular line and a width of the lane. 
     The operation performed at the time of the control portion  10  of the in-vehicle navigation device  1  according to the present embodiment detecting a position of the own vehicle (a lane in which the own vehicle is traveling) has been described above. By performing the process described in the present embodiment, it is possible to detect a position of the own vehicle with a higher accuracy similarly to the first and second embodiments. 
     Fourth Embodiment 
     Next, a fourth embodiment will be described. 
     In the description below, the same components as the components described in the first embodiment will be given the same reference numerals, and detailed description thereof will be omitted. 
       FIG. 10  is a diagram showing a vehicle position detection system  2  according to the fourth embodiment. 
     In the first to third embodiments described above, a device mounted in a vehicle executes a process for detecting a current location of the own vehicle. On the other hand, in the present embodiment, a control server  3  communicable with the device mounted in a vehicle via a network N executes the process. 
     In the present embodiment, the control server  3  functions as an “information processing device”. 
     As shown in  FIG. 10 , an in-vehicle device  1   b  according to the present embodiment is mounted in a vehicle. The in-vehicle camera  20  is connected to the in-vehicle device  1   b  according to the embodiment. 
     The in-vehicle device  1   b  is communicably connected to the control server  3  via the network N that is configured including the Internet. A configuration is also possible in which the in-vehicle device  1   b  is provided with a function of accessing the network N, and the in-vehicle device  1   b  directly accesses the network N. A configuration is also possible in which the in-vehicle device  1   b  and a terminal having a function of accessing the network N (for example, a mobile phone that a person in the vehicle possesses) are connected via near-field wireless communication or wired communication, or other communication systems, and the in-vehicle device  1   b  accesses the network N via the terminal. 
     The in-vehicle device  1   b  has a function of transmitting photographed image data inputted from the in-vehicle camera  20  to the in-vehicle navigation device  1  via the network N. 
     The control server  5  is provided with a server control portion  6  that is provided with a CPU, a ROM, a RAM, other peripheral circuits and the like and controls each portion of the control server  5  by cooperation between hardware and software, for example, reading and executing a program. 
     The server control portion  6  functions as a “control portion”. 
     The server control portion  6  receives photographed image data from the in-vehicle device  1   b , performs the processes corresponding to the flowchart of  FIG. 3, 6 or 8  on the basis of the received photographed image data and detects a relative position of the own vehicle relative to a road sign. As for information required for the processes for the detection (for example, information corresponding to the estimated current position described above, information included in the road information data  1211  and the like), the control server  5  stores the information itself or acquires the information from the in-vehicle device  1   b  at an appropriate timing as required. The server control portion  6  appropriately notifies the in-vehicle device  1   b  of information showing the detected relative position of the own vehicle relative to the road sign as a detection result. 
     The in-vehicle device  1   b  executes a corresponding process on the basis of the notification from the control server  5 . 
     The fourth embodiment has been described above. Even in configuration of the fourth embodiment, the in-vehicle device  1   b  mounted in a vehicle can acquire a relative position of the own vehicle relative to a road sign and execute a corresponding process on the basis of the acquired relative position. 
     The embodiments described above merely show aspects of the present invention and can be arbitrarily modified and applied within a scope of the present invention. 
     For example, in the embodiments described above, the in-vehicle navigation device  1  and the control server  5  detect a relative position of the own vehicle relative to a road sign as an object. The object, however, is not limited to a road sign but may be anything that can be photographed by the in-vehicle camera  20 . For example, the object may be a signal, a building, a signboard or the like. However, since a road sign has a characteristic that a position where the road sign is provided is restricted to some extent because of a relationship with a road, a characteristic of being managed with the map data  121 , and a characteristic that types are limited, and there is a shape standard for each of the types, the road sign is appropriate as an object. 
     Further,  FIGS. 1 and 10  are schematic diagrams in which functional components of the in-vehicle navigation device  1  and the control server  5  are shown being classified according to main pieces of processing content in order to cause the invention of the present application to be easily understood, and in the components of these devices also can be classified into more components according to processing content. Further, classification is also possible in which one component can execute more processes. Further, a process of each component may be executed by one piece of hardware or may be executed by a plurality of pieces of hardware. Further, the process of each component may be realized by one program or may be realized by a plurality of programs. 
     Further, processing units of the flowcharts described using drawings are obtained by division according to main pieces of processing content to cause the processes of the in-vehicle navigation device  1  and the control server  5  to be easily understood. The invention of the present application is not restricted by the way of division of processing units and the names of the processing units. The process of each device can be divided into more processing units according to processing content. Further, one processing unit can be divided so as to include more pieces of processing. Further, processing orders of the above flowcharts are not limited to the shown examples if similar free state judgment can be performed. 
     Further, though the in-vehicle navigation device  1  is configured to acquire photographed image data from the in-vehicle camera  20  which is an external device in the embodiments described above, a configuration is also possible in which the in-vehicle navigation device  1  has a photographing function. 
     REFERENCE SIGNS LIST 
     
         
           1  in-vehicle navigation device (information processing device) 
           5  control server (information processing device) 
           6  server control portion (control portion) 
           10  control portion 
           12  storage portion 
           15  interface 
           20  in-vehicle camera (photographing device)