JP2008128827A - Navigation device, navigation method, and program thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a navigation device for displaying road shape guide images, only when their need is high, by determining the degree of the need superimposing and displaying the road shape guide images indicating the shapes of roads for photographing images that indicate the forward state of a vehicle, and to provide a method and program of the device. <P>SOLUTION: The navigation device includes a photographic guide generating part, a road shape guide generating part, a necessity degree calculating part, and a guide control part. The photographic guide generation part generates the photographic guide images by using the photographic images. The road shape guide generating part generates the road shape guide images that indicate the shapes of roads displayed on photographic guide images. The necessity degree calculating part calculates the degree of need, indicating the degree of the need for display of the road shape guide images. The guide control part superimposes and displays the road shape guide images, generated by the road shape guide generating part, on the photographic guide images generated by the photographic guide generating part, based on the degree of the need calculated by the degree of necessity calculating part. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a navigation device, and more specifically, to a navigation device, a method thereof, and a program thereof that perform route guidance by displaying a live-action image showing a state in front of a vehicle on a screen.

  Conventionally, when a destination is set, navigation that guides the vehicle to the destination along the searched route after searching for a route from the current position to the destination using previously stored map data The device is widespread. Further, recent navigation apparatuses can store detailed map data using a large capacity information recording medium such as a HDD (Hard Disc Drive) or a DVD (Digital Versatile Disc). For example, various maps that pursue the visibility and reality of guide screens, such as images displayed in a three-dimensional bird's-eye view and driver's view using a highly visible three-dimensional CG (computer graphics) map image An image is used.

  The conventional navigation device displays an image of the vehicle front direction taken by the in-vehicle camera on the in-vehicle display, and a guide graphic (an intersection that requires a course change) created separately on the image of the vehicle front direction. And a figure such as an arrow indicating a direction in which the vehicle should travel at a guidance target point such as a branch point.

In addition, an image obtained by superimposing a guide arrow indicating a guide route on a live-action image taken by an imaging unit and an image obtained by converting a road edge, a center line, a lane, and the like of the taken image to CG (computer graphics). Is displayed (for example, refer to Patent Document 1).
JP 2003-121167 A

  However, in the conventional navigation device, when another intersection is approaching in front of the guidance target intersection, or when turning around the guidance target intersection having a complicated shape, among the roads reflected in the live-action image, The user was unable to grasp the road on which the vehicle should travel.

  Furthermore, in the conventional guidance image generating device disclosed in Patent Document 1, since the road edge, centerline, lane, and the like are displayed in CG, the road shape can be easily grasped. These guide displays conceal the live-action image of the background, so at intersections where it is easy to grasp the road shape, such as general intersection intersections, the guide display indicating the road shape will be an obstacle. There was a problem.

  Therefore, the present invention determines the degree of necessity of superimposing and displaying a road shape guide image showing the shape of a road on a real image showing the front of the vehicle, and only when the necessity is high An object of the present invention is to provide a navigation device and a navigation method capable of displaying an image, and a program thereof.

  The object of the present invention is achieved by a navigation device having the following configuration. 1st invention is a navigation apparatus which displays a real image which shows the mode ahead of vehicles on a screen, and performs route guidance. The navigation device includes a live-action guide generation unit, a road shape guide generation unit, a necessity calculation unit, and a guidance control unit. The live-action guide generation unit generates a real-life guide image using the real-action image. The road shape guide generation unit generates a road shape guide image indicating the shape of the road displayed in the live-action guide image. The necessity calculation unit calculates a necessity indicating the degree of necessity of displaying the road shape guide image. The guidance control unit superimposes and displays the road shape guide image generated by the road shape guide generation unit on the actual shooting guide image generated by the shooting guide generation unit based on the necessity calculated by the necessity calculation unit. Here, the degree of necessity may be calculated based on map information, may be calculated based on a live-action image, or may be calculated based on both of them. The road shape guide image only needs to indicate the shape of the road. For example, the road shape guide image may be an image showing the contour shape of the road or an image showing the center line of the road.

  In a second aspect based on the first aspect, the degree of necessity calculation unit is configured such that the distance between the guidance target intersection and the intersection just before the guidance target intersection and / or the guidance target intersection and the guidance target intersection. An intersection approach degree calculating unit that calculates an approach degree may be included according to the distance from the one intersection on the back side, and the necessary degree may be calculated based on the approach degree calculated by the intersection approach degree calculating unit. . Here, the guidance target intersection refers to an intersection or a branch point that needs to be changed such as a right or left turn, and navigation is a guidance target.

  In a third aspect based on the first aspect, the necessity calculation unit includes a complexity calculation unit that calculates a complexity indicating the complexity of the shape of the guidance target intersection, and the complexity calculated by the complexity calculation unit The necessary degree may be calculated based on the degree.

  In a fourth aspect based on the third aspect, the complexity calculating unit may calculate the complexity based on the number of roads connected to the guidance target intersection.

  In a fifth aspect based on the third or fourth aspect, the complexity calculation unit is configured to perform a complex operation based on an angle formed between a road on which the vehicle is currently traveling and a road on which the vehicle is to travel at a guidance target intersection. The degree may be calculated.

  In a sixth aspect based on the first aspect, the necessity calculation unit includes a shielding degree calculation unit that calculates a shielding degree by an obstacle in the front direction of the vehicle in the photographed image, and is calculated by the shielding degree calculation unit. The degree of necessity may be calculated based on the degree of shielding.

  In a seventh aspect based on the sixth aspect, the shielding degree calculation unit masks a ratio of an area overlapping the obstacle in the intersection area, which is an area where the guidance target intersection is displayed, in the photographed image. It may be calculated as a degree.

  In an eighth aspect based on the first aspect, the necessity calculation unit determines whether or not the photographed image includes all or part of an intersection area that is an area where the guidance target intersection is displayed. The guidance target intersection determination unit may be included, and the degree of necessity may be calculated based on the determination result of the guidance target intersection determination unit.

  In a ninth aspect based on the first aspect, the necessity calculation unit includes a distance calculation unit that calculates a distance from the current position of the host vehicle to the guidance target intersection, and calculates the distance calculated by the distance calculation unit. The degree of necessity may be calculated based on this.

  In a tenth aspect based on the first aspect, the necessity calculation unit determines whether or not there is a guidance object that serves as a mark of the guidance target intersection around the guidance target intersection. And the degree of necessity may be calculated based on the determination result of the guidance object determination unit.

  In an eleventh aspect based on the tenth aspect, the live-action guidance generating unit is an image showing the guidance target object when the guidance target object determining unit determines that there is a guidance target object around the guidance target intersection. And a landmark guide generation unit that generates the live action guide image by superimposing the image on the live action image.

  The object of the present invention is achieved by a navigation method comprising the following steps. A twelfth aspect of the present invention is a navigation method for a navigation apparatus that performs route guidance by displaying a live-action image showing a state in front of a vehicle on a screen. The navigation method includes a live-action guide generation step, a road shape guide generation step, a necessity calculation step, and a guidance control step. In the live-action guide generation step, a real-life guide image is generated using the live-action image. A road shape guide generation step and a road shape guide indicating the shape of the road displayed in the live-action guide image are generated. In the necessity calculation step, a necessity indicating the degree of necessity of displaying the road shape guide image is calculated. The guidance control step superimposes and displays the road shape guide image generated in the road shape guide generation unit on the live-action guide image generated in the live-action guide generation step based on the necessity calculated in the necessity calculation step.

  The object of the present invention is achieved by a navigation program comprising the following steps. A thirteenth aspect of the present invention is a navigation program for a navigation apparatus that displays a live-action image showing a state in front of a vehicle on a screen and performs route guidance. A computer of the navigation apparatus is caused to execute a live-action guide generation step, a road shape guide generation step, a necessity calculation step, and a guidance control step. In the live-action guide generation step, a real-life guide image is generated using the live-action image. A road shape guide generation step and a road shape guide indicating the shape of the road displayed in the live-action guide image are generated. In the necessity calculation step, a necessity indicating the degree of necessity of displaying the road shape guide image is calculated. The guidance control step superimposes and displays the road shape guide image generated in the road shape guide generation unit on the live-action guide image generated in the live-action guide generation step based on the necessity calculated in the necessity calculation step.

  According to the present invention, as is apparent from the above description, the degree of necessity of displaying the road shape guide image indicating the shape of the road in a superimposed manner on the live-action image indicating the state in front of the vehicle is determined. The road shape guide image can be displayed only when it is high. Therefore, a road shape guide can be appropriately displayed without impairing the visibility of the screen.

(First embodiment)
A navigation apparatus 100 according to an embodiment of the present invention will be described with reference to FIG. In addition, although the following embodiment is described using attached drawing about this invention, this is for the purpose of illustration and this invention is not intended to be limited to these. FIG. 1 is a functional block diagram showing the configuration of the navigation device according to the present embodiment. In each drawing, components not related to the present invention are omitted.

  In FIG. 1, the navigation device 100 includes an image acquisition unit 1, a positioning unit 2, a map DB 3, an operation input unit 4, a display unit 5, and a control unit 6.

  The image acquisition unit 1 acquires an image captured by a camera using, for example, a CCD (Charge Coupled Device) or a CMOS (Complementary Metal-Oxide Semiconductor). A camera that acquires an image is installed at a location such as a vehicle ceiling, a vehicle tip, or a rear surface of a room mirror, and images at least the vehicle front direction. In addition to the vehicle front direction, an image of the outside of the vehicle other than the front direction such as the left and right direction and the rear direction of the vehicle may be used. The image acquired by the image acquisition unit 1 may be a moving image, that is, a video.

  The positioning unit 2 measures the current position (for example, latitude, longitude, and altitude), speed, and direction of the vehicle. For example, the positioning unit 2 is a positioning sensor such as a GNSS (Global Navigation Satellite System) receiver, a vehicle speed sensor, and a gyro sensor. The GNSS receiver is a GPS (Global Positioning System) receiver, for example, and receives a radio wave from a satellite and demodulates it to measure the current position of the receiver.

  The map DB (Data Base) 3 is composed of, for example, an HDD (Hard Disc Drive) or a DVD (Digital Versatile Disc). The map DB 3 stores map information such as road shape data and intersection position data in advance. However, the present invention is not limited to this, and the map DB 3 includes a map information acquisition unit (not shown), and the map information is transmitted to a server in a website on a network such as the Internet through a communication unit (for example, a mobile phone) (not shown). For example, the map DB 3 may be downloaded as appropriate from the above and stored in the map DB 3. Moreover, you may make it update part or all of the map information previously stored in map DB3 using the acquired map information.

  Here, with reference to FIG. 2A-FIG. 2C, the map information stored in map DB3 is demonstrated. The map DB 3 stores, for example, node data, interpolation node data, link data, and the like. 2A to 2C are diagrams showing examples of map information extracted from a part of the map information related to the present embodiment, among the map information stored in the map DB 3.

  FIG. 2A is node data regarding a point (node) where a road branches in a plurality of directions such as an intersection or a junction. The node data includes position information such as latitude and longitude, the number of links connected to the node, and the link ID for each node. FIG. 2B is interpolation node data indicating bending points for expressing the shape of the link, such as when the link exists and is not linear. Interpolation node data is composed of position information such as latitude and longitude and a presence link ID indicating the interpolation node for each interpolation node. FIG. 2C shows link data indicating a road connecting nodes. The link data includes, for each link, a start node and an end node that are end points of the link, a link length (for example, a meter or a kilometer), a road type indicating a general road or a highway, a road width, the above-mentioned It consists of the number of interpolation nodes and an ID indicating the interpolation node. The link data may include information on the number of lanes or traffic restrictions.

  Next, an example of a map represented using node data, interpolation node data, and link data will be described with reference to FIG. In FIG. 3, the node (Node 15) is connected to three links, and is further connected to another node (Node 13) by a link L6. The link L6 includes interpolation nodes (CN8 and CN9) that form the shape of the link.

  The operation input unit 4 includes, for example, a remote controller, a touch panel, a voice input microphone and a voice recognition engine, and receives a user instruction. The instruction input by the user includes, for example, setting of a destination, selection of a searched route, start of route guidance, switching of screen display, and the like.

  The display unit 5 is configured by a display, for example, and displays information to the user. Specifically, a guidance image indicating guidance to the destination is displayed. The display unit 5 displays, for example, a guide image using map information generated by the map guidance control unit 9 described later and / or a guide image using a live-action image generated by the live-action guide generation unit 11 described later.

  The control unit 6 includes, for example, a CPU (Central Processing Unit) including a RAM (Random Access Memory) and a ROM (Read Only Memory). The control unit 6 includes a host vehicle position determination unit 7, a route search unit 8, a guidance control unit 9, a map guidance generation unit 10, a live-action guidance generation unit 11, a road shape guide generation unit 12, and a necessary degree calculation unit 13. It is out. The control unit 6 controls the operation of the entire navigation device.

  The own vehicle position determination unit 7 collates with map information using vehicle information such as the current position (for example, latitude, longitude and altitude), speed, and direction of the vehicle measured by each type of positioning sensor of the positioning unit 2. To determine the vehicle position.

  The route search unit 8 refers to the information on the destination input from the operation input unit 4, the vehicle position determined by the vehicle position determination unit 7, the map information stored in the map DB 3, and the like. Search for the optimal route from the destination to the destination.

  The guidance control unit 9 refers to the vehicle position determined by the vehicle position determination unit 7, the guidance route searched by the route search unit 8, and the map information stored in the map DB 3, from the current position of the vehicle. The distance to the next guidance target intersection to be passed is calculated. Further, the guidance control unit 9 controls whether to display either the map guidance image or the live-action guidance image on the display unit 5 based on the calculated distance from the current position of the vehicle to the next intersection to be guided. To do. When the calculated distance has not reached a predetermined distance (hereinafter referred to as a guidance mode switching distance D1), the guidance control unit 9 uses map information generated by the map guidance generation unit 10 described later. A guidance mode (hereinafter referred to as a map guidance mode) in which guidance images are displayed for guidance is set. On the other hand, when the calculated distance reaches the guide mode switching distance D1 or less, the guidance control unit 9 displays a guidance image using a live-action image generated by the real-life guide generation unit 11 to be described later for guidance. The guidance mode to be performed (hereinafter referred to as a live-action guidance mode) is set. In this embodiment, the guidance mode is described as being switched, but guidance may always be performed in the live-action guidance mode.

  Further, the guidance control unit 9 determines whether or not to superimpose and display a road shape guide image indicating the shape of the road of the live-action image acquired by the image acquisition unit 1 described later in the live-action guide mode. . The determination as to whether or not to display the road shape guide image in a superimposed manner is made according to the degree of necessity calculated by the degree-of-necessity calculation unit 13 described later. The guidance control unit 9 is a mode for superimposing and displaying a road shape guide image on a live-action guidance image (hereinafter referred to as a real-life guidance mode A) or a mode in which a road shape guide image is not superimposed and displayed on a real-life guidance image in the real-life guidance mode. (Hereinafter referred to as a live-action guidance mode B).

  The map guidance generation unit 10 generates a guide image of a predetermined area (hereinafter referred to as a map guide image) using map information stored in the map DB 3. Here, the predetermined area is an area that can be displayed on the display screen of the display unit 5. Furthermore, the map guidance generation unit 10 sets the display color of the route searched by the route search unit 8 to a color different from other roads on the map image. The searched route may be set so that the line width is displayed wider than that of other roads.

  The live-action guide generation unit 11 includes a guide route searched by the route search unit 8, a current position of the vehicle detected by the positioning unit 2, road shape data that is map information stored in the map DB 3, and the like (for example, node data, Based on the interpolation node data and the link data), an arrow-shaped guide graphic indicating the direction in which the vehicle should travel at the guidance target intersection is created. Further, the live-action guidance generating unit 11 generates a guide image (hereinafter referred to as a live-action guide image) in which a guide graphic is superimposed on the real-shot image acquired by the image acquisition unit 1.

  Here, with reference to FIG. 4 to FIG. 8, a method for generating a guide graphic and a photograph guide image in the photograph guide generation unit 11 will be described. FIG. 4 is a flowchart showing a flow of operations for generating a guide graphic and a live-action guide image in the live-action guide generating unit 11.

  First, the live-action guidance generating unit 11 is a parameter that determines the imaging direction and imaging range of a real-time image that shows a three-dimensional map based on map information stored in the map DB 3 and the front of the vehicle acquired by the image acquisition unit 1. Based on the camera position, camera angle (horizontal angle, elevation angle), focal length, and image size, a camera view space in the three-dimensional map is obtained (step S1). Here, the three-dimensional map is a map represented by latitude, longitude, and altitude position information. Further, the parameters for determining the imaging direction and the imaging range are not limited to those described above, and may be converted using other parameters such as the angle of view as long as the imaging direction and the imaging range are determined. A two-dimensional map obtained by removing altitude information from a three-dimensional map may be used.

  Further, the camera visual field space in step S1 is obtained by a method as shown in FIG. FIG. 5 is a diagram for explaining the camera visual field space. First, in FIG. 5, a point F separated from the viewpoint E (camera position) by the focal length f in the camera angle direction is obtained. Furthermore, a horizontal x vertical y plane (camera screen) corresponding to the aspect ratio of the display screen of the display unit 5 is set to be perpendicular to the vector connecting the viewpoint E and the point F. Next, a three-dimensional space obtained by a half line connecting from the viewpoint E to the four corner points of the camera screen is calculated. The three-dimensional space theoretically extends to infinity, but is censored at an appropriate distance from the viewpoint E, and the space is set as the visual field space.

  Next, in step S2, the live-action guide generation unit 11 detects a road existing in the camera visual field space obtained by the above-described method in the three-dimensional map (hereinafter referred to as a road detection process). FIG. 6 is a diagram illustrating a three-dimensional map including the guidance target intersection on the guidance route searched by the route search unit 8 and the camera field of view from above the vehicle traveling direction. Specifically, as shown in the example of FIG. 6, a region indicated by diagonal lines is detected as a road that exists in the camera visual field space. Furthermore, in the road detection process, the detected road shape data, road width, and the like are extracted based on the node data, interpolation node data, and link data stored in the map DB 3 described above. The road in the camera view space may be detected based on the result of detecting a white line on the road by a known image recognition technique.

  Next, in step S3, the live-action guide generation unit 11 is based on the road shape data and road width corresponding to the guide route searched by the route search unit 8 among the roads detected by the road detection process. A guidance figure (arrow) indicating the direction in which the vehicle should travel at the guidance target intersection is created. In addition, FIG. 7 is a figure for demonstrating how to obtain | require the shape and arrangement position of a guide figure. Subsequently, as in the example illustrated in FIG. 7, the created guide graphic is arranged on a road corresponding to the guide route among roads existing in the camera view space. Note that the guide graphic is not limited to the arrow shape shown in FIG. 7, and may be a simple broken line, for example.

  Next, in step S4, the live-action guide generation unit 11 performs perspective projection of the guide graphic arranged as described above using the camera screen shown in FIG. 5 as a projection plane (projection processing). Thereby, since the projection plane on which the guide graphic is projected matches the camera screen acquired by the image acquisition unit 1, the guide graphic is superimposed on the road (guide route) displayed in the live-action image (see FIG. 8). When superimposing a guide graphic on a live-action image, a known image recognition technique such as white line detection or road edge detection is used to detect the position of the road in the live-action image captured by the camera and superimpose the guide graphic. The position may be corrected.

  The road shape guide generation unit 12 generates an image (hereinafter referred to as a road shape guide image) indicating the shape of the road of the photographed image acquired by the image acquisition unit 1. In order to superimpose and display, the shape and position of the road shape guide to be superimposed on the live-action image are determined based on the shape of the road detected in the road detection process as described above.

  Specifically, as shown in the example of FIG. 9, the road shape guide generation unit 12 is a road shape indicated by a line (for example, a thick solid line) along the road edges at both ends of the road detected by the road detection process. A guide image is generated. For example, the position of the road edge may be calculated based on road width information stored in the map DB 3 or may be detected from a live-action image using a known image recognition technique such as road edge detection. . The position of the road shape guide is not limited to the position on the road edge described above, and may be arranged anywhere as long as the road shape is known. For example, you may arrange | position on a driving | running lane and may be arrange | positioned in the appropriate position along the road shape.

  Next, the road shape guide generation unit 12 performs a road shape guide projection process using the camera screen shown in FIG. 5 as a projection plane. Thereby, since the projection surface on which the road shape guide is projected matches the camera screen acquired by the image acquisition unit 1, the road shape guide is superimposed on the road (guide route) displayed in the live-action image. (See FIG. 10).

  As described above, by displaying the road shape guide image superimposed on the live-action guide image, the user can easily recognize the road shape near the guidance intersection. In particular, this effect is effective at highly complicated guidance target intersections. For example, even if there is another intersection just before or immediately behind the guidance target intersection, the user can recognize the situation where there is another intersection in the vicinity of the guidance target intersection to bend. In addition, since it is possible to easily determine whether the intersection where the own vehicle is to bend (a guidance target intersection) is an intersection in front or an intersection in the back, there is no doubt about which one to turn. In addition, for example, since the shape of the intersection can be easily recognized even at a complicated intersection where five or more roads intersect, it is possible to easily determine which road the guided route to which the vehicle should travel is.

  The necessity calculation unit 13 calculates a necessity that is an index indicating the necessity of superimposing and displaying a road shape guide image indicating the shape of the road on the live-action guide image. The road shape guide image has an advantage that it is easy to grasp the road shape near the intersection. On the other hand, there is a demerit that it hides the live-action image of the background and makes it difficult to see the scenery around the intersection. Therefore, the road shape guide image is displayed in a superimposed manner only when it is highly necessary to display the road shape guide image in a superimposed manner.

  Next, a specific operation of the necessity calculation unit 13 will be described. The necessity degree calculation unit 13 calculates the degree of proximity of the guidance target intersection with other intersections before and after the intersection, and the complexity of the guidance target intersection shape as elements for calculating the necessity degree. The shape complexity shown is calculated.

  The degree of approach of the intersection before and after the guidance target intersection to the guidance target intersection is determined by the distance between the guidance target intersection and the intersections before and after the intersection. For example, when the distance between the intersection near the guidance target intersection and the guidance target intersection among the intersections ahead and behind the guidance target intersection is within a predetermined distance D2 (for example, 50 m), is within the distance D2 Is set to a high value (for example, approach degree 1), and when the distance is D2 or more, the approach degree is set to a low value (for example, approach degree 0). In addition, the position information of the intersection required when calculating distance D2 is acquired from map DB3. Note that the distance between intersections may be detected from a photographed image using an image recognition technique.

  However, the present invention is not limited to this, and the approach degree may be set to a higher value as the distance is shorter, for example, according to the distance between the guidance target intersection and the intersections before and after the guide target intersection. Further, the value of the approach degree may be changed depending on whether or not an intersection near the guidance target intersection is in front of the guidance target intersection. For example, the road ahead of the guide route is larger in the live-action image and the user is more likely to mistake the guide route. Therefore, when the distance from the guide target intersection is almost the same, You may set the approach degree of the intersection in a higher value than the intersection in the back.

  The shape complexity is determined based on the number of roads connected to the guidance target intersection (number of connected roads) and the angle of the road intersecting at the guidance target intersection (connection angle). The number of connected roads is obtained by referring to the map DB 3 and extracting the number of links connected to nodes on the guidance target intersection. Note that the number of connection roads and the connection angle may be detected from a photographed image using an image recognition technique. The number of connected roads is 4 at the intersection of the cross road as shown in FIG. 11A, and the number of connected roads is 5 at the intersection of 5 roads as shown in FIG. 11B. The necessary degree calculation unit 13 increases the shape complexity (for example, 1) when a predetermined condition C1 (for example, the number of roads connected to the guidance target intersection is 5 or more) with respect to the shape complexity is satisfied. Set to.

  As shown in FIG. 12, the connection angle is an angle between a link of a road on which the host vehicle enters and a link of another road connected to the guidance target intersection. When there is a road whose connection angle is deviated from 90 degrees, 270 degrees which are perpendicular directions, and 180 degrees which are straight directions, the necessity degree calculation unit 13 is shaped like a general cross road or the like. Consider different shapes as complex intersections. In other words, the necessity calculation unit 13 satisfies a predetermined condition C2 regarding the shape complexity (for example, there is a link having a connection angle in the range of 80 to 100 degrees, 170 to 190 degrees, and 260 to 280 degrees). If it is, the shape complexity is set to a high value (for example, 1).

  From the above, the shape complexity is set to a high value (for example, shape complexity 1) when either the condition C1 related to the number of connected roads or the condition C2 related to the connection angle is satisfied, and in other cases Is set to a low value (for example, shape complexity 0).

  The necessity degree calculation unit 13 calculates the degree of necessity based on the approach degree and the shape complexity of the intersections before and after the guidance target intersection with respect to the guidance target intersection. For example, a value having a larger degree of approach and shape complexity of intersections before and after the guidance target intersection with respect to the guidance target intersection is set as the necessary degree. Specifically, when the proximity of the intersection before and after the guidance target intersection is 1 with respect to the guidance target intersection and the shape complexity is 0, the necessary degree is set to 1 based on the value of the larger proximity. . As a result, the guidance control unit 9 superimposes and displays the road shape guide image when the degree of necessity is greater than a predetermined threshold T (for example, 0.5), and displays the road shape guide image when the degree of necessity is less than the predetermined threshold. Do not overlay.

  Next, with reference to FIG. 13, the flow of operation of the navigation device 100 of the present embodiment will be described. FIG. 13 is a flowchart showing an operation flow of the navigation device 100 according to the present embodiment.

  In FIG. 13, the user inputs a destination from the operation input unit 4 and determines whether or not the destination is set (step S11). If the destination is set as a result of the determination (Yes in step S11), the positioning unit 2 detects the current position of the vehicle, and the route search unit 8 determines the vehicle position determined by the vehicle position determination unit 7. The optimum route from the destination to the destination is searched (step S12). In the subsequent step S13, when the route guidance is started, the positioning unit 2 detects the current position of the vehicle at a predetermined time interval. Subsequently, the current position of the vehicle is compared with the optimum route to determine whether or not the vehicle has arrived at the destination (step S14). As a result of the determination, if the destination has not been reached (No in step S14), the process proceeds to step S15. On the other hand, when the vehicle arrives at the destination (Yes in step S14), the process of FIG. 13 ends.

  Next, in step S15, the guidance control unit 9 searches for a guidance target intersection in the route from the current position of the vehicle to the destination. As a result of the search, when there is no guidance target intersection in the route from the current position of the vehicle to the destination (No in step S15), the process proceeds to step S18. In step S18, the guidance control unit 9 switches to the map guidance mode and performs route guidance using the map guidance image. On the other hand, when a guidance target intersection exists in the route from the current position of the vehicle to the destination (Yes in step S15), the process proceeds to step S16. Subsequently, in step S16, the guidance control unit 9 calculates the distance from the current position of the vehicle to the next intersection to be guided. In the following, it is assumed that the guidance control unit 9 periodically calculates the distance from the current position of the vehicle to the guidance target intersection (for example, every 100 msec).

  Next, in step S17, the guidance control unit 9 determines whether the distance from the vehicle calculated in step S16 to the guidance target intersection is equal to or less than a guidance mode switching distance D1 (for example, 200 m). As a result of the determination, when the distance to the guidance target intersection has not reached the guidance mode switching distance D1 (No in step S17), the process proceeds to step S18. On the other hand, when the distance to the guidance target intersection has reached the guidance mode switching distance D1 (Yes in step S17), the process proceeds to step S19. In step S <b> 19, the necessity calculation unit 13 calculates a necessity indicating the necessity of displaying the road shape guide image superimposed on the photograph guide image.

  In addition, the guidance control unit 9 switches to the shooting guide mode and performs route guidance using the shooting image acquired by the image acquisition unit 1. Here, in the live-action guidance mode, as described above, the process of superimposing the guidance arrow on the live-action image (steps S1 to S4) and the process of superimposing the road shape guide image on the live-action image are performed, and the real-life image is displayed to the user. The guidance used is performed.

  In subsequent step S20, the necessity calculation unit 13 determines whether or not the necessity calculated in step S19 is equal to or greater than a threshold value T. As a result of the determination, when the calculated degree of necessity is larger than the threshold T or more (Yes in step S20), the process proceeds to step S21. In step S21, as in the example of FIG. 14A, the guidance control unit 9 displays a live-action guidance mode A in which a road shape guide image is superimposed and displayed together with a guidance graphic. On the other hand, if the calculated degree of necessity is less than the threshold T (No in step S20), the process proceeds to step S22. In step S22, as in the example of FIG. 14B, the guidance control unit 9 displays a live-action guidance mode B in which only a guide graphic is displayed without displaying a road shape guide image. 14A is a live-action guidance image in the live-action guidance mode A, and FIG.

  As described above, the road only when there is a great merit in displaying the road shape guide image by determining whether or not to superimpose the road shape guide image according to the necessity calculated by the necessity calculation unit 13. A shape guide image can be displayed. That is, a road shape guide image is displayed together with a guide figure at a highly difficult intersection such as an intersection that is close to another intersection or an intersection with a complicated shape (that is, an intersection where the user tends to go to the wrong road). By doing so, it is possible to obtain an effect that it is easy to grasp the course to be taken by using the road shape guide image as a clue. On the other hand, at intersections where the degree of difficulty is not so high, the road shape guide image is not displayed because the effect obtained by displaying the road shape guide image is small. Thereby, the amount of information displayed on the screen can be reduced and the visibility of the guidance display can be increased.

  In the above embodiment, when the distance to the guidance target intersection reaches a predetermined distance or less, the guide graphic indicating the direction in which the vehicle should travel is displayed. Along with the display of the guidance graphic, the user may be notified by voice from a voice output unit (not shown) that the vehicle is approaching the guidance target intersection. For example, a voice such as “200 m ahead, turn left” may be output. Further, when the distance between the vehicle position and the guidance target intersection reaches a predetermined distance, for example, a voice such as “Soon to the left” may be output from the voice output unit.

  In the above-described example, the necessity calculation unit 13 uses the approach degree and the shape complexity of the intersections before and after the guidance target intersection as elements for calculating the necessity degree. Only one of them may be used, or the degree of necessity may be calculated in consideration of other factors.

  For example, the necessity calculation unit 13 calculates the degree of shielding of the guidance target intersection by an obstacle such as a preceding vehicle in a live-action image captured in front of the vehicle, and calculates the degree of necessity based on the calculated degree of shielding. Also good. Specifically, when the front landscape is blocked by an obstacle (when the degree of shielding is high), it is difficult for the user to visually recognize the vicinity of the intersection, and it is highly necessary to display the road shape. Set the necessity to a high value. On the other hand, when there is little obstruction of the front scenery by the obstacle (when the degree of concealment is low), the user can confirm the road shape near the intersection with the naked eye, and the necessity of displaying the road shape guide image is low. Set to a low value.

  For example, with reference to FIG. 15, the case where the necessity calculation part 13 acquires the shielding degree of the guidance object intersection by obstructions, such as a preceding vehicle, in the real image which imaged the front of the vehicle is demonstrated.

  First, the necessity calculation unit 13 detects an obstacle such as a preceding vehicle in a live-action image obtained by imaging the front of the vehicle. Specifically, the necessity calculation unit 13 detects an area in which an obstacle such as a preceding vehicle is displayed (hereinafter referred to as a preceding vehicle area).

  Here, as a method for detecting the preceding vehicle area, there is a known method using a monocular camera or a stereo camera, and either may be used in the present embodiment. For example, as a vehicle detection method using a monocular camera, a method of referring to a luminance value (a method of acquiring a luminance value on a lane and detecting an obstacle on a road surface), a method of using a projective transformation image (2 There are a method for detecting a moving object by taking the difference between the projective transformation images between frames, a method for detecting the edge of a preceding vehicle (a method for detecting an obstacle by detecting edges in the horizontal and vertical directions), and the like. As a vehicle detection method using a stereo camera, a method of extracting the contour of a preceding vehicle from a distance image, a method of detecting an object having height information using stereo inverse projection transformation, and a road plane region are extracted. To detect obstacles on the road. Furthermore, as another detection method, road image data taken in a state where no preceding vehicle is present is stored in a storage unit (not shown) in association with position information, and an image acquisition unit is based on the positioning result of the positioning unit 2. It is also possible to detect the preceding vehicle by taking the difference between the photographed image acquired by 1 and the road image data corresponding to the current travel position.

  Based on the above-described method, the preceding vehicle area is detected based on the photographed image acquired by the image acquisition unit 1. Specifically, in FIG. 15, the area indicated by the oblique lines is a preceding vehicle area. FIG. 15 is a diagram for explaining the degree of shielding by an obstacle such as a preceding vehicle in a live-action image showing a state in front of the vehicle. Moreover, the necessity calculation part 13 calculates the area of the detected preceding vehicle area | region, and acquires the said area as a shielding degree by obstructions, such as a preceding vehicle, in the real image which imaged the front of the vehicle. When a plurality of preceding vehicle areas are present in a photographed image obtained by capturing the front of the vehicle, the sum of the areas of the plurality of preceding vehicle areas may be calculated, and the calculated area may be used as the shielding degree.

  In addition, in the live-action image obtained by capturing the front of the vehicle, the necessity level calculation unit 13 is an area that overlaps the preceding vehicle area (hereinafter referred to as an overlapping area) in an area where the guidance target intersection is displayed (hereinafter referred to as an intersection area). May be acquired as a degree of occlusion. Here, the intersection area is an area surrounded by a dotted line including a guidance target intersection and a predetermined range around it as in the example of FIG. 16A. Moreover, the necessity calculation part 13 detects a preceding vehicle area | region with the above-mentioned method, and detects the overlapping area | region of an intersection area | region and a preceding vehicle area (refer FIG. 16B). Thereby, the necessity calculation part 13 acquires the ratio of the overlapping area which occupies for an intersection area | region as a shielding degree. Further, the greater the overlap between the intersection area and the preceding vehicle area, that is, the larger the overlapping area, the greater the degree of shielding. When setting the intersection area, the position of a predetermined range around the intersection area may be changed according to the direction in which the vehicle should travel at the guidance target intersection. For example, when the vehicle turns to the right at the guidance target intersection, the intersection area is set so as to include many right sides of the guidance target intersection (see FIG. 16C). Thereby, it is possible to detect whether or not the right side of the guidance target intersection can be seen.

  As another method for calculating the degree of shielding, the degree of shielding may be determined based on whether or not the guidance route (in this case, the guidance route ahead from the guidance target intersection) is blocked. Absent. When the guide route is visible as shown in FIG. 17A, the user can easily recognize the road shape near the intersection, and the necessity of displaying the road shape guide image is low. Set to. On the other hand, when the guide route is blocked by an obstacle such as a building or a car as shown in FIG. 17B, it is difficult for the user to grasp the position and shape of the guide route, and the necessity to display the road shape is high. To set the necessary degree to a high value.

  Whether or not the guide route is blocked is obtained by searching for an edge of the guide route by image recognition. That is, if an edge can be extracted, it is considered that there is no shielding, and if an edge cannot be extracted, it is considered that there is shielding. When searching for an edge of a guide route, a range where the guide route is expected to be reflected is calculated based on the result of the above-described projection processing (see FIG. 18), and an edge is extracted using that range as a search range. Do.

  Further, the necessity degree calculation unit 13 may determine the degree of necessity according to the distance from the own vehicle to the guidance target intersection. In general, when the guidance target intersection is away from the own vehicle, it is only necessary to know rough information about how many meters from the intersection to the intersection, and detailed guidance information is not necessary. On the other hand, as the guidance target intersection approaches, detailed guidance information such as which intersection is to be bent and the shape of the intersection is required. Therefore, when the guidance target intersection is more than a predetermined distance from the own vehicle, the necessity degree is set to a low value and the road shape guide image is not displayed. On the other hand, when the distance from the host vehicle to the guidance target intersection is less than or equal to a predetermined distance, the road shape guide image may be superimposed and displayed with a high necessity level.

  On the other hand, since the guidance target intersection shape is generally visible immediately before the guidance target intersection (for example, 30 m before the guidance target intersection), the road shape guide image is displayed when the distance to the guidance target intersection approaches. You may control so that it may not superimpose.

(Second Embodiment)
The navigation device of the first embodiment described above controls whether or not to display a road shape guide image based on the degree of approach and the shape complexity of the intersections before and after the guidance target intersection. The navigation device according to the second embodiment to be described below controls whether or not to display a road shape guide image according to the presence or absence of landmark guidance described later. Note that the configuration of the navigation device 200 according to the second embodiment is the same as that of the first embodiment, and the description thereof will be omitted. Also, the flowchart showing the flow of the operation of the navigation device according to the second embodiment is the same as that of the first embodiment, and is not shown. Further, the control unit 16 includes each unit included in the control unit 6 and a landmark guide generation unit 14.

  In the second embodiment, the map DB 3 further stores information about facilities such as stores. Further, as in the example of FIG. 20, the facility data includes facility location information, facility name, convenience store, restaurant type such as restaurant, and facility ID.

  The landmark guide generation unit 14 refers to the information that serves as a clue to specify the intersection to be turned in the live-action guidance mode, that is, the facility data described above, and displays landmarks around the guidance target intersection in a CG manner or emphasized. Display (landmark guidance). Here, description will be made assuming that landmark guidance is performed by CG display.

  Next, a specific operation of the landmark guidance generation unit 14 will be described. First, the landmark guidance generation unit 14 refers to the map DB 3 and selects a landmark used for landmark guidance. Here, a traffic light near the guidance target intersection or a facility near the guidance target intersection (for example, within 50 m) is selected as the landmark. Note that a plurality of landmarks may be selected and used as landmarks used for landmark guidance, or only one landmark may be selected.

  Next, the landmark guidance generation unit 14 arranges a three-dimensional object representing the size and shape of the landmark on the three-dimensional map in order to display the CG indicating the selected landmark on the live-action guidance image. Next, as described above, by performing projection conversion on the camera screen shown in FIG. 5, it is possible to superimpose a CG indicating that the landmark exists at an appropriate position on the live-action guide image. .

  FIG. 21 shows a guidance screen when performing landmark guidance. As shown in FIG. 21, landmark information in the vicinity of intersections such as traffic lights (landmark A) and facilities (landmark B) is displayed on the guide graphic in a CG manner and superimposed on the live-action guide image. Thus, the user can easily recognize an intersection that should be turned with the landmark as a clue, such as “turn right at an intersection with the next traffic light” or “turn right at an intersection with a convenience store”.

  Further, as described above, the landmark guidance method is not limited to CG display, and a landmark reflected in a live-action image may be highlighted. First, the location and shape of the facility are set on the three-dimensional map. The location and shape of the facility may be those stored in the map DB 3, or may be set to an appropriate shape when the shape of the facility is not stored in the map DB. Next, the facility arranged on the three-dimensional map is projected and converted on the camera screen in the same manner as the above-described processing for CG display. Thereby, the area | region where the object facility is reflected can be specified. Finally, an object for highlighting the specified area is drawn. For example, as shown in FIG. 22, highlighting may be performed by superimposing a circular figure surrounding a target landmark, or by superimposing a semi-transparent object. When highlighting in this way, as in the case of CG display, the user can easily recognize an intersection to be bent with a landmark as a clue.

  Further, the necessary degree calculating unit 13 may set the necessary degree depending on whether or not a landmark is selected by the landmark guidance generating unit 14, that is, whether or not there is a landmark for performing landmark guidance. Good. When there is a landmark for performing the landmark guidance, the landmark guidance allows the user to easily identify the intersection to be turned, so there is no need for other auxiliary guidance information such as road shape data. Lower. On the other hand, when there is no landmark for performing landmark guidance, auxiliary guidance information such as road shape data is important for identifying an intersection. Accordingly, the necessity level calculation unit 13 sets the necessity level to a low value when there is a landmark for performing landmark guidance, and sets the necessity level to a high value when it does not exist. As a result, when the landmark guidance is performed, the road shape guide image is not superimposed and displayed only when the landmark guidance cannot be performed.

  In addition, although several examples have been exemplified above regarding the calculation of the necessary degree, the present invention is not limited to these, and the above-described elements for calculating the necessary degree may be used alone, or some of them may be calculated. Or you may calculate combining all.

  In the present invention, the guide shape course guide is described as being superimposed on the actual image captured by the camera facing the front of the vehicle. However, it is acquired by the actual image or communication stored in the storage medium in advance. The guide shape course guide may be superimposed and displayed on the captured real image.

  Moreover, although this invention was demonstrated in detail, the said description is an illustration in all the meanings, and is not restrictive. Of course, many other modifications and variations are possible without departing from the scope of the invention.

  The navigation device according to the present invention is useful, for example, as a car navigation device installed in a vehicle, a navigation device in a mobile terminal such as a mobile phone, a drive simulator that simulates driving, or a game.

Functional block diagram showing the configuration of the navigation device according to the first embodiment The figure which shows an example of node data among the map information stored in map DB3 which concerns on 1st Embodiment. The figure which shows an example of interpolation data among the map information stored in map DB3 which concerns on 1st Embodiment. The figure which shows an example of link data among the map information stored in map DB3 which concerns on 1st Embodiment. The figure which shows an example of the map represented using node data, interpolation node data, and link data The flowchart which shows the flow of the operation | movement which produces | generates the guidance figure in the shooting guide production | generation part 11, and a shooting guide image Diagram for explaining how to determine the camera viewing space The figure which shows a mode from the upper direction with respect to a vehicle advancing direction about a three-dimensional map and camera visual field space The figure for explaining how to obtain the shape and arrangement position of the guide figure Display example of live-action guidance image according to the first embodiment The figure for explaining how to obtain the arrangement position of the road shape guide Display example of road shape guide image superimposed on live-action guide image The figure which shows an example of the shape of the intersection which consists of four roads The figure which shows an example of the shape of the intersection which consists of five roads Diagram for explaining how to calculate connection angle The flowchart which shows the flow of operation | movement of the navigation apparatus concerning this invention. Display example of live-action guide image in live-action guide mode A Display example of live-action guide image in live-action guide mode B The figure for demonstrating the shielding degree by obstructions, such as a preceding vehicle, in the real image which shows the mode of the front of a vehicle Diagram for explaining the intersection area Diagram for explaining overlap area and how to find it The figure for demonstrating the intersection area set when turning to the guidance intersection at the right Example of displaying a live-action guidance image when the guide route is not occluded Display example of live action guide image when guide route is blocked The figure for demonstrating the search area | region of the edge of a guide route Functional block diagram showing a configuration of a navigation device according to the second embodiment The figure which shows an example of the facility data memorize | stored in map DB Display example of live-action guidance image when CG display according to the second embodiment is used Display example of live-action guidance image when highlighting according to the second embodiment is used

Explanation of symbols

1 Image acquisition unit 2 Positioning unit 3 Map DB
DESCRIPTION OF SYMBOLS 4 Operation input part 5 Display part 6, 16 Control part 7 Own vehicle position determination part 8 Route search part 9 Guidance control part 10 Map guidance production | generation part 11 Live-action guidance production | generation part 12 Road shape guide production | generation part 13 Necessity calculation part 14 Landmark Guidance generator 100, 200 Navigation device

Claims (13)

A navigation device that provides route guidance by displaying a live-action image showing a state in front of a vehicle on a screen,
A live-action guide generating unit for generating a live-action guide image using the live-action image;
A road shape guide generating unit for generating a road shape guide image indicating the shape of the road displayed in the live-action guide image;
A necessity calculation unit for calculating a necessity indicating the degree of necessity of display of the road shape guide image;
A guidance control unit that superimposes and displays the road shape guide image generated by the road shape guide generation unit on the live-action guide image generated by the real-life guide generation unit based on the necessity calculated by the necessity calculation unit. And a navigation device.   The necessity calculation unit is configured to determine a distance between the guidance target intersection and an intersection just before the guidance target intersection and / or a distance between the guidance target intersection and one intersection on the back side of the guidance target intersection. The intersection degree calculating unit that calculates the degree of approach according to the information, and the degree of necessity is calculated based on the degree of approach calculated by the intersection degree calculating unit. Navigation device.   The necessity calculation unit includes a complexity calculation unit that calculates complexity indicating the complexity of the shape of the guidance target intersection, and calculates the necessity based on the complexity calculated by the complexity calculation unit. The navigation device according to claim 1, wherein:   The navigation device according to claim 3, wherein the complexity calculation unit calculates the complexity based on the number of roads connected to the guidance target intersection.   The complexity calculation unit calculates the complexity based on an angle between a road on which the host vehicle is currently traveling and a road on which the host vehicle is to travel at the guidance target intersection. The navigation device according to claim 3 or claim 4.   The necessary degree calculating unit includes a shielding degree calculating unit that calculates a shielding degree due to an obstacle in the vehicle front direction in the photographed image, and calculates the necessity degree based on the shielding degree calculated by the shielding degree calculating unit. The navigation device according to claim 1, wherein:   The shielding degree calculating unit calculates, as the shielding degree, a ratio of an area overlapping the obstacle in an intersection area that is an area where a guidance target intersection is displayed in the photographed image. The navigation device according to claim 6.   The necessity calculation unit includes a guidance target intersection determination unit that determines whether or not all or part of an intersection area that is an area where a guidance target intersection is displayed is included in the photographed image. The navigation device according to claim 1, wherein the degree of necessity is calculated based on the determination result of the target intersection determination unit.   The necessity calculation unit includes a distance calculation unit that calculates a distance from the current position of the host vehicle to a guidance target intersection, and calculates the necessity based on the distance calculated by the distance calculation unit. The navigation device according to claim 1, wherein the navigation device is characterized.   The degree-of-necessity calculation unit includes a guidance target object determination unit that determines whether or not the guidance target object serving as a landmark of the guidance target intersection exists around the guidance target intersection. The navigation device according to claim 1, wherein the degree of necessity is calculated based on the determination result.   The live-action guidance generation unit generates an image indicating the guidance target object when the guidance target object determination unit determines that the guidance target object is present around the guidance target intersection, and the image is displayed as the live-action guide The navigation apparatus according to claim 10, further comprising a landmark guide generation unit that generates a live-action guide image superimposed on an image. A navigation method for a navigation device that displays a live-action image showing a state in front of a vehicle and performs route guidance,
A live-action guide generating step for generating a live-action guide image using the live-action image;
A road shape guide generating step for generating a road shape guide indicating the shape of the road displayed in the live-action guide image;
A necessity calculation step of calculating a necessity indicating the degree of necessity of display of the road shape guide image;
A guidance control step of superimposing and displaying the road shape guide image generated in the road shape guide generation unit on the live-action guide image generated in the live-action guide generation step based on the necessity calculated in the necessity level calculation step. And a navigation method. There is a navigation program for a navigation device that performs route guidance by displaying on the screen a live-action image that shows the situation in front of the vehicle,
In the computer of the navigation device,
A live-action guide generating step for generating a live-action guide image using the live-action image;
A road shape guide generating step for generating a road shape guide indicating the shape of the road displayed in the live-action guide image;
A necessity calculation step of calculating a necessity indicating the degree of necessity of display of the road shape guide image;
Guidance control step of superimposing and displaying the road shape guide image generated in the road shape guide generation unit on the live-action guide image generated in the live-action guide generation step based on the necessity calculated in the necessity level calculation step And a navigation program to execute.

Images