JP3619076B2 - Navigation device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a navigation device that displays a map image around a vehicle position.
[0002]
[Prior art]
In general, a vehicle-mounted navigation device detects the current position of a vehicle, reads map data in the vicinity thereof from a data storage medium such as a CD or DVD, and displays the data on a screen. In addition, a vehicle position mark indicating the vehicle position is displayed in the center of the screen, and a map image of the neighborhood is scrolled as the vehicle progresses around the vehicle position mark, so that map information around the vehicle position is always known. It is like that.
[0003]
Recently, a method of displaying a map image of the traveling direction of the vehicle as a bird's eye view with a predetermined position above the own vehicle position as a viewpoint position has been widely used. In this way, when displaying as a bird's eye view, an image closer to the scenery that the driver actually sees is displayed than when displaying a map image in a two-dimensional manner (two-dimensional). There is an advantage that the traveling direction of the own vehicle can be easily confirmed.
[0004]
[Problems to be solved by the invention]
By the way, when the map information around the own vehicle position is displayed as a bird's eye view as described above, the map drawing data obtained when the forward direction of the vehicle is viewed obliquely from the viewpoint position above the own vehicle position is generated. There is a need to. In general, this map drawing data is obtained by performing a predetermined projection conversion. In order to generate map drawing data that changes every moment according to the progress of the vehicle position, this projection conversion is performed at predetermined time intervals. Therefore, there is a problem that the processing load required for drawing a map image is larger than that when generating two-dimensional map drawing data.
[0005]
The present invention was created in view of the above points, and an object of the present invention is to provide a navigation device that can reduce the processing load required for drawing.
[0006]
[Means for Solving the Problems]
In order to solve the above-described problem, the navigation device of the present invention has a convex center at the map drawing unit based on the map data necessary for the two-dimensional map image display stored in the map data storage unit. Map drawing data in which a horizon having a curved shape is arranged at the top of the screen is generated, and a map image is displayed by the display means based on the generated map drawing data. Since map drawing data having a horizon curved in a convex shape is generated based on map data necessary for two-dimensional map image display, complicated processing such as projection conversion is unnecessary, and the processing load required for drawing is reduced. Can be reduced. In particular, by displaying a rounded horizon, it is possible to easily obtain an image overlooking from the vicinity of the own vehicle position to a distant place, and it is possible to increase variations of map images that can be selected by the user.
[0007]
Further, the map drawing means generates distant view drawing data in which at least one of mountains and clouds and the sky are drawn above the horizon, and the map based on the map drawing data below the horizon with the display means. It is desirable to display an image and a distant view image based on the distant view drawing data on the upper side. By placing clouds and mountains in the distant view, a more realistic map image can be obtained.
[0008]
The map drawing means described above preferably generates map drawing data having a height set according to the display scale of the map image for the building included in the map image. Alternatively, the map drawing means described above desirably sets the curvature of the horizon included in the map drawing data variably according to the display scale of the map image. By changing the height of the building and the curvature of the horizon according to the display scale, the sense of reality of the map image can be further increased.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a navigation device according to an embodiment to which the present invention is applied will be described with reference to the drawings.
[0010]
(1) Overall Configuration of Navigation Device FIG. 1 is a diagram showing an overall configuration of an in-vehicle navigation device according to an embodiment to which the present invention is applied. The navigation device shown in FIG. 1 includes a navigation controller 1 that controls the whole, a DVD 2 that records various map data necessary for map display, route search, and the like, and a disk reader 3 that reads the map data recorded on the DVD 2. A remote control (remote control) unit 4 as an operation unit for a user to input various instructions, a GPS receiver 5 and an autonomous navigation sensor 6 for detecting the vehicle position and vehicle direction, a map image, and this And a display device 7 for displaying information on intersections.
[0011]
The disk reader 3 described above can be loaded with one or more DVDs 2 and reads map data from any of the DVDs 2 under the control of the navigation controller 1. The loaded disc is not necessarily a DVD but may be a CD. Further, both DVD and CD may be selectively loaded.
[0012]
The remote control unit 4 includes a search key for giving a route search instruction, a route guidance mode key used for setting the route guidance mode, a destination input key, left / right / up / down cursor keys, a map reduction / enlargement key, and a cursor on the display screen. Various operation keys such as a setting key for determining an item at a position are provided, and an infrared signal corresponding to the operation state of the key is transmitted to the navigation controller 1.
[0013]
The GPS receiver 5 receives radio waves transmitted from a plurality of GPS satellites, performs a three-dimensional positioning process or a two-dimensional positioning process, and calculates the absolute position and direction of the vehicle (the vehicle direction is determined by the current vehicle). Calculated based on the position and the vehicle position before one sampling time ΔT), and these are output together with the positioning time. The autonomous navigation sensor 6 includes an angle sensor such as a vibration gyro that detects the vehicle rotation angle as a relative direction, and a distance sensor that outputs one pulse for each predetermined travel distance. Detect orientation.
[0014]
Based on the image data output from the navigation controller 1, the display device 7 displays map information around the host vehicle together with a departure point mark, a destination mark, and the like, or displays a guidance route on this map.
[0015]
(2) Detailed Contents of Map Data Next, details of the map data recorded on the DVD 2 will be described. The map data recorded on the DVD 2 is in units of rectangular leaves separated by a predetermined longitude and latitude, and the map data of each leaf is specified and read by designating the leaf number. It becomes possible. FIG. 2 is a diagram showing the contents of the map data for each figure. As shown in FIG. 2, map data for each map leaf includes: (1) a drawing unit composed of various data necessary for map display; and (2) various processes such as map matching, route search, route guidance, and the like. Road units composed of necessary data and (3) intersection units composed of detailed data such as intersections. The drawing unit described above includes background layer data necessary for displaying buildings, rivers, and the like, and character layer data necessary for displaying city names, road names, and the like.
[0016]
FIG. 3 is a diagram showing the detailed contents of the intersection unit. As shown in FIG. 3, the intersection unit constitutes an intersection for each intersection, an intersection record including data regarding the intersection itself, an intersection direction information record including data regarding a road destination extending from the intersection, and the like. An intersection lane information record including data relating to each lane of the road is stored.
[0017]
Each intersection record corresponds to each of the existing intersections as shown in FIG.
a. "Intersection information flag" consisting of a signal flag indicating whether or not there is a signal at this intersection,
b. "Number of intersections" indicating how many differences this intersection is,
c. Display coordinates when displaying the intersection name,
d. Intersection name string to be displayed,
e. The storage location of the link ID of each link constituting this intersection and the intersection direction information record corresponding to this link (for the number of intersection differences),
Etc. are included.
[0018]
(3) Detailed Configuration and Operation of Navigation Controller Next, the detailed configuration of the navigation controller 1 shown in FIG. 1 will be described. The navigation controller 1 includes a data buffer 16 for displaying a predetermined map image or the like on the display device 7, a map readout control unit 18, a display scale detection unit 20, a map drawing unit 22, a coordinate conversion unit 24, a distant view drawing unit 26, VRAM 28, image composition unit 30, vehicle position calculation, map matching processing, route search processing, route guidance processing and vehicle position calculation unit 32 for displaying the results, route search processing unit 34, guidance route drawing Unit 36, mark image drawing unit 38, remote control unit 60 for displaying various operation screens for the user and transmitting operation instructions from remote control unit 4 to each unit, cursor position calculation unit 62, operation screen generation unit 64 And.
[0019]
The data buffer 16 is for temporarily storing map data read from the DVD 2 by the disk reader 3. When the vehicle position calculation unit 30 calculates the vehicle position, the map read control unit 18 sends a read request for map data in a predetermined range including the vehicle position to the disk reading device 3, and a map necessary for map display. Data is read from the DVD 2 and stored in the data buffer 16.
[0020]
The display scale detection unit 20 detects a display scale when displaying a map image given by the user via the remote control unit 4. The display scale has a plurality of selection candidate values prepared in advance, and each time a wide-area key or detail key provided on the remote control unit 4 is pressed, it is one step smaller than the value set at that time, or A large value is selected.
[0021]
The map drawing unit 22 is necessary for displaying a map image around the vehicle position based on the drawing unit included in the map data stored in the data buffer 16 and the display scale detected by the display scale detection unit 20. Create a map drawing data of dimensions. Further, when creating the map drawing data, the map drawing unit 22 has a substantially constant thickness in the height direction in order to show the height of the building in a pseudo manner, and is detected by the display scale detection unit 20. The thickness is variably set according to the displayed scale. For example, this thickness (building height) is set larger as the display scale is larger, and conversely, this thickness is set smaller as the display scale is smaller.
[0022]
The coordinate conversion unit 24 performs predetermined coordinate conversion processing on the map drawing data created by the map drawing unit 22, and a map drawing in which a horizon having a curved shape with a convex center is arranged at the top of the screen. Create data. The curvature of the horizon described above corresponds to the display scale. The larger the display scale, the smaller the horizon curvature, and the smaller the display scale, the larger the horizon curvature. That is, when performing detailed display, a horizon shape that is closer to a straight line is set, and a horizon shape that has a smaller radius is set as the display becomes wider. A specific example of the coordinate conversion process performed by the coordinate conversion unit 24 will be described later.
[0023]
The distant view drawing unit 26 creates distant view drawing data for drawing mountains, clouds, sky, and the like above the horizon included in the map image. The distant view drawing unit 26 of the present embodiment reads out map data corresponding to a distance in the traveling direction of the own vehicle based on the traveling direction of the own vehicle obtained by the vehicle position calculating unit 32 and creates distant view drawing data. Yes. For example, when there is a mountain far away in the direction of travel of the vehicle, a distant view drawing data consisting of a blue sky containing mountains and clouds is created, and when there is no mountain far away, circular drawing data consisting of clouds and blue sky is created. Created.
[0024]
Both the map drawing data created by the coordinate conversion unit 24 and the distant view drawing data created by the distant view drawing unit 26 are stored in the VRAM 28 and read by the image composition unit 30. The image composition unit 30 performs image composition by superimposing the map drawing data and the distant view drawing data read from the VRAM 28 and the image data output from each of the guide route drawing unit 36, the mark image drawing unit 38, and the operation screen generating unit 64. Do. The image synthesized by the image synthesis unit 30 is displayed on the screen of the display device 7.
[0025]
The vehicle position calculation unit 32 calculates the vehicle position based on the detection data of the GPS receiver 5 and the autonomous navigation sensor 6, and if the calculated vehicle position is not on the road of the map data, the vehicle position calculation unit 32 calculates the vehicle position. A map matching process for correcting the position is performed. The route search processing unit 34 searches for a travel route that connects a preset destination and departure place under a predetermined condition. For example, a guide route with the minimum cost is set under various conditions such as the shortest distance and the shortest time. As a typical method of route search, Dijkstra method and horizontal search method are known. The guide route drawing unit 36 generates guide route drawing data for drawing the guide route set by the route search processing unit 34 on the map image. The mark image drawing unit 38 generates a vehicle position mark at the own vehicle position after the map matching process, or generates a cursor mark having a predetermined shape.
[0026]
The data buffer 16 described above is displayed on the map data storage means, the display scale detection unit 20, the map drawing unit 22, the coordinate conversion unit 24, and the distant view drawing unit 26 are displayed on the map drawing unit, and the VRAM 28, the image composition unit 30 and the display device 7 are displayed. Each means corresponds.
[0027]
The entire navigation device and the navigation controller 1 have the above-described configuration. Next, specific examples of the coordinate conversion processing performed in the coordinate conversion unit 24 described above will be described. FIG. 5 is a diagram showing an outline of the coordinate conversion process. First, the map drawing unit 22 generates map drawing data corresponding to a rectangular map image as shown in FIG. This map drawing data includes an area (1) that is reduced in the vertical direction of the display screen and an area (2) that is not reduced.
[0028]
Next, the coordinate conversion unit 24 performs coordinate conversion for reducing only the map drawing data included in the region (1) in the vertical direction. Specifically, as shown in FIG. 5B, a reduction process in which the reduction ratio is the smallest in the vicinity of the central portion and the reduction ratio increases toward the left and right is centered on the lower side of the region (1). As a result, the display position (coordinates) of each pixel included in the region (1) is converted. As a result, the upper side of the area (1) is converted into a curved shape corresponding to an ellipse or a part of a circle, and map drawing data corresponding to the area (1) 'where the horizon appears by the upper side of the curved shape is created. The
[0029]
As described above, in this embodiment, map rendering data having a horizon curved in a convex shape is generated by performing predetermined coordinate transformation on map rendering data necessary for two-dimensional map image display. Thus, it is not necessary to perform processing such as projection conversion, and the burden of processing required for drawing can be reduced.
[0030]
By the way, as shown in FIG. 5C described above, in the map image displayed based on the map drawing data after the coordinate conversion processing by the coordinate conversion unit 24, nothing is displayed above the horizon. However, in this portion, a distant view image based on the distant view drawing data created by the distant view drawing unit 26 described above is arranged and displayed.
[0031]
Next, an operation procedure when displaying a map image around the vehicle position in the navigation device of the present embodiment will be described. FIG. 6 is a flowchart showing an operation procedure when a map image is displayed. First, the display scale detection unit 20 detects the display scale set by the user (step 100). The map reading control unit 18 sends an instruction to the disc reading unit 3 to read out map data corresponding to a predetermined number of sheets, with the vehicle position calculated by the vehicle position calculation unit 32 as the center. In accordance with this instruction, the disk reading unit 3 reads the map data from the DVD 2 and stores the read map data in the data buffer (step 101).
[0032]
Next, the display scale detection unit 20 determines whether or not the display scale setting has been changed (step 102). If the display scale has been changed, the display scale detection operation and subsequent steps in step 100 are repeated. If there is no change in the display scale, a negative determination is made in the determination process of step 102, and then the map drawing unit 22 uses the map data read from the data buffer 16 to display the display scale at that time. Map drawing data around the own vehicle position corresponding to is generated (step 103). In this map drawing data, the height of the building is set according to the display scale, and when the display scale is changed, the height of the building is also changed at the same time.
[0033]
Next, the coordinate conversion unit 24 performs the coordinate conversion process schematically shown in FIG. 5 on the map drawing data created by the map drawing unit 22 (step 104). The map image data that has been subjected to the coordinate conversion processing by the coordinate conversion unit 24, that is, the map image data in which the curved horizon line having a convex center is arranged at the top of the screen is stored in the VRAM 28. Next, the distant view drawing unit 26 creates distant view drawing data including a cloud or a mountain in addition to a cloud based on the display scale detected by the display scale detecting unit 20 (step 105). This distant view drawing data is stored in the VRAM 28. In addition, about the order which performs each process shown by the steps 103-105 mentioned above, it is not limited to this order in particular, It can replace arbitrarily. Moreover, you may make it perform the process of steps 103-105 simultaneously.
[0034]
Next, the image combining unit 30 combines the map drawing data and the distant view drawing data read from the VRAM 28 with various drawing data created by the mark image drawing unit 38 and the like, and an image obtained by the combining is displayed on the display. 7 is displayed (step 106). Thereafter, the process returns to step 102, and the operations after the determination process of whether or not there is a display scale change are repeated.
[0035]
FIG. 7 is a diagram illustrating an example of a map image displayed in the navigation device of the present embodiment. In FIG. 7, an image 100 shows a vehicle position mark indicating the own vehicle position, an image 110 shows a horizon, and an image 120 shows an example of a building having a height corresponding to the display scale. Further, the display area above the horizon corresponds to a distant view image, and an image 130 corresponding to a mountain (a hatched portion) and a plurality of images 140 corresponding to clouds are arranged. Further, in the distant view image area, portions other than the mountain (image 130) and the cloud (image 140) indicate the sky. As shown in FIG. 7, by arranging a horizon (image 110) having a curved shape with a convex center at the top of the screen, a map image having an atmosphere overlooking from the vicinity of the vehicle position to a distant place can be easily obtained. Can be obtained. In particular, a distant view image in which mountains, clouds, and sky are drawn is displayed on the upper side of the image 110 corresponding to the horizon, and a building having a height (such as the image 120) is displayed, thereby accurately projecting. It is possible to display a map image with a sense of presence similar to the case where the bird's eye view is displayed after conversion.
[0036]
As described above, the navigation device of the present embodiment has a horizon line having a curved shape with a convex center at the top of the screen based on map data necessary for two-dimensional map image display. A map image in which a distant view image in which mountains, clouds, and sky are drawn is arranged on the upper side is displayed. By displaying the rounded horizon in this way, it is possible to easily obtain an image having an atmosphere overlooking from the vicinity of the vehicle position to the distant place. In addition, a distant view image including mountains, clouds, sky, and the like is arranged on the upper side of the horizon, so that a realistic map image can be obtained. In particular, since the map drawing data including the horizon described above is created by performing a simple coordinate conversion process on a two-dimensional map image, complicated processing such as projection conversion is unnecessary, and map drawing is not necessary. The necessary burden can be reduced. Further, in the present embodiment, the height of the building and the curvature of the horizon included in the map image are changed corresponding to the display scale, and a more realistic map image can be displayed.
[0037]
In addition, this invention is not limited to the said embodiment, A various deformation | transformation implementation is possible within the range of the summary of this invention. For example, in the above-described embodiment, as shown in FIG. 5, after generating map image data corresponding to two areas (1) and (2), only the part corresponding to one area (1) is applied. However, as shown in FIG. 8, coordinate conversion may be performed by dividing into three (or more) regions as shown in FIG. By increasing the number of regions, the scale can be gradually reduced from the vicinity of the vehicle position toward the horizon, so that a more natural perspective can be obtained. Further, as shown in FIG. 9, the area image (1) is further reduced in the horizontal direction and then reduced in the vertical direction, whereby the sense of reality of the map image can be further increased.
[0038]
In the above-described embodiment, a map image having an atmosphere similar to that obtained when bird's-eye view display is performed can be obtained by performing simple coordinate conversion processing on two-dimensional map drawing data. By combining the three-dimensional display of the intersection guidance with the image, the stereoscopic effect of the map image can be further increased. FIG. 10 is a diagram illustrating a display example when a guide image is displayed for up to two intersections along the guidance route. The intersection guidance information provided corresponding to the two intersections included in FIG. 10 is created based on the detailed information of the intersection unit shown in FIG. 3 and the detailed information of the intersection record shown in FIG. In the display example shown in FIG. 10, the intersection guide information is displayed so as to correspond to the two intersections that first pass along the guidance route. For the above, similar intersection guidance information may be created and displayed.
[0039]
【The invention's effect】
As described above, according to the present invention, based on the map data necessary for displaying a two-dimensional map image, map drawing data in which the horizon having a curved shape with a convex center is arranged at the top of the screen is generated. In addition, since complicated processing such as projection conversion is unnecessary, it is possible to reduce the processing load required for drawing.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating an overall configuration of an in-vehicle navigation device according to an embodiment.
FIG. 2 is a diagram showing the contents of map data for each figure.
FIG. 3 is a diagram showing detailed contents of an intersection unit.
FIG. 4 is a diagram showing detailed contents of an intersection record.
FIG. 5 is a diagram showing an outline of a coordinate conversion process.
FIG. 6 is a flowchart showing an operation procedure when a map image is displayed.
FIG. 7 is a diagram showing an example of a map image displayed in the navigation device of the present embodiment.
FIG. 8 is a diagram showing a modification of the coordinate conversion process.
FIG. 9 is a diagram illustrating another modification of the coordinate conversion process.
FIG. 10 is a diagram showing a display example of a map image combined with an intersection guidance display.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Navigation controller 7 Display apparatus 16 Data buffer 20 Display scale detection part 22 Map drawing part 24 Coordinate conversion part 26 Distant view drawing part 28 VRAM
30 Image composition part

Claims (4)

Map data storage means for storing map data necessary for two-dimensional map image display;
Based on the map data, a map drawing unit for creating two-dimensional rectangular map drawing data necessary to display a map image around the vehicle position ;
By gradually reducing the reduction rate as approaching both ends in the horizontal direction, by performing coordinate conversion processing to move the display coordinates in the vertical direction of each pixel constituting the map image around the lower side of the rectangular shape, A coordinate conversion unit for generating map drawing data in which a curved horizon line having a convex center corresponding to the upper side of the rectangular shape before the coordinate conversion process is arranged below the upper side of the screen;
Display means for displaying a map image based on the map drawing data generated by the coordinate converter ;
A navigation device comprising: In claim 1,
The navigation device, wherein the coordinate conversion unit performs the coordinate conversion processing on the uppermost region when the display screen is divided into a plurality of regions along the vertical direction. In claim 2,
The coordinate conversion unit gradually sets the reduction rate to be closer to the upper side of the rectangular shape, and sets the horizontal display coordinates of each pixel constituting the map image with reference to the center along the horizontal direction of the rectangular shape. A navigation apparatus characterized by performing a coordinate conversion process for movement. In any one of Claims 1-3,
Based on the map data, when it is determined that there is a mountain in the traveling direction of the vehicle, it generates distant view drawing data consisting of a blue sky including mountains and clouds, and there is no mountain in the traveling direction of the vehicle A far-field drawing unit that generates far-field drawing data composed of a cloud and a blue sky when determined ,
The navigation device displays a map image based on the map drawing data on the lower side and a distant view image based on the distant view drawing data on the upper side with the horizon as a boundary.

Images