JPH08285630A - Birds-eye displaying navigation system with function of contraction changing display - Google Patents

Abstract

PURPOSE: To appropriately display the information of a display reference point and its periphery changing a birds-eye view display scale in a short time, by performing the perspective projection transformation of the similar map information of a contraction level indicated by a user by a coordinate transformation parameter determined by a display reference point to which similarity transformation is applied. CONSTITUTION: A display reference point coordinate transformation part 106 performs the similarity transformation of a display reference point coordinate value on the basis of the contraction value which is arbitrarily or automatically determined in a display scale determining unit 105, and on the basis thereof, a display object region on map data and a coordinate transformation parameter required for perspective projection transformation are determined in a display region determining part 107. Next, a region corresponding to the similar map information of a corresponding contraction level is inputted from an external memory device 101 to an internal memory part 109 by data access 108 on the basis of the determined display object region and the contraction value. The similar map information of a corresponding contraction level is inputted by a map data transformation part 110 from the memory part 109 on the basis of the contraction value 105, and perspective projection transformation is performed by using a coordinate transformation parameter and image display 104 is performed through an image data output part 111.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bird's-eye view display navigation system, and more particularly, to changing the display scale of a map on the display screen while the display position of the display reference point such as the vehicle position is fixed. The present invention relates to a bird's-eye view display navigation system with a display scale changing function having a function.

[0002]

2. Description of the Related Art As a conventional bird's-eye view display navigation system, there is, for example, Japanese Patent Application No. 6-34202 “Navigation system with a bird's-eye view display function” filed by the present applicant. As shown in FIG. 4, this system includes an external storage device 401 that stores map information, a display reference point determination device 402 that determines a reference point for determining a display area on a map, and a bird's eye view. An arithmetic processing unit 403 that performs a predetermined arithmetic process necessary for display and an image display unit 404 that displays a map image are configured.

When the arithmetic processing unit 403 is further broken down by function, as shown in the figure, the display target area on the map to be displayed and the coordinate conversion parameters necessary for perspective projection conversion are determined according to the output of the display reference point determining unit 402. A display area determination unit 405, a data access unit 406 that selects and reads the map information required for display from the external storage device 401 based on the determined display target area, and an internal storage that stores the read map data. 407, a map data coordinate conversion unit 408 for performing perspective projection conversion on the stored map data, and the image display device 404 for the converted map data.
And an image data output unit 409 for outputting to

The operation of the above configuration will be described. Generally, the map display of the navigation system is executed by repeating a series of procedures as shown in FIG. First, in step S501, the display area determination unit 405 sets the display reference point and the line-of-sight direction according to the output of the display reference point determination device 402, and determines the area on the map plane to be displayed (display target area). , Calculate the coordinate transformation matrix (coordinate transformation parameter) required for perspective projection transformation.

The display reference point and the line-of-sight direction will be described with reference to FIG. In the bird's-eye view display, the display target area is an isosceles trapezoid ABCD as shown.
It is assumed that the map information is defined here on the xy plane in the three-dimensional Cartesian coordinate system (x, y, z), and the viewpoint V is above the map plane and at a point of height h at the depression angle θ on the ground. Suppose you are looking down. It should be noted that the height h and the depression angle θ can be appropriately changed as necessary, but here they are fixed values for simplicity.

The display screen is placed perpendicular to the line of sight and describes a position on the screen in a two-dimensional plane coordinate system (x
s, ys) are defined as shown in the figure. Since it is general to display the vicinity of the current position of the host vehicle, for example, the host vehicle position Pc is always (0, -yc) as shown in the figure.
The position of the display target area must be determined so that it is displayed at the point. Alternatively, the point Pc may be one of the points registered in advance by the user, and the vicinity thereof may be displayed by the operation of calling the registered point by the user. In any case, in order to determine the position of the display target area on the map, a fixed point (0, -y
It is necessary to match c) with the position of the host vehicle. The point on the map corresponding to this fixed point is called a display reference point. As an example of the display reference point determination device 402, a GPS sensor that measures and outputs the current position of the host vehicle can be considered.

In order to determine the display target area, in addition to Pc, the direction of the line of sight on the xy plane, that is, the angle formed by the symmetry axis of the trapezoid ABCD with respect to the x axis or the y axis is required. is there. Here, it is assumed that the information on the line-of-sight direction is also given from the display reference point determination device 402 as the current traveling direction of the vehicle.

Returning again to the flowchart of FIG. 4, the display area etc. determining unit 405 determines the display target area from the given display reference point, line-of-sight direction, and parameters such as height h and depression angle θ. Further, since the position of the viewpoint V is also determined, the coordinate conversion matrix that realizes perspective projection conversion is also calculated.

Next, in step S502, the data access unit 406 reads necessary map information from the external storage device 401 according to the determined display target area. At this time, if some or all of the necessary information is already stored in the internal storage 407, it is not necessary to read the duplication again.

Further, in step S503, the map data coordinate conversion unit 408 performs perspective projection conversion on the map data stored in the internal storage 407 by the previously obtained coordinate conversion matrix. Details of the perspective projection conversion are omitted here.

Then, in step S504, the image data output unit 40 is applied to the converted individual map data.
9 performs processing such as clipping as necessary and outputs it to the image display device 404. Finally, in step S505, it is determined whether or not to end the display procedure. If not, the same procedure is repeated from step S501.

In the bird's-eye view display displayed on the image display device 404 in this manner, the general so-called display scale is continuously changing on the screen, and the display is enlarged near the viewpoint and reduced at a distance from the viewpoint. The scale distribution is displayed. Therefore, there is an advantage that both detailed information in the vicinity and wide area information up to the distant area can be obtained at the same time without switching the display scale.

[0013]

However, in the above-mentioned conventional bird's-eye view display navigation system, when it is desired to know a wider range of information or conversely to see the details in a more detailed manner, the information is continuously distributed on the screen. Although it is necessary to uniformly change the display scale that is present and to enlarge / reduce the size of the display target area in order to display the entire area as a bird's-eye view without any discomfort, in the above-mentioned conventional system, the display target area on the map is Since the size of is fixed, there was a problem that the display scale of the bird's-eye view could not be changed.

Further, for example, in a conventional bird's-eye view display navigation system, when the size of the display target area is simply enlarged / reduced so that the display scale of the bird's-eye view can be changed, However, there is a problem that the coordinate conversion of takes time and the processing time becomes long.

On the other hand, as a means for changing the display scale in the bird's-eye view display, for example, a method of changing the parameter h representing the height of the viewpoint V can be considered. Specifically, as shown in FIG. 7, if the viewing angle 2β and the line-of-sight depression angle θ are kept constant and only the height h of the viewpoint is changed, the display target area on the map is enlarged while maintaining a similar shape. By reducing the size of the map data and performing perspective transformation similar to the conventional one on the map data in this region, the target scale-changed image can be obtained.

However, in this method, the display position of the display reference point on the screen also moves. For example, in FIG. 7, the display reference point Pc in the enlarged display when the viewpoint is low
The position of ₁ deviates from the screen by raising the viewpoint. Further, the position of the display reference point Pc ₂ in the wide area display when the viewpoint is high moves away from the upper part of the screen by lowering the viewpoint. Although the display reference point is the point at which the user wants to know the details of the neighborhood, such as the current position of the vehicle, at that time, necessary information is lost by changing the height of the viewpoint. There is a problem.

Furthermore, a method for simply enlarging / reducing the size of the display target area and a parameter h indicating the height of the viewpoint V are used.
In this method, since the amount of map information in the external storage device that is the source of enlargement / reduction is constant, for example, the detailed information necessary for enlargement is insufficient, or unnecessary information is thinned out during reduction. There is also a problem that the processing time for this may increase.

The present invention has been made by paying attention to such conventional problems and problems expected to be solved against the problems, and it is possible to change the display scale of the bird's-eye view in a short time.
In addition, the objective is to be able to properly display the display reference point and its vicinity information when enlarging and reducing.

[0019]

In order to achieve the above object, a bird's-eye view display navigation system with a display scale changing function according to claim 1 has a plurality of similarities with different scale levels and information amounts as map information of the same area. An external storage means for storing map information, a display reference point determining means for determining a display reference point on the map, an arithmetic processing unit for performing arithmetic processing necessary for bird's eye view display, and an image display means for displaying map information, Display scale determining means for determining a scale value of the map information displayed by the image display means, and the arithmetic processing means further includes the display reference point determining means based on the scale value determined by the display scale determining means. On the basis of the display reference point coordinate conversion means for performing similarity conversion on the display reference point coordinate values determined in, and the display reference point subjected to similarity conversion by the display reference point coordinate conversion means, Based on the display target area on the map information and the coordinate conversion parameter necessary for perspective projection conversion, and the display target area determined by the determining means and the scale value determined by the display scale determining means. A map information input means for inputting a corresponding display target area of the similar map information of a corresponding scale level stored in the storage means, and an inside for storing the similar map information input by the map information input means for each scale level. Based on the storage means and the scale value determined by the display scale determination means, similar map information of the relevant scale level is input from the internal storage means, and perspective projection conversion is performed using the coordinate conversion parameters determined by the determination means. And image data output for outputting the similar map information after perspective projection conversion by the coordinate conversion means to the image display device. It is that a stage.

Further, in the bird's-eye view display navigation system with a display scale changing function according to claim 2, the display scale determining means determines the scale value based on the scale changing instruction inputted by the user, and causes the arithmetic processing means. It is what is output.

Further, in the bird's-eye view display navigation system with a display scale changing function according to claim 3, the display scale determining means automatically determines the scale value according to the moving speed of the vehicle, and the arithmetic processing unit. Is output to.

Further, in the bird's-eye view display navigation system with a display scale changing function according to claim 4, the display scale determining means automatically determines the scale value according to the attribute of the route on which the vehicle is currently traveling. Then, the data is output to the arithmetic processing unit.

Further, in the bird's-eye view display navigation system with a display scale changing function according to a fifth aspect of the present invention, the plurality of similar map information are described in a map coordinate system which has undergone similarity conversion in advance at different scales.

[0024]

In the bird's-eye view display navigation system with display scale changing function of the present invention (claim 1), in the arithmetic processing means, the display reference point coordinate converting means is based on the scale value determined by the display scale determining means. Similarity transformation is performed on the coordinate values, and the determining means determines the display target area on the map information and the coordinate transformation parameters necessary for perspective projection transformation based on the display reference points that have undergone the similarity transformation. When the corresponding display target area of the similar map information of the corresponding scale level stored in the external storage means is input based on the display target area determined by the determining means and the scale value determined by the display scale determining means, the internal Storage means
The input similar map information is stored for each scale level. Then, the coordinate transformation means inputs the similar map information of the relevant scale level from the internal storage means based on the scale value determined by the display scale determination means, performs perspective projection transformation using the coordinate transformation parameter, and outputs the image. The data output means outputs the similar map information after the perspective projection conversion to the image display device. As a result, the display scale of the map on the display screen is changed while the display position of the display reference point such as the position of the own vehicle on the screen is fixed. Further, a scale-changed bird's-eye view image in which the display reference points are fixed on the screen can be obtained with a smaller amount of calculation than the similarity conversion of the map information described in a single scale each time the scale is changed.

Further, in the bird's-eye view display navigation system with a display scale changing function of the present invention (claim 2), the display scale determining means determines the scale value based on the scale changing instruction inputted by the user, and the calculating means determines. By outputting, it is possible to select a bird's-eye view display with a display scale required according to the application without moving the position of the display reference point on the screen.

Further, in the bird's-eye view display navigation system with a display scale changing function of the present invention (claim 3), the display scale determining means automatically determines the scale value according to the moving speed of the host vehicle, and the arithmetic processing unit. By outputting to, the bird's-eye view display of an appropriate scale such as a wide scale when the vehicle is moving at high speed and a detailed scale when the vehicle is moving at low speed is automatically obtained. Also, the position of the display reference point on the screen is displayed without moving.

In the bird's-eye view display navigation system with a display scale changing function of the present invention (claim 4), the display scale determining means automatically sets the scale value according to the attribute of the route on which the vehicle is currently traveling. By determining and outputting to the arithmetic processing device, a bird's-eye view display of an appropriate scale, such as a wide-area scale when traveling on a main trunk line and a detailed scale when traveling on a narrow street, can be automatically obtained. Also,
For example, according to the legal speed of each track, a bird's-eye view display at an appropriate scale, such as a wide-area scale for traveling on a high-speed road and a detailed scale for traveling on a low-speed road, is automatically obtained as needed. Also, the position of the display reference point on the screen is displayed without moving.

Further, in the bird's-eye view display navigation system with a display scale changing function of the present invention (Claim 5), a plurality of similar map information are described in a map coordinate system which has undergone similarity conversion at different scales. , A scale-changed bird's-eye view image in which the display reference point is fixed on the screen can be obtained only by the coordinate conversion of the display reference point.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a bird's-eye view display navigation system with a display scale changing function of the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows a block diagram of a bird's-eye view display navigation system with a display scale changing function of the present embodiment, in which a plurality of map data (similar map information) having different scale levels and information amounts are stored as map information of the same area. The external storage device 101, the display reference point determination device 102 for determining the display reference point on the map, the arithmetic processing device 103 for performing the arithmetic processing necessary for the bird's eye view display, and the image display device 104 for displaying the map data, The display scale determining device 105 determines the scale value of the map data displayed on the image display device 104.

Here, the display scale determining device 105 may determine the scale value according to the scale change instruction input by the user, or depending on the moving speed of the own vehicle,
For example, the scale value may be automatically determined, such as a wide-area scale when moving at a high speed and a detailed scale when moving at a low speed. Alternatively, depending on attributes such as the type of route the vehicle is currently traveling on and legal speed, for example, when traveling on a main highway or a highway, the vehicle travels on a wide area scale, narrow streets, overcrowded roads, or low speed roads. When it is present, the scale value may be automatically determined like a detailed scale.

As the map data stored in the external storage device 101, map information corresponding to the same real area (that is, map information of the same area) is, for example, detailed map data 101a, medium scale map data 101b, wide area. The map data 101c is stored in each of three types.
In the detailed map data 101a, in the two-dimensional coordinate system (xd, yd) that describes the map coordinates, the size 1 in each axis direction.
It is assumed that a square closed region of 0 is one storage unit and a square region of 10 km square in the latitude / longitude direction on the real plane corresponds to this storage unit. If one point (x, y) on the real plane is expressed in km unit, (xd, y
d) = (x, y).

In the medium-scale map data 101b, a square closed area with one side 10 is similarly used as one storage unit in the two-dimensional map coordinate system (xm, ym), which corresponds to an area of 20 km square in the real plane. It shall be. Therefore, if one point (x, y) on the real plane is expressed in units of km, then (xm, ym) = (x / 2, y / 2).

Also in the wide area map data 101c, similarly, a square closed area of one side 10 in the map coordinate system (xg, yg) is used as a storage unit, and an area of 40 km square on the real plane is represented. Therefore, if one point (x, y) on the real plane is expressed in km units, (xg, yg) = (x / 4,
y / 4).

In other words, each map data 101a-10
The scale of 1c in memory is 1 / in the detailed map data 101a.
1, the medium area map data 101b is 1/2, the wide area map data 101c is 1/4, and the real area represented by one storage unit of the wide area map data 101c is 4 storage units of the middle size map data 101b. Minute, 1 of detailed map data 101a
This corresponds to 6 storage units. That is, the plurality of map data 101a to 101c are map coordinate systems ((x
d, yd), (xm, ym), (xg, yg)).

Further, when the arithmetic processing unit 103 is decomposed by function, a display for performing similarity transformation on the display reference point coordinate value determined by the display reference point determination unit 102 based on the scale value determined by the display scale determination unit 105. A display area for determining the display target area on the map data and the coordinate conversion parameters necessary for perspective projection conversion based on the reference point coordinate conversion unit 106 and the display reference point subjected to the similarity conversion by the display reference point coordinate conversion unit 106. The determination unit 107 and the display area determination unit 10
Display target area and display reference point determination device 1 determined in 7.
Based on the scale value determined in 02, the external storage device 101
The data access unit 108 for inputting the corresponding display target area of the map data of the corresponding scale level stored in
And an internal storage unit 109 for storing the map data input by the data access unit 108 for each scale level, and a scale value determined by the display reference point determination device 102 from the internal storage unit 109. A map data coordinate conversion unit 110 that inputs map data and performs perspective projection conversion using the coordinate conversion parameters determined by the display area determination unit 107, and a map after perspective projection conversion performed by the map data coordinate conversion unit 110. The image data output unit 111 outputs data to the image display device 104.

The operation of the above configuration will be described. In the system of the present embodiment, map display is performed by determining the display target area and coordinate conversion matrix, reading map data, as shown in steps S201 to S206 of FIG.
It is executed by repeating a series of procedures such as coordinate conversion and image output.

First, in step S201, the display scale determining device 105 responds to a scale change instruction input by the user, or according to the moving speed of the own vehicle, or the type of route on which the own vehicle is currently traveling. The scale value is automatically determined according to the attributes such as or legal speed.

Next, in step S202, the display area etc. determining unit 107 determines the display reference point and the line-of-sight direction given according to the output of the display reference point determining device 102, and the given viewpoint height h and line-of-sight. Using the fixed values such as the depression angle θ and the viewing angle β, the display target area is determined and the coordinate conversion matrix (coordinate conversion parameter) is calculated. In addition,
The processing up to this point is basically the same as when the display scale is not changed. However, the display reference point Pc used here
For the coordinate values of, the display reference point coordinate conversion unit 106
It is assumed that the output (xp, yp) from the display reference point determining device 102 is appropriately subjected to similarity conversion according to the scale value instructed by the display scale determining device 105.

For example, when the display by the detailed map data 101a is instructed, the above processing is performed by using (xp, yp) as the display reference point coordinate value. Also, when the display by the medium-scale map data 101b is instructed, (x
(p / 2, yp / 2) is again set as the display reference point coordinate value, and the above processing is performed. Further, when the display based on the wide area map data 101c is instructed, (xp / 4, yp / 4) is again set as the display reference point coordinate value, and the above processing is performed.

Further, in reading the map data in step S203, the data access unit 108 selects the display target area of the map data of the corresponding scale level from the external storage device 101 according to the scale value instructed by the display scale determining device 105. Read. Here, the data access unit 1
Internal storage unit 10 for storing map data read by 08
9 has a multiple structure in which storage areas for each scale level are independently provided, and when the display reference point does not move and only the display scale is changed, the external storage device 1 is newly added.
Since it is not necessary to read the map data from 01, the access frequency of the data can be reduced and the map can be displayed at higher speed. Therefore, the data access unit 108 manages whether or not the necessary map information already exists in the internal storage for each scale level, and the reading of duplicate information can be omitted.

Further, also in the coordinate conversion procedure of step S204, the map data coordinate conversion unit 110 sees only the map data of the scale level designated by the display scale determination device 105 among the map data stored in the internal storage unit 109. Perform projection conversion.

Then, in step S205, the image data output unit 11 outputs the converted individual map data.
1 performs processing such as clipping as necessary and outputs it to the image display device 104. Finally, in step S206, it is determined whether or not the display procedure is to be terminated. If not, the same procedure is repeated from step S201.

3A to 3C show examples of display screens obtained in this embodiment at each display scale when the display reference point does not move by such an operation.
3 (a) and 3 (b) show examples of bird's-eye view displays at detailed scales, medium-scale scales, and wide-scale scales, and the position of the display target area on the map data at each scale level at that time. Although the position coordinates of the reference point Pc are appropriately transformed in a similar manner at each scale, the size of the trapezoid area to be displayed and the relative position with respect to the display reference point are unchanged. Therefore, when viewing the bird's-eye view display examples of FIGS. 3A to 3C, the display target area is enlarged in the order of detailed scale → medium scale → wide scale while the position of the display reference point on the screen is fixed. You can see that it is done. As a result, it is possible to easily recognize the position of the own vehicle and improve the visibility of the screen when the screen is enlarged or reduced.

In the bird's-eye view display examples of FIGS. 3 (a) to 3 (c), only the scale level is changed and shown as map information of the same area in order to simplify the description. The display of detailed information increases in the order of wide area scale → medium scale → detailed scale. For example, as the information displayed in the vicinity of the road on the traveling route, the number of landmarks, place names, etc., which serve as landmarks, increases, or even smaller streets are displayed.

Further, when enlarging / reducing switching, coordinate conversion processing, thinning processing, etc. are not required, so that the display can be switched at high speed. Further, when the thinning processing is performed, unnaturalness appears on the display screen in some cases, but in the present embodiment, the external storage device 101 does not perform the thinning processing.
Since the map data of is displayed as it is, a smooth display screen can always be obtained.

[0047]

As described above, in the bird's-eye view display navigation system with the display scale changing function of the present invention (claim 1), the display reference point coordinate converting means is determined by the display scale determining means in the arithmetic processing means. Similarity conversion is performed on the display reference point coordinate value based on the scale value, and the determining unit determines the display target area on the map information and the coordinate conversion parameters necessary for perspective projection conversion based on the display reference point subjected to the similarity conversion. Based on the display target area determined by the determining means and the scale value determined by the display scale determining means, the map information input means determines that the similar map information of the relevant scale level stored in the external storage means is applicable. When the display target area is input, the internal storage unit stores the input similar map information for each scale level. Then, the coordinate transformation means
Based on the scale value determined by the display scale determining means, the similar map information of the corresponding scale level is input from the internal storage means, and perspective projection conversion is performed using the coordinate conversion parameter,
Since the image data output means outputs the similar map information after the perspective projection conversion to the image display device, the display scale of the bird's-eye view can be changed in a short time, and the display reference point and the display reference point at the time of enlargement and reduction. The neighborhood information can be displayed appropriately. That is, the display scale of the map on the display screen can be changed while the display position of the display reference point such as the position of the own vehicle is fixed, and the map information described in a single scale can be scaled. A scale-reduced bird's-eye view image in which the display reference points are fixed on the screen can be obtained with a smaller amount of calculation than the similarity conversion.

Further, since the correlation map information of the external storage means is displayed as it is without performing the thinning-out processing, a smooth display screen can be obtained at all times.

In the bird's-eye view display navigation system with a display scale changing function of the present invention (claim 2), the display scale determining means determines the scale value based on the scale changing instruction input by the user, and causes the arithmetic processing means. Since it is output, without moving the position of the display reference point on the screen,
At the same time, the user can select a bird's-eye view display with a required display scale according to the application.

Further, in the bird's-eye view display navigation system with display scale changing function of the present invention (claim 3), the display scale determining means automatically determines the scale value according to the moving speed of the host vehicle, and the arithmetic processing unit. Therefore, a bird's-eye view display of an appropriate scale, such as a wide scale when the vehicle is moving at high speed and a detailed scale when the vehicle is moving at low speed, can be automatically obtained. It can be displayed without moving the position of the display reference point on the screen.

In the bird's-eye view display navigation system with a display scale changing function of the present invention (claim 4), the display scale determining means automatically sets the scale value according to the attribute of the route on which the vehicle is currently traveling. In order to determine and output to the arithmetic processing unit, for example, when traveling on the main trunk line, a wide area scale,
When traveling on a narrow street, it is possible to automatically obtain a bird's-eye view display at an appropriate reduced scale such as a detailed reduced scale. Further, for example, according to the legal speed of each track, it is possible to automatically obtain a bird's-eye view display of an appropriate scale, such as a wide-area scale for traveling on a high-speed road and a detailed scale for traveling on a low-speed road. In addition, the display reference point can be displayed without moving the position on the screen.

Further, in the bird's-eye view display navigation system with a display scale changing function of the present invention (claim 5), a plurality of similar map information are described in a map coordinate system which has undergone similarity conversion at different scales. Only by converting the coordinates of the display reference points, it is possible to obtain a scale-changed bird's-eye view image in which the display reference points are fixed on the screen.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a bird's-eye view display navigation system with a display scale changing function of the present embodiment.

FIG. 2 is a flowchart showing the operation of this embodiment.

FIG. 3 is an explanatory diagram showing a screen display example according to the present embodiment.

FIG. 4 is an explanatory diagram showing a configuration of a conventional bird's-eye view display navigation system.

FIG. 5 is a flowchart showing a conventional operation.

FIG. 6 is an explanatory diagram showing a relationship among a viewpoint, a line of sight, a display screen, a display target area, and a display reference point.

FIG. 7 is an explanatory diagram showing a method of enlarging / reducing a display target area by changing the height of the viewpoint.

[Explanation of symbols]

101 external storage device (external storage means) 102 display reference point determination device (display reference point determination means) 103 arithmetic processing device (arithmetic processing means) 104 image display device (image display means) 105 display scale determination device (display scale determination means) ) 106 display reference point coordinate conversion unit (display reference point coordinate conversion unit) 107 display area etc. determination unit (determination unit) 108 data access unit (map information input unit) 109 internal storage unit (internal storage unit) 110 map data coordinate conversion Part (map data coordinate conversion means) 111 image data output part (image data output means)

Claims (5)

[Claims] 1. An external storage means for storing a plurality of similar map information having different scale levels and different information amounts as map information of the same area, a display reference point determining means for determining a display reference point on the map, and a bird's eye view display. An arithmetic processing unit that performs necessary arithmetic processing, an image display unit that displays map information, and a display scale determination unit that determines a scale value of the map information displayed by the image display unit are provided, and the arithmetic processing unit further comprises Display reference point coordinate conversion means for performing similarity conversion on the display reference point coordinate values determined by the display reference point determination means based on the scale value determined by the display scale determination means, and the display reference point coordinate conversion Deciding means for deciding the display target area on the map information and the coordinate transformation parameters necessary for perspective projection transformation, based on the display reference points subjected to similarity transformation by the means;
A map for inputting the corresponding display target area of the similar map information of the corresponding scale level stored in the external storage means based on the display target area determined by the determining means and the scale value determined by the display scale determining means. Information input means,
Based on the internal storage means for storing the similar map information input by the map information input means for each scale level and the scale value determined by the display scale determination means, the similar map of the corresponding scale level from the internal storage means Coordinate conversion means for inputting information and performing perspective projection conversion using the coordinate conversion parameters determined by the determination means, and outputting similar map information after perspective projection conversion by the coordinate conversion means to the image display device A bird's-eye view display navigation system with a display scale changing function, comprising: 2. The display scale changing function according to claim 1, wherein the display scale determining unit determines the scale value based on a scale changing instruction input by a user and outputs the scale value to the arithmetic processing unit. Navigation system with bird's-eye view display. 3. The display scale change according to claim 1, wherein the display scale determining means automatically determines the scale value according to the moving speed of the vehicle and outputs the scale value to the arithmetic processing unit. Navigation system with functional bird's-eye view display. 4. The display scale determining means automatically determines the scale value according to the attribute of the route on which the vehicle is currently traveling, and outputs the scale value to the arithmetic processing unit. 1. A bird's-eye view display navigation system with a display scale changing function described in 1. 5. The bird's-eye view display navigation with a display scale changing function according to claim 1, wherein the plurality of similar map information are described in a map coordinate system that has undergone similarity conversion in advance at different scales. system.