JP2004219182A - Navigation system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a navigation system having a simple constitution, capable of shortening a readout time of a texture when performing three-dimensional display, and reducing a cost. <P>SOLUTION: A texture transfer processing part 34 reads out precedently from a map buffer 10, texture data corresponding to a three-dimensional object arranged along a traveling route set by a route search, and writes in a texture region 64 in a VRAM 60. A texture mapping processing part 32 renders a three-dimensional map image corresponding to the actual vehicle position by using the texture data written in the texture region 64 in the VRAM 60. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a navigation device that generates and displays a three-dimensional image of a building or the like existing in front of a vehicle.
[0002]
[Prior art]
Some recent navigation devices have a three-dimensional display function of not only displaying a map around the position of the vehicle but also displaying an image of a building or the like that can be seen from the driver's eyes. By performing such display, it is possible to generate an image with a sense of reality, search for an intersection that is about to turn left or right while looking at an image similar to that when actually driving a vehicle, or specify in advance It becomes easy to search for a facility that has been set.
[0003]
By the way, as a conventional technique for performing three-dimensional display of an image, a technique is known in which a three-dimensional object such as a building is formed by polygons and a pattern is formed on a polygon surface by texture mapping. In order to obtain a more realistic image, the number of polygons constituting the 3D object increases, and the types of textures prepared in advance also increase. It is necessary to use a high processor or devise a configuration for performing texture mapping. For example, as a conventional technique devising a configuration for performing texture mapping, a drawing apparatus that performs texture mapping by pipeline processing is known (for example, see Patent Literature 1). By using this drawing apparatus, the number of times of reading the texture memory and the reading time can be reduced, and the whole drawing speed can be increased.
[0004]
[Patent Document 1]
JP-A-9-212680 (page 3-11, FIG. 1-21)
[0005]
[Problems to be solved by the invention]
By the way, in the drawing apparatus disclosed in Patent Document 1 described above, a plurality of processing units (engines) of the same type are required to perform pipeline processing, and the apparatus configuration is complicated, and it is difficult to reduce costs. there were. In particular, in the case of three-dimensional display in a navigation device, since textures to be used are biased depending on the traveling position, it is wasteful to hold all textures in a high-speed VRAM (video RAM). There is a demand for a technique that utilizes this feature, has a simple configuration, can easily reduce cost, and can reduce the texture reading time.
[0006]
The present invention has been made in view of the above points, and an object of the present invention is to reduce the time required to read textures when performing three-dimensional display, have a simple configuration, and reduce cost. An object of the present invention is to provide a navigation device that can be designed.
[0007]
[Means for Solving the Problems]
In order to solve the above-described problem, the navigation device of the present invention arranges a three-dimensional object simulating a structure seen from a traveling position of a vehicle in a virtual three-dimensional space corresponding to an installation state of an actual structure. In addition, in order to display a three-dimensional image of the virtual three-dimensional space viewed from the virtual viewpoint position, data on the arrangement and shape of the three-dimensional object included in the virtual three-dimensional space and texture data corresponding to the three-dimensional object , A vehicle position detecting means for detecting a vehicle position, and texture data corresponding to a three-dimensional object arranged along the traveling route of the vehicle are read from the map data storing means and stored in an image memory. Texture transfer means for transferring, and vehicle position detecting means using texture data stored in an image memory Therefore and a three-dimensional image drawing unit that draws a three-dimensional image corresponding to the detected vehicle position. Thereby, the texture data required along the traveling route can be selectively stored in the image memory, so that a simple structure in which the storage area for the texture data in the image memory is reduced, Cost can be reduced. Further, even when a small-capacity image memory is used, necessary texture data can be read from the image memory along the traveling route, and the texture reading time can be reduced.
[0008]
It is preferable that the apparatus further includes a route search processing unit that obtains a travel route to the destination by a route search process, and the texture transfer unit transfers the texture data along the travel route set by the route search processing unit. This makes it possible to reliably read ahead the texture data that is actually needed, and to transfer only the texture data that is really necessary for three-dimensional display. The storage area for the texture data can be further reduced, and the cost can be reduced by reducing the capacity of the image memory.
[0009]
When the route search processing means obtains a travel route by the route search processing means, the route search processing means previously extracts specific information of texture data corresponding to a three-dimensional object existing along the travel route, and the texture transfer means It is desirable to transfer the texture data based on the specific information when the vehicle actually travels. This makes it possible to speed up the process of transferring the texture data to the image memory.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an in-vehicle navigation device according to an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram illustrating a configuration of a navigation device according to an embodiment. The navigation device shown in FIG. 1 includes a navigation controller 1, a DVD 2, a disk reader 3, a remote control (remote control) unit 4, a vehicle position detector 5, a display device 6, and an audio unit 7.
[0011]
The navigation controller 1 controls the entire operation of the navigation device. The function of the navigation controller 1 is realized by executing a predetermined operation program using a CPU, a ROM, a RAM, and the like. The detailed configuration of the navigation controller 1 will be described later.
[0012]
The DVD 2 is an information recording medium that stores map data necessary for map display, facility search, route search, expressway guidance image display, and the like. The DVD 2 stores map data in units of rectangular figures divided into appropriate sizes by longitude and latitude. The map data of each leaf is specified by specifying the leaf number and can be read out.
[0013]
The disk reader 3 can load one or a plurality of DVDs 2 and reads map data from any one of the DVDs 2 under the control of the navigation controller 1. Note that the disc to be loaded is not necessarily a DVD, but may be a CD. Alternatively, both a DVD and a CD may be selectively loaded.
[0014]
The remote control unit 4 includes a joystick for designating directions such as up, down, left, and right, and various operation keys such as a numeric keypad for inputting numbers and a "decision key" for confirming various settings. A signal is output to the navigation controller 1.
[0015]
The vehicle position detection unit 5 includes, for example, a GPS receiver, a direction sensor, a distance sensor, and the like, detects a vehicle position (longitude, latitude) at a predetermined timing, and outputs a detection result.
The display device 6 displays a map image around the own vehicle position based on a video signal output from the navigation controller 1. The audio unit 7 outputs a guidance voice or the like generated based on a voice signal input from the navigation controller 1 into the vehicle interior.
[0016]
Next, a detailed configuration of the navigation controller 1 will be described. The navigation controller 1 shown in FIG. 1 includes a map buffer 10, a map readout control unit 12, a 2D (two-dimensional) image drawing unit 14, a vehicle position calculation unit 20, a route search processing unit 22, a search result storage unit 24, and a guide route drawing. It includes a unit 26, a voice guidance unit 28, a 3D (three-dimensional) image processing unit 30, a texture mapping processing unit 32, a texture transfer processing unit 34, an input processing unit 50, a VRAM 60, and a display processing unit 68.
[0017]
The map buffer 10 temporarily stores map data read from the DVD 2 by the disk reader 3. The map data includes data necessary for displaying a three-dimensional map in addition to data necessary for displaying a two-dimensional map. The data required for displaying a 3D map includes the arrangement of 3D objects that simulate structures seen from the vehicle's running position, the data of the polygons that make them up, and the texture mapping processing for the polygons. Texture data and the like are included. The map reading control unit 12 outputs a read request for map data in a predetermined range to the disk reading device 3 in accordance with the vehicle position calculated by the vehicle position calculating unit 20 and an instruction from the input processing unit 50. When instructed to display a two-dimensional map, the 2D image drawing unit 14 performs a drawing process necessary for displaying a two-dimensional map image based on the map data stored in the map buffer 10 to perform map processing. Create image drawing data. This drawing data is stored in the frame memory area 62 in the VRAM 60.
[0018]
The vehicle position calculation unit 20 calculates the own vehicle position based on the detection data output from the vehicle position detection unit 5, and calculates the own vehicle position when the calculated own vehicle position is not on the road in the map data. A map matching process to be corrected is performed.
The route search processing unit 22 searches for a traveling route (guidance route) that connects a departure place and a destination (or a waypoint) according to predetermined search conditions. Further, in parallel with the route search process, the route search processing unit 22 extracts a three-dimensional object included in a range that can be viewed along the traveling route, and extracts texture data used for drawing corresponding to the extracted three-dimensional object. (Also referred to as “texture ID”). These search results are stored in the search result storage unit 24. The guidance route drawing unit 26 generates guidance route drawing data for displaying the guidance route obtained by the search processing by the route search processing unit 22 in a superimposed manner on a map. The voice guidance unit 28 generates a voice signal such as an intersection guidance necessary for guiding the vehicle along the guidance route obtained by the search processing by the route search processing unit 22.
[0019]
When a three-dimensional map display is instructed, the 3D image processing unit 30 sets a virtual viewpoint position (for example, a driver's viewpoint position) corresponding to the vehicle position calculated by the vehicle position calculation unit 20. And performs perspective projection transformation on the three-dimensional object arranged in the virtual three-dimensional space. In the present embodiment, a three-dimensional object that simulates a structure that can be seen from the traveling position of the vehicle is created. In addition, these three-dimensional objects are configured by polygons, and perspective projection conversion is performed using the polygons that configure these three-dimensional objects and that are arranged in a range that can be seen from a virtual viewpoint position.
[0020]
The texture mapping processing unit 32 performs a texture mapping process of attaching a texture to each surface of the polygon on the result of the perspective projection conversion performed by the 3D image processing unit 30. Image data generated by the texture mapping process is stored in the frame memory area 62 in the VRAM 60. The texture transfer processing unit 34 writes the texture ID searched in parallel during the route search process into the texture ID area 66 in the VRAM 60, and when the vehicle is traveling along the travel route obtained by the route search process. Then, necessary texture data is read out and stored in the texture area 64 in the VRAM 60.
[0021]
The input processing unit 50 outputs an instruction for performing an operation corresponding to various operation instructions input from the remote control unit 4 to each unit in the navigation controller 1.
The VRAM 60 is an image memory capable of high-speed reading and writing, and has a frame memory area 62, a texture area 64, and a texture ID area 66. In the frame memory area 62, drawing data corresponding to the display screen is written. In the texture area 64, texture data read from the map buffer 10 by the texture transfer processing unit 34 is written. The texture area 64 functions as a texture cache, and the texture mapping processing unit 32 does not use the VRAM 60 that can read at high speed, but from the map buffer 10 configured by a DRAM (dynamic RAM) or the like, which takes a long time to read. The texture data is read from the texture area 64 of FIG. In the texture ID area 66, the texture ID obtained along with the travel route by the route search processing is written.
[0022]
The display processing unit 68 reads out the drawing data written in the frame memory area 62 in the VRAM 60 and performs a predetermined conversion process to generate a video signal. This video signal is input to the display device 6, and an image corresponding to the drawing data written in the frame memory area 62 is displayed.
[0023]
The above-described map buffer 10 serves as a map data storage unit, the vehicle position detecting unit 5, the vehicle position calculating unit 20 serves as a vehicle position detecting unit, the texture transfer processing unit 34 serves as a texture transfer unit, and the 3D image processing unit 30, a texture mapping process. The units 32 respectively correspond to three-dimensional image drawing means.
[0024]
The navigation device according to the present embodiment has such a configuration. Next, an operation related to a three-dimensional map display will be described.
FIG. 2 is a flowchart showing an operation procedure when a route search process is instructed. The route search processing unit 22 determines whether or not a route search has been instructed by the user of the navigation device (step 100). If not, a negative determination is made and this determination is repeated. When a user instructs a route search using the remote control unit 4 or the like, the route search processing unit 22 sets the vehicle position at that time as a departure place, and optimally travels to the designated destination. A route is obtained by a route search process (step 101). In parallel with this route search processing, the route search processing unit 22 extracts a three-dimensional object included in a range that can be seen along a traveling route connecting the departure place and the destination, and Is searched for the texture ID of the texture data used for drawing corresponding to (step 102). Further, the texture transfer processing unit 34 writes the texture ID obtained by the search processing in step 102 into the texture ID area 66 in the VRAM 60 (step 103).
[0025]
FIG. 3 is a flowchart showing a texture data transfer operation performed in parallel with the three-dimensional map display while the vehicle is traveling.
The texture transfer processing unit 34 determines whether or not a three-dimensional map display has been instructed by the user of the navigation device (step 200). If not, a negative determination is made and this determination is repeated. When the user instructs a three-dimensional map display using the remote control unit 4 or the like, the texture transfer processing unit 34 makes an affirmative determination, and then determines whether or not a route guidance operation is being performed (step 201). ). If the route guidance operation using the guidance route drawing unit 26 or the voice guidance unit 28 is not being performed, a negative determination is made, and the process returns to step 200 to repeat the determination of the presence or absence of the three-dimensional map display instruction.
[0026]
If the route guidance operation has been performed at the time when the three-dimensional map display is instructed, an affirmative determination is made in the determination of step 201, and then the texture transfer processing unit 34 reads the texture data in advance. (Step 202). In this pre-reading, the texture IDs of a predetermined section (for example, a predetermined distance after the current vehicle position) written in the texture ID area 66 in the VRAM 60 are read in advance, and the texture data corresponding to these texture IDs is mapped. This is performed by reading from the buffer 10. The read texture data is written to the texture area 64 in the VRAM 60.
[0027]
Next, the texture transfer processing unit 34 determines whether or not the vehicle has traveled a predetermined section (step 203). If the vehicle has not traveled, a negative determination is made, and then the three-dimensional map display ends. It is determined whether or not the process has been performed (step 204). If the vehicle has traveled for the predetermined section, an affirmative determination is made in the determination of step 203, and the process returns to step 202 to read the texture data for the next predetermined section in advance.
[0028]
In this way, every time the vehicle travels for a predetermined section, the texture data for the next predetermined section is read from the map buffer 10 and written to the texture area 64 in the VRAM 60. Therefore, the texture mapping processing unit 32 can read texture data from the VRAM 60 that can be read at high speed and perform texture mapping.
[0029]
As described above, only the texture data necessary for displaying a three-dimensional image along the traveling route can be selectively stored in the texture area 64 of the VRAM 60. Can be reduced, a simple structure using the VRAM 60 having a small capacity can be achieved, and the cost can be reduced. Further, even when the VRAM 60 having a small capacity is used, necessary texture data can be read from the VRAM 60 along the traveling route, and the time required to read the texture can be reduced.
[0030]
By the way, in the conventional navigation device, high-speed reading of the texture data is enabled by writing all the texture data necessary for displaying the three-dimensional map in the texture area in the VRAM. If it is attempted to make the texture data smaller, it is not possible to make each texture data too large. For this reason, conventionally, even in the case of a building or the like that actually has a different appearance, a relatively simple and uniform texture data is often used, and as shown in FIG. Had become.
[0031]
However, in the navigation device of the present embodiment, only the texture data corresponding to the three-dimensional object in the range actually required along the traveling route set by the route search can be read in advance. Even when a VRAM having the same capacity as that of the VRAM is used or a VRAM having a small capacity is used, the data amount of each piece of texture data can be increased. Therefore, it is possible to display a high-definition and realistic 3D map image as shown in FIG. 4, and since all the texture data is read from the VRAM 60, the speed of the texture mapping process can be reduced. There is no lowering.
[0032]
In the present embodiment, the texture ID of the texture data corresponding to the three-dimensional object existing along the travel route is extracted in advance at the same time as the route search and stored in the texture ID area 66 in the VRAM 60. When the texture data is transferred from the map buffer 10 to the texture area 64 in the VRAM 60, the time for specifying the texture data to be transferred can be reduced.
[0033]
Note that the present invention is not limited to the above embodiment, and various modifications can be made within the scope of the present invention. In the present embodiment, the texture data is read in advance when the travel route is set by the route search, but the present invention can be applied to the case where the travel route is not set by the route search. In this case, for example, advance reading of the texture data is performed for a predetermined range around the current position of the vehicle. Even in this case, it is possible to reduce the number of types of texture data to be written in the texture area of the VRAM in advance, and it is possible to increase the data amount of each piece of texture data. It is possible to display a high-definition and realistic 3D map image.
[0034]
【The invention's effect】
As described above, according to the present invention, texture data required along a traveling route can be selectively stored in an image memory. And a cost reduction can be achieved. Further, even when a small-capacity image memory is used, necessary texture data can be read from the image memory along the traveling route, and the texture reading time can be reduced.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a configuration of a navigation device according to an embodiment.
FIG. 2 is a flowchart showing an operation procedure when a route search process is instructed.
FIG. 3 is a flowchart illustrating a texture data transfer operation performed in parallel with a three-dimensional map display while the vehicle is traveling.
FIG. 4 is a diagram showing a specific example of a three-dimensional map display according to the embodiment.
FIG. 5 is a diagram showing a specific example of a conventional three-dimensional map display.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 navigation controller 4 remote control unit 5 vehicle position detection unit 6 display device 10 map buffer 14 2D map image drawing unit 20 vehicle position calculation unit 22 route search processing unit 24 search result storage unit 26 guidance route drawing unit 28 voice guidance unit 30 3D image Processing unit 32 Texture mapping processing unit 34 Texture transfer processing unit 34
50 input processing unit 60 VRAM (video RAM)
62 frame memory area 64 texture area 66 texture ID area 68 display processing unit

Claims (3)

A three-dimensional object simulating a structure visible from the traveling position of the vehicle is arranged in a virtual three-dimensional space in accordance with the actual installation state of the structure, and the virtual three-dimensional space is viewed from a virtual viewpoint position. Navigation device that displays a three-dimensional image
Map data storage means for storing data relating to the arrangement and shape of the three-dimensional object included in the virtual three-dimensional space, and texture data corresponding to the three-dimensional object;
Vehicle position detecting means for detecting a vehicle position;
Texture transfer means for reading the texture data corresponding to the three-dimensional object arranged along the traveling route of the vehicle from the map data storage means and transferring the texture data to an image memory;
Using the texture data stored in the image memory, three-dimensional image drawing means for drawing the three-dimensional image corresponding to the vehicle position detected by the vehicle position detection means,
A navigation device comprising: In claim 1,
Route search processing means for obtaining a travel route to the destination by route search processing;
The navigation device, wherein the texture transfer unit transfers the texture data along a travel route set by the route search processing unit. In claim 2,
The route search processing means, when determining a travel route by the route search processing means, previously extracting the specific information of the texture data corresponding to the three-dimensional object existing along the travel route,
The navigation device, wherein the texture transfer unit transfers the texture data based on the specific information when the vehicle is actually running.

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