Computer graphics processing and selective visual display system – Computer graphics processing – Three-dimension
Reexamination Certificate
2002-02-15
2004-06-01
Nguyen, Phu K. (Department: 2671)
Computer graphics processing and selective visual display system
Computer graphics processing
Three-dimension
Reexamination Certificate
active
06744431
ABSTRACT:
TECHNICAL FIELD
The present invention relates to three-dimensional map display devices, and more particularly to a device for simply displaying a three-dimensional configuration of a target area on a map.
BACKGROUND ART
A conventional car navigation system generally navigates along the route by displaying a two-dimensional map. In a case where a road is overlaying on another in parallel as shown on a display navigating a vicinity of freeway entrances and exits, however, a two-dimensional map without a longitudinal representation often puzzles a driver as to which way to go. Also, as to a multi-level intersection of a ordinary-type road to be navigated, when the display navigates to turn right after passing the multi-level intersection, it is difficult for the driver to instantaneously understand the navigated route as a conventional car navigation system does not represent the route stereoscopically.
Recently, various car navigation systems are being developed to display a map in a three-dimensional manner. Conventionally, when a map is three-dimensionally displayed, width and height information is manually provided to data about roads on a two-dimensional map in advance so as to generate three-dimensional polygon data from the map data having the information provided, and then the three-dimensional polygon data is stored in a map storage medium (CD-ROM, DVD, etc.). When a vehicle reaches a point to be navigated, a car navigation system in which this map storage medium is provided reads out corresponding three-dimensional polygon data from the map storage medium and displays a three-dimensional image.
The conventional system, however, requires width and height information to be added to every piece of road data on a two-dimensional map, which considerably complicates the processing. Further, it requires preparation such as measurements, and the like. Moreover, since two-dimensional map data contains a large amount of information which do not conform to the real-world road locations, an accuracy of a three-dimensional map obtained through such data on the two-dimensional map data is poor, which confuses the driver more. Information on road locations on a two-dimensional map may be corrected, or configuration data on a completed three-dimensional map may be corrected with a CAD tool, and the like in order to obtain a desired three-dimensional map. It will require a large number of additional processing steps. Further, since an accuracy of the conventional polygon automatic generating algorithm is poor, parts separated into small links and coupling/branching parts between two road links differing in width cannot be smoothly connected. That is to say, the polygon data does not coincide with the real-world road configuration, resulting in a reduction of the safety.
Moreover, in the conventional system, the three-dimensional polygon data itself is stored in a map storage medium (CD-ROM, DVD, etc.), and therefore the amount of map data to be stored is too large to three-dimensionally display many areas. To solve such an inconvenience, two-dimensional map data containing added width and height information may be stored in the map storage medium, in which case a car navigation system carried on a vehicle creates the three-dimensional polygon data. However, this method largely increases the load on a CPU of the car navigation system, resulting in another problem that the map cannot be scrolled at high speed.
Accordingly, an object of the present invention is to provide a three-dimensional map display method and a device which can easily and simply display the three-dimensional configuration of target areas on a map, with a largely reduced amount of data stored in a storage medium, and a device for creating data used in the method and device.
DISCLOSURE OF THE INVENTION
The present invention has the following features to achieve the object mentioned above.
A first aspect of the invention is directed to a device for creating model transforming data used to transform a three-dimensional map display model, wherein a three-dimensional configuration of a given part on a map is classified in advance into a plurality of patterns and a standard three-dimensional map display model is prepared for each pattern, and the model transforming data creating device comprises:
a two-dimensional map data storage portion for storing two-dimensional map data;
a parameter data extracting portion for extracting parameter data corresponding to the given part from the two-dimensional map data stored in the two-dimensional map data storage portion;
a parameter data analyzing portion for analyzing the parameter data extracted by the parameter data extracting portion to generate the model transforming data; and
a storage portion for storing the model transforming data generated by the parameter data analyzing portion.
As stated above, according to the first aspect, instead of the three-dimensional image data itself, the model transforming data for transforming a previously prepared three-dimensional map display model into a desired form is generated as data for obtaining a three-dimensional image of a given part on a map, and then the data for three-dimensional map display can be provided in an extremely compressed form as compared with conventional ones.
According to a second aspect which depends on the first aspect,
the model transforming data creating device further comprises a pattern model storage portion for storing pattern data defining sorts of parameters required when transforming the three-dimensional map display model for each pattern,
wherein the parameter data analyzing portion comprises:
a pattern data reading portion for reading the pattern data corresponding to the given part from the pattern model storage portion; and
a data converting portion for converting the parameter data extracted by the parameter data extracting portion into the model transforming data on the basis of the pattern data read out by the pattern data reading portion.
As stated above, according to the second aspect, the parameter data is converted into the model transforming data on the basis of the pattern data, and more detailed model transforming data can be created as compared with the case in which the model transforming data is created from only the parameter data.
According to a third aspect which depends on the second aspect,
the pattern data reading portion comprises a pattern determining portion for determining the pattern on the basis of the parameter data extracted by the parameter data extracting portion and reading out the pattern data corresponding to the determined pattern from the pattern model storage portion.
As stated above, according to the third aspect, the parameter data can be automatically read from the parameter data storage portion without requiring manual operation.
According to a fourth aspect which depends on the third aspect,
the pattern determining portion comprises:
a branching part road attribute deciding portion for deciding attributes of roads around a branching point on the basis of the parameter data extracted by the parameter data extracting portion; and
a branch type deciding portion for deciding the type of the branching on the basis of the road attributes decided by the branching part road attribute deciding portion to determine the pattern.
As stated above, according to the fourth aspect, the pattern is determined according to the road attributes at a branching point especially requiring three-dimensional display, which enables pattern discrimination more conforming with the real-world road configuration.
According to a fifth aspect which depends on the fourth aspect,
the parameter data analyzing portion further comprises:
a parameter data classifying portion for classifying the parameter data according to road function on the basis of the pattern determined by the pattern determining portion; and
a data integrating portion for integrating the parameter data classified by the parameter data classifying portion within each classified group, and
the data converting portion converts the pa
Ata Teruaki
Sakamoto Kiyomi
Takahira Yutaka
Ueyama Yoshiki
Matsushita Electric - Industrial Co., Ltd.
Nguyen Phu K.
Wenderoth , Lind & Ponack, L.L.P.
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