Communications: electrical – Vehicle position indication – Map display
Reexamination Certificate
2001-05-29
2003-11-18
Pham, Toan (Department: 2632)
Communications: electrical
Vehicle position indication
Map display
C340S995150, C340S995170, C340S995280, C701S212000
Reexamination Certificate
active
06650253
ABSTRACT:
This application is based on application No. 2000-160032 filed in Japan, the content of which is hereby incorporated by reference.
BACKGROUND OF THE INVENTION
(1) Field of the Invention
The present invention relates to a map display device, a map display method, and a computer program for use in a map display device, and in particular relates to road map display techniques used in car navigation devices.
(2) Related Art
Example applications for map display devices include a car navigation device. A map display device used in a car navigation device needs to enable the user, such as the driver, to comprehend a displayed map at a glance. Hence various map display techniques have been devised so that the driver can understand information at once. One of such techniques is a method of displaying with emphasis on information which is likely to be desired by the driver.
When driving a car, there are some points to which the driver seems to pay particular attention, such as an intersection and a destination location. Such points are hereinafter called “points of interest”. A conventional type of map display device displays an enlarged view of a point of interest and its vicinity. For example, when a car is approaching a main intersection, this type of map display device displays an enlarged view of the intersection and its vicinity, to help the driver judge which route he or she should take. Here, some map display devices display the enlarged view over a part of a map which is being displayed on a screen, rather than displaying the enlarged view on the whole screen.
Also, there are map display devices that display, over a part of a map which is being displayed on a screen, a wide area view of the periphery of an area covered by the map on a larger scale. This method allows the driver to consult the map, and at the same time consult the wide area view to check which roads run around the area covered by the map.
Thus, conventional map display devices emphasize information which is likely to be desired by the driver, by displaying an enlarged view of the vicinity of a point of interest or a wide area view of the periphery of an area shown by a map. In this way, the driver can quickly comprehend information displayed on the screen.
However, when displaying the enlarged view of the vicinity of the point of interest on the whole screen, the driver can view the enlarged view but cannot view the map of the area outside the vicinity of the point of interest, and therefore cannot check the roads existing around the vicinity of the point of interest.
Also, when displaying the enlarged view of the vicinity of the point of interest or the wide area view of the periphery of the area covered by the map on part of the screen, the driver cannot view the part of the map which is concealed by this display. Besides, there is no continuity between the map and the enlarged or wide area view whose scale is different with the map. This makes it difficult for the driver to quickly comprehend the relation between the two maps, in particular connections of roads between the two maps.
There is also a conventional technique of displaying a map using the law of perspective. This method displays distant objects to be small and close objects to be large in accordance with human visual characteristics, thereby helping the driver view the map in the right perspective. However, when displaying the vicinity of a point of interest in enlarged view or displaying the periphery of an area in wide area view, this technique has the same problem as above.
SUMMARY OF THE INVENTION
The present invention has an object of providing a map display device that enables a driver to accurately and quickly comprehend map information displayed on a display screen.
(1) The stated object can be achieved by a map display device that is characterized by mapping a map of an area which is specified by a current position of the map display device or by an instruction from a user, onto a curved surface to generate a mapped image, and displaying the mapped image.
With this construction, the map display device can display a map with one or more portions enlarged and/or contracted, while maintaining connections of roads. For instance, it is possible to enlarge a map portion the detailed information of which is likely to be desired by the driver, and at the same time contract a map portion of the periphery of the map so that the periphery is displayed in wide area view. As a result, the connections of the roads are maintained, and the driver can accurately and quickly comprehend the map information displayed on the display screen.
(2) Here, in the map display device of (1), the map has at least one portion which is to be enlarged and/or at least one portion which is to be contracted, the portion to be enlarged and the portion to be contracted being referred to as an enlarged portion and a contracted portion respectively, and the curved surface has a form which depends on a positioning of the enlarged portion and/or the contracted portion on the map.
With this construction, the map display device produces the same effect as (1).
(3) Here, the map display device of (2) includes: a map storing unit for storing map information; a map acquiring unit for acquiring map information that shows the map of the area specified by the current position of the map display device, from the map storing unit; a surface storing unit for storing surface information that defines the curved surface whose form depends on the positioning of the enlarged portion and/or the contracted portion on the map shown by the acquired map information; a mapping unit for mapping the map shown by the acquired map information, onto the curved surface defined by the surface information, to generate the mapped image; and a projecting/displaying unit for projecting the mapped image onto a flat virtual screen, and displaying the projected image.
With this construction, the map display device produces the same effect as (1).
(4) Here, in the map display device of (3), the curved surface defined by the surface information has the following property: when the map is mapped onto the curved surface by the mapping unit and projected onto the virtual screen by the projecting/displaying unit, (a) an angle formed between a part of the curved surface to which the enlarged portion of the map is mapped and a line of sight directed to the part of the curved surface in the projection is larger than any angles formed between other parts of the curved surface and lines of sight directed to the other parts of the curved surface in the projection, and (b) an angle formed between a part of the curved surface to which the contracted portion of the map is mapped and a line of sight directed to the part of the curved surface in the projection is smaller than any angles formed between other parts of the curved surface and lines of sight directed to the other parts of the curved surface in the projection.
With this construction, the map display device produces the same effect as (1).
(5) Here, the map display device of (4) further includes an altitude storing unit for storing altitude information showing a correspondence between positions of points shown in the map and altitudes of the points, wherein the mapping unit includes a surface deforming unit for providing undulations corresponding to the altitudes shown by the altitude information, to the curved surface at positions to which the points on the map at the corresponding positions shown by the altitude information are to be mapped, to generate a deformed curved surface, and the mapping unit maps the map onto the deformed curved surface.
With this construction, the map display device displays the map of three-dimensional appearance relating to the altitudes, so that the map which delivers the same degree of realism as the view when looking at the actual terrain from the sky can be presented to the driver. Accordingly, in addition to the effect of (1), the driver's understanding of the terrain is facilitated.
(6) Here, in the map display device of (5), the
Mochizuki Yoshiyuki
Nishimura Kenji
Senda Keiichi
Matsushita Electric - Industrial Co., Ltd.
Pham Toan
LandOfFree
Map display device, map display method, and computer program... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Map display device, map display method, and computer program..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Map display device, map display method, and computer program... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3185048