JPH07104668A - Character display method in navigation device - Google Patents

Abstract

PURPOSE:To provide a character display method capable of improving the visibility of a character without impairing the map information of a road, etc., plotted under the character in an on-vehicle navigation device. CONSTITUTION:This method is the character display method in a navigation device which displays by superimposing the character on a map, and the plotting of the character in a second color different from a first color is performed at plural positions shifted by the number of dots decided in advance in the periphery of the display position of the character when the character of first color is displayed on the display position indicated on the map(S21-S28), and after that, the plotting of the character is performed at the display position in the first color(S29).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle-mounted navigation device for displaying a map on a display device in an automobile or the like and providing the driver with directions.

[0002]

2. Description of the Related Art In a map display of a navigation device, a map is subject to processing such as enlargement / reduction, whereas characters such as place names are displayed in a predetermined size from the viewpoint of visibility. ing. Therefore, with character data,
It is stored separately from the other map data etc. (non-character data) and displayed separately.

When displaying characters on a map, in order to display characters, roads, buildings, etc. in a limited display area, there is a technique for preventing characters from overlapping with each other or intersections. It is proposed in Kaihei 2-157892.

[0004]

However, in the above-mentioned conventional techniques, it is unavoidable to superimpose and display characters on a road or a building, and the character color and the color of the road or the building are not displayed. However, if the colors and contrasts are similar, there is a problem that the character becomes difficult to read. For example, in the example as shown in FIG. 7, the "large" character of the display character "What University" overlaps with the straight line indicating the road, and the character is similar to the background color. , It can be seen that the visibility of the characters has deteriorated.

In order to avoid this problem, a rectangular display area for the number of characters is filled and displayed, and white characters are drawn in the rectangular display area.
Place names are conventionally displayed (see "Edobashi", "Takaracho", "Kyobashi", etc. in Fig. 3).

In this case, since a part of the background of the character is filled in for displaying the character, there is a problem that information such as roads is lost more than necessary.

An object of the present invention is to provide a character display method capable of improving the visibility of characters in a vehicle-mounted navigation device without unnecessarily damaging map information such as roads drawn under the characters. To do.

[0008]

In order to achieve the above object, a character display method in a navigation device according to the present invention is a character display method for displaying characters in a superimposed manner on a map, wherein the characters of a first color are displayed. When displaying at a given display position on the map, a second color different from the first color is provided at a plurality of positions around the display position of the character, which are displaced by a predetermined number of dots. Draw the character and then
The character is drawn at the display position with the first color.

[0009]

In the present invention, first, the character is drawn in a peripheral portion of the character to be written on the map in a color different from the color (second color) with a shift of a few dots from the original position.
Drawing is performed in the original color (first color) of the character so as to overlap the original position. As a result, it is possible to form a border having a color different from the character color around the character. With this border, regardless of where the characters are displayed, that is,
Whether on the road or on a building, the visibility of the character can be improved.

The edging can be formed by drawing only the edging portion around the character, but in that case, it is necessary to calculate drawing coordinate data only for the edging portion. On the other hand, according to the procedure of the present invention, after drawing the characters with different colors, the characters are finally overwritten in the original character position in the original character color. The edging can be formed very easily without the need for calculation.

Further, since the border is limited to one dot (or several dots) around the character and does not fill the rectangular background portion of the character as in the conventional case, there is no loss of map information due to character display. Can be kept to a minimum.

[0012]

Embodiments of the present invention will now be described in detail with reference to the drawings.

First, FIG. 4 shows a hardware configuration of a navigation device to which the present invention is applied. This device
A traveling direction detection device 41 for detecting the current traveling direction of the vehicle
And a travel distance detection device 42 for detecting the travel distance of the vehicle.
And an input device 43 such as a touch panel or a key for receiving an input from the user, and a control circuit (microprocessor, drawing processor,
Display controller, etc.) 44, a volatile memory (RAM) 45 that can store display data and various data, and can also store a program if necessary, and a nonvolatile memory that stores various control programs and fixed data. A memory (ROM) 46, a display 47 that displays road information and the like under the control of the control circuit 44, and an external storage device 48 such as an optical disk device and a magnetic disk device that stores a relatively large amount of data such as road information. Consists of. RAM45
Includes a display memory (VRAM) for storing display data. The traveling direction detection device 41 is a device that detects the traveling direction of the vehicle using, for example, a geomagnetic sensor, an optical fiber gyro, or the like. The traveling distance detecting device 42 is, for example, a device that detects traveling distance by an ABS (antilock brake) sensor of a wheel or a speedometer.

FIG. 5 shows a functional configuration of the control circuit 44 shown in FIG. As a function of this device, based on both outputs of the traveling direction detection device 41 and the traveling distance detection device 42,
A current position calculation function 51 for detecting the current position of the vehicle, a display data search function 52 for extracting data (background data, road data, character data) to be displayed based on the detected current position information from the ROM 46, and this extracted data. It has a road background display control function 53 for displaying the displayed display data on the display 47, and a character display control function 54 for controlling the character display according to the present invention. As background data, land, water system, green space, buildings, etc. are defined by polygonal or line data. The road data defines the road as line data. Further, in the character data, characters, symbols, etc. are described by codes.

FIG. 6 shows the structure of character data used in this embodiment. Each character data to be displayed in the map is usually defined as a character string composed of a plurality of characters. Each character data has the number of characters 61, the character type 62, the X coordinate 63 and the Y coordinate 64 that determine the position of this character data, the character code 65 of the first character that constitutes this character data, and the character code of the second character. 66, ..., Character code 70 of the Nth character. The character type 62 is for distinguishing what name the character data is, and as the type, there are road names (highway names, national road names, etc.), place names, facility names, and the like. The position of the character data is determined by the position of the first character in this embodiment.

Regarding the display color (character color) of the character, the control program has a table (not shown) showing the correspondence between the character type 62 and the character color. Is determined.

Next, a specific procedure for displaying characters in this embodiment will be described with reference to the flowchart of FIG. This process is activated each time map data is drawn in the VRAM.

First, the current position of the vehicle is calculated (S1
1), the background data and road data of the area corresponding to the position are read from the external storage device 48 (S12, S1).
3). Similarly, the character data to be displayed at the relevant location in the area is read (S14). A character color is assigned as one of the character attributes. As the character color, a unique color can be assigned depending on the type of road. For example,
National highway names are red, and highway names are blue.

Subsequently, after drawing the read background data (S16), the overlapping of characters is checked (S17). This determination can be made based on the X and Y coordinates of the character data and the number of characters. If it is determined that the characters overlap (S18), the position of the characters is changed (S19). The process S19 is repeated until the characters do not overlap at the changed position. If there is no character overlap, the position of the character data is determined as the display position coordinate (X, Y) (S20).

Therefore, in the eight steps S21 to S28, the eight points (X-1,
Y), (X-1, Y + 1), (X, Y + 1), (X +
1, Y + 1), (X + 1, Y), (X + 1, Y-1),
(X, Y-1), (X-1, Y-1) are sequentially drawn in the background color (A color) of the map. In addition,
It should be noted that the “background” of the background color here indicates a portion other than the display target such as a road or a building. As the A color, a color having a large contrast with the B color (character color) (for example, a complementary color of the B color) may be selected instead of the background color. Further, the execution order of S21 to S28 is not limited to this order, and may be any order. Finally, the character is drawn in the character color designated as the attribute of the character at the coordinates (X, Y) (S29). When there are a plurality of character data, step S17 is performed for each character data.
Perform the following processing.

FIG. 2 shows a drawing result when the processing of FIG. 1 is applied to the example of the “large” character explained in FIG.

First, when a character is drawn in the color A (X-1, Y), the drawing result 200 is obtained. This is the original character position shifted to the left by one dot. Next, the same character is drawn in (X-1, Y + 1) with A color. This is the original character position shifted one dot to the upper left. As a result, the drawing result 205 is obtained. In the figure, the A-colored character drawn at that time is already drawn
For the sake of convenience, the densities of the both are made different in order to distinguish them from the color letters, but they are actually the same color. Next, with color A (X,
Draw the same character in Y + 1). This is the original character position shifted right above by one dot. As a result, the drawing result 210 is obtained. Similarly, a drawing 215 (X + 1, Y +) in which the original character position is shifted to the upper right by one dot
1), drawing 220 (X + 1, shifted to the right by one dot)
Y), a drawing 225 (X + 1, shifted to the lower right by one dot)
Y-1), a drawing 230 (X,
Y-1), a drawing 235 (X-
1, Y-1), and finally, the character is drawn at the original position (X, Y) with the original character color B. As a result, the final drawing result 240 is obtained. As can be seen from comparison with the conventional drawing result 245, according to the present embodiment, since a 1-dot A-colored edging portion is formed around the character, the character visibility is irrespective of the background of the character. Is improved. Moreover, since the portion drawn in the A color has only a limited area around the character, the road information or the like is hardly damaged.

A practical display example is shown in FIG. In this example, the method of this embodiment is applied to the letters "Hibiya Park". In FIG. 3, in order to show the difference from the conventional display result, other characters are left as they are.

In the description of the above embodiment, the amount of displacement of the character from the original display position in the eight directions of up, down, left, right is set to 1 dot, but it may be set to several dots if the effect is low with 1 dot.

[0025]

According to the present invention, in a vehicle-mounted navigation device, the visibility of characters can be improved without unnecessarily damaging the data such as roads drawn under the characters.

[Brief description of drawings]

FIG. 1 is a flowchart of a process according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram of an example of a drawing result used to explain the processing of FIG.

FIG. 3 is an explanatory diagram of an example of a practical display screen by the processing of FIG.

FIG. 4 is a block diagram showing a hardware configuration of an apparatus to which the present invention is applied.

5 is a block diagram showing functions of the control circuit of FIG. 4 in the embodiment.

FIG. 6 is an explanatory diagram showing a structure of character data in the embodiment.

FIG. 7 is an explanatory diagram of conventional character display.

[Explanation of symbols]

41 ... advancing direction detecting device, 42 ... running distance detecting device, 4
3 ... Input device, 44 ... Control circuit, 45 ... RAM, 46 ...
ROM, 47, display, 48, external storage device,
51 ... Current location calculation function, 52 ... Display data search function, 5
3 ... Road background display control function, 54 ... Character display control function.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical display location G09G 5/40 9471-5G (72) Inventor Keiichi Yoshioka 1-280, Higashi Renegoku, Kokubunji, Tokyo Inside Hitachi Design Laboratory

Claims (3)

[Claims] 1. A character display method in a navigation device for displaying characters in a superimposed manner on a map, wherein when displaying a character of a first color at a given display position on the map, the display position of the character. The character is drawn in a second color different from the first color at a plurality of positions around the circumference that are shifted by a predetermined number of dots, and then the character is drawn in the first position at the display position. A method for displaying characters in a navigation device, which is characterized in that characters are drawn. 2. The character display method in a navigation device according to claim 1, wherein the second color is a background color of a map. 3. The navigation according to claim 1, wherein the drawing of the character in the second color is performed at a position shifted by one dot in eight directions vertically, horizontally and diagonally from the display position of the character. Character display method on device.