JP2001148026A - Method and device for graphic processing, and recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a graphic processor capable of drawing a smooth graphic even though data quantity to be processed is made to be small, and a recording medium. SOLUTION: In a step 100, coordinates are inputted from a map data input device 5. In a step 110, a spline interpolation function is calculated so as to connect the coordinates with a smooth curve. In a step 120, coordinate strings of resolution necessary to a display scale are obtained from a point on the spline interpolation function. In a step 130, display data obtained by connecting the obtained coordinate strings with a straight line are outputted to a display device 11. In a step 140, the display device 11 displays a map.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a graphic processing method, a graphic processing apparatus, and a recording medium applicable to, for example, a car navigation system.

[0002]

2. Description of the Related Art In recent years, some vehicles include a car navigation system (hereinafter also referred to as a navigation system) as a device for road guidance or the like. The navigation system includes a GPS (Global Positioning System) signal that detects the position of the vehicle based on radio waves from satellites, a geomagnetic sensor, a gyro, and other sensors that detect the running state of the vehicle, maps, etc. CD that stores data etc.
A storage device such as a ROM, a display for displaying map data, a navigation system control device which is a computer for controlling the map data, and the like.

[0003]

In the navigation system described above, for example, when a line indicating a road or the like is drawn, a plurality of coordinate points are given, and a straight line is interpolated between the coordinate points.
This method has an advantage that data can be created and displayed in a simple procedure, but has the following disadvantages.

When the shape is complicated, the number of coordinate points increases, and the data amount increases. For this reason, the processing time becomes longer, and much time is required for drawing. In addition, since linear interpolation is used, the display is bent in a straight line, and the display is not smooth.

[0005] It is necessary to prepare data in which the thinning rate is changed in accordance with the display scale, so that there is a waste in storing duplicate data for each scale. For example, as shown in FIG. 6, in the case of a map of 10,000, 40,000 and 160,000 maps, data (coordinate data) of coordinate points (indicated by black circles) corresponding to each scale is stored. , And drawn figures of each scale using the coordinate data. FIG.
Although the figures are drawn with different sizes to show the positions of the corresponding figures, the figures are actually the same size on the display.

The reason for storing coordinate data for each scale as described above is that if, for example, it is attempted to draw 160,000 figures using fine coordinate data suitable for 10,000 figures, the amount of data becomes enormous. This is because processing cannot be performed. Conversely, 1
This is because trying to draw a fine figure of 10,000 figures using coarse coordinate data suitable for 60,000 figures becomes a simple line, and a sufficiently accurate curve cannot be drawn.

The present invention has been made in view of the above problems, and has as its object to provide a graphic processing method, a graphic processing apparatus, and a recording medium capable of drawing a smooth graphic even when the amount of data to be processed is reduced. I do.

[0008]

Means for Solving the Problems (1) In order to achieve the above object, the invention according to claim 1 uses basic coordinate data indicating basic coordinates and connects the coordinates indicated by the basic coordinate data. An interpolation function, which is a function passing through the coordinates or a neighborhood thereof, is obtained. Interpolation coordinate data for realizing a predetermined drawing accuracy by complementing the coordinate data with the interpolation function is obtained, and the basic coordinate data and the interpolation coordinate data are obtained. The gist of the present invention is a graphic processing method characterized by drawing a graphic by connecting the coordinates indicated by.

According to the present invention, a figure is created by obtaining interpolated coordinate data from basic coordinate data by an interpolating method such as Lagrange interpolation or the like, and drawing a line connecting the coordinates by using the interpolated coordinate data. . Thereby, a smooth line or the like can be drawn from a small amount of basic coordinate data.

Here, the predetermined drawing accuracy indicates, for example, when a line is drawn, the degree of smoothness of the curve of the line. (2) The invention according to claim 2 is a storage means for storing basic coordinate data indicating basic coordinates, and using the basic coordinate data, the coordinates or the coordinates thereof so as to connect the coordinates indicated by the basic coordinate data. Interpolating function calculating means for obtaining an interpolating function that is a function passing through the vicinity; and interpolating coordinate data calculating means for obtaining, from the interpolating function, interpolating coordinate data for complementing the basic coordinate data and achieving predetermined drawing accuracy. And a figure creating means for drawing a figure by connecting the coordinates indicated by the basic coordinate data and the interpolation coordinate data.

In the present invention, an interpolation function such as a spline interpolation function for smoothly connecting the basic coordinate data is obtained by the interpolation function calculating means using the basic coordinate data stored in the storage means. Next, the interpolation coordinate data calculating means obtains the interpolation coordinate data according to the accuracy (smoothness) of the figure to be created by using the interpolation function. Then, a figure is drawn by the figure creating means by connecting the coordinates indicated by the basic coordinate data and the interpolation coordinate data.

Thus, as in the first aspect, a smooth line or the like can be drawn from a small amount of basic coordinate data. (3) The graphic processing apparatus according to (2), wherein the coordinates indicated by the basic coordinate data and the interpolated coordinate data are connected by a straight line.

The present invention exemplifies means for connecting the coordinates indicated by the respective coordinate data, and here, the respective coordinates are connected by a straight line. As a result, the process of creating a figure can be simplified. In addition, since interpolation coordinate data suitable for desired drawing accuracy is obtained, a sufficiently smooth curve or the like can be obtained even when each coordinate is connected by a straight line.

(4) The graphic processing apparatus according to the above (2) or (3), wherein the interpolation coordinate data is determined in accordance with the resolution of the scale of the graphic to be created. Make a summary. Even if the figures have the same shape, if the scales are different, the required resolution is different.

For example, in the case of a large scale (for example, 10,000 figures)
Since a fine figure is drawn, a large resolution is required. Therefore, it is necessary to obtain a large amount of interpolated coordinate data and smoothly draw a highly accurate line or the like. On the other hand, in the case of a small scale (for example, 160,000 figures), a coarse figure is obtained, so that a very high resolution is not required. Therefore, it is sufficient to roughly draw a line or the like using a relatively small number of interpolation coordinate data (only basic coordinate data in some cases).

Therefore, in the present invention, the interpolation coordinate data and the like to be used are determined according to the scale of the figure to be created. As a result, since only the necessary data amount needs to be processed at all times, there is an advantage that the memory can be saved and the calculation speed is improved. (5) According to a fifth aspect of the present invention, there is provided a graphic processing apparatus according to any one of the second to fourth aspects, wherein the graphic is a graphic showing a map.

The present invention exemplifies the types of figures. Here, a map is given as an example of a graphic. For example, when a line indicating a road or the like is drawn on each of different scales, if the above-described drawing method is applied, the accuracy (smoothness) according to the scale is obtained. This has a remarkable effect that an optimum line can be drawn.

(5) The graphic processing apparatus according to any one of claims 2 to 5, wherein the graphic is a graphic used for displaying road information in a navigation system. Make a summary.

In this navigation system,
For example, a terrain, a road, a route, and the like can be displayed on a display such as a liquid crystal display based on the map data. A curve or the like can be drawn with optimal accuracy (smoothness) according to the scale.

Further, in the conventional navigation system, coordinate data is redundantly stored in accordance with each scale. In the present invention, however, it is not necessary to store coordinate data redundantly, so that the memory is largely saved. There is an advantage that you can. (7) According to a seventh aspect of the present invention, there is provided a recording medium storing means for executing a process by the graphic processing device according to any one of the second to sixth aspects.

According to the present invention, there is provided a recording medium storing means for executing control by the graphic processing apparatus according to any one of claims 2 to 6. For example, examples of the recording medium include various recording media such as an electronic control unit configured as a microcomputer, a microchip, a floppy disk, a hard disk, and an optical disk.

That is, there is no particular limitation as long as it stores means such as a program which can execute the control of the graphic processing apparatus described above.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a graphic processing apparatus and a recording medium according to the present invention will be described below in detail with reference to the drawings using examples (embodiments). (Embodiment) In this embodiment, a car navigation system (hereinafter, referred to as a navigation system) mounted on a vehicle will be described as an example of a graphic processing apparatus.

A) First, a schematic configuration of the navigation system according to the present embodiment will be described with reference to FIG. As shown in FIG. 1, in the navigation system, an electronic control device (control circuit) 1 includes a position detector 3, a map data input device 5, an operation switch group 7, an external memory 9, a display device 11, and an external information input device. 13 and a remote control sensor 15 and the like.

Hereinafter, each configuration will be described. The electronic control unit 1 is configured as a microcomputer,
Inside, well-known CPU, ROM, RAM, I / O
O and a bus line connecting them (not shown).

The position detector 3 includes a geomagnetic sensor 17, a gyroscope 19, a distance sensor 21 for detecting a distance, and a GP for detecting the position of a vehicle based on radio waves from a satellite.
It has a GPS receiver 23 for S (Global Positioning System). Since these sensors 17 to 23 have errors having different properties, they are configured to be used while interpolating by a plurality of sensors. Note that, depending on the accuracy, the above-described sensors 17 to 2
3 may be used, and a steering rotation sensor, a wheel sensor for each rolling wheel, or the like may be used (not shown).

The map data input device 5 includes map matching data, map data,
And various types of data including mark data. The medium for storing the data is the external memory 9.
-A ROM is generally used, but various media such as a memory card and a DVD can be used.

The operation switches 7 include, for example, a touch switch integrated with the display device 11 disposed on the dashboard of the driver's seat, a mechanical switch provided on an operation panel (not shown), and the like. . By operating the operation switches 7 by a driver or the like, the coordinates of the destination can be input to the navigation system.

The display device 11 is a color display device (display). The screen of the display device 11 displays the current vehicle position mark input from the position detection device 3 and the map data input from the map data input device 6. And additional data such as a guidance route to be displayed on a map can be displayed in a superimposed manner.

The external information input / output device 13 is a device that receives information provided from the outside (for example, a VICS system) and transmits information to the outside. Information received from outside is processed by the electronic control unit 1 and, if necessary,
The information processed by the electronic control unit 1 is transferred to the external information input / output unit 1
Output from 3.

In this navigation system, a remote control terminal (remote control) 25 sends a remote control sensor 1
When the position of the destination is input via the control switch 5 or the operation switch group 7, an optimal route from the current position to the destination is automatically selected, and a guidance route is formed and displayed. Has functions. Note that various methods such as the Dijkstra method are known as a method for automatically setting the optimum route.

B) Next, the principle of drawing a line such as a road in the navigation system having the above configuration will be described. Given n points, the value of the function f (x) is given as f _i
= F (x _i ) (i = 1,2,... N), obtaining the value of F (x _t ) at another point x _t is called an interpolation method.
Lagrange interpolation is a typical interpolation method for the entire function.

The Lagrange interpolation method is, for example, i =
2 (when x ₁ , f ₁ , x ₂ , f ₂ are known), as an example, the following function (i−1) (and thus a linear function in this case) Can be approximated. and _{f 1 = ax 1 + b f} 2 = ax 2 + b, a, setting the _{b, f 1 -f 2 = a} (x 1 -x 2) _{thus, a = (f 1 -f 2} ) / (x 1 −x ₂ ) b = {(f ₂ −f ₁ ) / (x ₁ −x ₂ )} * x ₁ + f _{2 From} this, the straight line F (x) to be obtained is given by the following equation.

F (x) = {(x−x ₂ ) / (x ₁ −x ₂ )} * f ₁ + {(x−x ₁ ) / (x ₂ −x ₁ )} * f ₂ Then, for example, in order to obtain the curve shown in FIG. 2A, a large amount of position data was necessary to connect the coordinates P1 to P9 with a straight line. However, if Lagrange interpolation is used, FIG. As shown in FIG. 2B, a quadratic function (y = y) using data (coordinates P1, P5, P9) having a small three-point portion is used.
ax ² + bx + c)
A smooth curve can be obtained.

As an application of Lagrange interpolation,
Spline interpolation is known. The spline interpolation is an interpolation method in which approximation using different n-order polynomials is performed in each section so that the derivatives of the (n-1) th order become equal at the joint of the sections. By using this, it is possible to obtain an interpolation function that smoothly connects continuous coordinate sequences.

Specifically, as shown in FIG. 3, for example, when coordinates Q1 to Q5 are given, data of three points (coordinates Q1 to Q3) in the first section are used and a quadratic function is used. Approximation is performed, and data for three points (coordinate Q
3 to Q5), approximation is performed by a quadratic function. At the same time, the curve is adjusted so that the derivatives of the two quadratic functions become equal at the coordinates Q3 at the boundary of the section.

As a result, a smooth curve can be obtained over the entire section. Further, among the spline interpolations, general cubic spline interpolation will be described. -Divide all sections [a, b] into n small sections.

I = [x ₀ , x ₁ ], I ₂ = [x ₁ , x ₂ ],
..., represented by _{I n = [x n-1} , x n] a cubic expression defined in each interval I _k f _k (I _k
Valid only with). If the first- and second-order derivatives are equal at the joint of the section, f _k ′ = f ′ _{k + 1} , f _k ″ = f ″ _{k + 1} , (k = 1, 2,・ ・, N-1) ・ Based on the above conditions, the three-dimensional polynomial f
_k , (k = 1, 2,..., n-1).

[0039] · f _"k is a first-order equation, f in x = x _k" and put the _{f "k-1 = F k} -1 in the _{k = F k x = x k} -1, the following formula (1 ) Is obtained.

[0040]

(Equation 1)

If this is differentiated twice, the following equation (2) is obtained.

[0042]

(Equation 2)

.F_k-1, F_kIs f_k-1= F_k-1・ ｛(H_k ^Two) / 6｝ + C_kx_k-1+ D_k f_k= F_k・ ｛(H_k ^Two) / 6｝ + C_kx_k-1+ D_k  ・ Solving this, C_k= (1 / h_k) ・ ｛(F_k−f_k-1)-(H_k ^Two/ 6)
(F_k-F_k-1)｝ D_k= (1 / h_k) ・ ｛(X_k・ F_k-1-X_k-1・ F_k)-(H_k ^Two/ 6) (x_k・ F_k-X_k-1・ F_k-1Substituting this into equation (2) yields equation (3) below.
You.

[0044]

(Equation 3)

In order to obtain Fk, the following equation (4) is obtained by differentiating equation (3) and setting f ' _k = f' _k-1 .

[0046]

(Equation 4)

In the above equation (4), F ₀ =
If F _n = 0, the following equation (5) is obtained.

[0048]

(Equation 5)

Solving this, finding F _k and substituting it into equation (3) yields the spline interpolation polynomial f _k . -Here, when the section widths are equal (when h _k = h)
Obtains the following equation (6).

[0050]

(Equation 6)

That is, spline interpolation can be performed by performing the above calculations in the electronic control unit 1.
Therefore, in the present embodiment, as described below, the above-described spline interpolation is performed, and a smooth line indicating a road or the like can be drawn from a small amount of coordinate data.

C) Next, a control process performed by the electronic control unit 1 based on the above principle will be described with reference to flowcharts and the like. As shown in the flowchart of FIG. 4, first, in step 100, coordinates are input from the map data input device 5.

Thus, for example, coordinates R1 to R3 (coordinates indicated by basic coordinate data) as shown by black circles in FIG. 5A are given. Although only three points are shown here for the sake of simplicity, actually, in a subsequent step 110 of inputting a large number of coordinates, a spline interpolation function is used to connect the coordinates with a smooth curve. Ask for. For example, by performing the above-described cubic spline interpolation, FIG.
An interpolation function showing a smooth curve as shown in FIG.

In the following step 120, a coordinate sequence (coordinate sequence indicated by interpolation coordinate data) having a resolution required for the display scale is obtained from a point on the spline interpolation function, for example. Here, the resolution is an ability to realize a curve with a desired accuracy (smoothness) at each scale, and the resolution is represented by a required number of coordinates. Therefore, in order to realize high resolution, it is necessary to obtain many coordinates. In FIG. 5C, the coordinates indicated by white circles are the coordinates obtained from the spline interpolation function.

In the following step 130, display data in which the obtained coordinate sequence represented by white circles and black circles (coordinate sequence represented by basic coordinate data and interpolation coordinate data) is connected to a straight line is output to the display device 11. As a result, FIG.
Can be displayed as a smoothly curved line as shown in FIG.

In the following step 140, a map is displayed on the display device 11, and the present process is terminated once. As described above, in the present embodiment, coordinate data (interpolated coordinate data) having a resolution corresponding to the scale of the figure to be drawn is obtained from the spline interpolation function using a given small number of coordinate data (basic coordinate data), and these coordinates are obtained. By drawing a straight line so as to connect the coordinates indicated by the data, a line such as a road can be drawn.

That is, in the present embodiment, as shown in FIG. 6 of the related art, each scale does not have coordinate data, but as shown in FIG. With the coordinate data, necessary coordinate data is obtained from the coordinate data by spline interpolation or the like, and a figure can be drawn from the coordinate data. FIG. 7 shows an image area equivalent to 40,000 figures.

For example, in the case of 10,000 figures, the coordinates S1 to S4
Not only obtained by spline interpolation (coordinates S1
〜S2, S2ＳS3, S3〜S4), and based on these coordinates, a precise road figure similar to FIG. 6A can be drawn.

For example, in the case of 40,000 figures, the coordinates S1
Not only S4 but also coarser than the 10,000 figure obtained by spline interpolation, but coordinates (between the coordinates S1 to S4) are obtained, and based on these coordinates, the same as FIG. You can draw precise road shapes.

Further, for example, in the case of 160,000 figures, the coordinates S
Coordinates required for 160,000 figures (S1, S4,
S8) is selected, and based on these coordinates, FIG.
You can draw road shapes similar to. The coordinates of other areas are selected with the same roughness.

That is, in the present embodiment, since a figure is drawn by the above-described method, it is not necessary to have a large amount of coordinate data as in the related art. Therefore, there is a remarkable effect that a minimum memory is required even when a large-scale figure such as 10,000 figures is drawn. In addition, by obtaining necessary coordinate data using a spline interpolation function as compared with the conventional linear interpolation, a smooth curve can be drawn.

In particular, in the past, in the case of a small scale such as 160,000 figures, the line was extremely linear, but in this embodiment, a smooth curve can be realized without increasing the coordinate data so much. There is an advantage that you can. It is needless to say that the present invention is not limited to the above-described embodiments, and can be implemented in various modes without departing from the technical scope of the present invention.

(1) For example, in the above-described embodiment, spline interpolation has been described as an example of the interpolation method, but other interpolation methods such as interpolation using a Bezier curve and interpolation using a Nurves can be used. Here, the Bezier curve is one of the techniques for expressing a curve, a curved surface, or the like in graphics or the like, and based on some given points (control points), a smooth connecting them. Curve (curved surface)
Ask for.

The Bezier curve, unlike the spline curve, passes only the first and last control points among the given control points, but the control points between them are used only to determine the shape of the curve. No (just pass nearby).
-Nervs is one of the methods of expressing free curves and free-form surfaces, and expresses curves and surfaces as piecewise rational expressions using parameters, using the names of conventional Beziers and B-splines. It is a generalized version of a piecewise polynomial curve / surface called.

In this nervous system, a B-spline curve / surface in a four-dimensional space having (x, y, z, w) coordinates is projected H: (x, y, z, w) → (x / w, y / W, z /
Through w), it is mapped to a three-dimensional space that is an actual modeling target. (2) In the above-described embodiment, the graphic processing device in the car navigation system has been described.
Applicable for many applications.

In particular, when drawing figures with different scales using the same position data, position data at all scales can be reduced, which is a great effect for saving memory. (3) Further, the present invention is not limited to a graphic processing device such as a car navigation system, but also includes a recording medium storing means for executing control by the graphic processing device.

Examples of the recording medium include various recording media such as an electronic control unit configured as a microcomputer, a microchip, a floppy disk, a hard disk, and an optical disk. That is, there is no particular limitation as long as it stores means such as a program that can execute the control of the graphic processing apparatus described above.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram illustrating a navigation system according to an embodiment.

FIG. 2 is an explanatory diagram showing a basic interpolation method.

FIG. 3 is an explanatory diagram showing a spline interpolation method.

FIG. 4 is a flowchart illustrating graphic processing according to the embodiment.

FIG. 5 is an explanatory diagram illustrating a procedure of graphic processing according to the embodiment;

FIG. 6 is an explanatory diagram showing a conventional graphic process at each scale.

FIG. 7 is an explanatory diagram showing graphic processing for all scales according to the embodiment.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 electronic control device (control circuit) 3 position detector 5 map data input device 11 display device

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) G09B 29/00 G06F 15/62 335 5H180 29/10 15/66 410 F term (reference) 2C032 HB22 HC08 HC24 2F029 AA02 AB01 AB07 AB09 AC02 AC04 AC14 5B050 AA10 BA07 BA17 EA21 FA02 5B057 AA13 CA12 CB12 CD05 CF05 5B080 AA01 AA06 AA07 FA16 5H180 AA01 BB02 BB04 BB12 BB13 FF04 FF05 FF12 FF13 FF22 FF27 FF32

Claims (7)

[Claims] 1. An interpolating function which is a function passing through the coordinates or its vicinity so as to connect the coordinates indicated by the basic coordinate data is obtained using basic coordinate data indicating basic coordinates,
This interpolation function complements the coordinate data to obtain interpolation coordinate data for realizing a predetermined drawing accuracy, and draws a figure by connecting the coordinates indicated by the basic coordinate data and the interpolation coordinate data. Figure processing method. 2. A storage means for storing basic coordinate data indicating basic coordinates, and a function passing through the coordinates or its vicinity so as to connect the coordinates indicated by the basic coordinate data using the basic coordinate data. Interpolation function calculation means for obtaining a certain interpolation function; interpolation coordinate data calculation means for obtaining interpolation coordinate data for complementing the basic coordinate data to achieve a predetermined drawing accuracy from the interpolation function; and the basic coordinate data. And a figure creating means for drawing a figure by connecting the coordinates indicated by the interpolated coordinate data. 3. The graphic processing apparatus according to claim 2, wherein the coordinates indicated by the basic coordinate data and the interpolated coordinate data are connected by a straight line. 4. The graphic processing apparatus according to claim 2, wherein the interpolation coordinate data is determined according to a resolution of a scale of a graphic to be created. 5. The graphic processing apparatus according to claim 2, wherein said graphic is a graphic showing a map. 6. The graphic processing apparatus according to claim 2, wherein the graphic is a graphic used for displaying road information in a navigation system. 7. A recording medium storing means for executing processing by the graphic processing device according to claim 2. Description: