JPH05290160A - Method for approximating position data - Google Patents

Abstract

PURPOSE:To smoothly connect approximation position data of adjacent sections by performing approximation processing by dividing position data of a dot array shape into two straight and curved sections according to the values of the inner products at respective points of the position data. CONSTITUTION:When the approximation position of the position data is started, the inner product values at the respective points on the contour are calculated. A point where the inner product value is <=-0.99 is searched for. This point is the start point of a straight line. Then it is judged whether or not the inner product value at a point following the start point of the straight line is <=-0.99. When so, it is judged whether or not >=33 points where the inner product values are <=-0.99. When so, the section is extracted as the straight section. The section other than the extracted straight section is all extracted as the curved section. Then the points on the contour are classified by the straight section and curved section and then the respective sections are approximated with a specific function to generate approximation position data.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a position data approximation method for approximating point sequence shape position data using a function.

[0002]

2. Description of the Related Art Generally, shapes such as characters and figures are read by an image scanner, taken as image data into a computer or the like, reproduced by an output device such as a CRT or a printer, or recorded in a storage medium such as an FD. There are a lot of things to do.

In this case, it is called an outline font,
It has been practiced to read the position data of only the outline portion of characters, figures, etc. and reproduce the portion surrounded by the outline portion as characters, figures, etc.

Graphic processing using such an outline font captures the contours of characters, graphics, etc. as a point sequence shape and reads or reproduces it, but today, the position data of the original graphic is used as it is. Don't
Approximate position data obtained by approximating this using an arbitrary function is used. This is because the position data of the original figure generally requires a large capacity to be stored in the memory because of a large change, a long time is required for various data processing, and a long time is required for reproduction. By approximating this using, for example, an arbitrary cubic function, the position data can be compressed, the storage capacity can be reduced, various data processing can be speeded up, and the reproduction time can be shortened. It is possible to reproduce the reproduced figure.

In the conventional position data approximation method,
For example, when approximating the splashed portion at the lower left corner of the original figure “i” shown in FIG. 3A, the contour points of the original figure are equally divided for each desired number of points as shown in FIG. An approximate section is formed, and the position data is approximated to each of the sectioned sections using an arbitrary function.

[0006]

However, in the above-mentioned conventional position data approximation method, when determining the section to be approximated by using a function, the contour points of the original figure are set for each desired number of points. Since it was done by dividing it evenly, there are both straight and curved parts in the section,
When the approximated position data is reproduced, as shown in the approximate reproduction figure of FIG. 3C, the joint condition at the connection points of the adjacent sections is not theoretically smooth, and the reproduction quality of the position data is much higher than that of the original figure. There was an inconvenience of being inferior.

The present invention has been made in view of these points, and overcomes the above-mentioned problems in the conventional ones.
It is an object of the present invention to provide a position data approximation method capable of smoothly joining the approximate position data of adjacent sections.

[0008]

In order to achieve the above-mentioned object, the position data approximation method according to the present invention is a method for approximating position data in the form of a point sequence, which divides the position data into a section and uses a function to approximate the position data. The position data having a point sequence shape is divided into two sections, a straight section and a curved section, and approximated based on the value of the inner product at each point of the position data.

[0009]

According to the position data approximating method of the present invention having the above-described structure, when a section is divided, it is divided into a straight section and a curved section by using the inner product value of each point of the contour with respect to the position data. Therefore, the approximate position data approximated based on this is joined very smoothly, and the accuracy of the approximate position data reproduced with respect to the position data of the original figure can be made to have a desired content.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 is a flow chart showing a position data approximation method according to the present invention, FIG. 2 is a view showing a case where contour points are divided by the position data approximation method of the present invention, and FIG. 3 is an approximation. It is a figure which shows the original figure of an example of an object, and the approximate reproduction figure by the method of this invention, and the conventional method.

As shown in FIG. 1, when the position data approximation method is started, the value of the inner product at each point of the contour is calculated in step ST10.

Next, in step ST11, a point whose inner product value is -0.99 or less is searched for. This point is the starting point of the straight line.

Next, in step ST12, it is judged whether the value of the inner product of the point next to the start point of the straight line (end point of the straight line) is -0.99 or less, and if the judgment in step ST12 is YES, step The process proceeds to ST13, the end point of the straight line is extended (point next to the start point of the straight line), the process returns to step ST12, and the end point of the straight line is sequentially extended and repeated until the determination in step ST12 is NO.

If the determination in step ST12 is NO, the process proceeds to step 14.

In step 14, the value of the inner product is -0.
It is determined whether or not the points 99 or less are 33 points or more in succession, and if the determination in step 14 is YES, step S
The process proceeds to T15 and is extracted as a straight line section, and then proceeds to the next step ST16.

If the determination in step ST14 is NO, the process proceeds to step ST17 to make a curved section, and the process proceeds to step ST16.

Next, in step ST16, it is judged whether or not the judgment is completed for all points of the contour,
If the determination in step ST16 is no, step ST
The process returns to step 11 and is repeated until the determination in step ST16 is YES.

If the determination in step ST16 is YES, the process proceeds to the next step ST18, all sections other than the straight section are extracted as curved sections, and the next step ST18
Proceeding to 19, the attribute of the starting point of each section, that is, whether it is a straight line or a curve is determined, and a series of processing is ended.

As described above, in this embodiment, the point whose inner product of contour points is -0.99 or less is set as the start point of the straight line in step ST11, and the value of the inner product is-
When 33 points or more in succession of 0.99 or less are extracted as a straight line section, the remaining section is extracted as a curve section.

FIG. 2 shows an example of dividing the contour points by using the inner product as described above. This FIG. 2 is the same as FIG.
The present invention is applied to the original figure shown in FIG.

In this embodiment, when the inner product value of -0.99 or less is continuous for 33 points or more, the straight line section is used. However, the inner product value and the number of continuous points may be determined by the design concept. However, the present invention is not particularly limited to this example.

As described above, after the contour points are divided into straight line sections and curved section, each section is approximated with a predetermined function as in the conventional case to obtain approximate position data.

Next, the method of calculating the value of the inner product at each point of the contour will be described in detail.

In general, the shape of binary data can be held by a closed loop of one or a plurality of aligned point sequences. If the point sequences P1, P2, ..., Pn on the contour respectively correspond to the coordinates (X1, Y1), (X2, Y2) ... (Xn, Yn), then a certain point Pi (Xi, Yi). (N
= 1,2, ..., n), the value of the inner product can be any number
k Two points Pi-k (Xi-k, Yi-k) determined by a positive integer
), Pi + k (Xi + k, Yi + k) and using two vectors Pi-k Pi, Pi Pi + k formed by these three points Pi, Pi-k, Pi + k It can be obtained from the following equation 1.

[0026] The value of the arbitrary number k may be determined according to the design concept and is not particularly limited to this embodiment.

As described above, according to this embodiment, the value of the inner product of the points of the contour is calculated, and the point which is smaller than a predetermined value among the values of the inner product is used to approximate the straight section and the curved section. Since the reproduced approximated figure has an extremely smooth connection between the straight line and the curved line, the approximated accuracy in each approximated section can be improved.

FIG. 3 shows a concrete example according to the method of the present invention. The original figure of FIG. 3a is approximate reproduced based on the method of the present invention, and the figure of FIG. 3b is approximate reproduction based on the conventional method. It can be seen that the reproduction accuracy is extremely superior to the figure shown in FIG.

The present invention is not limited to the above embodiment, but can be modified as necessary.

[0030]

As described above, according to the position data approximating method of the present invention, the reproduced approximate figure has a very smooth connection state between adjacent approximating sections, and the approximation within each approximating section is made. It has an extremely excellent effect of improving accuracy.

[Brief description of drawings]

FIG. 1 is a flowchart showing a method of approximating position data according to the present invention.

FIG. 2 is a diagram showing a case where contour points are divided by the position data approximation method of the present invention.

3A is an original figure that is a target of approximate reproduction, b is an approximate reproduction figure by the method of the present invention, and c is an approximate reproduction figure by a conventional method.

FIG. 4 is a diagram showing a case where contour points are divided by a conventional method.

Claims (1)

[Claims] 1. A method for approximating position data in which point position shape position data is divided into intervals and is approximated using a function, the point sequence shape position data is calculated based on an inner product value at each point of the position data. A method for approximating position data, characterized by dividing and approximating into two approximation sections, a straight section and a curved section.