JP2807251B2 - Graphic data smoothing processing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method of tracking pixel data input by a high-resolution input device such as a scanner to obtain numerical values from graphic data represented by a unit vector group. The present invention relates to a smoothing processing method of graphic data for generating numerical data used for controlling a control machine tool.

[Conventional technology]

In recent years, in various manufacturing fields, processing such as cutting or cutting a raw material into a desired shape using a numerically controlled machine tool has been automatically performed.

For this purpose, numerical data is required as machining data.Conventionally, a machining shape is defined using a predetermined numerical control programming language, or a machining shape model is created and traced with a tool. And inputting the position directly.

However, creating the numerical data for machining by such a method requires a great deal of labor and cost.

Therefore, recently, a method of creating an original drawing of a machining shape (tool trajectory), inputting the original drawing with a high-resolution input device such as a scanner, and generating numerical data to be used for controlling a numerically controlled machine tool from the graphic data. Has come to be taken.

In this case, since the input graphic data is represented by a unit vector group by tracking pixel data, if it is output as it is as numerical data and processed by a numerically controlled machine tool, the cut or cut surface becomes sharp, and Since there is much data, the tool life is shortened.

For this reason, a smoothing process is performed in which an approximate line is determined for the read graphic data (representing a shape closed from the start point to the end point by a unit vector group) and converted into smooth data close to the original drawing.

As such a conventional smoothing processing method for graphic data, for example, the following method has been adopted.

First, the starting point of the read graphic is set as the first vertex, and a straight line connecting from the first vertex to the third vertex is drawn as an approximate straight line candidate. Then, the distance between the straight line and the second vertex is obtained, and it is compared with a preset error to determine whether the straight line is appropriate as an approximate straight line.

If the comparison result is within the error range, a straight line connecting the first vertex and the fourth vertex is then drawn as an approximate straight line candidate, and the distance between this straight line and the second vertex and the distance between the third vertex are calculated. Then, each is compared with the setting error.

Here, if both are within the error range, the same operation is performed using the straight line connecting the first vertex and the next vertex as an approximate straight line candidate, but if any one exceeds the set error, the approximation is performed. The operation of extending the straight line candidate is stopped, and the immediately preceding candidate is determined as the approximate straight line.

That is, here, a straight line connecting the first vertex and the third vertex is the first approximate straight line.

Next, the second approximate straight line is determined by starting the above operation from the third vertex.

In this way, the approximate straight line is sequentially determined by comparing the distance between the approximate straight line candidate and the vertex, and processing is performed until the approximate straight line is connected to the starting point of the figure.

There is also a method of performing such smoothing processing by arc approximation.

[Problems to be solved by the invention]

However, in such a conventional smoothing processing method, when a straight line is approximated, the connection point is not smooth, and the curved portion of the figure cannot be faithfully represented.

Then, to connect the vertices of the figure to an approximate straight line,
Since the change of the figure between the approximated vertices is considerably averaged, there is a problem that a part different from the figure of the original drawing is formed.

In addition, even when approximation is performed using arcs, since approximation is also performed between vertices of a figure, smoothing faithful to the original drawing, which captures a change in the figure between the approximated vertices, is not achieved.

The present invention has been made in view of the above points, and has as its object to perform smoothing processing on graphic data read to create numerical data for control of a numerically controlled machine tool into a shape faithful to the original drawing.

[Means for solving the problem]

In order to achieve the above object, the present invention provides a method for input data of a closed figure represented by a connection between a start point and a unit vector. When the position of the next vertex is checked and a change pattern in which the position of the vertex with respect to the above-mentioned extended line is located on the right side or the left side twice consecutively is detected, the vertex that appears first of the two vertices is approximated. An approximate section determining section that determines an approximate section of the input data based on the position that separates the approximate section, and all adjacent sections in the approximate section determined by the approximate section determining section; A midpoint calculation unit for obtaining coordinates of a midpoint between matching vertices, and a straight line for obtaining an approximate straight line or an approximate arc by the least squares method for each approximate section based on each midpoint obtained by the midpoint calculation unit The arc approximation unit and the approximation straight line or approximation arc obtained by the straight line / arc approximation unit are evaluated under preset conditions.If the conditions are satisfied, the approximation line is determined.If not, the approximation interval is shortened. An approximate line evaluation unit that determines the approximate line that satisfies the set condition by repeating the processing by the midpoint calculation unit and the straight line / arc approximation unit for the section that has been set, and an approximate line determined by the approximate line evaluation unit An intersection / arc element calculation unit for obtaining the coordinates of the intersection with the approximation line of the matching approximation section, and the coordinates of the intersection obtained by the arc element calculation unit and the data of the approximation line determined by the approximation line evaluation unit are recorded. A graphic data smoothing processing device including a data writing unit is provided.

Also, for input data of a closed figure represented by the connection of the start point and the unit vector, the position of the next vertex with respect to the extension line of the unit vector of the adjacent side is sequentially checked from the side having the start point as the start point, When a change pattern in which the position of the vertex with respect to the extension line is located on the right side or the left side twice consecutively is detected, the vertex appearing first of the two vertices is determined as a position separating the approximate section. An approximate section determining unit that determines an approximate section of the input data based on a position separating the approximate section; and coordinates of a midpoint between all adjacent vertices in the approximate section determined by the approximate section determining unit. A midpoint calculating section to be obtained, a straight line / arc approximating section for obtaining an approximate straight line and an approximate arc by the least squares method for each approximation section based on each midpoint obtained by the midpoint calculating section; The approximate straight line and the approximate arc obtained by the section are evaluated under preset conditions, and the one that satisfies the conditions is determined as the approximate line. An approximation line evaluation unit that determines an approximation line that satisfies the set conditions by repeating the processing by the unit and the straight line / arc approximation unit, and an approximation line of an approximation section adjacent to the approximation line determined by the approximation line evaluation unit. An intersection / arc element calculation unit for obtaining the coordinates of the intersection of the data, and a data writing unit for recording the coordinates of the intersection determined by the intersection / arc element calculation unit and the data of the approximate line determined by the approximate line evaluation unit. And a graphic data smoothing processing device comprising:

Further, in the graphic data smoothing processing device as described above, when the approximate line determined by the approximate line evaluation unit is an approximate arc, the data writing unit sets the starting angle as the approximate line data together with the coordinates of the intersection. It is preferable to record the arc element data such as, the end angle, the radius, and the rotation direction.

(Operation)

According to the graphic data smoothing processing device of the present invention, input data of a closed graphic represented by a connection between a start point and a unit vector is read, and an extension line of a unit vector of an adjacent side is sequentially read from the side starting from the start point. When the position of the next vertex is checked and a change pattern in which the position of the vertex with respect to the extension line is located on the right side or the left side twice consecutively is detected, the vertex that appears first of the two vertices is approximated as an approximate section. Is determined, and an approximate section of the input data is determined based on the position dividing the approximate section.

Then, the midpoint between all adjacent vertices in the approximation section is obtained, and an approximation line or an approximation line of an approximation arc is obtained by the least squares method based on each midpoint. The approximate line that satisfies the set conditions is determined by shortening the approximate section and repeating the above processing, and the approximate line data is recorded together with the coordinates of the intersection with the approximate line of the adjacent approximate section. A smoothing process faithful to the original drawing can be performed without averaging the intervals.

Also, if both the approximate straight line and the approximate arc are obtained as the approximate line of each approximate section, and the one that satisfies the preset condition is determined as the approximate line, the straight line portion and the curved portion of the figure are represented more faithfully. be able to.

When the approximation line is an approximation arc, if the arc element data such as the start angle, the end angle, the radius, and the rotation direction is recorded as the data, the approximation arc can be accurately stored with the minimum data. .

〔Example〕

Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.

FIG. 1 is a block diagram showing a functional configuration of a microcomputer which is an embodiment of the graphic data smoothing processing device of the present invention.

The functions of this microcomputer are: an input data reading unit 1, an approximate section determination unit 2, an intermediate calculation unit 3, a straight line / arc approximation unit 4,
Approximate line evaluation unit 5, intersection / arc element calculation unit 6, data writing unit 7
It is composed of

The input data reading unit 1 reads graphic data (data in which a shape of a graphic is represented by a unit vector group having a starting point position and the starting point position as a starting point) stored in an input file.

The approximate section determination unit 2 checks the next vertex position with respect to the extension line of the unit vector with the start point position of the data read by the input data reading unit 1 as a start point, and determines the approximate section based on the pattern.

The midpoint calculator 3 obtains the coordinates of the midpoint between all adjacent vertices in the approximate section for each approximate section determined by the approximate section determiner 2.

The straight line / arc approximating unit 4 calculates an approximate straight line and an approximate arc for each approximate section by the least squares method based on each midpoint group obtained by the midpoint calculating unit 3.

The approximate line evaluation unit 5 calculates the distance between the vertex in the approximate section and the approximate straight line calculated by the straight line / arc approximation unit 4 and the distance between the approximate arc and compares them with a preset condition, that is, an allowable error.
The one within the error range is determined as an approximate line.

If neither the approximate straight line nor the approximate arc is within the error range, the approximate section is shortened until an approximate line within the error range appears, and one of the approximate straight line and the approximate arc is determined as the approximate line.

The intersection / arc element calculation unit 6 obtains the coordinates of the intersection between the approximation line of the approximation section determined by the approximation line evaluation unit 5 and the approximation line of the adjacent approximation section, and at least one of the intersecting approximation lines is an approximation arc. In some cases, the starting angle, the ending angle, the radius, and the rotation direction are also obtained as arc elements of the approximate arc.

The data writing unit 7 records the data of the arc element when the coordinates of the intersection obtained by the intersection / arc element calculation unit 6 and the approximate line have an approximate arc.

Next, the smoothing processing of a figure by the microcomputer of this embodiment will be described in more detail with reference to FIGS.

 FIG. 2 is an explanatory diagram of a unit vector.

A figure read by the input data reading unit 1 is represented by a connection between a starting point position and a unit vector. The unit vector is, as shown in FIG. Centering on the second row, as shown in FIG.
A basic unit that represents positions in eight directions at 45 ° intervals. The length of a vector in the vertical and horizontal directions is a fixed unit length,
For a 45 ゜ vector, its unit length Is the length of

The unit vector is represented by a numerical value from 0 to 7, and the position from the first row to the first column to the third column is “0:
Upward left ”,“ 1: Upward ”,“ 2: Upper right ”, 2nd row, 1st and 3rd columns are“ 3; Leftward ”and“ 4: Rightward ”, from 3rd row, 1st column 3
Up to the column, "5: left down", "6: down", and "7: right down", respectively.

In other words, the graphic data to be read is obtained by expressing the starting point position of the outer periphery of the figure and the unit vector connected from the starting point position in the above-described arrangement of numerical values.

 FIG. 3 is a diagram showing an example of graphic data.

In this graphic data, the x coordinate “12” of the starting point is in the first 4 bytes of the storage area, and the y coordinate “3” of the starting point is in the next 4 bytes.
Are stored, and numerical values indicating the unit vectors in the order of connection from the starting point are stored as “4”, “4”, “2”,..., “7”.

FIG. 4 shows the trajectory of the figure based on the figure data of FIG.
FIG. 3 is a diagram represented in a dimensional coordinate system.

This coordinate system has the origin at the lower left corner, the X axis to the right,
Take the Y axis in the upward direction, and move to the right and upward from the origin, respectively.
In a coordinate system with an area of 23 units (23 × 23), point A (x,
y) = (12,3) as a starting point, connecting the unit vectors of the graphic data in FIG. 3 to A, B, C,
……, a closed figure that connects each point of Z and A with a straight line is drawn.
Points A to Z in the figure are positions where the direction of the unit vector has changed and indicate vertices of the figure. For convenience of the following description, the starting point position is set to A and is added counterclockwise in alphabetical order. .

As described above, a graphic on which the smoothing process is not performed has a locus having many irregularities.

Next, the procedure in which the microcomputer performs the smoothing process on the graphic data shown in FIG. 4 includes (1) determination of an approximate section, (2) calculation of a middle point, (3) calculation of an approximate line, and (4). Evaluation and determination of the approximate line, and (5) calculation of intersection and arc information will be described in this order.

(1) Determination of Approximate Section First, as shown in an enlarged manner in FIG. 5, the position of vertex C with respect to a straight line extending side AB in the direction of vertex B is examined.
The vertex C is located on the left side with respect to the extension direction of this straight line.
Next, when the side BC and the vertex D are similarly examined, the vertex D is located on the right side.

As described above, when the position of the next vertex with respect to the extension line of the unit vector of the adjacent side such as the side AB and the vertex C and the side BC and the vertex D is checked, the position of the vertex with respect to the extension line becomes 2 There are times when it is located on either the right or left side successively. When this pattern appears, the first vertex of the two vertices is determined as a position separating the approximate section.

Therefore, in the example of FIG. 4, since the vertex G with respect to the side EF and the vertex H with respect to the side FG are continuously located on the left side, the vertex G is assumed to be the first point dividing the approximate section, and The section is determined as the first approximate section.

The second approximation section starts from the vertex F immediately before the first divided vertex, and finds a pattern in which the vertex position is on the same side twice consecutively with respect to the above-mentioned extended line.
The first one of the vertices is defined as the break position.

Thus, in the example shown in FIG. 4, the vertices A to G are the first approximated sections, and the vertices F to H, GM, L to N, M to Q, P to R, and Q to Eight approximate sections from Y to vertices X to B are sequentially determined.

(2) Calculation of Midpoint Next, a midpoint is obtained between all adjacent vertices in the approximate section, that is, for each same direction vector.

For example, vertex A, which is the first approximate section shown in FIG.
~ G, the section of the same direction vector is AB, BC, CD, DE, E
Since there are six F and FG, if the respective midpoints are a, b, c, d, e, and f, the coordinates of the respective midpoints are calculated and obtained as a (1
3,3), b (14.5,3.5), c (15.5,4), d (16.5,4.5), e (1
8,5), f (20,6).

(3) Calculation of approximation line Next, using the coordinate data of each midpoint obtained in (2), an approximation straight line and an approximation arc are obtained by approximating each approximation section by the least squares method.

For example, for the approximate section AG, its midpoints a, b, c, d, e, f
When obtaining an approximate line by the least square method from the equation of the straight line for the approximate straight _{line, (Al 1) x + (} Bl 1) y + (Cl 1) = 0 ... coefficient Al ₁ satisfying, Bl _1, Cl ₁ (the A , B, C and A, B, C in the following equation are independent of the vertices A, B, C).

For the approximate arc, coefficients Aa ₁ , Ba ₁ , and Ca ₁ satisfying the equation of a circle, x ² + y ² + (Aa ₁ ) x + (Ba ₁ ) y + (Ca ₁ ) = 0.

When all the midpoints in the approximation section are on a straight line, the approximation arc is not determined because the approximation line is clearly a straight line.

(4) Evaluation and Determination of Approximation Line Next, the distance between the approximation straight line and the approximation arc approximating the approximation section and each vertex in the corresponding approximation section is calculated. For example, when the coordinates of each vertex in the approximate section AG are represented by (XQ, YQ), the distance L1 to the approximate straight line is calculated by the following equation based on the above equation.

The distance La between each vertex coordinate (XQ, YQ) and the approximate arc is
Above formula variant expression a _{... (x + (Aa 1)} / 2) 2 + (y + (Ba 1) / 2) 2 = (Aa 1) 2/4 + (Ba 1) 2 / 4- (Ca 1) It is calculated by the following formula based on the above.

Thus, the distance Ll between each vertex in the approximation section and the approximation straight line
The distance La between the distance and the approximate arc is set to a predetermined error Llimit and 1
We will compare the magnitude relation one by one.

 Then, it corresponds to one of the following four evaluations.

B) When all Ll satisfies Ll ≦ Llimit, and at least one La exceeds Llimit.

B) When all Las satisfy La ≦ Llimit and at least one Ll exceeds Llimit.

C) When both Ll and La exceed Llimit.

D) When Ll and La are all within Llimit.

Here, in the case of a), the approximate straight line is determined as the approximate line, and in the case of b), the approximate arc is determined as the approximate line.

In the case of d), the sum of LlΣthe sum of Ll and LaΣ
La is calculated, and its magnitude is compared, and the smaller one is determined as an approximate line.

In case (c), since the approximate line cannot be determined as it is, the approximate section is shortened and the above-described processing is performed again to obtain the approximate straight line and the approximate arc, and the above comparison is performed.

For example, if this case is satisfied in the approximate section AG,
This approximate section AG is shortened by dividing it into a section AF and a section EG.

Thereafter, an approximate straight line and an approximate arc of the section AF are obtained based on the middle points a to e shown in FIG. 5, and an approximate straight line and an approximate arc in the section EG are obtained from the middle points e and f.
Determine the approximate line by comparing with imit.

If the above case (c) is met again,
Until the case of (b) or (d) is satisfied, the approximation section is sequentially shortened to obtain an approximate line. If the two approximated lines do not satisfy the condition of Ll ≦ Llimit, the vertex coordinates are also recorded as numerical data.

(5) Calculation of Intersection and Arc Information Next, the coordinates of the intersection of the approximate lines of the adjacent approximate sections determined in (4) are determined.

In this calculation, two solutions may be calculated. At this time, the intersection located at a position closer to the midpoint of the line segment belonging to both of the two approximate sections is set as the intersection.

For example, when the intersection of the approximate arcs in the two sections, the approximate section AG and the approximate section FH, is obtained, the one closer to the midpoint f is adopted as the solution.

When the intersection of the approximate arcs is obtained, the start angle, the end angle, the radius, and the rotation direction are also calculated as the arc element data for drawing the arc.

Here, the start angle and the end angle are angles formed by a reference line (for example, X axis) of a straight line connecting the start point and the end point of the arc with the center, and the rotation direction is a direction in which the angles are measured.

The coordinates of the intersection and the data of the arc element thus obtained are recorded as graphic data.

FIG. 6 shows a recording state and a recording format of graphic data obtained by performing a smoothing process on the graphic shown in FIG.

In this table, the columns from a) to h) show the coordinates of the intersection, and the fourteenth column records the same intersection coordinates as the first column to close the figure.

For example, since the arc between the intersections B and C is a circular arc, the columns between the columns B) and C) record the starting angle, the end angle, the radius, and the rotation direction, which are the arc elements.

FIG. 7 shows a graphic drawn by using the graphic data subjected to the smoothing process, and the data has a smaller amount of data than the graphic of FIG. 4, and a smooth locus is drawn.

Next, the procedure of another smoothing process in this microcomputer will be described with reference to the flowchart of FIG.

First, in steps 1 to 3, the unit vectors are read in order from the starting point of the figure, and the first approximate section is determined by the above-described method of determining the approximate section.
When the first approximation section is determined, an approximation straight line and an approximation arc are obtained in steps 4 and 5 for this approximation section.

Further, in Steps 4 and 5, the distances between the respective vertices in the approximation section and the approximation straight line and the approximation arc are calculated, and in Steps 6 to 9, comparisons are made with the set errors, and the approximation lines within the error range are determined. I do.

Here, if it is determined in step 6 that neither the approximate straight line nor the approximate arc is applicable, and in step 7 it is determined that the approximate straight line is more appropriate, the approximate line of this approximate section is determined as an approximate straight line and the process proceeds to step 10. .

If the condition is not satisfied in step 7 and the approximate arc is better in step 8, this approximate line is determined as an approximate arc and the process proceeds to step 17.

If it is determined in step 8 that both are not applicable, the approximation line cannot be determined as it is. Therefore, the approximation section is shortened in step 16, and the process returns to steps 4 and 5 to find the approximation straight line and the approximation arc again.
Then, the determination in step 9 is performed.

If it is determined in step 6 that both of the conditions are satisfied, the process proceeds to step 9, where the sum of the distance between the approximate straight line and the vertex is compared with the sum of the distance between the approximate arc and the vertex, and the smaller one is determined as the approximate line. .

If the approximate straight line is determined, the process proceeds to step 10, and if the approximate arc is determined, the process proceeds to step 17.

At step 10, it is determined whether or not the determined approximate line is that of the first approximate section. If it is the first time, at step 15, the data of this approximate line is temporarily recorded.

If it is the second or later approximate section, the intersection with the approximate line of the adjacent approximate section that has already been temporarily recorded is determined in step 11.

Then, at step 12, when the approximate line is determined to be an approximate arc, an arc element is calculated at step 13, and data of the intersection and the arc element are recorded. At step 14, only the intersection data is recorded if it is not an approximate arc. Thereafter, in step 15, data of the approximate straight line is temporarily recorded.

When the approximate arc is determined in step 8 or step 9, it is determined in step 17 whether or not the approximate arc is that of the first approximate section. If the approximate arc is the first approximate section, the process proceeds to step 21 to temporarily record the approximate arc data. I do.

In the case of the second and subsequent approximate sections, the intersection with the approximate line of the adjacent approximate section that has already been temporarily recorded is calculated in step 18, the arc element is calculated in step 19, and the intersection and the arc element are calculated in step 20. Record the data.

Then, in step 21, the approximate arc data is temporarily recorded.

When the processing of step 21 or step 17 is completed, the process proceeds to step 22, and it is determined whether or not all of the initially determined approximate sections have been completed. Here, if there is any remaining section when the approximate section is shortened in step 16, step 4
And the process of determining the approximate line is repeated.

If there is no remaining section, the approximation of one approximation section has been completed, so the process returns to step 1 to find the next approximation section.
The above processing is performed, and data of the approximate line is recorded.

After recording the data of the approximation line of the last approximation section in this manner, the process returns to step 1 and reads the unit vector of the figure. However, since there is no data to be read, the process proceeds from step 2 to step 23.

In step 23, the coordinates of the intersection of the approximate line of the first approximate section and the approximate line of the last approximate section are calculated.

Thereafter, if it is determined in step 24 that the first approximation section is an approximate arc, an arc element is calculated in step 25 to obtain the coordinates of the intersection and the data of the arc element. Record and end the process.

In this embodiment, an approximation straight line and an approximation arc are obtained as approximation lines of each approximation section, and the one having a smaller error is selected and determined as the approximation line. Even if only one of them is determined, it is determined based on the midpoint between the vertices, so that a smoothing process more faithful to the original drawing can be performed.

〔The invention's effect〕

As described above, according to the graphic data smoothing processing apparatus of the present invention, compared with the above-described conventional smoothing processing method, there is no variation in processed graphic data, and graphic data faithful to the original drawing can be provided.

Then, when the graphic data smoothed by the graphic data smoothing processing apparatus of the present invention is used as numerical data and processed by a numerically controlled machine tool, it can be processed into a shape closer to the designed shape.

Further, since the data is reduced by the smoothing process, the load on the numerically controlled machine tool is reduced, and the life of the tool and the like can be extended.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a functional configuration of a microcomputer which is an embodiment of a graphic data smoothing processing apparatus according to the present invention, FIG. 2 is an explanatory diagram of a unit vector representing graphic data to be input, and FIG. FIG. 4 is a diagram showing an example of graphic data represented by a unit vector. FIG. 4 is an explanatory diagram for explaining an embodiment of the present invention showing an input graphic drawn in a coordinate system based on the data of FIG. FIG. 5 is an explanatory view showing a part thereof in an enlarged manner, FIG. 6 is a view showing a recording state of graphic data obtained by smoothing processing by the microcomputer of this embodiment, and FIG. FIG. 8 is a flowchart showing the procedure of smoothing processing by the microcomputer of this embodiment.

Claims (3)

(57) [Claims] 1. For input data of a closed figure represented by a connection between a start point and a unit vector, a position of a next vertex with respect to an extension line of a unit vector of an adjacent side is sequentially determined from a side having the start point as a start point. When a check is made and a change pattern in which the position of the vertex with respect to the extension line is located on the right or left side twice consecutively is detected, the vertex appearing first of the two vertices is determined as a position separating the approximate section. And
An approximation interval determining unit that determines an approximation interval of the input data based on a position dividing the approximation interval; and determining an intermediate point coordinate between all adjacent vertices in the approximation interval determined by the approximation interval. A point calculation unit, a straight line / arc approximation unit for obtaining an approximate straight line or an approximate arc by the least squares method for each approximation section based on each midpoint obtained by the unit, and an approximate line or approximation obtained by the unit The arc is evaluated under a preset condition, and if the condition is satisfied, it is determined as an approximation line. If the condition is not satisfied, the processing by the midpoint calculation unit and the straight line / arc approximation unit is repeated for a section obtained by shortening the approximation section. An approximation line evaluation unit that determines an approximation line that satisfies the set conditions; an intersection / arc element calculation unit that obtains coordinates of an intersection between the approximation line determined by the unit and an approximation line of an adjacent approximation section; Exchange requested by the department Graphic data smoothing processing apparatus characterized by comprising a data writing unit for storing data of the approximate line determined by the coordinates and the approximate line evaluation unit. 2. With respect to input data of a closed figure represented by a connection between a start point and a unit vector, a position of a next vertex with respect to an extension line of a unit vector of an adjacent side is sequentially determined from a side having the start point as a start point. When a check is made and a change pattern in which the position of the vertex with respect to the extension line is located on the right or left side twice consecutively is detected, the vertex appearing first of the two vertices is determined as a position separating the approximate section. And
An approximation interval determining unit that determines an approximation interval of the input data based on a position dividing the approximation interval; and determining an intermediate point coordinate between all adjacent vertices in the approximation interval determined by the approximation interval. A point calculation unit, a straight line / arc approximation unit for obtaining an approximate straight line and an approximate arc by the least squares method for each approximation section based on each midpoint obtained by the unit, and an approximation line to the approximate line obtained by the unit The arc is evaluated under a preset condition, and the one that satisfies the condition is determined as an approximation line. If neither of the conditions is satisfied, the intermediate point calculation unit and the straight line / arc approximation unit perform the shortening of the approximate interval. An approximation line evaluation unit that repeats the process to determine an approximation line that satisfies the set conditions; and an intersection / arc element calculation unit that obtains coordinates of an intersection between the approximation line determined by the unit and an approximation line of an adjacent approximation section. And asked by the department Graphic data smoothing processing apparatus characterized by comprising a data writing unit for recording data of the determined approximate line by the coordinates and the approximate line evaluation of intersection were. 3. The graphic data smoothing processing device according to claim 1, wherein when the approximate line determined by the approximate line evaluation unit is an approximate arc, the data writing unit approximates the coordinates of the intersection. A graphic data smoothing processing apparatus characterized by recording arc element data such as a start angle, an end angle, a radius, and a rotation direction as line data.