JPH0535862A - Automatic shaping system for outline vector - Google Patents

Abstract

PURPOSE:To obtain the automatic shaping system for the outline vector which generates a character pattern of high quality. CONSTITUTION:A point as a corner is judged from tracking code arrays in four directions at the boundary point of a contour boundary picture element and regarded preferentially as an inflection point to generate a vector. Namely, the boundary point is tracked clockwise in a rightward tracking direction 0, an upward tracking direction 1, a leftward direction 2, and a downward direction 3 to obtain '110100' as the tracking code array at the boundary point of the boundary picture elements where one picture element is absent at the corner part. Tracking code arrays are applied to a prepared table in order and when a coincidence is obtained, -1 is added to the (x) and (y) values of the boundary point corresponding to a 4th tracking code '1' to move the boundary point to the corner part. Then the boundary point is tracked including the boundary point according to the tracking codes to obtain '111000'. Then this corrected corner point is the boundary point of the picture element at the corner part, so this boundary point is set preferentially as the inflection point of the vector.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an outline vector automatic shaping method for automatically vectorizing an outline (contour) of a character pattern formed as a dot pattern.

[0002]

2. Description of the Related Art Conventionally, a character read by a scanner or the like is converted into outline data for use, or a ROM is used.
When enlarging / reducing a character pattern that is configured as a dot pattern stored in a storage device such as a storage device, vectorization processing is performed to shape the contour of the character pattern and make it a clean and unbroken character. Is going.

Various outline vector automatic shaping methods have been considered in the past. For example, in Japanese Patent Laid-Open No. 64-68889, a chain code code string for tracking the center of a boundary pixel is used to outline a figure. There is disclosed a method in which the right-angled portion is detected by determining the bending state of and the neighboring pixels are selected as vector points. In addition, JP-A 1-9279
No. 5 discloses a method for eliminating noise in a right-angled portion by obtaining an angle of a contour line between horizontal / vertical components of a contour vector and generating an intersection under a certain threshold condition. Has been done.

[0004]

In the conventional outline vector automatic shaping method, when an angle is obtained and an intersection is generated, it takes a long time to obtain the angle. The method of doing was desired. In the case of using the chain code code string for tracking the center of the boundary pixel, when the straight line of one pixel width is projected, the center of one boundary pixel is made to correspond twice, so the character is enlarged. In this case, there is a problem in that this straight line remains the width of one pixel. In particular, when an image is input with a scanner or the like, pixels at the corners are often missing, but if there are no pixels at the boundaries of the corners, the pixels near the boundary pixels Since pixels are vector points, there is a drawback that distortion occurs when vectorized.

Therefore, an object of the present invention is to provide an automatic outline vector shaping method capable of generating a character pattern of higher quality than before with a short processing time.

[0006]

As means for achieving the above object, in an outline vector automatic shaping system for extracting some of boundary pixels which are contours of a binary image and vectorizing them, the boundary pixels are The four-direction tracking code string of the boundary point is determined, a corner point is determined from the tracking code string, the boundary point is moved to this position, and the moved boundary point is preferentially defined as a bending point. The present invention is intended to provide an outline vector automatic shaping method characterized by performing vectorization.

[0007]

In the present invention, attention is paid to the fact that pixels at the corners are often missing, and in order to correct the missing pixels, the boundary points of the boundary pixels are traced and the corners are arranged according to the arrangement of the boundary points. Then, by moving the point to the position where the horizontal / vertical lines intersect in this part, and generating the vector by preferentially using this moved point as the contour point of the bent part, It is possible to minimize the distortion of the portion that becomes.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the automatic outline vector shaping method of the present invention will be described with reference to the drawings. In this embodiment, a figure (character pattern) consisting of black pixels in the input image
, The image is scanned from left to right and from top to bottom, and the boundary point around the black pixel, which is the boundary pixel starting from the upper left black pixel found first, becomes the right pixel. When generating an outline vector of a character pattern from a tracking code string obtained by tracking around, if a pixel at a corner is missing, it is considered to correct the missing pixel. In this embodiment, as shown in FIG.
The direction of tracking the boundary point of the black pixel that becomes this boundary pixel is
Define the basic tracking code as "0" for rightward direction, "1" for upward direction, "2" for leftward direction, "3" for downward direction, The boundary point which is the original part of this tracking code (arrow) is defined as the boundary point corresponding to this tracking code. Then, when the input image includes a figure as shown in FIG. 2, the boundary point around the boundary pixel is set to the right according to the tracking code shown in FIG. When traced around, a trace code string "000033333221112211" is obtained.

Since the portion where the value of the tracking code is the same in this tracing code string shows a straight line, vectorization may be performed using the portion where the value of the tracking code changes. , If the pixel at the corner such as the pixel b is missing, the values of the tracking codes of the pixels c and d on both sides of the pixel are changed, so that the vector amount is increased or the character is distorted when the vector is generated. It becomes a cause. Therefore, the missing pixel is corrected and then vectorized. Even if the scanning direction (starting point) is changed, the correction pattern described below is the same as long as the tracking is performed in the clockwise direction.

First, if there is no one pixel at the corner,
A case will be described where the boundary pixels of two vertical pixels are used to correct this pixel. If there is no 1 pixel per corner,
Four cases shown in (A) to (D) can be considered. Then, when the boundary points of the boundary pixels of horizontal / vertical two pixels at this time are traced clockwise according to the tracking code shown in FIG. 1, they become as shown in FIGS. 4 (A) to 4 (D), respectively. Figure 3
(A) shows a case where the pixel in the upper left corner is missing. The tracking code string at the boundary point of the boundary pixels at this time is “110100” as shown in FIG. Then, when such a tracking code string is obtained, the boundary point corresponding to the fourth tracking code “1” is moved by (x, y) = (− 1, −1), and again according to the tracking code. If the boundary point is traced, it becomes “111000”. Explaining this in a little more detail, a table for moving points as shown in FIG. 5 is prepared, and tracking code strings are sequentially applied to this table. When this tracking code string matches “110100”, Then, by adding -1 to each of the x value and the y value of the boundary point corresponding to the fourth tracking code "1", the boundary point is moved to a position where the pixel moves to a corner portion. .. And
When the boundary point is traced again according to the tracking code including the moved boundary point, it becomes “111000”. Note that x and y are the boundary points of the upper left pixel of the image (0,0)
Is the value when the x axis is in the right direction and the y axis is in the down direction. Then, since the moved and corrected boundary point becomes a boundary point for the pixel in the corner portion, as shown in FIG. 6A, this boundary point is preferentially set so as to become a vector bending point P. By doing so, the upper left corner can be vectorized without error.

FIG. 3B shows the case where the pixel in the upper right corner is missing, and FIGS. 3C and 3D show the pixel in the lower left corner and the lower right corner, respectively. The case is shown. Then, the tracking code strings at the boundary points of the boundary pixels at this time are "0" shown in FIGS. 4B to 4D, respectively.
03033 ”,“ 221212 ”, and“ 332322 ”. In these cases as well, as in the case where the pixel in the upper left corner is missing, when the tracking code string matches the tracking code string shown in FIGS. The fourth tracking code “0” in the tracking code string,
The boundary points corresponding to "2" and "3" are respectively (x, y)
= (+ 1, -1), (-1, +1), (+1, +1) A table for moving is prepared, the tracking code sequence is sequentially applied, and the same tracking code as in FIGS. When it becomes a line, by moving the boundary point to the corner part and then again tracking the boundary point according to the tracking code,
A tracking code string (“000333”, “22211”) that includes boundary points corresponding to the pixels of the corners that have been moved and corrected.
1 ”,“ 333222 ”) can be obtained. Then, the boundary points of the corrected corners are respectively shown in FIG.
By preferentially setting the bending point P of the vector as shown in (B) to (D), the corner portion can be vectorized without error. In this embodiment, the tracking code string is applied to the pattern of the tracking code string prepared in each table, and when they match, the boundary point (pixel) is moved to generate the tracking code again. I is a tracking code in a certain direction, and this tracking code i and 9
If a tracking code different by 0 ° is j, the tracking code string in this case where there is no one pixel in one corner is “iijijj”, so this tracking code string may be directly converted to “iiiijj”.

Next, if there is no pixel at one corner,
A case will be described in which this pixel is corrected from the boundary pixels of three vertical pixels. When there is no one corner pixel, as in the case shown in FIGS. 3A to 3D described above, FIGS.
Four cases shown in (D) can be considered. Then, when the boundary points of the boundary pixels for each of the horizontal / vertical three pixels at this time are traced clockwise according to the tracking code shown in FIG. 1, the results are as shown in FIGS. FIG. 7A shows a case where the pixel in the upper left corner is missing.
The tracking code string at the boundary point of the boundary pixels at this time is shown in FIG.
As shown in (A), it is “11101000”. In the case of such a tracking code string, the boundary point corresponding to the fifth tracking code “1” is (x, y) = (− 1, −)
1) When a boundary point is moved to a corner portion using a moving table and the boundary point is traced again according to the tracking code, the result is “1110000”. Since the corrected boundary point becomes the boundary point of the pixel in the corner portion, the corner portion is vectorized without error by preferentially setting the boundary point so as to be the bending point of the vector. be able to.

Also, when the pixels at the upper right corner, the lower left corner, and the lower right corner shown in FIGS. 7B to 7D are missing, the tracking code of the boundary point of the boundary pixel is similarly obtained. The columns are
“0003033” shown in FIGS. 8B to 8D, respectively.
3 ”,“ 22212111 ”, and“ 33323222 ”. And in these cases, as in the case above,
Apply the tracking code sequence to the table in sequence, and
When the tracking code strings shown in (B) to (D) are matched,
The fifth tracking code “0”, “2” in the tracking code string,
The boundary points corresponding to “3” are (x, y) = (+
1, −1), (−1, +1), (+1, +1) to make a boundary point that becomes a corner part, and again by tracking the boundary point according to the tracking code, the moved and corrected corner A tracking code string (“00003333”, “22222111”, “3
3332222 ") can be obtained. Then, by preferentially setting the corrected boundary points of the corner portions so as to be the bending points of the vector, the corner portions can be vectorized without error. Also in this embodiment, if the tracking code in a certain direction is i and the tracking code different from this tracking code i by 90 is j, the tracking code string in this case where there is no one pixel in one corner is "iiiijijj".
j ”, this trace code string is changed to“ iiiiiijjj
It may be converted into “j”.

Both of the above-described two embodiments show the case where there is no one pixel at one corner, but when the correction is made from the boundary pixels of every two horizontal / vertical pixels, the correction can be made with a small amount of information. Suitable for complex characters or Gothic characters with many corners such as characters and Chinese characters with few pixels. When correcting from boundary pixels of 3 pixels, hiragana with many curves and many pixels Suitable for letters and Mincho typeface. Therefore, more accurate correction can be performed by properly selecting whether to perform correction with 2 pixels or with 3 pixels depending on the size and type of character, the type of font, and the like.

As a third embodiment, a case will be described in which, when there are no two corner pixels, this pixel is corrected from neighboring horizontal and vertical three boundary pixels. When there are no two corner pixels, eight cases shown in FIGS. 9A to 9H can be considered. Then, when the boundary points of the boundary pixels at this time are tracked in the clockwise direction according to the tracking code shown in FIG. 1, the results are as shown in FIGS. FIG. 9A shows the case where the pixel in the upper left corner is missing. The tracking code string at the boundary point of the boundary pixels at this time is shown in FIG.
As shown in (A), it is “111001000”.
In the case of such a tracking code string, the boundary points corresponding to the fifth and sixth tracking codes “01” are both (x, y).
= (-1, -1) Use a table that moves so that the boundary point moves to the missing corner part and its neighbor, and again when tracking the boundary point according to the tracking code,
It becomes "111100000". Since this moved and corrected boundary point becomes a corner point and a boundary point between pixels adjacent to it, the boundary point becomes the corner point (the boundary point corresponding to the fifth tracking code “0”). By preferentially setting B to be the bending point of the vector, the corner portion can be vectorized without error even when there are no two pixels in the upper left corner.

Further, FIGS. 9B to 9H show other examples in which two corner pixels are missing, and the tracking code strings at the boundary points of these boundary pixels are respectively shown in FIGS. 1
0 (B) to (H). Also in this case, as in the case described above, the tracking code strings are sequentially applied to the table, and when the same tracking code string as shown in FIGS. 10B to 10H is obtained, the fifth and sixth tracking codes are obtained. A table for moving the boundary points corresponding to is prepared, the tracking code strings are sequentially applied, and when the same tracking code string as shown in FIGS. By compensating for the boundary point and then again tracking the boundary point according to the tracking code, it is possible to obtain a tracking code string including the corrected boundary point of the corner portion. Then, by preferentially setting the corrected boundary points of the corner portions so as to be the bending points of the vector, the corner portions can be vectorized without error. Note that when the two corner pixels are missing, the above-described eight ways are possible, but FIGS. 9A and 9E both show the case where the pixel in the upper left corner is missing. , The boundary points corresponding to the 5th and 6th tracking codes are (x, y) = (− 1, −)
1) It suffices to move the corners in the upper right corners of FIGS. 7B and 7F, the lower left corner of FIGS. 9C and 9G, and the lower right corner of FIGS. This is the case where the partial pixels are missing, so that the boundary points respectively corresponding to the fifth and sixth tracking codes are (x, y) = (+ 1, −1), (−
Since it is sufficient to move (1, +1), (+1, +1), substantially four types of movement are sufficient.

If a tracking code in a certain direction is i and a tracking code different from the tracking code i by 90 degrees is j, the tracking code string in this case having no two corner pixels is "iiiijj".
ijjj ”or“ iiijiijjj ”,
These tracking code strings are respectively referred to as “iiiiiijjj”.
j "," iiiijjjjj "and converted to the first tracking code" j "(5th or 6th tracking code)
May be prioritized as the bending point of the vector.

Finally, description will be given of a case where the pixel is corrected when there are not three corner pixels. Here, for the sake of convenience, consideration will be given only to the case where one horizontal / vertical pixel and one corner pixel are missing. If there are not three corner pixels,
Four cases shown in (A) to (D) can be considered. Then, when the boundary points of the boundary pixels at this time are traced clockwise according to the tracking code shown in FIG. 1, FIGS.
become that way. FIG. 11A shows the case where the pixel in the upper left corner is missing. The tracking code string at the boundary point of the boundary pixels at this time is “1110101000”, as shown in FIG. When such a tracking code string is obtained, the fifth to seventh tracking codes “1
The boundary points corresponding to “01” are both (x, y) = (− 1, −
1) Use a moving table so that the boundary points move to the missing corner and both sides of it, and again
When the boundary points are tracked according to the tracking code, “11111
It becomes "00000". Since the moved and corrected boundary point becomes the corner point and the boundary points of the pixels on both sides thereof, the boundary point (the boundary point corresponding to the sixth tracking code “0”) becomes the corner section. By preferentially setting B to be the bending point of the vector, the corner portion can be vectorized without error even when there are not three pixels in the upper left corner.

Further, FIGS. 11B to 11D show examples in which the upper right corner, the lower left corner, and the lower right corner 3 pixels are missing, respectively, and the tracking code strings at these boundary points are: 12B to 12D, respectively. Then, in this case as well, in the same manner as described above, the tracking code strings are sequentially applied to the table, and when the same tracking code string as in FIGS. 12B to 12D is obtained, the fifth to seventh tracking codes are obtained. A table for moving the boundary points corresponding to is prepared, the tracking code strings are sequentially applied, and the table shown in FIGS.
When the same tracking code string is obtained, the corners and the boundary points that are on both sides of the corner are corrected, and the boundary points are traced again according to the tracking code, so that the corrected boundary points of the corners are included. The tracking code string can be obtained. And
By preferentially setting the corrected boundary points of the corner portions so as to be the bending points of the vector, the corner portions can be vectorized without error. In addition,
If the tracking code in a certain direction is i and the tracking code different from this tracking code i by 90 degrees is j, the tracking code string in this case where there are no three pixels in the corner is "iiiijijijjj". "Iiiiiij
Alternatively, the vector may be converted into “jjjj”, and the boundary point corresponding to the sixth tracking code “j” may be prioritized as the bending point of the vector. In each of the above-described embodiments, an example in which tracking is performed clockwise (clockwise) is shown, but counterclockwise (counterclockwise).
However, it can be carried out in the same manner.

[0020]

According to the outline vector automatic shaping method of the present invention, since it is not necessary to obtain an angle, vector generation processing can be performed at high speed. Since the boundary points of the boundary pixels are tracked, the tracking code does not return to the same place even when a straight line having a width of one pixel projects.
When the character is enlarged, the line width can be enlarged without the straight line remaining one pixel width. Further, compared to tracking the center of the boundary pixel, there is an effect that the error of the outline is small. Since the corners are detected and corrected before being vectorized, it is possible to obtain a high-quality image even if the image is input with a scanner or the like and the pixels at the corners are missing. effective.

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing an embodiment of a tracking code used in an outline vector automatic shaping method of the present invention.

FIG. 2 is a conceptual diagram showing an example of a state in which a trace code string is attached to a figure.

FIGS. 3A to 3D are conceptual diagrams showing a case where there is no one pixel in one corner.

4 (A) to (D) are shown in FIG. 3 (A) to (D), respectively.
It is a conceptual diagram which shows the tracking code sequence of.

FIG. 5 is a diagram showing a table for moving a boundary point when there is no one pixel in a corner of FIG.

6 (A) to (D) are shown in FIG. 3 (A) to (D), respectively.
It is a conceptual diagram which shows the priority point in the tracking code sequence of.

7A to 7D are conceptual diagrams showing a case where there is no one pixel in one corner.

8A to 8D are respectively FIGS. 7A to 7D.
It is a conceptual diagram which shows the tracking code sequence of.

9A to 9H are conceptual diagrams showing a case where there are no two corner pixels.

10A to 10H are respectively shown in FIGS.
It is a conceptual diagram which shows the tracking code sequence of (H).

11A to 11D are conceptual diagrams showing a case where there are not three corner pixels.

12A to 12D are respectively FIGS.
It is a conceptual diagram which shows the tracking code sequence of (D).

[Explanation of symbols]

 a to d pixel P bending point

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Claims (1)

Claim: What is claimed is: 1. An outline vector automatic shaping method for extracting some of boundary pixels which are contours of a binary image and vectorizing the outline pixels. A four-direction tracking code for boundary points of the boundary pixels. A line is obtained, a corner point is determined from this tracking code sequence, the boundary point is moved to this position, and the vectorization is performed with the moved boundary point as a bending point preferentially. Automatic outline vector shaping method.