JP2569049B2 - How to modify characters - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a character correcting method, and more particularly to a character correcting method for correcting the shape of a character taken into a computer by an image input device or the like.

[Conventional technology]

A character font is composed of raster data expressed as a set of many pixels. There are two methods for creating character fonts: a method in which an operator creates purely a computer using only a computer, and a method in which actual characters drawn on an original such as paper are captured as raster data on a computer using an image input device or the like. is there. In the latter method, digital data obtained from the image input device (for example, 256 values are obtained for one pixel) is converted into binary data,
That is, it is expressed with or without pixels. In general, characters drawn on a document have non-uniform density, and the conversion result is significantly different depending on the setting of conversion conditions for binary data, and a desired character shape may not be obtained. This usually results in some of the contours not being smooth. Also, if there is a stain on the original, the stain is recognized as a part of the character, and the converted character will have white spots or black spot stains.

As described above, in the method of inputting a character from the image input device, an operation of correcting the shape of the character after inputting the character is required. Conventionally, therefore, a method has been adopted in which input characters are displayed on a display device, and an operator performs correction input interactively while watching the display.

[Problems to be solved by the invention]

However, the conventional character correction method depends on the manual operation of the operator, and if there are many correction points, a great deal of labor and time is required, resulting in extremely inefficient operation.

Accordingly, an object of the present invention is to provide a character correction method that can automatically correct characters input from an image input device or the like without manual intervention.

[Means for solving the problem]

The present invention provides a method for correcting a character input from an image input device or the like, comprising: inputting raster data of a character expressed as a set of a large number of pixels to an XY coordinate system; A contour extraction step of extracting a contour formed by a closed loop from input raster data, and tracing each pixel that is a component of the contour one pixel at a time along the closed loop to smooth the contour. Thus, a tracking correction step of correcting the position coordinates of a predetermined pixel, a filling step of filling a portion serving as a character body in the closed area surrounded by the contour with pixels, a pixel forming the contour and And (c) outputting the corrected raster data of the character based on the position coordinates of the pixels filled in the painting step.

(Operation)

In the character correcting method according to the present invention, first, only the outline is extracted from the raster data of the input character. This contour forms a closed loop consisting of one-dimensionally continuous pixels. Subsequently, an operation of smoothing the contour along this closed loop is performed. As a result, the contour itself is corrected to a smooth one. Thereafter, if the inside of the outline is filled with pixels, a character surrounded by a smooth outline is formed. Since the above procedures are all procedures that can be performed by a computer, automatic correction can be performed without manual intervention.

〔Example〕

Hereinafter, the present invention will be described based on the illustrated embodiments.
FIG. 1 is a flowchart showing a procedure of a character correcting method according to the present invention. In the following, this correction procedure will be described with reference to the katakana character "B" as an example.

First, in step S1, character raster data is input. This is an image input device that converts raster data of a character expressed as a set of many pixels into XY
This is the procedure for inputting into the coordinate system. The character “b” is input to the XY coordinate system as raster data as shown in FIG. 2A, for example. Here, an XY coordinate system is defined with the horizontal direction being the X direction and the vertical direction being the Y direction. Also,
Hatching indicates that a large number of pixels are dense.

Next, in step S2, contour lines are extracted. The contour to be extracted here is formed by a closed loop made up of one-dimensionally continuous pixels. In this example, as shown in FIG. 2 (d), the outer contour 1 and the inner contour 2 are extracted. FIG. 3 is a partially enlarged view of the outer contour 1. As can be seen from FIG. 3, the contour line is one in which pixels are arranged one-dimensionally, that is, linearly, and forms one closed loop as a whole. In order to extract such a contour, for example, a process based on the following algorithm may be performed. First, the raster data obtained as shown in FIG. 2A is sequentially scanned in the X direction just like the image scanning of a television, and a start pixel and an end pixel are obtained.
Here, the start pixel is a pixel existing at a change position when the state changes from the state without the pixel to the state with the pixel, and the end point pixel is a change when the state changes from the state with the pixel to the state without the pixel. It refers to a pixel at a position. In the example of FIG. 2A, the pixel x1 is determined as the first start pixel. The scanning is continued to the right with the pixels x2 and x3 along the arrow in the figure, and changes from the state with pixels to the state without pixels at the pixel x4. Therefore, it is determined as the end point pixel from the pixel x4. Subsequently, the scanning of the pixels one row below is performed from left to right, and an end pixel x5 and an end pixel x6 are obtained. By extracting and plotting only the start pixel and the end pixel obtained in this way, the second pixel is obtained.
As shown in FIG. 7B, partial contours 14, 24, 22, 12 are obtained. Next, the same scanning is performed in the Y direction to extract and plot the starting pixel and the ending pixel, as shown in FIG.
As shown in (1), partial outlines 11, 21, 23, and 13 are obtained. By synthesizing the partial outlines obtained in this way, an outer outline 1 and an inner outline 2 as shown in FIG. 2D can be obtained.

Next, in step S3, the contour is tracked and corrected.
In other words, for each contour line extracted in step S2, each component pixel is tracked one pixel at a time along a closed loop, and the work of correcting the position coordinates of predetermined pixels so that the contour line is smoothed. Do it. For this, for example, processing based on the following algorithm may be performed. First, an arbitrary pixel constituting the contour is taken as a starting point, a tracking operation is performed from one pixel to the next pixel in a clockwise or counterclockwise direction, and processing for returning to the starting point is performed again. . At this time, when moving to the next pixel, a flag expressing the moving direction as ± X, ± Y in the XY coordinate system is set. How to set this flag is shown in the chart of FIG. That is, the position of the pixel before the movement is set as the origin, and the flag 0 is set when the next pixel is located at the upper, lower, left and right positions with respect to the origin, and when the next pixel is at an oblique position, the rightward movement from the origin is Is set as + X, left movement is indicated by -X, upward movement is indicated by + Y, and downward movement is indicated by -Y. For example, to move to the upper left,
The X and + Y flags are set. Then, when a flag with a sign opposite to this flag is set after a certain flag is set, the pixel section corresponding to both flags is corrected. This correction is made by moving the pixels in a direction to smooth the outline.

The above algorithm will be described in more detail with reference to the example shown in FIG. Now, it is assumed that the contour obtained in step S2 is composed of 20 pixels as shown in FIG. One of these 20 pixels is chosen as a starting point. In this example, the pixel P0 is the starting point. Any pixel can be selected as the starting point pixel. Next, a tracking operation is performed on a pixel adjacent to the starting point pixel P0, that is, a pixel connected vertically, horizontally, or diagonally. As described above, since the pixels are connected so as to form a closed loop, each pixel is adjacent to two pixels. For example, the pixel P0 is connected to two pixels P1 and P19. The tracking operation may be performed in either of these directions, but once it is determined to be clockwise or counterclockwise, the subsequent tracking operation must proceed in the determined direction. In this example, the tracking starts from the pixel P0 to the pixel P1, and eventually the tracking is performed counterclockwise. In the tracking from P0 to P1, since the movement to the lower left has been performed, the flags -X and -Y are set from FIG. Further, in the tracking from P1 to P2, the flag 0 is set because the movement is performed right below. Eventually, the flags obtained by tracking P0 → P1 → P2 → P3 are (−X, −Y), (0), (+ X, −
Y). Here, paying attention to the flag in the X direction, -X
Is set, and + X is set, indicating that a flag of the opposite sign has been generated. Therefore, at this point, P0 → P1 → P2 → P3
The position of the pixels P1 and P2 between the tracking sections
And P2 'to smooth the contour.
The moving direction of the pixel may be determined based on the flag that stands second. For example, in this example, since the flag of the opposite sign is + X, it is moved in the direction in which X increases, that is, in the right direction. In this way, if the tracking and correction are performed counterclockwise along the closed loop until returning to the original starting point pixel P0, the unevenness of the contour generated by the conditions at the time of image input becomes a smooth line. Can be modified.

FIG. 5 shows an example in which each pixel is considerably enlarged for convenience of explanation. However, in actuality, each pixel is very minute, and the character has an unevenness compared to the original shape of the character itself. Here, the unevenness of the pixel array corrected here is very small. Therefore, the original shape of the character is not deformed by the tracking correction operation.

Next, in step S4, an intermediate coating operation of the outline is performed. This is an operation of filling a portion serving as a character body in the closed region surrounded by the contour corrected in step S3 with pixels. In this embodiment, unnecessary contour lines are first deleted in this intermediate coating work. Unnecessary outlines here are outlines for unnecessary white spots and black spots on characters. As described above, such white spots and black spots are mixed during image input and cannot be removed by the processing up to step S3.
As shown in FIG. 6 (a), a white outline 3 and a black spot outline 4 are generated together with the outer outline 1 and the inner outline 2 of the character. In order to remove the unnecessary outlines, the area of the closed region surrounded by each outline is obtained, and when the area is equal to or smaller than a predetermined reference value, the operation of deleting the outline is performed. This utilizes the property that white spots and black spot stains are not generally generated over a very large area. In the example of FIG. 6A, the closed areas surrounded by the contour lines 3 and 4 are both deleted because they are smaller than a predetermined reference area.
As shown in FIG. 6B, only the contour lines 1 and 2 remain.

Therefore, the actual middle coat operation is performed using these two contour lines 1,
Only done for 2. In order to perform the intermediate coating, it is necessary to perform an operation of filling pixels only in a portion serving as a character body, in this example, a hatched portion in FIG. 6D. This operation can be processed by the following algorithm, for example. That is, so that the intermediate coating work always proceeds sequentially from the outer contour to the inner contour, and
In each intermediate coating work, if the closed area within the contour line to be subjected to the intermediate coating is in a state without pixels, all of the closed area is set to a state with pixels. That is, the work of making the state without pixels is performed.
For example, in the example of FIG. 6B, first, the outer contour line 1 is coated with the middle coat. Since the closed area in the outer contour line 1 has no pixels, pixels are buried in all the areas in the closed area as shown in FIG. 6 (c). Subsequently, middle coating is performed on the inner contour line 2. At this point, since the closed area in the inner contour line 2 has pixels, the pixels in all the areas in the closed area are deleted as shown in FIG. 6 (d).

Finally, in step S5, the raster data of the character thus corrected is output. That is, the sixth
As shown in FIG. 6D, the position data of the pixels constituting the contour lines 1 and 2 and the pixels of the portions indicated by hatching filled with the intermediate paint are output. Thus, the shape of the input character can be corrected.

As described above, the present invention has been described based on one embodiment. However, individual algorithms for implementing the present invention are not limited to the above-described embodiments, and any algorithm that can obtain the same result can be used. , Can be implemented using other algorithms.

〔The invention's effect〕

As described above, according to the present invention, a contour line is extracted from an input character, the contour line is corrected so as to be smooth, and then the character is corrected such that the inside of the contour line is painted. With this configuration, it is possible to automatically perform the character and correction without manual operation.

[Brief description of the drawings]

FIG. 1 is a flow chart showing the procedure of a method for correcting a character according to the present invention, FIG. 2 is a diagram showing a specific example of a contour extraction step in the method shown in FIG. 1, and FIG. 3 is shown in FIG. FIG. 4 is a partially enlarged view of the contour extracted by the method, FIG. 4 is an explanatory view of a flag used in the contour correction step of the contour in the method shown in FIG. 1, and FIG. 5 is a diagram of the contour in the method shown in FIG. FIG. 6 is a diagram showing a specific example of the tracking stage, and FIG. 6 is a diagram showing a specific example of the intermediate coating stage of the outline in the method shown in FIG. 1 ... Outer outline, 2 ... Inner outline, 3 ... Outline outline, 4 ... Outline of black spot stain, 11-14, 21-24 ...
Partial contours, S1 to S5 ... Each step in the flow chart, P0 to P19
... Pixels on the outline.

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-61-238086 (JP, A) JP-A-62-57079 (JP, A) JP-A-61-245286 (JP, A) 82985 (JP, A) JP-A-60-214080 (JP, A) JP-A-57-111786 (JP, A)

Claims (4)

(57) [Claims] An input step of inputting raster data of a character represented as a set of a large number of pixels into an XY coordinate system, and an outline formed by a closed loop composed of one-dimensionally continuous pixels is input. A contour extraction step of extracting from the raster data, and tracking each pixel that is a component of the contour one by one along a closed loop, and performing a tracking operation from one pixel to the next pixel. A flag is set in which the moving direction is expressed by ± X and ± Y in the XY coordinate system. When the second flag having the opposite sign to the first flag is set after the first flag is set, the first flag is set. From the pixel that caused the flag to the pixel immediately before the pixel that caused the second flag,
A tracking correction step of correcting the position coordinates of the pixel by moving the contour in a direction in which the contour becomes smooth; and, in a closed area surrounded by the contour, an intermediate coating step of filling a portion serving as a character body with pixels, An output step of outputting raster data of the corrected character based on the position coordinates of the pixels constituting the contour line and the pixels filled in the intermediate coating step. 2. In a contour line extraction step, raster data is scanned in the X direction or the Y direction, and a change position when a state changes from a state with pixels to a state without pixels or from a state without pixels to a state with pixels is detected. 2. The character correcting method according to claim 1, wherein the pixels existing in the character string are extracted as pixels constituting the outline. 3. In an intermediate coating stage, before performing a process of filling pixels, an area of a closed region surrounded by each contour line is determined, and when the area is smaller than a predetermined reference value, the contour line is deleted. 3. A method for correcting a character according to claim 1, wherein the method is performed. 4. In the intermediate coating step, the intermediate coating operation is sequentially performed from the outer outline to the inner outline, and in each intermediate coating operation, the outline inside closed area to be subjected to the intermediate coating is removed. The method according to claim 1, characterized in that when there is no pixel, all of the inside of the closed area is in a state of having a pixel, and when there is a pixel, operation of making all of the inside of this closed area is in a state of no pixel. A method for correcting a character according to any one of Items 1 to 3.