JPH0636019A - Method for reducing and displaying image data - Google Patents

Abstract

PURPOSE:To prevent a ruled-line display from being absent when image data are reduced and displayed by discriminating a ruled-line part and other parts according to the frequency distributions of vertical and horizontal illuminating pixels of the image data and reducing the image data so that the ruled-line part is left. CONSTITUTION:The numbers of the vertical and horizontal illuminating pixels of the image data, which are stored in the memory of an arithmetic part 2 and not reduced yet, are detected to extract the ruled-line part. In this case, the ruled-line part is extracted by setting flags for the numbers of rows and columns showing frequency distributions exceeding a threshold value as the reference value for discriminating between the ruled-line part and other parts. Then, the ruled-line part which is discriminated from other data and has its flag set is processed. In this case, illuminating pixels are preferentially extracted nearby the columns and rows whose flags are set by this image data reducing method without fail, so the absence of the ruled-line part on a reduction screen can securely be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of displaying reduced image data.

[0002]

2. Description of the Related Art Generally, since ruled line data created by a word processor or the like is recognized as an attribute, when reducing the data file, the ruled line processing can be performed based on the attribute.

On the other hand, in the bit image data read by an image scanner or the like, the data regarding ruled lines cannot be distinguished from other data. Therefore, when reducing and outputting image data input from an image scanner or the like, a method of thinning out pixels according to the reduction rate is also used for ruled lines, like other data.

For example, an image of 400 dpi is converted to 200 dpi
In the case of i, two pixels are displayed as one pixel as shown in a of FIG. At that time, data relating to figures and characters can be recognized even if some pixels are thinned and reduced.

[0005]

However, as shown in FIG. 10B, when data related to ruled lines (black dots in the figure) are thinned out, the ruled line display may be omitted from the table. There was a case where the function as was significantly reduced.

The present invention has been made in view of these points, and an object thereof is to provide a reduced display method of image data in which ruled line display is not missed when the image data is reduced and displayed.

[0007]

In order to achieve the above object, a reduced display method of image data according to claim 1 of the present invention is a reduced display method of image data which is performed by thinning out pixels according to a reduction ratio. The method is characterized in that the ruled line portion and other portions are discriminated based on the frequency distribution of the lighted pixels in both the vertical and horizontal directions of the image data, and the image data is reduced by leaving the ruled line portion.

The image data reduction display method according to a second aspect is the image data reduction display method according to the first aspect, wherein when the image data is reduced by 1 / k, the image data is reduced within k × k dots. If there is a ruled line portion, priority is extracted as a pixel to leave the lighting pixel, and if there is no ruled line portion in k × k dots, it is extracted as a pixel to leave an arbitrary pixel.

According to a third aspect of the image data reduction display method of the present invention, in the image data reduction display method of the first aspect, when the image data is reduced by 1 / k, first, the ruled line portion is turned on. It is characterized in that all k × k dots around the pixel are turned on and then 1 / k is reduced.

According to a fourth aspect of the present invention, there is provided a reduced image data display method according to the first aspect, wherein when the image data is reduced by 1 / k, the image data is reduced to 1 / k. It is characterized in that it is reduced by k, and then a ruled line is displayed at the 1 / K coordinate value of the ruled line portion.

[0011]

According to the reduced display method of image data of the present invention, by having the ruled line extraction means, it is possible to perform a single ruled line processing for reduced display based on the data regarding the ruled line portion which is differentiated from other data. Since it is possible, the ruled lines are not missing in the reduced display, and the function as a table can be fulfilled without fail.

[0012]

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

FIG. 1 outlines the means for carrying out the method of the invention.

In the present invention, as shown in FIG. 1, the image data read by the image scanner 1 or the image data transmitted by a facsimile or the like is displayed in a reduced size.
It is temporarily stored in the memory of the computing unit 2 such as a computer. After that, the reduced data reduced in accordance with the method of the present invention in the calculation unit 2 is displayed by the display device 3 such as a CRT and / or the printer 4.

Next, the method of the present invention executed in the arithmetic unit 2 will be described.

In the present embodiment, first, for the image data before reduction as shown in FIG. 2 stored in the memory in the arithmetic unit 2, the pixels which are turned on in both the vertical and horizontal directions of the display screen. The number is detected and the ruled line portion is extracted. The size of the display screen in the vertical direction L is 1 ≦ L ≦ L
n, and the size in the horizontal direction M is 1 ≦ M ≦ Mn.

FIG. 3 is a flowchart showing a method of extracting the ruled line portion. First, in step ST11,
Expand image data on memory.

Next, at step ST12, first, 1 is substituted for L (L = 1) in order to detect the number of lit pixels in the first row in the horizontal direction.

In step ST13, the horizontal direction (1≤
The frequency of the lighted pixel of M ≦ Mn) is detected, and the value is saved in the designated line (S1). For example, the frequency may be stored in the table for each row.

In step ST14, the next line (L = L
+1) is selected, and in step ST15, it is determined whether the selected row L exceeds Ln (L> Ln?), And the procedure from step ST13 is repeated until the answer is YES.

After the detection of the frequency of the last line is completed, step ST
If the answer to step 15 is YES, then in step ST16, first, 1 is substituted for M (M = 1) in order to detect the number of lit pixels in the first column in the vertical direction.

In step ST17, the frequency in the vertical direction (1.ltoreq.L.ltoreq.Ln) is detected in the same manner as in the horizontal direction, and the value is saved in the designated column (S2).

In step ST18, the next column (M = M
+1) is selected, and in step ST19, it is determined whether the selected column M exceeds Mn (M> Mn?), And the procedure from step ST17 is repeated until the answer is YES.

After that, when the detection of the frequency of the last row is finished and the answer in step ST19 is YES, step ST20
In, the values saved in each row and each column (S1, S2)
The threshold value is obtained from this and the ruled line portion is detected. The row and column numbers showing the frequency distribution exceeding the threshold value are flagged, and the extraction of the ruled line portion is completed in step ST20.

The method of determining the threshold will be described in detail with reference to FIG.

FIG. 4A shows an example of image data of a display screen of a general table, and FIG. 4B shows a frequency distribution showing the number of vertically lit pixels of the display screen.
The display screen is displayed in a screen area frame (not shown) of a predetermined size.

On the display screen displaying the table, there is a large difference between the number of lit pixels in the ruled line part and the number of lit pixels in the part other than the ruled line part. Looking at the vertical frequency distribution of the table in the screen area frame shown in FIG. 4B, the number of lit pixels in the ruled line portion shown by A in the figure is 85% in the frequency distribution (Aa in the figure). On the other hand, the frequency distribution of the number of lit pixels (Ba in the figure) shows only 60% even in the dense portion of the character information such as the "####" mark shown in B in the figure. .
As described above, the number of lit pixels other than the ruled line is about 70% of the number of lit pixels in the ruled line even at the maximum value. Therefore,
It is advisable to detect the number of lit pixels of the image data and set the threshold value to a value of about 70% of the maximum value of all lit pixels. Of course, this threshold setting condition may be changed. Further, the threshold value may be set in advance.

As described above, the threshold value becomes a reference value for differentiating between the ruled line part and the part other than the ruled line.

Next, a method of processing a ruled line portion having a flag, which is differentiated from other data, will be described.

FIG. 5 is a flow chart showing an embodiment of the ruled line reduction processing.

First, in step ST31, 1 / k reduction of image data is requested.

Next, in step ST32, 1 is substituted for M (M = 1) in order to indicate the starting point for vertical reduction. Similarly in the horizontal direction, 1 is substituted for L (L = 1) in step ST33.

In step ST34, the presence or absence of the flag for displaying the above-mentioned ruled lines in the vertical and horizontal directions is checked in the k × k dot area starting from the designated row L and column M. If there is no flag, in step ST35-1, one dot with an arbitrary or prespecified relative coordinate is extracted. On the other hand, if there is the flag, in step ST35-2, the lighting coordinates are preferentially extracted and lighting processing is performed.

For example, a case in which image data input at 400 dpi is reduced to 100 dpi will be described with reference to FIG. In FIG. 6A showing the state of 400 dpi, the row L and the column M, which are confirmed as ruled lines in the image data before reduction and which are flagged, are indicated by white arrows, respectively.
Illuminated pixels are indicated by black circles.

When the reduction is ¼, the area is 1
6 pixels are reduced to 1 pixel, and in each of the vertical and horizontal directions, it is reduced from 4 columns and 4 rows to 1 column and 1 row.

In FIG. 6A, there is a flagged column in 16 dots in frame A, but there is no lighting pixel to be preferentially extracted, so arbitrary coordinates are extracted. As a result, b in FIG.
In the reduced screen of, the pixel is a light-off pixel.

On the other hand, in FIG. 6A, in 16 dots in the frame B, there are a row L and a column M in which a flag is set, and there are also lit pixels. Therefore, the reduced screen of FIG. 6b is a lit pixel.

In this way, the pattern of FIG.
When reduced by 4, the pattern becomes as shown in b of FIG.

Next, in step ST36 of FIG. 5, L + k is substituted for the numerical value of the next designated row L, and it is determined in step ST37 whether or not the value of the next designated row L exceeds the maximum value Ln. If the answer is no, the procedure returns to step ST34 and the procedure is repeated until the reduction process for one column is completed.

If the answer is YES, the process proceeds to step ST38, where M + k is substituted for the numerical value of the next designated column M, and at step ST39, the next designated column M is the highest value Mn of the column M.
If the answer is NO, the process returns to step ST33 and the procedure is repeated until the reduction processing in the row direction (horizontal direction) is completed.

If the answer is YES, the image data reduction processing is terminated.

According to such a method of reducing image data, the lit pixels are always preferentially extracted in the vicinity of the flagged columns and rows. Therefore, it is possible to reliably prevent the missing of the ruled line portion on the reduced screen. You can

FIG. 7 is a flow chart showing another embodiment of the present invention.

First, in step ST51, 1 / k reduction of image data is requested.

Next, in step ST52, all the k × k dots in the vicinity of the lit pixels in the column and row in which the flag is set are lit.

In step ST53, 1 is substituted for M (M = 1) in order to post the starting point for vertical reduction.
To do. Similarly in the horizontal direction, step ST54
In, 1 is substituted for L (L = 1).

In step ST55, the previous step S
Extract any one dot from k × k dots starting from the column and row substituted in T53 and step ST54,
Perform reduction processing.

Next, in step ST56, L + k is substituted for the numerical value of the next designated row L, and it is determined in step ST57 whether or not the value of the next designated row L exceeds the maximum value Ln, and the answer is NO. In case of, return to step ST55,
The procedure is repeated until the reduction process for one column is completed.

If the answer is YES, the process proceeds to step ST58, where M + k is substituted into the numerical value of the next designated column M, and in step ST59, whether the next designated column M exceeds the maximum value Mn of the column M or not. If the answer is NO, the process returns to step ST54 and the procedure is repeated until the reduction processing in the row direction (horizontal direction) is completed.

If the answer is YES, the image data reduction processing is terminated.

In the image data reducing method according to the present embodiment, all the k × k dots around the lighting pixel indicated by a black circle in FIG. Since dots are extracted, for example, k
If one dot at the upper left corner in the area of × k dots is extracted, ruled line processing is performed as shown in b of FIG.
If dots are extracted, ruled line processing is performed as shown in FIG. Thus, even if the dots to be extracted are arbitrary, the table can be surely displayed without missing the ruled line portion on the reduced screen.

FIG. 9 is a flow chart showing another embodiment of the present invention.

In this embodiment, first, step ST71.
In 1), 1 / k reduction of the image data is requested.

In step ST72, 1 is substituted for M (M = 1) in order to designate the starting point for vertical reduction.
To do. Similarly in the horizontal direction, step ST73
In, 1 is substituted for L (L = 1).

In step ST74, the previous step S
Extract any one dot from k × k dots starting from the column and row substituted in T72 and step ST73,
Perform reduction processing.

Next, in step ST75, L + k is substituted for the numerical value of the next designated row L, and in step ST76, it is judged whether or not the value of the next designated row L exceeds the maximum value Ln, and the answer is If NO, the process returns to step ST74 and the procedure is repeated until the reduction process for one column is completed.

When the answer is YES, the process proceeds to step ST77, where M + k is substituted for the numerical value of the next designated column M, and at step ST78, whether the next designated column M exceeds the maximum value Mn of the column M or not. If the answer is NO, the process returns to step ST73, and the procedure is repeated until the reduction processing in the row direction (horizontal direction) is completed.

If the answer is yes, step ST
At 79, 1 / k of the flagged columns and rows described above
The ruled line portion is written by forcibly lighting the pixel of the reduced display data corresponding to each coordinate value of.

Then, the image data reduction processing is terminated.

The image data reduction display method of the present invention is performed by combining the above-described ruled line portion extraction and any one of the above-described ruled line portion processings. Even if the ruled line portion processing means of is adopted, the individual ruled line processing can be performed for the reduced display based on the data related to the ruled line portion that is different from other data, so that the reduced display does not lose the ruled line and the Can always fulfill its function as.

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

[0062]

As described above, since the reduced display method of image data of the present invention is constructed and operates, it is provided with means for extracting ruled lines, and based on the data on the ruled line portion differentiated from other data. Since independent ruled line processing can be performed for the reduced display, there is an effect that the reduced display can perform the reduced display in which the ruled lines are not missing in the reduced display and the function as a table can be always performed.

[Brief description of drawings]

FIG. 1 is a schematic view of means for implementing a reduced display method of image data according to the present invention.

FIG. 2 is a schematic diagram of image data.

FIG. 3 is a flowchart showing a method of extracting a ruled line portion.

4A is a display screen showing an example of a table, and FIG. 4B is a diagram showing a frequency distribution in the column direction.

FIG. 5 is a flowchart showing an embodiment of ruled line processing according to the method of the present invention.

6A is an enlarged view of one embodiment of a dot pattern, and FIG. 6B is an enlarged view of one embodiment of a 1/4 reduced dot pattern.

FIG. 7 is a flowchart showing another embodiment of the present invention.

FIG. 8A is an enlarged view of an example of a dot pattern, and b and c are enlarged views showing an example of a 1/4 reduced dot pattern, respectively.

FIG. 9 is a flowchart showing still another embodiment of the present invention.

FIG. 10A is an enlarged view showing an embodiment of a 1/2 reduced pattern, and b is an enlarged view showing an embodiment of a 1/2 reduced pattern.

[Explanation of symbols]

 ST11-ST21 Flowchart Steps ST31-ST40 Flowchart Steps ST51-ST60 Flowchart Steps ST71-ST80 Flowchart Steps

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location G09G 5/36 9177-5G

Claims (4)

[Claims] 1. A reduced display method of image data, which is performed by thinning out pixels according to a reduction rate, to determine a ruled line portion and other portions based on a frequency distribution of lit pixels in both vertical and horizontal directions of image data. Then, the image data is reduced and displayed by reducing the image data while leaving the ruled line portion. 2. The reduced display method of image data according to claim 1, wherein when the image data is reduced by 1 / k, if the ruled line portion is present in k × k dots, the pixel to leave the lit pixel A method for reducing display of image data, characterized in that, when the ruled line portion does not exist within k × k dots, the pixel is extracted as a pixel to leave an arbitrary pixel. 3. The reduced display method of image data according to claim 1, wherein when reducing the image data by 1 / k, first, all k × k dots around the lighting pixels of the ruled line portion are turned on, and then, A reduced display method of image data, characterized by reducing by 1 / k. 4. The image data reduction display method according to claim 1, wherein when the image data is reduced by 1 / k, first, the image data is reduced by 1 / k, and then the 1 / K coordinate of the ruled line portion. A reduced display method of image data characterized by displaying a ruled line on the value.