JP3518085B2 - Image processing apparatus and image processing method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image processing apparatus suitable for being provided in a document filing system, an image processing system or the like for storing a document as image data, and capable of reducing characters of image data without deformation. And an image processing method.

[0002]

2. Description of the Related Art Conventionally, a document filing system for saving newspapers, magazines, etc. as image data has been known. Such a document filing system, as shown in FIG. 16, includes an image scanner 31 for inputting a document as image data, and an information processing device 32 including a personal computer, a workstation, etc. to which the image data is supplied from the image scanner 31. And a data storage device 33 including an optical disk device, a magnetic disk device, a data storage device, and the like for recording image data, and a printer device 34 for printing the image data.

In such a document filing system, when a user inputs a document reading instruction,
The image scanner 31 is instructed to read the document. The image scanner 31 reads a document and supplies image data to the information processing apparatus 32 under the control of the information processing apparatus 32.

Then, the information processing device 32 supplies the image data from the image scanner 31 to the storage device 33 for recording or reads the image data recorded in the storage device 33 according to an instruction from the user. It can be displayed on the display unit or can be supplied with image data to the printer device 34 for printing.

Such a document filing system has an image editing function for performing image processing such as enlargement, reduction, extraction, and composition on the image data of the input document. When the image data is reduced by such an image editing function, if the logical sum of a plurality of adjacent pixels is calculated to obtain a new pixel, the white portion of the character is crushed as shown in FIG. There is a problem that it becomes difficult to identify characters. Further, if the pixels of the image data of the document are simply thinned out and reduced, some of the pixels forming the character are lost and the character becomes faint, which makes it difficult to identify the character. is there.

Therefore, in such a document filing system, when the image data is reduced, the image data of the character is subjected to a thinning process. This thinning processing is performed by extracting the image data of each character and thinning out the pixels of each line segment until the thickness of each line segment forming the character becomes, for example, one pixel.

In the image data subjected to the thinning process as described above, since each line segment forming the character is thin, the white portion of the character is not crushed even if the image data is reduced, and therefore the image data can be easily identified. You can

[0008]

However, when performing thinning processing on the image data of a document as described above,
As shown in FIG. 3, a character having a large black portion, a symbol, or the like is deformed as shown in FIG. 3 when it is thinned, which makes it difficult to identify.

Therefore, the image data of the document shown in FIG.
It is considered that the thinning processing is not performed on the area containing the characters as shown in, but in this case, it is necessary to determine the area that is not thinned for each document, and a large number of documents are There are very annoying issues to deal with.

The present invention has been made in view of the above problems, and provides an image processing apparatus and an image processing method capable of easily identifying a character even if the image data of a document is reduced. The purpose is to

[0011]

An image processing apparatus according to the present invention is a protected area for detecting a protected area containing image data of a character that is not subjected to thinning processing from image data of a document composed of a plurality of characters. Detection means, thinning processing means for performing thinning processing of the image data on image data other than the protected area in the image data of the document, and a plurality of adjacent pixels in the image data subjected to the thinning processing. Image data reduction means for reducing the image data by using the logical sum as a new pixel, and the protection area detection means detects 1 from the image data of the document.
Image data for one character is extracted, and the extracted image for one character
It is checked whether there is a black part larger than a predetermined size in the data.
If there is no black area larger than the specified size,
Set the area containing the image data for one character as the protected area
If there is a black part of a predetermined size or more,
The protected area is the area that contains the image data for the characters.
And are characterized.

[0012]

Further, in the image processing apparatus according to the present invention, the thinning processing means has a structure in which the pixels of the image data obtained by thinning the image data of the document in the vertical direction and the image data obtained by thinning the image data of the document in the horizontal direction. The image data of the document is thinned in the vertical direction or the horizontal direction by thinning the image data whose logical sum with the pixel is a new pixel.

An image processing method according to the present invention detects a protected area containing image data of a character which is not subjected to thinning processing from image data of a document composed of a plurality of characters, and detects the protected area in the image data of the document. Image data is thinned to image data other than the protected area, and the logical sum of adjacent pixels in the thinned image data is used as a new pixel to reduce the image data, and the protected area is When detecting
Image data of one character is extracted from the document image data
The size of the extracted image data for one character
Detects whether or not there is an upper black part, and determines whether the black part has
If there is no copy, the image data for the one character is
A black area with a size equal to or larger than a specified size is not included in the protected area.
Is present, the image data for the one character is included.
The area to be protected is defined as a protected area.

[0015]

Further, in the image processing method according to the present invention, when the thinning processing is performed, the pixels of the image data obtained by thinning the image data of the document in the vertical direction and the pixels of the image data of the document in the horizontal direction are thinned. The image data of the document is thinned in the vertical direction or the horizontal direction by thinning the image data whose new pixel is the logical sum of the pixels of the image data.

[0017]

DETAILED DESCRIPTION OF THE INVENTION An image processing system to which an image processing apparatus and an image processing method according to the present invention are applied will be described below.

As shown in FIG. 1, this image processing system includes an image scanner 1 which optically reads a document such as a newspaper or a magazine and outputs it as image data, and information to which the image data is supplied from the image scanner 1. Processor 2
A data storage device 3 for recording image data and the like, and a printer 4 for outputting an image according to the image data.

The information processing device 2 comprises a personal computer, a workstation, etc., and as shown in FIG. 1, a central processing unit (hereinafter referred to as CPU).
11, a memory 12 in which image data, control programs and the like are stored, a display unit 13 for displaying image data and the like, a keyboard 14 and a mouse 15 for inputting instructions and the like from the user, the image scanner 1, the storage device 3, an input / output control unit 16 that controls input / output with the printer device 4, a bus 17 to which the CPU 11 to the input / output control unit 16 are connected, and the like.

The storage device 3 is an optical disk device 3 for recording / reproducing data on / from an optical disk.
a, a fixed disk device 3b for recording / reproducing data on / from a magnetic disk, a data storage device 3c for recording / reproducing data on / from a magnetic tape, etc., and is adapted to record image data, a control program, etc. from the information processing device 2. There is.

In the information processing apparatus 2, the CPU 11 is
By executing a control program stored in the storage device 3 or the like, processing such as reading of a document by the image scanner 1, editing of image data, and output is performed.

The operation of this image processing system will be described below.

In this image processing system, the user first sets a document on the image scanner 1 and instructs the reading of the document by the keyboard 14, the mouse 15 and the like. When the user gives an instruction to read the document, the CPU 11 instructs the image scanner 1 to read the document. The image scanner 1 reads a document according to an instruction from the CPU 11, and, for example, one page of a newspaper is read by 720
The binary image data of 0 × 9600 pixels is supplied to the input / output control unit 16. The input / output control unit 16 includes the CPU 11
The image data supplied from the image scanner 1 is supplied to the memory 12 via the bus 17 under the control of.
As a result, the image data of the document is stored in the memory 12.

Further, the CPU 11 displays the image data from the image scanner 2 on the display unit 1 in response to an instruction from the user.
3 and supplies an image corresponding to the image data to the display unit 13
Is displayed on the display screen of. If the image displayed on the display unit 13 is acceptable, the user instructs recording of image data corresponding to this image.

When instructed to record the image data, the CPU 11 performs thinning processing on the image data, thins out and reduces the image data, and then compresses the data and supplies it to the storage device 3.

Here, when the high-resolution image data supplied from the image scanner 1 is reduced, if the logical sum of a plurality of adjacent pixels is calculated to obtain a new pixel, the white part of the character is crushed. There is a problem that it is difficult to identify characters. Further, if the pixels of the image data of the document are simply thinned out and reduced, some of the pixels forming the character are lost and the character becomes faint, which makes it difficult to identify the character. is there.

Therefore, in this image processing system, when the image data is reduced, the image data of the character is subjected to the thinning process. In this thinning process, image data of each character is extracted, and the thickness of each line segment forming the character is
For example, it is performed by thinning out pixels of each line segment until one pixel is obtained.

Further, since newspapers, magazines, and the like include images such as photographs in addition to characters, the CPU 11 sets, for example, the above-mentioned 7200 × 96 for image data of characters.
After thinning the high-resolution binary image data of 00 pixels, the image data is thinned out to form binary image data of 2400 × 3200 pixels with an intermediate resolution. And C
The PU 11 performs data compression on the intermediate resolution binary image data, adds character information corresponding to the intermediate resolution image data, key information for searching a document, and supplies the storage device 3 with the added information.

On the other hand, the CPU 11 extracts, for image data of an image, image data of, for example, 300 × 600 pixels from the above-mentioned high-resolution image data of 7200 × 9600 pixels, and the extracted image data is pseudo-multiplied. 100 × 20 thinned out by the dither method which is a gradation expression method
Image data of 0 pixels of intermediate resolution is formed, and the multi-valued image data of intermediate resolution is data-compressed and supplied to the storage device 3. At this time, the CPU 11 adds, to the image data of the image, insertion position information indicating the insertion position when the image data of the image is inserted into the image data of the character.

Further, the CPU 11 has the above-mentioned 7200 × 9.
Multivalued image data of 16 gradations of 340 × 480 pixels is formed from the binary image data of 600 pixels, and this image data is data-compressed and supplied to the storage device 3 as low-resolution image data for display.

The storage device 3 records intermediate-resolution character and image image data and low-resolution image data for display on a recording medium such as an optical disk, a magnetic disk, or a magnetic tape.

Further, in this image processing system, the image data recorded on the recording medium as described above is read out, supplied to the display unit 13 and displayed on the display screen, and enlarged or reduced in accordance with an instruction from the user. After being subjected to editing such as extraction or composition, it can be output by the printer device 4 or recorded by the storage device 3.

When the user gives an instruction to read out the image data, the CPU 11 instructs the storage device 3 to read out the above-mentioned low-resolution image data for display.
The storage device 3 reads the above-mentioned low-resolution image data from a recording medium such as an optical disk, a magnetic disk, or a magnetic tape, and C is read via the input / output control unit 16.
Supply to PU11.

When the low-resolution image data for display is supplied from the storage device 3, the CPU 11 decompresses this image data and displays an image based on this image data on the display section. The user gives an instruction to print this image data if the image displayed on the display unit is acceptable.

When printing is instructed by the user, C
The PU 11 instructs the storage device 3 to read image data of intermediate resolution characters and images corresponding to the image currently displayed on the display unit. Then, when these image data are supplied from the storage device 3, the CPU 11 expands these image data, and converts the image data of the image into the image data of the character based on the position information added as described above. The image data for printing is inserted to form the image data for printing, and the formed image data for printing is supplied to the printer device 4.

The printer device 4 prints an image based on the image data supplied from the CPU 11 on a paper surface. As a result, a high-quality image formed from the above intermediate resolution is output.

By the way, as described above, if the thinning processing is performed on the image data of all the characters when the thinning processing is performed on the high resolution image data supplied from the image scanner 1, as shown in FIG. Characters, symbols, and the like having large black portions are deformed as shown in the drawing when thinned, and there is a problem that it becomes difficult to identify them. For this reason,
In this image processing system, an area including characters, symbols and the like having a large black portion as shown in FIG. 3 is set as a protected area not subjected to the thinning processing, and thinning processing is performed on image data other than the protected area.

Specifically, the input of the character image data, the thinning process, and the formation of the intermediate resolution image data as described above are performed according to the flowchart shown in FIG.

That is, in step S1, the CPU 11 instructs the image scanner 1 to read the document as described above, and the image scanner 1 supplies the high resolution image data of the read document to the information processing apparatus.

Then, in step S2 and thereafter, the CPU 11 sequentially extracts the image data of one character from the high resolution image data, and determines whether to perform the thinning process for each extracted image data of one character. To judge.

In step S2, the CPU 11 determines whether or not the thinning process has been completed for the entire high resolution image data of 7200 × 9600 pixels.
If it is completed, the process proceeds to step S7, and the high resolution image data is thinned out as described above to form the intermediate resolution image data, and the process is completed. On the other hand, if the thinning process has not been completed, the process proceeds to step S3. In step S3, the CPU 11 extracts the image data for one character from the high resolution image data, and proceeds to step S4.

In step S4, the CPU 11 determines whether or not a rectangular black portion having a predetermined size is present in the extracted image data for one character, and if not,
After proceeding to step S5, the image data for one character is subjected to the thinning process, and then proceeds to step S6. On the other hand, when applicable, since the extracted image data for one character includes a large character, symbol, etc. in a large black portion as shown in FIG. 3, the image data for one character is set as the protected area. ,
The image data is not subjected to the thinning processing, and the process proceeds to step S6.

In step S6, when the thinning process is performed in step S5, the CPU 11
The image data for one character that has been thinned is used as a pixel of new image data, and if the thinning process has not been performed, the image data for one character extracted in step S3 is used as a pixel of new image data. Save and return to step S2.

As a result, the processing from step S2 to step S6 is repeated for the entire high-resolution image data, and after it is determined whether or not the thinning processing is performed for each image data of one character, the thin line processing is performed. The chemical treatment is applied. Then, after performing thinning processing on the entire high resolution image data, in step S7, the high resolution image data is reduced as described above to form intermediate resolution image data. Therefore, it is possible to perform thinning processing only on other characters and the like without performing thinning processing on characters and symbols having large black areas as shown in FIG. Can be prevented.

Here, whether or not the image data for one character includes a rectangular black portion of a predetermined size in step S4 is determined according to the flowchart shown in FIG.

That is, when the image data for one character is extracted from the high resolution image data in step S3, the CPU 11 proceeds to step S10, where the image data for one character as shown in FIG. The image data of a rectangular area of a predetermined size is extracted, and step S11
Proceed to.

Then, in step S11, the CPU
11 detects whether or not all the image data of the rectangular area extracted in step S10 is a black part, and if it is true, the black part as shown in FIG. 3 is included in the image data for one character. Since large characters, symbols, etc. are included, the process proceeds to step S6.

On the other hand, if not applicable, the CPU 11
In step S12, it is determined whether or not the extracted rectangular area reaches the right end of the image data for one character, and if not, the rectangular area extracted from the image data for one character is extracted. The region is shifted to the right by one pixel and the process proceeds to step S11. As a result, in step S until the rectangular area to be extracted reaches the right end of the image data for one character.
The processing from 11 to step S13 is repeated.

If the rectangular area has reached the right end of the image data for one character in step S12, the CPU 11 proceeds to step S14, where the extracted rectangular area is an image for one character. It is determined whether the bottom of the data has been reached, and if not, the following step S
In step 15, the rectangular area extracted from the image data for one character is shifted down by one pixel, and the process proceeds to step S10. As a result, the processing from step S10 to step S15 is repeated until the rectangular area to be extracted reaches the lower end of the image data for one character.

If the rectangular area reaches the lower end of the image data for one character in step S14, the CPU 11 causes the black portion as shown in FIG. 3 in the image data for one character. It is determined that a large character, symbol, etc. are not included, and the process proceeds to step S5 described above,
The thinning process is performed on the image data for the characters.

By performing the above processing, the CP
U11 sequentially extracts the image data included in a rectangular area of a predetermined size from the upper left to the lower right of the image data for one character, and determines whether all the extracted image data are black areas. Then, it is determined whether or not the image data for one character includes a large black character, a symbol, etc. as shown in FIG.

Here, since the character, symbol, etc., whose shape changes when the thinning process is performed, is a character, symbol, etc. having a large black portion as described above, the black portion of the predetermined rectangular shape is formed as described above. By detecting the presence, it is possible to reliably detect these characters, symbols, etc., and it is possible to prevent the characters, symbols, etc. from being deformed as a protected area that is not subjected to thinning processing.

Further, the size of the above-mentioned rectangular area is the rectangular shape included in characters, symbols, etc. that change in shape when the thinning processing as shown in FIG. 3 is performed in advance. It is obtained from the size of the black part according to the flowchart shown in FIG.

The user previously prints characters, symbols, etc., which are not subjected to thinning processing, by the printer device 4 or the like,
The keyboard 14 and the mouse 15 are operated to instruct reading of a document on which such characters and symbols are printed.
When instructed to read such a document, the CPU 11 instructs the image scanner 1 to read the document.
The image scanner 1 reads a document according to an instruction from the CPU 11 and supplies image data to the input / output control unit 16.

The input / output control unit 16 supplies the image data from the image scanner 1 to the memory 12 via the bus 17 according to the instruction from the CPU 11. Also, the CPU 11
Sets the initial value of the size of the rectangular area,
Hold at 2.

Then, the CPU 11 extracts the image data of one character from the image data stored in the memory 12 in step S20, and determines whether or not the extraction of the image data of one character is completed in step S21. If the extraction of the image data is completed, the process ends. If the extraction of the image data is not completed, the process proceeds to step S22.

In step S22, the CPU 11
The largest rectangular black portion included in the image data for one character is detected, and the process proceeds to step S23. In step S23, the CPU 11 compares the size of the maximum rectangular black portion detected in step S22 with the size of the rectangular area held in the memory 12, and determines the maximum rectangular black portion detected in step S22. If the size is smaller, the process proceeds to the subsequent step S24, the maximum rectangular black part size detected in step S22 is held in the memory 12, and then the process returns to step S20.

On the other hand, the CPU 11 causes the above step S23.
In step S22, if the size of the largest rectangular black portion detected in step S22 is larger, the process returns to step S20.

Then, the CPU 11 starts from step S20.
By repeating the processing up to step S24, the memory 12
The image data for one character is sequentially extracted from the image data such as characters and symbols that are not subjected to the thinning processing stored in the. Further, the CPU 11 detects the maximum size of the rectangular black part included in the extracted image data for one character, and the detected size of the black part is equal to the size of the rectangular region held in the memory 12. If the comparison result is smaller, the size of the detected black portion is held in the memory 12.

As a result, the characters not subjected to the thinning process,
The minimum value of the sizes of the largest rectangular black portions in the image data of each character such as a symbol is obtained and stored in the memory 12. The CPU 11 uses the size of the rectangular region thus obtained to detect a character that is not subjected to the thinning process in step S4 or the flowchart shown in FIG.

The thinning process in step S5 of the flow chart shown in FIG. 4 is performed according to the flow chart shown in FIG.

That is, in step S4, the CPU
If there is no character, symbol, or the like to which the thinning processing is not performed in the image data for one character extracted in step S3, the process proceeds to step S30.

In step S30, the CPU 11
Thinning is sequentially performed in the horizontal direction from the upper left pixel of the image data for one character extracted in step S3. Specifically, C
As shown in FIG. 9, the PU 11 moves the reference pixel from the upper left of the image data for one character to the right, and when the reference pixel reaches the right end of the image data for one character, the PU11 detects one pixel of the current reference pixel. The pixel at the left end of the minute is set as the next reference pixel, and the movement of the reference pixel is continued.

Then, the CPU 11 moves the reference pixel as described above and erases the reference pixel in accordance with the pattern of 8 pixels around the reference pixel. By repeating such movement and deletion of the reference pixels, the width of each line segment forming a character can be set to one pixel. CPU11
Holds the image data in which the width of each line segment corresponds to one pixel in this way in the memory 12 and proceeds to step S31.

Next, in step S31, the CPU 1
In No. 1, thinning is sequentially performed in the vertical direction from the upper left pixel of the image data for one character extracted in step S3. Specifically, the CPU 11 sets the reference pixel to 1 as shown in FIG.
When the reference pixel reaches the lower end of the image data for one character by moving downward from the upper left of the image data for one character, the pixel at the upper left one pixel of the current reference pixel is set as the next reference pixel,
The movement of the reference pixel is continued.

Then, the CPU 11 moves the reference pixel as described above, and erases the reference pixel in accordance with the pattern of 8 pixels around the reference pixel as in step S30. By repeating such movement and deletion of the reference pixels, the width of each line segment forming a character can be set to one pixel as in step S30. The CPU 11 holds the image data in which the width of each line segment is one pixel in this way in the memory 12 as in step S30, and proceeds to step S32.

Further, in step S32, the CPU
11 forms image data in which the logical sum of each pixel of the two image data subjected to the thinning processing in step S30 and step S31 is set as a new pixel and holds the image data in the memory 12, and the process proceeds to step S33. In step S33,
The CPU 11 performs the thinning processing similar to that in step S31 on the image data formed in step S32,
It is stored in the memory 12 and the process proceeds to step S6.

As a result, the image data obtained by reading the document as shown in FIG. 11 is subjected to the thinning process to form the image data in which the width of each line segment forming the character as shown in FIG. 12 is one pixel. It

Here, if only one of the thinning processes in step S30 or step S31 is performed, a part of the pixels forming each line segment in the image data is lost when performing the thinning process. There is a risk that it will end up. Therefore, in this thinning processing, steps S30 and S30 are performed.
In 31, the pixel is prevented from being lost by performing the thinning process again on the image data of the logical sum of the image data subjected to the thinning process by changing the moving direction of the reference pixel.

The image data reduction processing in step S7 is specifically performed according to the flowchart shown in FIG.

That is, when the CPU 11 detects in step S2 in FIG. 4 that the thinning processing has been completed for all high-resolution image data, it proceeds to step S40. In this step S40, CPU1
In step 1, a predetermined number of pixels corresponding to the resolution ratio are extracted from the upper left of the high resolution image data, and the process proceeds to step S41.

In step S41, the CPU 11
The logical sum of the pixels extracted in step S40 is obtained and the pixel of the image data of the intermediate resolution is obtained, and the process proceeds to step S42. Specifically, as shown in FIGS. 14A and 14B, the CPU 11 sets the intermediate resolution pixel to the black part when one or more of the extracted pixels are the black part,
As shown in FIG. 7C, when all of the extracted pixels are white areas, the intermediate resolution pixels are white areas.

In step S42, the CPU 11
It is detected whether or not the area for extracting a predetermined number of pixels from the high resolution image data reaches the right end of the high resolution image data, and if so, the process proceeds to step S44, and if not, the process proceeds to step S43. . In step S43, the CPU 11 moves the area for extracting the predetermined number of pixels from the high-resolution image data to the right by a predetermined number of pixels to extract the predetermined number of pixels, and returns to step S41.

As a result, the CPU 11 sequentially starts from the high resolution image data until the area for extracting a predetermined number of pixels from the high resolution image data reaches the right end of the image data.
A predetermined number of pixels are extracted to form intermediate resolution image data.

On the other hand, when it is detected in step S42 that the region for extracting a predetermined number of pixels from the high resolution image data has reached the right end of the high resolution image data,
The CPU 11 proceeds to step S44.

In step S44, the CPU 11
Detects whether the area for extracting a predetermined number of pixels from the high-resolution image data reaches the right end of the high-resolution image data, and when applicable, the reduction processing has been completed for all pixels. Therefore, the process is terminated, and if not applicable, the process proceeds to step S45.

Then, in step S45, the CPU
Reference numeral 11 moves a region for extracting a predetermined number of pixels from the high-resolution image data downward by a predetermined number of pixels and returns to step S40. Then, in step S40, a predetermined number of pixels are extracted from the left end of the region moved downward by a predetermined amount.

As a result, step S4 is carried out until the reduction processing is completed for all the pixels of the high resolution image data.
The processing from 0 to step S45 is repeated.

By performing such processing, image data of intermediate resolution as shown in FIG. 15 is formed from the high resolution image data subjected to the thinning processing as shown in FIG.

In this image processing system, as described above, after thinning the image data in advance, the image data is reduced using the logical sum of a plurality of adjacent pixels of the high resolution image data as a new pixel. Therefore, even if the image data is reduced, it is possible to prevent the white part of the character or the like from being crushed or the black part of the character to be fainted, and the character cannot be discriminated. Can be prevented.

[0081]

According to the present invention, a protected area containing image data of a character that is not thinned is detected from image data of a document consisting of a plurality of characters, and the protected area in the image data of the document is detected. Image data is thinned to image data other than the above, and the image data is reduced by using a logical sum of a plurality of adjacent pixels in the thinned image data as a new pixel. Also, when detecting the protected area,
Image data of one character is extracted from the image data of the document,
If the extracted image data for one character is larger than a predetermined size,
Detects whether there is a black area, and if a black area with a size larger than
If it does not exist, the image data for the one character is included.
The protected area is not defined as the
If present, the image data for the one character is included.
The area is the protected area. This ensures a protected area
It is possible to detect and reliably prevent the deformation of the character.

[0082]

Further, according to the present invention, when the thinning process is performed, the pixel of the image data obtained by thinning the image data of the document in the vertical direction and the pixel of the image data obtained by thinning the image data of the document in the horizontal direction. By performing thinning processing on the image data of the document by thinning the image data whose logical sum is a new pixel in the vertical direction or the horizontal direction, it is possible to prevent pixel loss and reliably prevent character deformation. You can

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an image processing system when the image processing apparatus and the image processing method according to the present invention are applied to the image processing system.

FIG. 2 is a flowchart showing a flow of image data in the image processing system.

FIG. 3 is a diagram showing a character, a symbol, etc., whose shape changes when the thinning process is performed, and a pattern when the thinning process is performed on these characters, symbols, etc.

FIG. 4 is a flowchart showing a processing procedure of thinning processing and reduction processing for image data in the image processing system.

FIG. 5 is a flowchart showing a procedure for detecting a protected area in image data in the image processing system.

FIG. 6 is a conceptual diagram for explaining a determination process in detecting the protection area.

FIG. 7 is a flowchart showing a processing procedure for obtaining a judgment reference value in the judgment processing.

FIG. 8 is a flowchart showing a specific processing procedure of thinning processing for image data in the image processing system.

FIG. 9 is a conceptual diagram showing a first thinning process of the thinning process.

FIG. 10 is a conceptual diagram showing a second thinning process of the thinning process.

FIG. 11 is a diagram showing image data of a document read by an image scanner in the image processing system.

FIG. 12 is a diagram showing a processing result of performing thinning processing on the image data of the document.

FIG. 13 is a flowchart showing a specific processing procedure of reduction processing for image data subjected to thinning processing in the image processing system.

FIG. 14 is a conceptual diagram showing pixel thinning in the reduction processing.

FIG. 15 is a diagram showing image data formed by performing OR thinning after performing thinning processing in the image processing system.

FIG. 16 is a block diagram showing a configuration of a conventional document filing system.

FIG. 17 is a diagram showing image data subjected to reduction processing in a conventional document filing system.

[Explanation of symbols]

1 image scanner 2 Information processing equipment 3 storage devices 3a optical disc device 3b Fixed disk device 3c data storage device 4 Printer 11 CPU 12 memories 13 Display 14 keyboard 15 mice 16 I / O controller 17 bus

─────────────────────────────────────────────────── --- Continuation of the front page (56) References JP-A-58-182952 (JP, A) JP-A-2-125390 (JP, A) JP-A-56-116183 (JP, A) JP-A-60- 39978 (JP, A) JP 3-244273 (JP, A) JP 7-262369 (JP, A) JP 8-125850 (JP, A) JP 60-27463 (JP, B2) (58) Fields investigated (Int.Cl. ⁷ , DB name) G09G 5/22-5/32 H04N 1/38-1/393

Claims (4)

(57) [Claims] 1. A protected area detecting unit for detecting a protected area containing image data of a character that is not subjected to thinning processing from image data of a document including a plurality of characters, and the protection in the image data of the document. Thinning processing means for performing thinning processing of image data on image data other than the area, and reducing the image data using a logical sum of a plurality of adjacent pixels in the thinned processing image data as a new pixel. Image data reduction means, and the protected area detection means detects 1 from the image data of the document.
Image data for one character is extracted, and the extracted image for one character
It is checked whether there is a black part larger than a predetermined size in the data.
If there is no black area larger than the specified size,
Set the area containing the image data for one character as the protected area
If there is a black part of a predetermined size or more,
The protected area is the area that contains the image data for the characters.
An image processing device characterized by: 2. The thinning processing means performs a logical sum of a pixel of image data obtained by thinning the image data of the document in the vertical direction and a pixel of image data obtained by thinning the image data of the document in the horizontal direction. The image processing apparatus according to claim 1, wherein the image data of the document is thinned in a vertical direction or a horizontal direction to perform thinning processing on the image data of the document. 3. A protected area containing image data of a character that is not subjected to thinning processing is detected from image data of a document including a plurality of characters, and image data other than the protected area in the image data of the document is detected. The image data is subjected to a thinning process with respect to the image data, and the image data is reduced using the logical sum of a plurality of adjacent pixels in the image data subjected to the thinning process as a new pixel to detect the protected area. Image data of the document
Image data for one character is extracted from
Whether there is a black area larger than a certain size in the image data
If there is no black area larger than the specified size,
Protects the area containing the image data for one character.
If there is a black part larger than a predetermined size, instead of the area,
The area containing the image data for the one character is the protected area.
An image processing method comprising: 4. A pixel of image data obtained by vertically thinning the image data of the document when performing the thinning processing,
A thinning process is performed on the image data of a document by thinning the image data in which the logical addition of the pixels of the image data of the document in the horizontal direction is added to the pixel of the image data as a new pixel in the vertical or horizontal direction. The image processing method according to claim 3, wherein