JP3249644B2 - 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 method for encoding and compressing image file data in which multi-valued image data and binary image data are mixed in one page, and a multi-valued read-out using a scanner. The present invention relates to an image processing method for encoding and compressing multi-valued image data in page units.

[0002]

2. Description of the Related Art Generally, when image data is encoded and compressed, multi-value image compression encoding conversion or binary image compression encoding is performed depending on the type of image to be processed, regardless of the contents of the original image. Converting. Here, as the multi-valued image coding method, there is, for example, the JPEG method, and as the binary image compression coding method, for example, the JBIG method, the MMR method, the MR method, and the M
H method and the like.

[0003]

However, such a conventional apparatus has the following disadvantages.

[0004] That is, if multi-valued image compression coding conversion or binary image compression conversion is applied to an image of one page regardless of the content of the image, there may be a problem that the coding efficiency is deteriorated.

The present invention has been made in view of such circumstances, and has as its object to provide an image processing method capable of efficiently encoding and compressing an image file in which a multi-valued image and a binary image are mixed.

[0006]

According to the present invention, there is provided an image processing method for encoding and compressing data of an image file in which multi-valued image data and binary image data are mixed in one page. When the ratio of the multi-valued image data is equal to or more than a predetermined value, the binary image data included in the processing target page is converted into the multi-valued image data, and the image data for one page is subjected to the multi-valued image compression coding. When the ratio of the multi-valued image data included in the page to be processed is less than the predetermined value, the multi-valued image data included in the page to be processed is converted into the binary image data, and the data for one page is converted. The image data is subjected to binary image compression coding conversion.

In an image processing method for encoding and compressing multi-valued image data obtained by multi-value reading using a scanner in page units, it is determined whether the multi-valued image data included in the page to be processed belongs to a character area. Or, it is determined on a pixel-by-pixel basis whether the pixel belongs to a non-character area. In addition to the conversion, the binary image data for one page is subjected to the binary image compression coding conversion. When the ratio of the pixels determined as the character area is less than the predetermined value, the multi-valued data included in the page to be processed is processed. The image data is subjected to multi-value image compression coding conversion.

In an image processing method for encoding and compressing multi-valued image data obtained by multi-value reading using a scanner in page units, it is determined whether the multi-valued image data included in the page to be processed belongs to a character area. Or, it is determined whether a pixel belongs to a non-character area on a pixel-by-pixel basis. Converts multi-valued image data into binary image data,
For pixels in an area determined as a non-character area of a page to be processed, multi-valued image data is converted into binary image data by performing pseudo halftone binarization processing, and the converted binary image of one page The data is subjected to binary image compression encoding conversion, and when the ratio of pixels determined as the character area is less than the predetermined value, the multivalued image data included in the processing target page is subjected to multilevel image compression encoding conversion. It is like that.

[0009]

Therefore, of the multi-valued image or the binary image,
Since the image content having a large ratio can be appropriately code-compressed, the coding compression efficiency can be improved.

[0010]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 shows a data processing apparatus according to an embodiment of the present invention.

In FIG. 1, a CPU (central processing unit) 1
Is for executing various processing such as operation control processing and image editing processing of each part of the data processing apparatus,
The ROM (read only memory) 2 is for storing various data and the like referred to in the processing executed by the CPU 1, and is a RAM (random access memory) 3
Is for configuring a main memory and a work area of the CPU 1, and the clock device 4 is for outputting current time information and the like.

The color scanner 5 is for reading and inputting a full-color original image at a predetermined resolution.
Therefore, the image data obtained from the color scanner 5 is multi-valued image data. The color printer 6 is a printer capable of full-color recording, such as a sublimation type thermal transfer color printer.

The binary image encoding / decoding unit 7 is, for example,
The binary image data is encoded and compressed by a binary image encoding process such as the BIG system, the MMR system, the MR system, and the MH system, and the binary image data that has been encoded and compressed is converted to the original binary image data. Is decrypted.

The multi-valued image encoding / decoding unit 8 includes, for example, J
The multi-value image coding process of the PEG method encodes and compresses the multi-value image data and decodes the multi-value image information that has been subjected to the code compression into the original multi-value image data.

The magnetic disk device 9 is for storing a system program of the data processing device, an application program such as an image editing application, and accumulating image data and image information.

The display control unit 10 is for controlling display contents of the CRT display device 11, and is provided with an input control unit 12.
Is for taking in input data of the keyboard device 13 and the screen instruction device 14.

These CPU1, ROM2, RAM3,
Clock device 4, color scanner 5, color printer 6, binary image encoding / decoding unit 7, multi-value image encoding / decoding unit 8,
The magnetic disk device 9, the display control unit 10, and the input control unit 12 are connected to a system bus 15, and data exchange between these elements is mainly performed through the system bus 15.

In this data processing apparatus, an image in which a multi-valued image and a binary image are mixed in one page can be formed by an image editing application. In the image data thus formed, one page of the image data constitutes one image file.

As shown in FIG. 2, this image has a configuration in which one or more rectangular blocks are arranged in one page in an arbitrary manner, and each block includes a multi-valued image or a binary image. A value image is arranged. The upper left point of each block is defined as a coordinate reference point, and the dimensions in the X and Y directions are specified from this reference point to indicate the size of each block.

As shown in FIG. 3A, the data format of the image file formed by the image editing application is firstly represented by a file header and an image file for identifying the image file. The layout information includes layout information indicating the arrangement state of one or more blocks in the image data, and content information indicating the contents of the image data arranged in each block.

As shown in FIG. 3B, the file header includes a file name for identifying each image file, the date and time when the image file was created, and a comment arbitrarily added by the user (author). .

As shown in FIG. 2C, the layout information stores a page size for storing the size of a page on which the image data of the image file is arranged, and the number of blocks included in the image data. And the layout of block layout information indicating the arrangement state of each block.

As shown in FIG. 3D, one block layout information includes block identification information (ID) for identifying each block, a reference point address indicating the coordinates of a reference point of the block, and the block. Size in the X direction, representing the size of the block in the X direction, and Y in the block
It consists of a Y-direction size representing the size in the direction and a data attribute representing the attribute value of the image data arranged in the block.

The data attribute is, as shown in FIG.
The image data includes a data type indicating whether the image data is multi-valued image data or binary image data, an X-direction resolution indicating the X-direction resolution, and a Y-direction resolution indicating the Y-direction resolution.

The content information is, as shown in FIG. 1F, composed of an array of block content information representing the content (content) of each block. As shown in FIG. 3G, one piece of block content information includes block identification information for identifying each block, a data size representing the data length of image data,
And image data. Here, as the value of the block identification information of the block content information, a value equal to the value of the block identification information of the corresponding block layout information is used.

In this embodiment, when the contents of the original image file are encoded and compressed, the image data of the image file is processed as if it consists of one block corresponding to one page.

The image information file formed by encoding and compressing the multi-valued image data or the binary image data is a file for identifying each image information file as shown in FIG. It is formed from a header and compressed data.

The file header includes a file name, attributes of the image information file, creation date and time, and a comment, as shown in FIG. The content of the comment is the same as the content of the comment in the file header of the original image file.

The attribute is, as shown in FIG.
A file type indicating whether the image information file is a file of image data formed by multi-level encoding compression or a file of binary image data, a page size, an X-direction resolution, a Y-direction resolution, And a compressed data size.

FIG. 5, FIG. 6, and FIG. 7 show processing examples when encoding and compressing image data created by the image editing application.

First, layout information of an image file to be processed is read (process 101), and variables i, AB, and AM are read.
Is initialized to 0 (process 102).

Next, one block layout information is selected (step 103), and the value of the variable i is increased by one (step 10).
4). It is checked whether the value of the data type of the data attribute of the block layout information selected at this time is a value corresponding to the binary image data (decision 105).

If the result of decision 105 is YES,
The area of the block corresponding to the selected block layout information is calculated based on the size in the X direction and the size in the Y direction, and the value of the calculated area is added to the value of the variable AB (process 106). Is NO, the value of the area calculated in the same manner as described above is replaced with the variable AM
(Process 107).

When the process for one block layout information is completed in this way, it is checked whether the value of the variable i has become equal to the value of the number of blocks (m) (decision 108), and the result of the decision 108 is NO. , The process returns to the process 103 to perform a process relating to the next block layout information.

If the result of decision 108 is YES, it is checked whether the value of variable AB is greater than or equal to the value of variable AM (decision 109). The result of decision 109 is Y
When the ES becomes ES, the ratio of the binary image of the image data to be processed at that time is large, so that the entire image data is subjected to the binary image encoding process.

First, the value of the variable i is initialized to 0 (step 110), and the value of the variable i is increased by one (step 111). Then, the i-th block is selected as a processing target block (processing 112), and it is determined whether the block is a binary image block by referring to the contents of the block layout information corresponding to the selected block (determination). 11
3).

If the result of the determination 113 is YES, the image data of the block content information of the block is developed in a work area formed in the RAM 3 (process 114). At this time, the address of the image data in the work area is determined by referring to the contents of the block layout information.

When the result of the determination 113 is NO, the block selected at that time is a multi-valued image data block, and the image data of the block content information of the block is converted into binary image data by a well-known conversion process. And converts the converted binary image data into a work area formed in the RAM 3 (step 115). Also at this time, the address of the image data in the work area is determined by referring to the contents of the block layout information.

Then, it is checked whether the value of the variable i is equal to the number of blocks (m) (decision 116). When the result of the determination 116 is NO, the process returns to the process 110, where the next processing block is selected and the process for the selected block is performed.

When the result of the determination 116 is YES, the image data for one page to be coded and compressed at that time has been developed in the work area. The data is encoded and compressed by the decoding unit 7 (process 117), and the coded data obtained thereby is collected into the above-described compressed data file and stored in the magnetic disk device 9 (process 118).

When the result of the judgment 109 is YES, it means that the ratio of the multivalued image of the image data to be processed at that time is large, so that the entire image data is subjected to the multivalued image encoding process.

First, the value of the variable i is initialized to 0 (step 119), and the value of the variable i is increased by one (step 120). Then, the i-th block is selected as a processing target block (processing 121), and it is checked whether the block is a multi-valued image block by referring to the contents of the block layout information corresponding to the selected block (determination). 12
2).

When the result of decision 122 is YES,
The image data of the block content information of the block is developed in a work area formed in the RAM 3 (process 123). At this time, the address of the image data in the work area is determined by referring to the contents of the block layout information.

If the result of the determination 122 is NO, the block selected at that time is a binary image data block, and the image data of the block content information of the block is converted into multi-valued image data by a well-known conversion process. And the converted multi-valued image data is developed in a work area formed in the RAM 3 (process 124). Also at this time, the address of the image data in the work area is determined by referring to the contents of the block layout information.

Then, it is checked whether or not the value of the variable i is equal to the number of blocks (m) (decision 125). When the result of the determination 125 is NO, the process returns to the process 120, where the next processing block is selected, and the process for the selected block is performed.

If the result of the determination 125 is YES, the image data for one page to be coded and compressed at that time has been developed in the work area. The encoding is compressed by the decoding unit 8 (process 126), and the process proceeds to process 118, where the encoded data obtained is collected into the above-described compressed data file and stored in the magnetic disk device 9.

As described above, when encoding and compressing the image data created by the image editing application, 1
When the proportion of binary image data in the image data of a page is large, the image data of the page is subjected to binary image encoding and compression. When the proportion of multi-valued image data is large, the image data of the page is encoded with a multi-valued image code. Compression. As a result, the image data can be encoded and compressed efficiently and with good image quality.

FIG. 8 shows an example of an image encoding process when a document image is read and input using the color scanner 5.

First, the image reading operation of the color scanner 5 is started (process 201), and an image storage process for storing multi-valued image data taken from the color scanner 5 in a predetermined work area is started (process 202). Based on the multi-valued image data, for each pixel,
An area determination process for determining whether a pixel belongs to a character area is started (process 203).

Here, in the area determination processing, the degree of correlation between the neighboring pixel and the target pixel to be processed is calculated.
When the degree of correlation is equal to or more than a predetermined value, it is determined that the target pixel belongs to the character area, and when the degree of correlation is smaller than the predetermined value, it is determined that the pixel of interest does not belong to the character area. can do.

Then, the process waits until the reading and accumulation of the image for one page is completed (NO loop of decision 204). When the result of decision 204 is YES, the result of the area decision processing is input (process 205). If the number of pixels determined to belong to the character area is greater than the number of other pixels, it is determined whether to apply the binary image encoding process at that time (decision 206).

When the result of the determination 206 is YES, the target pixel to be processed is set (process 207), and it is determined whether or not the target pixel belongs to the character area by referring to the determination result of the area determination processing. (Decision 208). When the result of the determination 208 is YES, the multi-valued image data of the target pixel is subjected to simple binarization processing (processing 209). When the result of the determination 208 is NO, the multi-valued image data of the target pixel is simulated. Halftone binarization processing (processing 21
0). Then, the binary image data formed by these binarization processes is stored in a work area (an area for temporarily storing a binary image) corresponding to the position of the target pixel (process 21).
1).

It is checked whether or not this binarization process has been completed for all pixels (decision 212).
When it becomes O, the process returns to the process 207 to execute the binarization process of the next target pixel.

When the result of the determination 212 is YES, the image data in the work area is encoded and compressed by the binary image encoding / decoding section 7 (process 213), and the encoded data obtained thereby is compressed as described above. The data files are collectively stored in the magnetic disk device 9 (process 214).

If the result of determination 206 is NO, the multi-valued image data accumulated at that time is encoded and compressed by the multi-valued image encoding / decoding unit 8 (process 215), and the process proceeds to process 214. Then, the encoded data obtained thereby is put together in the above-mentioned compressed data file and stored in the magnetic disk device 9.

As described above, when reading an image from the color scanner 5, a binary image encoding process or a multi-value image encoding process is applied according to the content of the image, and the image is encoded and compressed. I have.

FIG. 9 shows an example of the area determination processing.

First, a target pixel is set (process 301).
By executing the above-described character area determination processing (processing 302),
It is checked whether the target pixel belongs to the character area (decision 302). When the result of determination 302 is YES, the pixel of interest is set in the character area (step 304), and when the result of determination 302 is NO, the pixel of interest is set in the non-character area (step 305).

Then, it is checked whether the processing has been completed for all the pixels (decision 306), and the result of the decision 306 is N
When it becomes O, the process returns to the process 301, and the same process is executed for the next target pixel. The result of decision 306 is YE
When S is reached, this process ends.

FIG. 10 shows an example of processing when displaying a compressed data file.

First, the file header of the compressed data file is read (process 401), and it is checked whether the compressed data at that time is a binary image (decision 402). When the result of the determination 402 is YES, the compressed data at that time is decoded by the binary image encoding / decoding unit 7 (process 403), and when the result of the determination 402 is NO, the compressed data at that time is increased. The image is decoded by the value image encoding / decoding unit 8 (process 404), and the obtained image data is displayed on the CRT display device 11 (process 405).

In this state, the system waits until the user issues a command to terminate the display (NO loop of decision 406). When the user issues a command to terminate the display and the result of decision 406 becomes YES, the display is terminated (step 407). .

FIG. 11 shows a facsimile apparatus according to another embodiment of the present invention. In the figure, the same parts as those in FIG. 1 and corresponding parts are denoted by the same reference numerals.

In the figure, a CPU 21 mainly performs control processing of each section of the group 4 facsimile apparatus, and a ROM 22 stores a control processing program executed by the CPU 21 and various kinds of programs necessary for executing the processing program. It stores data and the like.
M23 constitutes a work area of the CPU 21, and the operation display section 24 is for operating the facsimile apparatus, and is composed of various operation keys and various displays.

The ISDN interface circuit 25 connects the group 4 facsimile apparatus to the ISDN, and also performs a layer 1 signal processing function, a D channel (signal channel) signal, and two B channels (information channels).
The D-channel transmission control unit 26 has a function of integrating / separating signals such as call setup / call release procedure processing.
This is for performing signal processing on the D channel of the DN, and the B channel transmission control unit 27 is for realizing a group 4 facsimile transmission procedure function performed on the B channel.

Then, the CPU 21, ROM 22, RAM
23, a color scanner 5, a color printer 6, an operation display unit 24, a binary image encoding / decoding unit 7, a multi-level image encoding / decoding unit 8, a magnetic disk device 9, a D-channel transmission control unit 26, and B The channel transmission control unit 27 is connected to a system bus 28, and data exchange between these elements is mainly performed through the system bus 28.

FIG. 12 shows an example of processing performed by the group 4 facsimile apparatus when making a call.

First, in a state where the transmission original image is read and stored, a destination designated at that time is called (process 501). When a predetermined call setting procedure is executed (process 502) and an information channel (B channel) is established with the partner terminal (process 503), a predetermined pre-transmission procedure is executed on the established information channel. Then, the transmission function to be used at that time is set with the partner terminal (process 504).

At this time, if the partner terminal can handle only binary images, and if the result of determination 505 is YES, the stored image data is subjected to binary image encoding processing (processing 5).
06) If the partner terminal can handle multi-valued images and the result of determination 505 is NO, the accumulated image data is encoded and compressed by the multi-valued image encoding / decoding unit 8 (process 507). , Forming transmission image information.

Then, the formed transmission image information is transmitted to the partner terminal according to a predetermined procedure (Step 508).
When the transmission operation is completed, a predetermined post-transmission procedure is executed (step 509), and the information channel is ended (step 51).
0), and executes a predetermined line disconnection / release procedure (process 51).
1), a series of transmission operations ends.

FIG. 13 shows an example of a binary image encoding process.

First, regarding the stored image data,
The same area determination processing as described above is executed (processing 601).
Next, a target pixel to be processed is set (process 602),
Referring to the determination result of the area determination processing, it is determined whether or not the pixel of interest belongs to the character area (determination 603).
When the result of the determination 603 is YES, the multivalued image data of the target pixel is subjected to simple binarization processing (processing 60
4) If the result of the determination 603 is NO, the multi-valued image data of the target pixel is subjected to pseudo halftone binarization processing (processing 605). Then, the binary image data formed by the binarization processing is stored in a work area (area for temporarily storing a binary image) corresponding to the position of the target pixel (process 606).

It is checked whether or not this binarization process has been completed for all pixels (decision 607).
When it becomes O, the process returns to the process 602 to execute the binarization process of the next target pixel.

If the result of determination 607 is YES, the image data in the work area is encoded and compressed by the binary image encoding / decoding section 7 (process 608).

FIG. 14 shows an example of processing performed by the group 4 facsimile apparatus when an incoming call is detected.

When an incoming call is detected, the contents of the call setup message SETUP received at that time are analyzed (step 70).
1) It is checked whether or not connection with the partner terminal is possible (decision 702). When the result of the judgment 702 is NO,
The incoming call at that time is ignored (process 703).

When the result of the judgment 702 is YES, a response message CONN is responded (step 70).
4) An information channel is established (process 705), a predetermined pre-transmission procedure is executed (process 706), and image information is received and stored (process 707).

When the reception of image information is completed, a predetermined post-transmission procedure is executed (step 708), the information channel is ended (step 709), and a line disconnection release procedure is executed (step 7).
10).

Next, it is determined whether or not the image information received at that time is that of a binary image based on the image type information notified from the partner terminal (decision 711). When the result of the determination 711 is YES, the stored received image information is decoded into the original image data by the binary image encoding / decoding unit 7 (processing 712), and the result of the determination 711 is NO. In some cases, the stored received image information is decoded into the original image data by the multi-level image encoding / decoding unit 8 (process 713). Then, the image data thus formed is transferred to the color printer 6, and the received image is recorded and output (process 714).

In the above embodiment, the case where the present invention is applied to the group 4 facsimile apparatus has been described. However, the present invention can be similarly applied to other data transmission apparatuses.

[0082]

As described above, according to the present invention,
Since the image content having a large ratio among the multi-valued image and the binary image can be appropriately code-compressed, the effect of improving the coding and compression efficiency can be obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a data processing device according to one embodiment of the present invention.

FIG. 2 is a schematic diagram showing an example of image data.

FIG. 3 is a schematic view illustrating the type of data processed by the apparatus of FIG. 1;

FIG. 4 is a schematic diagram showing an example of a compressed data file.

FIG. 5 is a flowchart showing a part of an encoding process of the apparatus shown in FIG. 1;

FIG. 6 is a flowchart showing another part of the encoding process of the apparatus of FIG. 1;

FIG. 7 is a flowchart showing still another part of the encoding process of the apparatus in FIG. 1;

FIG. 8 is a flowchart illustrating a processing example when reading an image.

FIG. 9 is a flowchart illustrating an example of a region determination process.

FIG. 10 is a flowchart illustrating an example of a display process.

FIG. 11 is a block diagram showing a group 4 facsimile apparatus according to another embodiment of the present invention.

FIG. 12 is a flowchart showing a processing example at the time of calling by the apparatus of FIG. 11;

FIG. 13 is a flowchart illustrating an example of a binary image encoding process.

FIG. 14 is a flowchart showing a processing example at the time of an incoming call of the apparatus of FIG. 11;

Claims (3)

(57) [Claims] An image processing method for encoding and compressing data of an image file in which multi-valued image data and binary image data are mixed in one page, wherein a ratio of the multi-valued image data included in a page to be processed is predetermined. If the value is equal to or more than the value, the binary image data included in the processing target page is converted into multi-valued image data, and the image data for one page is subjected to multi-valued image compression encoding conversion, and is converted to the processing target page. When the ratio of the multivalued image data included is less than the predetermined value, the multivalued image data included in the page to be processed is converted into binary image data, and the image data for one page is converted into a binary image compression code. An image processing method, comprising: 2. An image processing method for encoding and compressing multi-valued image data obtained by multi-value reading using a scanner in page units, wherein the multi-valued image data included in a processing target page belongs to a character area. Or, it is determined for each pixel whether the pixel belongs to a non-character area, and when the ratio of the pixels determined as the character area is equal to or more than a predetermined value, the multi-valued image data of the processing target page is converted to the binary image data. The binary image data for one page is subjected to the binary image compression coding conversion, and when the ratio of the pixels determined as the character area is less than the predetermined value, the multi-valued data included in the page to be processed is converted. An image processing method, wherein image data is subjected to multi-level image compression coding conversion. 3. An image processing method for encoding and compressing multi-valued image data obtained by multi-value reading using a scanner in page units, wherein the multi-valued image data included in the processing target page belongs to a character area. Or, it is determined whether a pixel belongs to a non-character area on a pixel-by-pixel basis. Converts the multi-valued image data into binary image data, and performs pseudo-halftone binarization processing on the multi-valued image data for pixels in an area determined as a non-character area of the page to be processed. To
The binary image data for one page after the conversion is subjected to the binary image compression coding conversion, and when the ratio of the pixels determined as the character area is less than the predetermined value, the multi-value included in the processing target page An image processing method, wherein image data is subjected to multi-level image compression coding conversion.