JP2011019153A - Image processing apparatus, image processing system, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve encoding efficiency of image data by providing an encoding process selector.SOLUTION: In an image processing apparatus, a code selector 410 compares code data based on a reversible model with a code amount of code data based on an irreversible model, and selects the one with the smaller code amount. An encoding process selector 420 determines which of the reversible model or the irreversible model is used to generate code data with higher encoding efficiency, based on feature information of image data inputted from a first conversion selector 300 (Fig.3), or an irreversible part 304. The encoding process selector 420 outputs the image data to a prediction encoding part 400 when determined the reversible model is used, and for the rest, outputs the image data to a picture element value extracting part 404 and a bitmap generating part 406.

Description

  The present invention relates to an image processing apparatus, an image processing system, and a program.

  In Patent Document 1, when converting a raster format into a block format, image data generated by a camera processor is separated for each color component and stored in one line memory, and then read in block units in an order suitable for reading into the block format. An image processing apparatus for transmitting to a JPEG engine is disclosed.

JP 2004-159330 A

  An object of the present invention is to provide an image processing apparatus capable of increasing the encoding efficiency of image data.

  The present invention according to claim 1 is a lossless encoding means for losslessly encoding received image data, an irreversible encoding means for irreversibly encoding the image data, the lossless encoding means, and the lossy code. And encoding means for selecting one of the lossless encoding means and the lossy encoding means when one of the encoding means exhibits higher encoding efficiency for the image data than the other. One of the selected lossless encoding means and the lossy encoding means is an image processing apparatus that outputs code data generated by encoding the image data.

  According to a second aspect of the present invention, when the image data is irreversibly converted, the pixels of the image data are rearranged in a predetermined structure to convert the image data, and the output The image processing apparatus according to claim 1, further comprising: a control unit that controls the image data to be converted by the conversion unit when the encoded data is irreversibly decoded.

  According to a third aspect of the present invention, there is provided a conversion means for converting the image data by rearranging the pixels of the image data into a predetermined structure, and a first data holding for holding the output code data. And second data holding means for holding code data other than the code data held in the first data holding means or image data converted by the converting means among the outputted code data The image processing apparatus according to claim 1, further comprising:

  According to a fourth aspect of the present invention, there is provided a reversible decoding means for reversibly decoding the received code data, a second decoding means for irreversibly decoding the code data, and depending on the encoding format of the code data, An image generated by decoding the code data, wherein the selected one of the lossless decoding means and the lossy decoding means is one of a lossless decoding means and a decoding selection means for selecting one of the lossy decoding means. An image processing apparatus that outputs data.

  According to a fifth aspect of the present invention, there is provided conversion means for converting image data by rearranging each pixel of the output image data into a predetermined structure, and the received code data is an irreversible encoding. 5. The image processing apparatus according to claim 4, further comprising a control unit that controls the image data to be converted by the conversion unit when the image data is generated by the conversion unit.

  According to a sixth aspect of the present invention, there is provided a conversion means for converting the image data by rearranging each pixel of the output image data into a predetermined structure, and a first holding the received code data. The image processing apparatus according to claim 4, further comprising a data holding unit and a second data holding unit that holds the received code data or the image data converted by the conversion unit.

  The present invention according to claim 7 is a lossless encoding means for losslessly encoding received image data, an irreversible encoding means for irreversibly encoding the image data, the lossless encoding means, and the lossy code. And encoding means for selecting one of the lossless encoding means and the lossy encoding means when one of the encoding means exhibits higher encoding efficiency for the image data than the other. One of the selected lossless encoding means and the lossy encoding means is an image processing system that outputs code data generated by encoding the image data.

  The present invention according to claim 8 is characterized in that the lossless decoding means for reversibly decoding the received code data, the second decoding means for irreversibly decoding the code data, and the encoding format of the code data, An image generated by decoding the code data, wherein the selected one of the lossless decoding means and the lossy decoding means is one of a lossless decoding means and a decoding selection means for selecting one of the lossy decoding means. An image processing system for outputting data.

  The present invention according to claim 9 is a lossless encoding step for losslessly encoding received image data, an irreversible encoding step for irreversibly encoding the image data, the lossless encoding step, and the lossy code. When one of the encoding steps exhibits higher encoding efficiency for the image data than the other, an encoding selection step for selecting one of the lossless encoding step and the lossy encoding step is performed on a computer. One of the selected lossless encoding step and the lossy encoding step is a program that outputs code data generated by encoding the image data.

  According to a tenth aspect of the present invention, the lossless decoding step of reversibly decoding the received code data, the second decoding step of irreversibly decoding the code data, and the encoding format of the code data, And causing the computer to execute a lossless decoding step and a decoding selection step for selecting one of the lossy decoding steps, and one of the selected lossless decoding step and the lossy decoding step is generated by decoding the code data. Is a program for outputting processed image data.

  According to the first aspect of the present invention, it is possible to provide an image processing apparatus capable of increasing the encoding efficiency of image data as compared with the case where the present configuration is not provided.

  According to the second aspect of the present invention, in addition to the effect of the present invention according to the first aspect, the image processing capable of inputting and outputting the encoded data between the image processing apparatuses performing different decoding processes. An apparatus can be provided.

  According to the third aspect of the present invention, in addition to the effect of the present invention according to the first aspect, the data holding means required for the image data encoding process is compared with the case where the present configuration is not provided. An image processing apparatus that can be reduced in size can be provided.

  According to the fourth aspect of the present invention, it is possible to provide an image processing apparatus capable of increasing the decoding efficiency of encoded data as compared with the case where the present configuration is not provided.

  According to the fifth aspect of the present invention, in addition to the effect of the present invention according to the fourth aspect, the encoded data input / output between the image processing apparatuses performing different encoding processes is correctly decoded. It is possible to provide an image processing apparatus that can

  According to the sixth aspect of the present invention, in addition to the effect of the present invention according to the fourth aspect, compared with the case where the present configuration is not provided, the data holding required for the decoding process of the encoded data is performed. An image processing apparatus capable of reducing the size of the means can be provided.

  According to the seventh aspect of the present invention, it is possible to provide an image processing system capable of increasing the encoding efficiency of image data as compared with the case where the present configuration is not provided.

  According to the eighth aspect of the present invention, it is possible to provide an image processing apparatus capable of increasing the decoding efficiency of encoded data as compared with the case where the present configuration is not provided.

  According to the ninth aspect of the present invention, it is possible to provide a program that can increase the encoding efficiency of image data as compared with the case where the present configuration is not provided.

  According to the tenth aspect of the present invention, it is possible to provide a program capable of increasing the decoding efficiency of encoded data as compared with the case where the present configuration is not provided.

(A) is a figure which illustrates the structure of a general lossless encoding program, (B) is a figure which illustrates the structure of a general first lossy encoding program, (C) FIG. 3 is a diagram illustrating a configuration of a general second lossy encoding program. It is a figure which illustrates the hardware constitutions of the image processing apparatus which concerns on this invention. It is a figure which illustrates the structure of the 1st encoding program which operate | moves on the image processing apparatus shown in FIG. FIG. 4 is a diagram illustrating a first configuration of an encoding unit illustrated in FIG. 3. It is a figure which illustrates the 2nd structure of the encoding part shown in FIG. It is a figure which illustrates the structure of the 1st decoding program which operate | moves on the image processing apparatus shown in FIG. It is a figure which illustrates the structure of the decoding part shown in FIG. The configuration of the first encoding program shown in FIG. 3 that operates using the first buffer and the second buffer on the image processing apparatus shown in FIG. 2, and the first decoding program shown in FIG. FIG. (A) is a figure which illustrates the structure of the 2nd encoding program which operate | moves on the image processing apparatus shown in FIG. 2, (B) is a figure which operates on the image processing apparatus shown in FIG. It is a figure which illustrates the structure of 2 decoding programs. (A) is a figure which illustrates the structure of the 3rd encoding program which operate | moves on the image processing apparatus shown in FIG. 2, (B) is a figure which operates on the image processing apparatus shown in FIG. It is a figure which illustrates the structure of 2 decoding programs. It is a figure which illustrates the structure of the 3rd decoding program which operate | moves on the image processing apparatus shown in FIG. It is a figure which illustrates the structure of the 4th encoding program which operate | moves on the image processing apparatus shown in FIG.

[Background to the Invention of the Present Invention]
Prior to the description of the embodiments of the present invention, in order to help understanding thereof, general lossless encoding processing and irreversible encoding processing will be shown to explain the background of the present invention. .
In the following description, a case where image data is output to a printing apparatus will be described as a specific example for the purpose of specific description and clarification.
In the following, “encoding” means “compression encoding”.
Further, the lossless encoding process and the lossy encoding process can be realized by any of a combination of general-purpose hardware, dedicated hardware, a combination of general-purpose software, or dedicated software. For clarification and realization, a specific example is given of a case where the lossless encoding process and the lossy encoding process are realized by dedicated software that operates on general-purpose computer hardware.

[Lossless encoding]
FIG. 1A is a diagram illustrating a configuration of a general lossless encoding program 80.
As shown in FIG. 1A, a general lossless encoding program 80 includes a predictive encoding unit 400.
The predictive encoding unit 400 receives image data read by raster scanning from a reading device or the like, performs predictive encoding on the received image data, and generates predictive encoded data.
Predictive coding refers to, for example, a pixel other than a pixel of image data to be predictively encoded (hereinafter referred to as “target pixel”) (for example, a pixel adjacent to the target pixel), and calculates a predicted value of the target pixel A prediction error value indicating a difference value between the generated prediction value and the pixel value of the target pixel is encoded.
In the following, in each figure, substantially the same components and processes are denoted by the same reference numerals.

A raster scan generally scans from the left edge of the top row of the image to the right edge in the horizontal direction, then from the left edge of the next lower row to the right edge as well, and this operation Is a method for acquiring image data and arranging it in a one-dimensional structure by repeating to the right end of the bottom row.
Generally, lossless encoding for image data arranged by raster scanning has a lower processing load than lossy encoding described later.
Therefore, in general, lossless encoding is used in a low-speed printing apparatus that is relatively inexpensive, has a low processing capability such as a printing process, and has a low printing speed.

[First lossy encoding]
FIG. 1B is a diagram illustrating a configuration of a general first lossy encoding program 82.
As shown in FIG. 1B, a general first lossy encoding program 82 includes a conversion unit 302 and an irreversible encoding unit 820.
The first lossy encoding program 82 generally performs lossy encoding on image data obtained by converting image data arranged by raster scanning into an arrangement by block scanning.
In block scanning, generally, image data is divided into blocks having a predetermined two-dimensional structure (for example, blocks of 8 × 8 pixels), and lossy encoding processing is performed for each block. Is a method of arranging

The conversion unit 302 receives the image data arranged by the raster scan, rearranges each pixel of the received image data, converts it to a two-dimensional structure arranged by the block scan, and converts the converted image data to the non-image data. The data is output to the lossless encoding unit 820.
Hereinafter, the above-described conversion performed by the conversion unit 302 is described as “data conversion”.
In addition, the image data arranged in a two-dimensional structure by the conversion unit 302 is processed in a one-dimensional structure that is sequentially connected from the first line to the last line even if each process is performed in the two-dimensional structure. May be made.
The lossy encoding unit 820 encodes the image data input from the conversion unit 302 by transform encoding for each block having a two-dimensional structure, and generates encoded data.
In transform coding, for example, image data having a two-dimensional structure is frequency-transformed by discrete cosine transform, the transformed data is quantized, and the quantized data is coded.

[Second lossy encoding]
FIG. 1C is a diagram illustrating a configuration of a general second lossy encoding program 84.
As shown in FIG. 1C, a general second lossy encoding program 84 includes a conversion unit 302, an irreversible unit 304, an inverse conversion unit 504, and a predictive encoding unit 400. .
The second lossy encoding program 84 generally performs lossy and predictive encoding on image data.

The irreversible unit 304 irreversibly converts the image data input from the conversion unit 302 into two-dimensional structure blocks by quantizing pixel values, and the irreversible image data to the inverse conversion unit 504. Output.
The inverse conversion unit 504 performs processing opposite to the data conversion performed by the conversion unit 302 on the image data input from the irreversible unit 304.
That is, the inverse conversion unit 504 rearranges the pixels of the image data arranged in a two-dimensional structure by block scanning, for example, and converts the pixels into image data arranged in a one-dimensional structure by raster scanning.
Further, the inverse transform unit 504 outputs the transformed image data to the predictive coding unit 400.
Hereinafter, the conversion performed by the inverse conversion unit 504 is described as “data inverse conversion”.

In general, irreversible encoding requires a processing load higher than that of lossless encoding because it requires the above-described image data conversion processing by the conversion unit 302.
Therefore, in general, lossy encoding is used in a high-speed printing apparatus that is more expensive than a low-speed printing apparatus that uses lossless encoding, has a high processing capability such as printing processing, and has a high printing speed.

  Table 1 below summarizes the encoding methods used for the general lossless encoding processing and lossy encoding processing as described above, and the arrangement method of image data.

As shown in Table 1, the encoding method and the arrangement of image data differ depending on whether lossless encoding or lossy encoding is used.
Therefore, as described above, when a different encoding method is selected for each type of printing device, such as a low-speed printing device using lossless encoding and a high-speed printing device using irreversible encoding, It is considered necessary to design a configuration (hardware, software, etc.) corresponding to the selected encoding method.
In addition, if the encoding method and the arrangement of image data necessary for encoding are different for each type of printing device, the compatibility of the encoding method between the printing devices may not be achieved.
The present invention has been made based on the background described above, and has been devised so that image data can be efficiently encoded as compared with the case where the configuration of the present invention is not provided. .

[Image processing device]
Hereinafter, an image processing apparatus 1 that performs encoding processing and decoding processing according to the present embodiment will be described.
FIG. 2 is a diagram illustrating a hardware configuration of the image processing apparatus 1 (image processing apparatus) according to the present embodiment.
As shown in FIG. 2, the image processing apparatus 1 includes a control device 20 including a CPU 202 and a memory 204, a communication device 22 for performing data communication, a user interface (UI) device 24 including a keyboard, a touch panel, a display device, and the like. In addition, the recording apparatus 26 includes a recording device 26 such as a hard disk.
The image processing apparatus 1 is, for example, a processing apparatus provided in the printing apparatus 10. The image processing apparatus 1 encodes image data received via the communication device 22 or the recording medium 28, decodes the encoded image data, and performs UI processing. The data is output to the display device of the device 24 or the printing device 10.

[Encoding program]
Hereinafter, the first encoding program 3 executed on the image processing apparatus 1 (FIG. 2) will be described.
FIG. 3 is a diagram illustrating a first encoding program 3 executed on the image processing apparatus 1.
As shown in FIG. 3, the first encoding program 3 includes a first conversion selection unit 300, a conversion unit 302, an irreversible unit 304, and an encoding unit 40.
For example, the first encoding program 3 is stored in the memory 204 (FIG. 2), supplied to the control device 20, and controlled on an OS (not shown) installed in the control device 20 as necessary. The hardware resources of the device 20 are specifically used for execution.
The first encoding program 3 encodes image data in accordance with selection information described later.

The selection information includes, for example, printing image quality setting in the printing apparatus 10 (FIG. 2), contents of image data to be printed, type of printing command (for example, simple printing mode), printing speed of the printing apparatus 10, and installed memory capacity. , And the content being processed (for example, during FAX reception).
The selection information is input via the UI device 24 (FIG. 2), stored in the memory 204 or the recording device 26, and output to the first conversion selection unit 300, for example.
In addition, the selection information may be stored in advance in the memory 204, the recording device 26, or the like, for example, like the printing speed of the printing apparatus 10 and the installed memory capacity.

The first conversion selection unit 300 receives the image data received via the communication device 22 or the recording medium 28 (FIG. 2) based on the selection information received via the memory 204 or the recording device 26 (FIG. 2). On the other hand, whether to perform the reversible process or the irreversible process is selected.
Specifically, for example, the first conversion selection unit 300 selects the reversible process when the print image quality setting indicated by the selection information is set to a high image quality, and otherwise, Select reversible processing.
When the first conversion selection unit 300 selects to perform the irreversible process, the first conversion selection unit 300 outputs the received image data to the conversion unit 304 and selects to perform the reversible process. The received image data is output to the encoding unit 40.

The conversion unit 302 converts the image data input from the first conversion selection unit 300, and outputs the converted image data to the irreversible unit 304.
The irreversible unit 304 performs irreversible processing on the image data input from the conversion unit 302 and outputs the irreversible image data to the encoding unit 40.
When the first conversion selection unit 300 selects to perform the reversible processing, the encoding unit 40 encodes the image data input from the first conversion selection unit 300 to generate code data. (Details with reference to FIG. 4).
The encoding unit 40 generates code data by encoding the image data input from the irreversible unit 304 when the first conversion selection unit 300 selects to perform the irreversible process. (Details will be described with reference to FIG. 4).

FIG. 4 is a diagram illustrating the configuration of the encoding unit 40 (FIG. 3).
As shown in FIG. 4, the encoding unit 40 includes a predictive encoding unit 400, a variable length encoding unit 402, a block truncation coding (BTC) unit 404, and a code selection unit 410. .
The encoding unit 40 divides the image data arranged in a one-dimensional structure by a predetermined number of pixels (for example, the number of pixels from the left side to the right side of the image), and in units of a predetermined number of pixels, Perform the process described.
Hereinafter, a part of image data processed in units of a predetermined number of pixels may be simply described as “image data”.

The predictive encoding unit 400 performs predictive encoding on the image data input from the first transform selection unit 300 (FIG. 3) or the irreversible unit 304, and variable the predictive encoded image data. This is output to the long encoding unit 402.
In general, predictive encoding is performed on image data that has not undergone data conversion (that is, image data that has been subjected to lossless encoding) rather than image data that has undergone data conversion (that is, image data that has undergone lossy encoding). It is suitable for doing.
Therefore, hereinafter, the image data that has been predictively encoded by the predictive encoding unit 400 is described as “code data based on a lossless model”.

The BTC unit 404 includes a pixel extraction unit 406 and a bitmap generation unit 408.
The pixel value extraction unit 406 extracts each pixel value of the image data input from the first conversion selection unit 300 (FIG. 3) or the irreversible unit 304, and outputs each pixel value to the bitmap generation unit 408. Output.
The bitmap generation unit 408 converts each pixel value of the image data input from the pixel value extraction unit 406 into, for example, a 1-bit bit value representing two colors (for example, “0” for white, “ 1 ") to generate a bitmap.
Also, the bitmap generation unit 408 outputs the generated bitmap to the variable length encoding unit 402.
Note that the colors used in the bitmap may be three or more colors, and a bitmap having a number of bits that can express all the colors may be generated.

The block truncation encoding performed by the BTC unit 404 is generally more suitable for image data that has been subjected to color reduction processing by irreversibility than image data that is subjected to lossless encoding.
Therefore, hereinafter, the image data subjected to block truncation coding by the BTC unit 404 is described as “code data based on an irreversible model”.
Note that the encoding based on the irreversible model may use another encoding corresponding to the image data processing (for example, resolution reduction processing) by irreversible instead of block truncation encoding.

The variable length coding unit 402 performs variable length coding on the code data based on the lossless model input from the predictive coding unit 400 and the code data based on the lossy model input from the BTC unit 404, respectively. The variable length code data is generated and output to the code selection unit 410.
Examples of variable length coding include Huffman coding or arithmetic coding.
Hereinafter, the variable length code data generated from the code data based on the lossless model is described as “variable length code data based on the lossless model”, and the variable length code data generated from the code data based on the lossy model is referred to as “variable length code data based on the lossless model”. , “Variable length code data based on lossy model”.

In addition, hereinafter, “code data based on a lossless model”, “variable length code data based on a lossless model”, “code data based on an irreversible model”, and “variable length code data based on an irreversible model” are distinguished. Instead, it may be simply described as “code data”.
The code selection unit 410 selects, from the variable length code data based on the lossless model and the variable length code data based on the irreversible model, input from the variable length coding unit 402, the one with higher coding efficiency.
Specifically, for example, the code selection unit 410 compares the code data based on the reversible model and the code amount of the code data based on the irreversible model, and selects the one with the smaller code amount.

Note that the selection of the reversible / irreversible process in the first conversion selection unit 300 (FIG. 3) of the first encoding program 3 and the selection of the reversible / irreversible model in the code selection unit 410 are not necessarily performed. There is no need to match.
That is, for example, when the irreversible processing is selected in the first conversion selection unit 300 of the first encoding program 3, the irreversible image data is encoded based on the reversible model. If the encoding efficiency is higher than that based on the lossy model, the code selection unit 410 selects the lossless model.
In addition, the code selection unit 410 adds a code (hereinafter referred to as “identification code”) for identifying whether the code data is generated based on the reversible model or the irreversible model to the selected code data. To do.

For example, as the identification code, the code selection unit 410 adds a value of “0” for the lossless model and a value of “1” for the lossy model to the head of the selected code data.
Further, the code selection unit 410 outputs the code data to which the identification code is added to the memory 204 or the recording device 26 of the image processing apparatus 1 (FIG. 2).
Hereinafter, the code data to which the identification code is added may be simply described as “code data” without being distinguished from the code data to which the identification code is not added.
Further, instead of the encoding unit 40, a modified encoding unit 42 as described below with reference to FIG. 5 may be used.

FIG. 5 is a diagram illustrating a configuration of an encoding unit 42 obtained by modifying the encoding unit 40 (FIG. 4).
As illustrated in FIG. 5, the encoding unit 42 has a configuration in which the code selection unit 410 is removed from the configuration of the encoding unit 40 and an encoding process selection unit 420 is added.
The encoding unit 42 selects in advance whether to generate the code data based on either the reversible model or the irreversible model before generating the respective code data.

The encoding process selection unit 420 uses either the reversible model or the irreversible model based on the feature information of the image data input from the first transformation selection unit 300 (FIG. 3) or the irreversible unit 304. It is determined whether code data with higher coding efficiency can be generated.
The feature information indicates, for example, image feature amounts such as image color information and image change points, and image data types (for example, photographs and texts).
For example, when the encoding process selection unit 420 determines from the color information of the image that the peripheral image of the processing target portion of the image data has a continuous monochromatic configuration, generally, the encoding process selection unit 420 is more likely than the irreversible model. Therefore, it is determined that a reversible model with high encoding efficiency is used for image data having a continuous single color.

Also, in the configuration of the encoding unit 42, since it is selected which of the reversible model and the irreversible model to use based on the feature information of the image data, the image data is also converted into the reversible model in the decoding unit 60 described later. And the irreversible model can be identified (described later with reference to FIG. 7).
Therefore, the configuration of the encoding unit 42 does not add an identification code to the code data as in the encoding unit 40 (FIG. 4).
Also, the encoding process selection unit 420 outputs the image data to the prediction encoding unit 400 when determining that the lossless model is used, and otherwise outputs the image data to the pixel value extraction unit 404. Output for.

When the encoding process selection unit 420 determines that the lossless model is used, the variable length encoding unit 410 performs variable length encoding on the code data based on the lossless model input from the predictive encoding unit 400.
In addition, when the encoding process selection unit 420 determines that the irreversible model is used, the variable length encoding unit 410 performs variable length encoding on the code data based on the irreversible model input from the bitmap generation unit 408. To do.
The variable length encoding unit 410 also stores variable length code data generated by variable length encoding code data based on a lossless model or code data based on an irreversible model in the memory of the image processing apparatus 1 (FIG. 2). 204 or the recording device 26.

[Decryption program]
Hereinafter, the first decoding program 5 executed on the image processing apparatus 1 (FIG. 2) will be described.
FIG. 6 is a diagram illustrating the first decoding program 5 executed on the image processing apparatus 1.
As shown in FIG. 6, the first decoding program 5 includes a decoding unit 60, a first inverse transformation selection unit 502, and an inverse transformation unit 504.
The decoding unit 60 decodes the code data generated in the first encoding program 3 (FIG. 3) into image data (detailed with reference to FIG. 7).
The decoding unit 60 outputs the decoded image data to the first inverse transformation selection unit 502.

Based on the selection information received via the memory 204 or the recording device 26 (FIG. 2), the first inverse transformation selection unit 502 has performed irreversible processing on the image data input from the decoding unit 60. Judge whether or not.
The selection information is the same as the selection information used in the first conversion selection unit 300 (FIG. 3) of the first encoding program 3.
When the first inverse transformation selection unit 502 determines that the irreversible processing has been performed, the first inverse transformation selection unit 502 outputs the decoded image data to the inverse transformation unit 504. Otherwise, the first inverse transformation selection unit 502 decrypts the decoded image data. The image data is output as it is to the printing apparatus 10 (FIG. 2).
The inverse conversion unit 504 performs inverse conversion on the image data input from the first inverse conversion selection unit 502 and outputs the image data.

FIG. 7 is a diagram illustrating a configuration of the decoding unit 60 (FIG. 6).
As illustrated in FIG. 7, the decoding unit 60 includes a variable length decoding unit 602, a decoding process selection unit 604, a prediction decoding unit 606, and a block generation unit 608.
The variable length decoding unit 602 receives code data via the memory 204 or the recording device 26 (FIG. 2).
In addition, when the encoding unit 40 (FIG. 4) is used as the encoding unit of the first encoding program 3 (FIG. 3), the variable length decoding unit 602 obtains an identification code from the received code data. The removed code data is subjected to variable length decoding to generate image data, and the image data and the identification code are output to the decoding process selection unit 604.
Further, when the encoding unit 42 (FIG. 5) is used as the encoding unit of the first encoding program 3 (FIG. 3), the variable length decoding unit 602 Lossy decoding is performed, image data is generated, and output to the decoding process selection unit 604.

When the identification code is input from the variable length decoding unit 602, the decoding process selection unit 604 converts the image data input from the variable length decoding unit 602 based on the identification code into the predictive decoding unit 606 or the block generation unit 608. Output for.
Specifically, for example, when the identification code is “0”, the decoding process selection unit 604 performs variable length decoding on the prediction decoding unit 606 that performs decoding corresponding to encoding based on the lossless model. The processed image data is output.
When the identification code is not input from the variable length decoding unit 602, the decoding process selection unit 604 selects the encoding process of the encoding unit 42 based on the feature information of the image data input from the variable length decoding unit 602. Similar to the unit 420 (FIG. 5), it is selected whether to use the reversible model or the irreversible model.

The decoding process selection unit 604 outputs image data to the predictive decoding unit 606 when selecting a lossless model, and outputs image data to the block generation unit 608 when selecting an irreversible model. To do.
The predictive decoding unit 606 performs predictive decoding on the image data input from the decoding process selection unit 604, and outputs the predictive decoded image data to the printing apparatus 10 (FIG. 2) or the like.
The block generation unit 608 converts each bit value of the image data input from the decoding process selection unit 604 into a pixel value, and outputs the image data converted into the pixel value to the printing apparatus 10 (FIG. 2) or the like. Output.

[First embodiment]
Hereinafter, as a first example, an image data encoding process and a decoding process using a buffer, which is an example of a data holding unit, performed by the image processing apparatus 1 (FIG. 2) according to the present embodiment will be described.
FIG. 8 is a diagram illustrating the configuration of the first encoding program 3 and the first decoding program 5 in the first embodiment of the image processing apparatus 1 shown in FIG.
As shown in FIG. 8, in the first embodiment, the configuration of the first encoding program 3 (FIG. 3) and the first decoding program 5 (FIG. 6) includes a first buffer 700 and a second buffer. 702, a first data control unit 704, and a second data control unit 706 are added.

In the first embodiment, the first conversion selection unit 300 outputs the selection result to the first data control unit 704.
In the first embodiment, the encoding unit 40 encodes the image data input from the first conversion selection unit 300 or the irreversible unit 304, divides the encoded image data into two, The respective data are output to the first buffer 700 and the first data control unit 704.
The number of divisions of the encoded image data may be three or more according to the configuration of the image processing apparatus 1.
In the above description, “encoding unit 40” is described. However, “encoding unit 40” may be replaced with “encoding unit 42”. The same applies to the following description.

When the selection result input from the first conversion selection unit 300 indicates that the reversible processing is selected, the first data control unit 704 converts the code data input from the encoding unit 40 into the second data Are output to the buffer 702.
In other cases (hereinafter, described as “when irreversible processing is selected”), the first data control unit 704 sends the code data input from the encoding unit 40 to the first buffer 700. Output.
That is, when the irreversible process is selected, the code data input from the encoding unit 40 is stored only in the first buffer 700.
In addition, when the irreversible processing is selected, the first data control unit 704 outputs the image data input from the conversion unit 302 to the second buffer 702, and converts the second buffer 702 into the conversion. Used as a working buffer for data conversion by the unit 302.

In the first embodiment, the first inverse transformation selection unit 502 outputs the determination result to the second data control unit 706.
When the second data control unit 706 indicates that the determination result input from the first inverse transformation selection unit 502 indicates that the reversible processing has been performed, the code stored in the second buffer 702 The data is output to the decoding unit 60.
In other cases, the second data control unit 706 outputs the image data input from the inverse conversion unit 504 to the second buffer 702, and causes the second buffer 702 to be output to the inverse conversion unit 504. Used as a working buffer for data reverse conversion by

The first buffer 700 stores the code data input from the encoding unit 40.
Further, the first buffer 700 outputs the stored code data to the decoding unit 60.
The second buffer 702 stores the code data input from the encoding unit 40 via the first data control unit 704.
The second buffer 702 serves as a working buffer for the conversion unit 302 to perform data conversion processing when the encoded data is not input from the encoding unit 40 via the first data control unit 704. The image data input via the first data control unit 704 is buffered.

In addition, the second buffer 702 outputs the stored code data to the decoding unit 60 via the second data control unit 706.
Further, the second buffer 702 is input via the second data control unit 706 as a working buffer for the inverse conversion unit 504 to perform the data inverse conversion process when the code data is not stored. Buffer image data.
As described above, the second buffer 702 is shared for storing code data and for work for data conversion / inverse conversion.

[Example of operation in the first embodiment]
Hereinafter, an operation example of the image processing apparatus 1 in the first embodiment will be described.
The first encoding program 3 (FIG. 8) executed on the image processing apparatus 1 selects whether to perform reversible processing or irreversible processing on the received image data.
When selecting the reversible processing, the first encoding program 3 encodes the image data and outputs the encoded data to the first buffer 700 and the second buffer 702.
When selecting the irreversible process, the first encoding program 3 uses the second buffer 702 as a work buffer, converts the image data, encodes the converted image data, Data is output to the first buffer 700.

The first decoding program 5 executed on the image processing apparatus 1 is encoded data of image data that has been subjected to lossless processing or encoded data of image data that has been subjected to lossy processing. It is judged whether it is.
When determining that the reversible processing has been performed, the first decoding program 5 decodes the code data stored in the first buffer 700 and the second buffer 702, respectively.
When the first decoding program 5 determines that the irreversible processing has been performed, the first decoding program 5 decodes the code data stored in the first buffer 700.
When the first decoding program 5 determines that the irreversible processing has been performed, the second buffer 702 is used as a work buffer, and the decoded image data is inversely converted, and the inversely converted image data is converted into the inversely converted image data. Otherwise, the decoded image data is output.

[Second Embodiment]
Hereinafter, as a second example, an encoding process and a decoding process of image data transmitted and received by a plurality of image processing apparatuses 1 (FIG. 2) according to the present embodiment will be described.
In the following description of the second embodiment, the image processing apparatus 1 provided with a low-speed printing apparatus using lossless encoding and a high-speed printing apparatus using lossy encoding for the purpose of clarifying and clarifying the invention. A specific example is processing between the image processing apparatus 1 and the image processing apparatus 1.
Hereinafter, the “image processing apparatus 1 provided with a low-speed (high-speed) printing apparatus” may be simply referred to as “low-speed (high-speed) printing apparatus”.
Further, the “low-speed printing device” and the “high-speed printing device” are not distinguished from each other and may be simply described as “printing device”.

FIG. 9 is a diagram illustrating the configurations of the second encoding program 32 and the second decoding program 52, which are executed on the image processing apparatus 1 provided with the low-speed printing apparatus. 2 is a diagram illustrating a configuration of a second encoding program 32, and (B) is a diagram illustrating a second decoding program 52. FIG.
As shown in FIG. 9A, the second encoding program 32 includes only the encoding unit 40 in the configuration of the first encoding program 3 (FIG. 3).
As shown in FIG. 9B, the second decryption program 52 uses the first inverse transform selection unit 502 in the configuration of the first decryption program 5 (FIG. 6) to select the second inverse transform. It replaces with the part 522, and the code data receiving part 520 is added.
The second encoding program 32 (FIG. 9A) is configured to perform lossless encoding on image data, which has a lower processing load than lossy encoding.

The second decoding program 52 (FIG. 9B) performs processing described below depending on whether the code data is input from the low-speed printer or the code data input from the high-speed printer. Do.
The code data receiving unit 520 receives the code data input from the low-speed printing apparatus or the high-speed printing apparatus, and also identifies identification information (for example, the manufacturing number of the printing apparatus) of the low-speed printing apparatus or high-speed printing apparatus that has output the received code data. To get.
Also, the code data receiving unit 520 outputs the received code data to the decoding unit 60 and outputs the acquired identification information to the second inverse transform selection unit 522.

The second inverse transform selection unit 522 receives the image data input from the decoding unit 60 and the identification information input from the code data receiving unit 520.
Further, the second inverse conversion selection unit 522 determines whether the received image data is encoded by the low-speed printing apparatus or the high-speed printing apparatus based on the received identification information.
Specifically, for example, the second reverse conversion selection unit 522 sets printing device information (for example, the manufacturing number of the printing device and the type of the printing device) stored in the second reverse conversion selection unit 522. A table is searched for the type of printing apparatus that matches the manufacturing number of the printing apparatus indicated by the identification information, and it is determined whether the printing apparatus is a low-speed printing apparatus or a high-speed printing apparatus.
Further, when the second inverse conversion selection unit 522 determines that the code data is input from the low-speed printing apparatus, the second inverse conversion selection unit 522 outputs the received image data as it is.
The second inverse conversion selection unit 522 outputs the received image data to the inverse conversion unit 504 when determining that the code data is input from the high-speed printing apparatus.

FIG. 10 is a diagram illustrating the configuration of each of the third encoding program 34 and the second decoding program 52 executed on the image processing apparatus 1 provided with the high-speed printing apparatus. 3 is a diagram illustrating the configuration of the third encoding program 34, and (B) is a diagram illustrating the second decoding program 52. FIG.
As shown in FIG. 10A, the third encoding program 34 has a configuration in which the first conversion selection unit 300 is excluded from the configuration of the first encoding program 3 (FIG. 3).
As shown in FIG. 10B, the decryption program has the same configuration as the second decryption program 52 (FIG. 9B).
The third encoding program 34 (FIG. 10A) is configured to perform irreversible encoding, which has a higher processing load than lossless encoding, on image data.

[Example of operation in the second embodiment]
Hereinafter, an operation example of the image processing apparatus 1 in the second embodiment will be described.
The second encoding program 32 (FIG. 9A) executed on the image processing apparatus 1 provided with the low-speed printing apparatus outputs code data obtained by reversibly encoding the image data to the printing apparatus.
The third encoding program 34 (FIG. 10A) executed on the image processing apparatus 1 provided with the high-speed printing apparatus transmits code data obtained by irreversibly encoding the image data subjected to data conversion to the printing apparatus. Output.
The code data output target printing device indicates, for example, the printing device itself that outputs the code data, or one or more other printing devices.
A second decoding program 52 (FIG. 9B) executed on the image processing apparatus 1 provided with the low-speed printing apparatus, and a second decoding program 52 executed on the image processing apparatus 1 provided with the high-speed printing apparatus. In FIG. 10B, the encoded data is decoded to generate image data.
The second decoding program 52 outputs the decoded image data when the code data is input from the low-speed printing apparatus, and the decoded image data when the code data is input from the high-speed printing apparatus. Is inversely transformed, and the inversely transformed image data is output.

[Modification]
Hereinafter, modified examples of encoding processing and decoding processing of image data transmitted and received by the plurality of image processing apparatuses 1 according to the second embodiment will be described.
Even when the decoding program of the low-speed printing device cannot take the same configuration as the second decoding program 52 (FIG. 10B) of the high-speed printing device, the plurality of image processing devices 1 in the modification example As in the first embodiment, image data to be transmitted / received to each other is encoded and decoded.
FIG. 11 is a diagram illustrating the configuration of the third decoding program 54 executed on the image processing apparatus 1 provided with the low-speed printing apparatus.
FIG. 12 is a diagram illustrating a configuration of the fourth encoding program 36 that is executed on the image processing apparatus 1 provided with the high-speed printing apparatus.

As shown in FIG. 11, the third decryption program 54 is composed only of the decryption unit 60 in the configuration of the first decryption program 5 (FIG. 6).
As shown in FIG. 12, the fourth encoding program 36 has a configuration in which a second conversion selection unit 360 is added to the configuration of the second encoding program 34 (FIG. 10A).
For example, the second conversion selection unit 360 selects whether to output the code data to the low-speed printing apparatus or the high-speed printing apparatus from the content of the image data indicated by the selection information.
When the second conversion selection unit 360 determines to output to the low-speed printing apparatus, the second conversion selection unit 360 outputs image data to the irreversible unit 304 and determines to output to the high-speed printing apparatus. Outputs the image data to the conversion unit 302.
Note that the first encoding program 5 may be used instead of the fourth encoding program 36 as an encoding program executed on the image processing apparatus 1 provided with the high-speed printing apparatus.

1 ... Image processing device,
10: Printing device,
20 ... Control device,
202... CPU
204... Memory
22: Communication device,
24 ... UI device,
26 ... Recording device,
28 ... Recording medium,
3, 32, 34, 36 ... encoding program,
300, 360 ... conversion selection unit,
302 ... conversion unit,
304... Irreversible part,
40, 42 ... encoding unit,
400: Predictive encoding unit,
402... Variable length encoding unit,
404 ... BTC part,
406 ... Image extraction unit,
408 ... Bitmap generation unit,
410 ... code selection unit,
420 ... Encoding process selection section,
5, 52, 54 ... decryption program,
60: Decoding unit,
602... Variable length decoding unit,
604 ... Decoding processing selection unit,
606 ... Predictive decoding unit,
608 ... Block generation unit,
502, 522 ... Inverse transformation selection unit,
504 ... Inverse conversion unit,
700, 702 ... buffer,
704, 706... Data control unit,
80: General lossless encoding program,
82, 84 ... General lossy encoding program,
820 ... Lossy encoding unit

Claims (10)

Lossless encoding means for losslessly encoding received image data;
Irreversible encoding means for irreversibly encoding the image data;
When one of the lossless encoding means and the lossy encoding means exhibits higher encoding efficiency for the image data than the other, one of the lossless encoding means and the lossy encoding means is Coding selection means for selecting, and
One of the selected lossless encoding means and the irreversible encoding means is an image processing apparatus that outputs code data generated by encoding the image data. Conversion means for converting the image data by irreversibly encoding the image data, rearranging each pixel of the image data into a predetermined structure;
The image processing apparatus according to claim 1, further comprising: a control unit that controls the image data to be converted by the conversion unit when the output code data is irreversibly decoded. Conversion means for converting the image data by rearranging the pixels of the image data into a predetermined structure;
First data holding means for holding the outputted code data;
Among the output code data, there is code data other than code data held in the first data holding means, or second data holding means for holding image data converted by the conversion means. The image processing apparatus according to claim 1. Reversible decoding means for reversibly decoding the received code data;
Second decoding means for irreversibly decoding the code data;
Decoding selection means for selecting one of the lossless decoding means and the lossy decoding means according to the encoding format of the code data,
One of the selected lossless decoding means and the irreversible decoding means is an image processing device that outputs image data generated by decoding the code data. Converting means for converting the image data by rearranging the pixels of the output image data into a predetermined structure;
The image processing apparatus according to claim 4, further comprising: a control unit that controls the image data to be converted by the conversion unit when the received code data is generated by lossy encoding. Converting means for converting the image data by rearranging the pixels of the output image data into a predetermined structure;
First data holding means for holding the received code data;
The image processing apparatus according to claim 4, further comprising: second data holding unit that holds the received code data or image data converted by the conversion unit. Lossless encoding means for losslessly encoding received image data;
Irreversible encoding means for irreversibly encoding the image data;
When one of the lossless encoding means and the lossy encoding means exhibits higher encoding efficiency for the image data than the other, one of the lossless encoding means and the lossy encoding means is Coding selection means for selecting, and
One of the selected lossless encoding means and the irreversible encoding means is an image processing system that outputs code data generated by encoding the image data. Reversible decoding means for reversibly decoding the received code data;
Second decoding means for irreversibly decoding the code data;
Decoding selection means for selecting one of the lossless decoding means and the lossy decoding means according to the encoding format of the code data,
One of the selected lossless decoding means and the irreversible decoding means outputs an image data generated by decoding the code data. A lossless encoding step for losslessly encoding the received image data;
An irreversible encoding step for irreversibly encoding the image data;
When one of the lossless encoding step and the lossy encoding step shows higher encoding efficiency for the image data than the other, one of the lossless encoding step and the lossy encoding step is performed. The encoding selection step to be selected and
One of the selected lossless encoding step and the lossy encoding step is a program for outputting code data generated by encoding the image data. A lossless decoding step for lossless decoding of the received code data;
A second decoding step for irreversibly decoding the code data;
A decoding selection step of selecting one of the lossless decoding step and the lossy decoding step according to the encoding format of the code data;
One of the selected lossless decoding step and the lossy decoding step is a program for outputting image data generated by decoding the code data.

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