JP4635662B2 - Encoding apparatus, encoding method, and program - Google Patents

Description

  The present invention relates to a binary image encoding apparatus and encoding method, and more particularly, to a binary image encoding apparatus and encoding method including an image element painted with a pattern image.

For example, Non-Patent Document 1 discloses JBIG2 that efficiently encodes image elements. In JBIG2, in addition to encoding processing of a generic region (Generic Region), encoding processing of a text region (Text Region) is defined.
However, the method disclosed in Non-Patent Document 1 does not consider the encoding process and encoding method for a plurality of overlapping image elements.

ITU-T Recommendation T.88 (02/00), “Lossy / lossless coding of bi-level images”, [online], 1999, ITU-T, [searched on February 21, 2005], Internet < URL: http://www.itu.int/rec/recommendation.asp?type=folders&lang=e&parent=T-REC-T.88>

  The present invention has been made from the above-described background, and an object thereof is to provide an encoding apparatus and an encoding method for encoding a plurality of overlapping image elements while suppressing deterioration in image quality.

In order to achieve the above object, a first encoding device according to the present invention is an image composed of a shape of an image element composed of binary pixels and a binary pattern in which halftone dots are regularly arranged. a receiving means for receiving elements, and the shape encoding means for encoding the shape of the image element that has been accepted by the accepting means, by the shape coding means of at least one image element of the shape of the image element to be encoded A shape reversing unit that inverts the value of a binary pixel constituting the shape , and a pattern encoding unit that encodes a binary pattern of the image element received by the receiving unit, and the shape encoding unit The shape to be encoded and the binary pattern encoded by the pattern encoding means are encoded as a pair of encoded data .

Preferably, the shape inversion means inverts the value of a binary pixel constituting the shape of one image element when the image elements received by the receiving means overlap each other .

In order to achieve the above object, a second encoding device according to the present invention is an image composed of a shape of an image element composed of binary pixels and a binary pattern in which halftone dots are regularly arranged. a receiving means for receiving elements, and the shape encoding means for encoding the shape of the image element that has been accepted by the accepting means, and a pattern encoding means for encoding the binary pattern of the image element that has been accepted by the accepting means A shape inversion means for inverting at least one of the binary patterns encoded by the pattern encoding means, and the shape encoded by the shape encoding means and the pattern encoding The binary pattern encoded by the means is encoded as a pair of encoded data .

Preferably, the pattern reversing unit reverses the binary pattern of one image element when the image elements received by the receiving unit overlap each other .

According to a first program of the present invention, in an encoding device including a computer, an image element composed of a shape of an image element composed of binary pixels and a binary pattern in which halftone dots are regularly arranged. A receiving step for receiving, a shape encoding step for encoding the shape of the received image element, and values of binary pixels constituting the shape of at least one image element among the shapes of the encoded image elements A program for causing the computer of the encoding apparatus to execute a shape inversion step for inverting the pattern and a pattern encoding step for encoding a binary pattern of the received image element, and the encoded shape; The binary pattern to be encoded is encoded as a pair of encoded data .

According to a second program of the present invention, in an encoding device including a computer, an image element composed of a shape of an image element composed of binary pixels and a binary pattern in which halftone dots are regularly arranged. A receiving step for receiving, a shape encoding step for encoding the shape of the received image element , a pattern encoding step for encoding a binary pattern of the received image element, and the binary to be encoded A program for causing a computer of the encoding device to execute a shape inversion step of inverting at least one binary pattern among patterns, wherein the encoded shape and the encoded binary pattern are: It is encoded as a pair of encoded data .

  According to the encoding apparatus of the present invention, code data of an image including a plurality of overlapping image elements can be generated with high image quality and high compression rate.

First, in order to help understanding of the present invention, its background and outline will be described.
FIG. 1 is a diagram illustrating an encoding process and a decoding process based on JBIG2. FIG. 1 (A) illustrates the encoding process, and FIG. 1 (B) illustrates the decoding process.
As shown in FIG. 1A, when an image element shape, a binary pattern, image element identification information and position information included in an image are input, the image processing apparatus receives the image element shape (image shape). 1, 2) and shape information including position information, and pattern of image elements (halftone images 1, 2) and pattern information including position information are separated and encoded. The shape of the image element is generated by a processing system such as software that directly generates a set of patterns and shapes, or the input multi-valued image is binarized or input. The binary image is input to the image processing apparatus, for example, by generating the image element pattern and shape separately.

  Such binary image pattern information is encoded by JBIG2 halftone region encoding. The code data of the pattern information includes a binary image pattern (halftone dot image) and position information indicating the position where this pattern exists. The shape information of each image element is encoded by JBIG2 text area encoding or generic area encoding. In the text area encoding process, an image shape is registered in an image dictionary in association with an index for identifying the image shape, and is encoded using the image dictionary. The generic region encoding is a method for encoding an image shape without creating an image dictionary or the like. More specifically, generic region encoding encodes an image shape using local pixel array statistics (eg, context).

  As shown in FIG. 1B, the decoding process is performed by a logical sum (OR) operation and a logical product (AND) operation. In the decoding process, the halftone image registered in the pattern dictionary is arranged by logical sum operation based on the code data of the pattern information, and the image shape indicating the shape of the image element is determined based on the code data of the shape information. This is done by calculating the product of the image shape for the generated image. However, when decoding a plurality of image elements, an area where the image elements overlap may become a white area.

[First Embodiment]
A first embodiment of an image processing apparatus 2 according to the present invention will be described.
2A and 2B are diagrams for explaining the outline of the encoding process and the decoding process in the present embodiment. FIG. 2A shows the encoding process, and FIG. 2B shows the decoding process.
As shown in FIG. 2A, the image processing apparatus 2 according to the present embodiment receives at least one image element shape, binary pattern, image element identification information and position information included in the image. Inverts the shape value of one image element, and stores the shape information including the shape of the image element (image shape 1, inverted image shape 2) and position information, the pattern of the image element (halftone image 1, 2), and position information. The pattern information included is separated and encoded. Similar to the image shape, the inverted image shape is encoded by text region encoding or generic region encoding.

  As shown in FIG. 2B, the image element decoding process is performed by an exclusive OR (XOR) operation and an AND operation. The decoding process is performed by performing at least two exclusive OR operations when image elements are drawn in an overlapping manner. In this way, since a plurality of image elements are encoded by separating shape information and pattern information and decoded using exclusive OR operation, the image elements are highly compressed even when they overlap. It can be coded at a rate and decoded appropriately.

[Hardware configuration]
A hardware configuration of the image processing apparatus 2 in the present embodiment will be described.
FIG. 3 is a diagram illustrating the hardware configuration of the image processing apparatus 2 to which the encoding method and the decoding method according to the present invention are applied, centering on the control apparatus 20.
As illustrated in FIG. 3, the image processing apparatus 2 includes a control device 20 including a CPU 202 and a memory 204, a communication device 22, a storage device 24 such as an HDD / CD device, an LCD display device or a CRT display device, and a keyboard. A user interface device (UI device) 26 including a touch panel and the like is included.
The image processing apparatus 2 is, for example, a general-purpose computer in which an encoding program 4 and a decoding program 5 to be described later are installed as a part of a printer driver. Data such as an image shape is transmitted via the communication device 22 or the storage device 24. , And the obtained data is encoded or decoded and transmitted to the printer apparatus 10. Further, the image processing apparatus 2 acquires image data via the communication device 22 or the storage device 24, and acquires image shape data by a processing system that generates the shape, pattern, etc. of the image element by software or the like. May be. Further, the image processing apparatus 2 may acquire image data optically read by the scanner function of the printer apparatus 10 and acquire and encode data such as an image shape based on the acquired image data.

[Encoding program]
FIG. 4 is a diagram illustrating a functional configuration of the encoding program 4 that is executed by the control device 20 (FIG. 3) and implements the encoding method according to the present invention.
As illustrated in FIG. 4, the encoding program 4 includes a reception unit 400, a shape inversion unit 420, and a code generation unit 440. The code generation unit 440 includes a shape information encoding unit 442 and a halftone dot information encoding unit 444.
Note that all or some of the functions of the encoding program 4 may be realized by an ASIC provided in the printer apparatus 10 or the like.

In the encoding program 4, the reception unit 400 receives data indicating the shape of an image element included in an image, data indicating a binary pattern (halftone dot image), an image, and the like via the communication device 22 or the storage device 24. Element identification information and data indicating position information in the binary pattern image are acquired, and the acquired shape and the like are output to the shape inversion unit 420 and the code generation unit 440.
Based on the shape of the image element and the position information of the image element, the shape reversing unit 420 reverses the value of the shape of one image element when the image element overlaps with another image element. An image shape is generated and output to the code generation unit 440.

The code generation unit 440, based on the shape of the image element input from the reception unit 400, the binary pattern, the identification information and position information of the image element, and the inverted image shape generated by the shape inversion unit 420, Image element shape information and pattern information are encoded, and the encoded data is output to the storage device 24 (FIG. 3), the printer device 10, or the like.
The shape information encoding unit 442 encodes the shape, identification information, and position information of the image element by text region encoding or generic region encoding.
The halftone information encoding unit 444 encodes the pattern, identification information, and position information of the image element by halftone region encoding.
Here, the shape or the like encoded by the shape information encoding unit 442 and the pattern or the like encoded by the halftone information encoding unit 444 are encoded so as to form a pair based on the identification information. .

FIG. 5 is a diagram illustrating an image shape and the like input to the encoding program 4, FIG. 5A illustrates image element identification information and position information, and FIG. 5B illustrates an image element. FIG. 5C illustrates the shape of the image element.
As illustrated in FIG. 5A to FIG. 5C, each image element is separated into a shape and a binary pattern, is given an index (identification information), is associated with position information, and is received. Input to the unit 400.

FIG. 6 is a diagram illustrating an image shape and the like encoded by the encoding program 4, FIG. 6A illustrates image element identification information and position information, and FIG. 6B illustrates an image. FIG. 6C illustrates the shape of an image element.
As shown in FIG. 6A and FIG. 6B, the halftone dot information encoding unit 444 uses a pair of position information indicating a region of an image element and a binary pattern index of the image element as a pattern. It is the code data of information.
As shown in FIGS. 6A and 6C, the shape information encoding unit 442 converts the position information indicating the region of the image element and the binary pattern index of the image element into the shape information. Code data. The shape information includes at least one inverted image shape whose value is inverted by the shape inversion unit 420.

FIG. 7 is a diagram illustrating code data 900 generated by the encoding program 4.
As illustrated in FIG. 7, the code data 900 includes a header including data attribute information and the like, a pattern dictionary including a plurality of patterns to which indexes are added, and a shape including a plurality of image shapes to which indexes are added. An image dictionary comprising a dictionary, a halftone area code corresponding to code data of pattern information of the first image element (triangle), and a text area code corresponding to code data of shape information of the first image element (triangle) (Or generic area code), a halftone area code of the second image element (circle), and a text area code (or generic area code) corresponding to the code data of the inverted shape information of the second image element (circle) And a second halftone region code of the second image element (circle).
In the pattern dictionary, binary patterns and indexes for identifying these binary patterns are registered in association with each other. In the shape dictionary, the shape of the image element and the index for identifying this shape are registered in association with each other.
The code data 900 exemplifies the case of encoding a character image. When the shape information is encoded by generic area encoding, the shape dictionary is not included in the code data 900.

The halftone area codes of the first image element and the second image element include a pair of an index corresponding to the binary pattern and position information indicating an area where these binary patterns exist.
The text area code (or generic area code) of the first image element includes a pair of an index corresponding to the shape of the image element and position information indicating a position where these image elements exist.
Further, the text region code (or generic region code) of the second image element includes an index corresponding to an inverted shape obtained by inverting the value of the shape of the image element included in the input image, and a position where these image elements exist. A pair with position information indicating is included.

[Encoding operation]
FIG. 8 is a flowchart showing the encoding process (S10) by the encoding program 4.
As shown in FIG. 8, in step 100 (S100), the reception unit 400 receives data indicating the shape of the image element included in the binary image, data indicating the binary pattern, identification information of the image element, and the binary information. Data indicating position information in the value pattern image is acquired and output to the shape inversion unit 420 and the code generation unit 440.
In step 102 (S102), the shape inversion unit 420 inverts one of the overlapping image elements based on the position information of the image element to generate an inverted image shape, and the code generation unit 440 Output.

In step 104 (S104), the shape information encoding unit 442 performs the shape information by text region encoding or generic region encoding based on the index corresponding to the shape of the image element or the inverted shape and the position information of the image element. Encode.
In step 106 (S106), the halftone dot information encoding unit 444 encodes the pattern information by halftone region encoding based on the index corresponding to the binary pattern of the image element and the position information of the image element.
In step 108 (S108), the code generation unit 440 outputs the shape information (index and position information corresponding to the shape or inverted shape) output from the shape information encoding unit 442, and is output from the halftone information encoding unit 444. Code data (FIG. 7) including pattern information (index and position information corresponding to the pattern), pattern dictionary, and shape dictionary is generated and output.

[Decryption program]
FIG. 9 is a diagram illustrating a functional configuration of the decryption program 5 that is executed by the control device 20 (FIG. 3) and implements the decryption method according to the present invention.
As illustrated in FIG. 9, the decoding program 5 includes a decoding processing unit 500, a density decoding unit 510, a shape decoding unit 520, and a decoded image generation unit 530.
Note that all or some of the functions of the decryption program 5 may be realized by an ASIC provided in the printer apparatus 10 or the like.

  In the decoding program 5, the decoding processing unit 500 decodes the input code data 900 (FIG. 7) into a set of indexes and position information, an image dictionary (density dictionary (pattern dictionary) and shape dictionary), and the like. The index of information (pattern information) and position information (that is, halftone area code) and the density dictionary are output to the density decoding unit 510, and the index and position information of shape information (that is, text area code or generic area code). The shape dictionary is output to the shape decoding unit 520.

  The density decoding unit 510 decodes the density information of the binary image based on the density information index and position information input from the decoding processing unit 500 and the density dictionary. More specifically, the density decoding unit 510 arranges halftone dot patterns registered in the density dictionary in accordance with the density information index and position information input from the decoding processing unit 500, and is illustrated in FIG. A halftone dot image is generated.

  The shape decoding unit 520 decodes the shape information of the image element included in the input image based on the shape information index and position information input from the decoding processing unit 500 and the shape dictionary. More specifically, the shape decoding unit 520 arranges shape patterns (including inverted shape patterns) registered in the shape dictionary in accordance with the index and position information of the shape information input from the decoding processing unit 500. Thus, an image shape as illustrated in FIG. 2 is created. Note that the shape dictionary is used for decoding processing by text region decoding, and is not used for decoding processing by generic region decoding.

  The decoded image generation unit 530 decodes the code data based on the density information decoded by the density decoding unit 510 and the shape information decoded by the shape decoding unit 520, and generates a binary decoded image. . More specifically, the decoded image generation unit 530 first selects the first halftone image created by the density decoding unit 510 (a network arranged by, for example, an exclusive OR operation according to the index and position information). The first image is obtained by performing a join operation (for example, a product operation) between the point pattern) and the first image shape (the shape pattern arranged according to the index and position information) created by the shape decoding unit 520. An element (“triangle” shown in FIG. 2) is generated. Further, the decoded image generation unit 530 performs an exclusive OR operation on the second halftone image on the generated image, and then performs a second OR operation on the image after the exclusive OR operation. A product operation is performed on the image shape, and then the second halftone image is again subjected to an exclusive OR operation on the image after the product operation, thereby obtaining a second image element (“circle” shown in FIG. 2). )).

[Decryption operation]
FIG. 10 is a flowchart showing the decryption process (S20) by the decryption program 5.
As shown in FIG. 10, in step 200 (S200), the decoding processing unit 500 (FIG. 9) converts the input code data 900 (FIG. 7) into a halftone area code (index of density information and set of position information). ), A text area code or a generic area code (shape information index and position information set) and an image dictionary (density dictionary and shape dictionary), and the density information index, position information, and density dictionary are decoded by the density decoding unit 510. The shape information index, position information, and shape dictionary are output to the shape decoding unit 520.

In step 202 (S202), the density decoding unit 510 extracts the halftone dot pattern 1 from the density dictionary based on the density information index and the position information input from the decoding processing unit 500, and extracts the extracted halftone dot pattern. It arrange | positions to the area | region shown by this positional information. The image in which the halftone dot pattern is arranged is input to the decoded image generation unit 530 as the halftone image 1 (FIG. 2).
The decoded image generation unit 530 generates an image by performing an exclusive OR operation on the halftone image 1 created by the density decoding unit 510 and the generated image.

In step 204 (S204), the shape decoding unit 520 extracts a shape pattern corresponding to the index from the shape dictionary based on the index and position information of the image shape 1 input from the decoding processing unit 500, and extracts the extracted shape. The pattern is arranged in the area indicated by the position information. The image in which the shape pattern is arranged is input to the decoded image generation unit 530 as the image shape 1 (FIG. 2).
In step 206 (S206), the decoded image generation unit 530 performs a product operation on the image shape 1 created by the shape decoding unit 520 and the generated image to generate an image.

In step 208 (S208), the density decoding unit 510 extracts the halftone dot pattern 2 from the density dictionary based on the density information index and the position information input from the decoding processing unit 500, and the extracted halftone dot pattern is displayed. It arrange | positions to the area | region shown by this positional information. The image in which the halftone dot pattern is arranged is input to the decoded image generation unit 530 as the halftone image 2 (FIG. 2).
The decoded image generation unit 530 generates an image by performing an exclusive OR operation on the halftone image 2 created by the density decoding unit 510 and the generated image.

In step 210 (S210), the shape decoding unit 520 extracts a shape pattern corresponding to the index from the shape dictionary based on the index and position information of the inverted image shape 2 input from the decoding processing unit 500, and the extracted shape pattern is extracted. The shape pattern is arranged in the area indicated by the position information. The image in which the shape pattern is arranged is input to the decoded image generation unit 530 as the inverted image shape 2 (FIG. 2).
In step 212 (S212), the decoded image generation unit 530 performs a product operation on the inverted image shape 2 created by the shape decoding unit 520 and the generated image to generate an image.

In step 214 (S214), the density decoding unit 510 extracts the halftone dot pattern 2 again and arranges it in the region indicated by the position information. The image on which the halftone dot pattern is arranged is input again to the decoded image generation unit 530 as the halftone image 2.
The decoded image generation unit 530 performs an exclusive OR operation on the halftone image 2 and the generated image again to generate a decoded image (FIG. 2).

As described above, the image processing apparatus 2 according to the present embodiment is configured with a halftone dot pattern in a state in which edge information of image elements is held by separating and encoding shape information and density information. A binary image can be efficiently encoded.
Further, since the image processing apparatus 2 can independently reduce the redundancy of the shape information and the redundancy of the density information, a higher compression rate can be expected.
Further, the image processing apparatus 2 encodes the inverted image shape information obtained by inverting the shape value of the image element, uses the inverted image shape for the decoded image, and performs the exclusive OR operation on the halftone image at least twice. Since the calculation is performed, a plurality of image elements can be appropriately overlapped and drawn.

[Second Embodiment]
A second embodiment of the image processing apparatus 2 according to the present invention will be described.
FIG. 11 is a diagram for explaining the outline of the encoding process and the decoding process in the present embodiment, FIG. 11A shows the encoding process, and FIG. 11B shows the decoding process.
As shown in FIG. 11A, the image processing apparatus 2 according to the present embodiment encodes the image elements constituting the input image based on the shape information and encodes the halftone image based on the density information. The inverted halftone image obtained by inverting the value of at least one halftone image is encoded. The inverted halftone image is encoded by halftone region encoding in the same manner as the halftone image.
As shown in FIG. 11B, the decoding process of the image element is performed by an exclusive logical sum negation (XNOR) operation and a logical sum (OR) operation. The decoding process is performed by performing an exclusive OR negation operation at least twice when image elements are drawn in an overlapping manner. Thus, since a plurality of image elements are encoded with shape information and density information separated, the image elements can be encoded with a high compression rate. In addition, since at least one halftone image is inverted and encoded, and is decoded using an exclusive OR negation operation, even when image elements overlap, it can be appropriately decoded.

[Encoding program]
FIG. 12 is a diagram illustrating a functional configuration of the encoding program 6 which is executed by the control device 20 (FIG. 3) and implements the encoding method according to the present invention.
As illustrated in FIG. 12, the encoding program 6 includes a reception unit 400, a pattern inversion unit 620, and a code generation unit 440. The code generation unit 440 includes a shape information encoding unit 442 and a halftone dot information encoding unit 444. The encoding program 6 has a configuration in which the shape inversion unit 420 is deleted from the encoding program 4 (FIG. 4) and a pattern inversion unit 620 is added. 12 that are substantially the same as those shown in FIG. 4 are denoted by the same reference numerals.

In the encoding program 4, the reception unit 400 receives data indicating the shape of an image element included in an image, data indicating a binary pattern (halftone dot image), an image, and the like via the communication device 22 or the storage device 24. Element identification information and data indicating position information in the binary pattern image are acquired, and the acquired shape and the like are output to the pattern inversion unit 620 and the code generation unit 440.
Based on the binary pattern and the position information of the image element, the pattern inversion unit 620 inverts the value of the binary pattern of one image element when the image element overlaps with another image element, An inverted halftone image (inverted pattern) is generated and output to the code generation unit 440.

FIG. 13 is a diagram illustrating code data 910 generated by the encoding program 6.
As illustrated in FIG. 13, the code data 910 includes code data including a header including data attribute information, an image dictionary including a pattern dictionary and a shape dictionary, and pattern information of the first image element (triangle). Of the halftone area code corresponding to, the text area code (or generic area code) corresponding to the code data of the shape information of the first image element (triangle), and the inversion pattern information of the second image element (circle) A halftone area code corresponding to code data, a text area code (or generic area code) corresponding to code data of shape information of the second image element (circle), and a second second image element (circle) Halftone region codes. The code data 910 differs from the code data 900 shown in FIG. 7 in that the code data 910 includes a pattern inverted with respect to the second image element (circle) and shape information that is not inverted.

[Encoding operation]
FIG. 14 is a flowchart showing the encoding process (S30) by the encoding program 6.
As illustrated in FIG. 14, in S <b> 100, the reception unit 400 acquires the shape and the like of image elements included in the binary image and outputs the acquired image elements to the pattern inversion unit 620 and the code generation unit 440.
In step 300 (S300), the pattern inversion unit 620 inverts one of the overlapping image elements based on the position information of the image element, generates an inversion pattern, and outputs the inversion pattern to the code generation unit 440. To do.
The encoding program 6 encodes shape information and pattern information in the processing of S104 to S108, generates code data, and outputs it.

[Decryption operation]
FIG. 15 is a flowchart showing the decryption process (S40) by the decryption program 7. Note that the decryption program 7 has substantially the same components as the decryption program 5 shown in FIG.
As shown in FIG. 15, in S <b> 200 to S <b> 206, the decoding program 7 decodes the input code data 910 and draws the first image element (triangle) by the halftone image 1 and the shape information 1.

In step 400 (S400), the density decoding unit 510 extracts the inverted pattern 2 from the pattern dictionary based on the index and position information of the pattern information input from the decoding processing unit 500, and extracts the extracted inverted pattern at this position. Place in the area indicated in the information. The image on which the inverted halftone pattern is arranged is input to the decoded image generation unit 530 as the inverted halftone image 2 (FIG. 11).
The decoded image generation unit 530 performs the exclusive OR operation on the inverted halftone image 2 created by the density decoding unit 510 and the generated image, and arranges the pattern.

In step 402 (S402), the shape decoding unit 520 extracts a shape pattern corresponding to the index from the shape dictionary based on the index and position information of the image shape 2 input from the decoding processing unit 500, and extracts the extracted shape. The pattern is arranged in the area indicated by the position information. The image in which the shape pattern is arranged is input to the decoded image generation unit 530 as the image shape 2 (FIG. 11).
In step 404 (S404), the decoded image generation unit 530 calculates the sum of the image shape 2 created by the shape decoding unit 520 and the generated image to generate an image.

In step 406 (S406), the density decoding unit 510 extracts the inverted pattern 2 again and arranges it in the region indicated by the position information. The image in which the inverted halftone dot pattern is arranged is input again to the decoded image generation unit 530 as the inverted halftone image 2.
The decoded image generation unit 530 performs an exclusive OR operation on the inverted halftone image 2 and the generated image again to generate a decoded image (FIG. 11).

  As described above, the image processing apparatus 2 according to the present embodiment encodes the inverted pattern obtained by inverting the binary pattern value corresponding to the density information of the image element, and applies the inverted pattern to the decoded image. Since the exclusive OR operation is performed at least twice, a plurality of image elements can be appropriately overlapped and drawn.

[Third Embodiment]
A third embodiment of the image processing apparatus 2 according to the present invention will be described.
In this embodiment, the intermediate halftone area and refinement area of JBIG2 are used. First, in order to help understanding of the present invention, an outline of the intermediate halftone area and the refinement area will be described.
JBIG2 defines two types of buffers in which an image that is a decoding result of a region is placed. One of the buffers is a page buffer, which serves as an output of the decoder. The other is an auxiliary buffer, which is a buffer for placing intermediate data.
All regions, such as halftone regions, text regions, generic regions, can have an “intermediate” attribute. When the area has an intermediate attribute, the decoding result is placed not in the page buffer but in the auxiliary buffer. The area arranged in the auxiliary buffer can be drawn in the page buffer by using a refinement area described later. At this time, the area of the auxiliary buffer can be simply drawn in the page buffer, or can be drawn in the page buffer after changing the image.

FIGS. 16A and 16B are diagrams for explaining the relationship between the page buffer and the auxiliary buffer in decoding. FIG. 16A shows decoding of a text area, and FIG. 16B shows decoding of an intermediate text area.
As shown in FIG. 16A, when the text area has no intermediate attribute, the decoding result is arranged in the page buffer. As shown in FIG. 16B, when the text area has an intermediate attribute, the decoding result is arranged not in the page buffer but in the auxiliary buffer. Also in the halftone area and the generic area, if these areas have intermediate attributes, the decoding result is placed in the auxiliary buffer.

The refinement region is a region in which a known image is changed and an image different from this image is generated. As the known image of the refinement area, an area in the auxiliary buffer (that is, an area having an intermediate attribute) and an arbitrary area of the page buffer can be used.
FIG. 17 is a diagram for explaining the refinement area decoding. FIG. 17A shows the relationship between the auxiliary buffer area and the refinement area decoding, and FIG. 17B shows the page buffer and the refinement area. The relationship with the decryption of the comment area is shown.
As shown in FIG. 17A, when the refinement area is decoded with respect to the auxiliary buffer area, an image arranged in the auxiliary buffer is used and rendered in the page buffer. As shown in FIG. 17B, when the refinement area is decoded for the page buffer, the image in the page buffer is used and rendered in the page buffer. Also, the auxiliary buffer area can be used without changing the image and can be directly drawn in the page buffer.

[Encoding program]
FIG. 18 is a diagram illustrating code data 920 generated by the encoding program 8 of this embodiment. The encoding program 8 (not shown) has the same components as the encoding program 4 (FIG. 4).
As illustrated in FIG. 18, the code data 920 is data encoded by the encoding program 8 and represents the intermediate halftone area code (halftone area having an intermediate attribute) of the second image element (circle). Including. Code data 900 (FIG. 7) includes a plurality of halftone area codes of the same content, whereas code data 920 includes only one intermediate halftone area code for each pattern information.
In this way, the encoding program 8 can reduce the amount of code data.

[Encoding operation]
FIG. 19 is a flowchart showing the encoding process (S50) by the encoding program 8.
As shown in FIG. 19, in the processing of S100 to S106, the encoding program 6 acquires the shape of the image element, the binary pattern, the image element identification information and the position information included in the binary image, and obtains the shape information. And shape information including the inverted image shape is encoded by text region encoding or generic region encoding.
In step 500 (S500), the encoding program 8 encodes the pattern information of the first image element (triangle) by halftone area encoding, and has the pattern information of the second image element (circle) having an intermediate attribute. Encoding is performed by halftone area encoding.
Further, the encoding program 8 outputs the encoded data 920 shown in FIG. 18 in the process of S108.

[Decryption operation]
FIG. 20 is a flowchart showing the decryption process (S60) by the decryption program 9. The decryption program 9 (not shown) has the same components as the decryption program 5 (FIG. 9).
As shown in FIG. 20, in the process of S200, the decoding program 9 decodes the input code data (FIG. 18). When the intermediate halftone area is decoded, it is placed in the auxiliary buffer.
In step 600 (S600), the decoding program 9 decodes the halftone area of the page buffer to generate a halftone image 1.
In the processing of S202 to S206, the decoding program 9 draws the first image element (triangle) using the halftone image 1 and the image shape 1.

In step 602 (S602), the decoding program 9 generates an intermediate halftone area for the halftone image 2.
The decoding program 9 generates a refinement region using an auxiliary buffer, and generates a halftone image 2.
In the processing of S208 to S212, the decoding program 9 draws the second image element (circle) using the halftone image 2 and the image shape 2.
In step 604 (S604), the decoding program 9 generates the refinement region again using the auxiliary buffer, generates the halftone image 2, and performs the exclusive OR operation again to obtain the decoded image. Generate.
In this way, the decoding program 9 generates a halftone image 2 by generating an intermediate halftone region and a plurality of refinement regions. Since the halftone image 2 is encoded using the intermediate halftone area, it can be appropriately decoded even if it is not encoded a plurality of times.

  As described above, since the image processing apparatus 2 according to the present embodiment performs encoding using the intermediate halftone area, the code amount of the code data can be reduced. In addition, since the image processing apparatus 2 generates an intermediate halftone region and a plurality of refinement regions, the image processing apparatus 2 can perform at least two exclusive logical operations on image elements that are not encoded a plurality of times. The image elements can be appropriately overlapped and drawn.

It is a figure which illustrates the encoding process and decoding process based on JBIG2, FIG. 1 (A) shows an encoding process, FIG.1 (B) shows a decoding process. FIGS. 2A and 2B are diagrams for explaining the outline of an encoding process and a decoding process in the first embodiment, FIG. 2A shows the encoding process, and FIG. 2B shows the decoding process. It is a figure which illustrates the hardware constitutions of the image processing apparatus 2 with which the encoding method and decoding method concerning this invention are applied centering on the control apparatus 20. FIG. It is a figure which illustrates the function structure of the encoding program 4 which implement | achieves the encoding method concerning this invention. FIGS. 5A and 5B are diagrams illustrating image shapes and the like input to the encoding program 4, FIG. 5A illustrates identification information and position information of image elements, and FIG. 5B illustrates a binary pattern of image elements. FIG. 5C illustrates the shape of the image element. FIGS. 6A and 6B are diagrams illustrating image shapes and the like encoded by the encoding program 4, FIG. 6A illustrates identification information and position information of image elements, and FIG. 6B illustrates binary image elements. A pattern is illustrated and FIG.6 (C) illustrates the shape of an image element. It is a figure which illustrates the code data 900 produced | generated by the encoding program 4. FIG. It is a flowchart which shows the encoding process (S10) by the encoding program 4. It is a figure which illustrates the function structure of the decoding program 5 which implement | achieves the decoding method concerning this invention. It is a flowchart which shows the decoding process (S20) by the decoding program 5. FIG. It is a figure explaining the outline of the encoding process and decoding process in 2nd Embodiment, FIG. 11 (A) shows an encoding process and FIG. 11 (B) shows a decoding process. It is a figure which illustrates the function structure of the encoding program 6 which implement | achieves the encoding method concerning this invention. It is a figure which illustrates the code data 910 produced | generated by the encoding program 6. FIG. It is a flowchart which shows the encoding process (S30) by the encoding program 6. FIG. It is a flowchart which shows the decoding process (S40) by the decoding program 7. FIG. It is a figure explaining the relationship between the page buffer and auxiliary buffer in decoding, FIG. 16 (A) shows decoding of a text area, FIG.16 (B) shows decoding of an intermediate text area. FIG. 17A is a diagram for explaining the decoding of the refinement area. FIG. 17A shows the relationship between the auxiliary buffer area and the refinement area decoding, and FIG. 17B shows the page buffer and the refinement area decoding. Shows the relationship. It is a figure which illustrates the code data 920 produced | generated by the encoding program 8. FIG. It is a flowchart which shows the encoding process (S50) by the encoding program 8. FIG. It is a flowchart which shows the decoding process (S60) by the decoding program 9. FIG.

Explanation of symbols

2 ... Image processing device 10 ... Printer device 20 ... Control device 202 ... CPU
204 ... Memory 22 ... Communication device 24 ... Storage device 4 ... Encoding program 400 ... Receiving unit 420 ... Shape reversing unit 440 ... Code generating unit 442 ... Shape information Encoding unit 444 ... halftone dot information encoding unit 5 ... decoding program 500 ... decoding processing unit 510 ... density decoding unit 520 ... shape decoding unit 530 ... decoded image generation unit 900 ... Code data

Claims (6)

Accepting means for receiving an image element composed of a shape of an image element composed of binary pixels and a binary pattern in which halftone dots are regularly arranged ;
Shape encoding means for encoding the shape of the image element received by the receiving means;
Shape inversion means for inverting the value of a binary pixel constituting the shape of at least one image element among the shapes of image elements encoded by the shape encoding means;
Pattern encoding means for encoding a binary pattern of image elements received by the receiving means,
An encoding device, wherein the shape encoded by the shape encoding means and the binary pattern encoded by the pattern encoding means are encoded as encoded data that makes a pair . The encoding apparatus according to claim 1, wherein the shape reversing unit reverses the value of a binary pixel constituting the shape of one image element when the image elements received by the receiving unit overlap each other . Accepting means for receiving an image element composed of a shape of an image element composed of binary pixels and a binary pattern in which halftone dots are regularly arranged ;
Shape encoding means for encoding the shape of the image element received by the receiving means;
Pattern encoding means for encoding a binary pattern of image elements received by the receiving means;
Shape reversing means for reversing at least one of the binary patterns encoded by the pattern encoding means;
An encoding device, wherein the shape encoded by the shape encoding means and the binary pattern encoded by the pattern encoding means are encoded as encoded data that makes a pair . The encoding apparatus according to claim 3, wherein the pattern inversion unit inverts a binary pattern of one image element when the image elements received by the reception unit overlap each other . In an encoding device including a computer,
An accepting step for receiving an image element composed of a shape of an image element composed of binary pixels and a binary pattern in which halftone dots are regularly arranged ;
A shape encoding step for encoding the shape of the accepted image element;
A shape inversion step of inverting the value of a binary pixel constituting the shape of at least one image element among the shapes of the encoded image elements;
A program for causing a computer of the encoding device to execute a pattern encoding step of encoding a binary pattern of the received image element ,
A program in which the encoded shape and the encoded binary pattern are encoded as a pair of encoded data . In an encoding device including a computer,
An accepting step for receiving an image element composed of a shape of an image element composed of binary pixels and a binary pattern in which halftone dots are regularly arranged ;
A shape encoding step for encoding the shape of the accepted image element;
A pattern encoding step for encoding the binary pattern of the accepted image elements ;
A program for causing a computer of the encoding device to execute a shape inversion step of inverting at least one of the binary patterns to be encoded,
A program in which the encoded shape and the encoded binary pattern are encoded as a pair of encoded data .

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