JP2006166355A - Image processing apparatus, image processing method, image processing program and recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently reduce a file size by suppressing image quality deterioration without determining characters and non-characters. <P>SOLUTION: An image processing apparatus includes a binary image generating means 102 for generating a binary image from a multi-level image and a multi-level image generating means 104 for generating a first multi-level image and a second multi-level image based on the binary image. If one pixel value of a binary image corresponding to pixel positions of a multi-level image is present for the first and second multi-level images, the multi-level image generating means 104 sets pixel values of pixels of each of the multi-level images based on pixel values within a multi-level image at a corresponding position. Pixel values of non-determined pixels in a multi-level image, of which values are not set yet, near determined pixels of each multi-level image of which values are set already, are set using pixel values of determined pixels near non-determined pixels. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image processing apparatus, an image processing method, an image processing program, and a recording medium.

  Various methods for reducing the file size of color document images and the like have been proposed. For example, a method called JPEG (Joint Photographic Experts Group) has been widely distributed.

  There is also known a method of reducing the file size by separating a character from a non-character, compressing the character separately as a binary image and compressing the non-character as a multi-valued image, and expressing them by overlapping (for example, , See Patent Document 1).

  There is also a method of reducing distortion such as block noise and mosquito noise included in the compressed and decompressed image (see, for example, Patent Document 2). In the method of Patent Document 2, a pixel that satisfies a certain condition is selected from pixels in the vicinity of the target pixel, the target pixel is replaced with an average value of the selected pixels, and the execution of the replacement is performed depending on the presence or absence of an edge in the target block. By judging the above, noise can be reduced and the file size can be reduced.

In addition, there is an encoding method in which an image is divided into blocks and compressed and encoded (see, for example, Patent Document 3). The method of Patent Document 3 binarizes pixels in a block with a threshold value, classifies the pixels according to each of the binary values, calculates an average value of each, and when an edge exists in the block, the vicinity of the edge In this method, the average value of the pixel values is used as the threshold value.
JP 2002-368986 A JP 2001-245179 A JP 2003-087570 A

  However, the above-described JPEG method has a problem that noise tends to occur around characters (boundary portions) when an image containing many characters is compressed, and compression efficiency is not good. For example, in the JPEG method, an unexpected color may occur around a character, which is a cause of deterioration in image quality. In addition, there is a method of executing JPEG after reducing the resolution in order to reduce the file size. However, in the case of characters, the outline is blurred as the resolution is lowered, so there is a problem that the image quality is greatly deteriorated.

  Further, in the method of Patent Document 1 described above, it is generally difficult to determine characters and non-characters, and there is a problem that image quality deteriorates if the determination is incorrect.

  Further, the method disclosed in Patent Document 2 described above has a problem in that the reproducibility of characters or the like is not good because the edge is weakened by replacing the pixel with another pixel value when there is a strong edge.

  The method of Patent Document 3 described above is intended to preserve edge information, and has a problem that it cannot be applied unless the compression format supports binary coding.

  The present invention has been made in view of the above points, and an object of the present invention is to suppress image quality deterioration and efficiently reduce a file size without performing determination of characters and non-characters.

  Therefore, in order to solve the above-described problem, the present invention provides an image processing apparatus that processes an image, a multi-value image acquisition unit that acquires a multi-value image, and a binary that generates a binary image from the multi-value image. Image generation means, and multi-value image generation means for generating a first multi-value image and a second multi-value image based on the multi-value image and the binary image, the multi-value image generation means If one pixel value of the binary image exists in the binary image at a position corresponding to the pixel position of the first multi-valued image, it corresponds to the position where one pixel value of the binary image exists. A first multi-value image pixel value setting means for setting a pixel value of a pixel of the first multi-value image based on a pixel value in the multi-value image at a position of the position, and a position of the pixel of the second multi-value image If the other pixel value of the binary image exists in the binary image at the position corresponding to Second multi-value image pixel value setting means for setting a pixel value of a pixel of the second multi-value image based on a pixel value in the multi-value image at a position corresponding to a position where the other pixel value exists; The pixel value of the undecided pixel in the first multi-valued image in which the value is not set near the decided pixel in the first multi-valued image in which the value is set, and the pixel value of the decided pixel in the vicinity of the undecided pixel A first multi-value image pixel non-set pixel setting means that is set using and a second multi-value image that has no value set in the vicinity of the determined pixel of the second multi-value image that has been set. And a second multi-value image pixel non-set pixel setting unit that sets the pixel value of the pixel using the pixel value of the decided pixel in the vicinity of the decided pixel.

  According to the present invention, there is provided an image processing apparatus for processing an image, a multi-value image acquisition unit that acquires a multi-value image, a binary image generation unit that generates a binary image from the multi-value image, and the multi-value image Multi-value image generation means for generating a first multi-value image and a second multi-value image based on the value image and the binary image, and the multi-value image generation means comprises the first multi-value image. If one pixel value of the binary image exists in the binary image at a position corresponding to the position of the pixel, the multi-value image at a position corresponding to the position where one pixel value of the binary image exists A first multi-value image pixel value setting means for setting a pixel value of a pixel of the first multi-value image based on a pixel value of the first multi-value image; and the second multi-value image at a position corresponding to the position of the pixel of the second multi-value image. If the other pixel value of the binary image exists in the value image, the position where the other pixel value of the binary image exists Second multi-value image pixel value setting means for setting a pixel value of a pixel of the second multi-value image based on a pixel value in the multi-value image at a corresponding position; A first multi-value that sets a pixel value of an undecided pixel of the first multi-valued image in the vicinity of the decided pixel of the value image, for which no value is set, using a pixel value of the decided pixel in the vicinity of the decided pixel An image pixel non-set pixel setting means, and a pixel value of an undecided pixel of the second multi-valued image in which no value is set in the vicinity of the decided pixel of the second multi-valued image in which a value has been set, The second multi-valued image pixel non-set pixel setting means that is set using the pixel value of the determined pixel in the vicinity of, suppresses image quality deterioration without performing determination of characters and non-characters, The file size can be reduced efficiently.

  Note that the image processing apparatus corresponds to, for example, an image processing apparatus 1 described later. The multi-value image acquisition unit corresponds to, for example, a multi-value image acquisition unit 101 described later. Further, the binary image generation means corresponds to, for example, a binary image generation means 102 described later. The multi-value image generation means corresponds to, for example, first and second multi-value image generation means 104 described later. The first multi-value image pixel value setting unit corresponds to, for example, a first multi-value image pixel value determination unit 105 described later. The second multi-value image pixel value setting unit corresponds to, for example, a second multi-value image pixel value determination unit 107 described later. The first multi-value image pixel non-set pixel setting unit corresponds to, for example, a first multi-value image non-determined pixel determination unit 106 described later. The second multi-value image pixel non-set pixel setting unit corresponds to, for example, a second multi-value image non-determined pixel determination unit 108 described later.

  Further, as means for solving the above problems, an image processing method, an image processing program, and a recording medium may be used.

  According to the present invention, it is possible to suppress image quality deterioration and efficiently reduce the file size without performing determination of characters and non-characters.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a conceptual diagram showing basic processing in this embodiment. As shown in FIG. 1, in this embodiment (the same applies to the embodiments described below), the original image (or multi-value image) is divided into three layers (first multi-value image, second multi-value image, and The basic processing is a binary image) and a process of compressing and encoding each of the images and combining them into a form that can be superimposed and displayed.

  As will be described later, the image processing apparatus 1 displays the black pixel portion in the binary image using the pixel value of the first multi-value image, and the white pixel portion in the binary image as the second multi-value image. The pixel value is used for display.

  An example of the configuration of the image processing apparatus 1 is shown in FIG. FIG. 2 is a configuration diagram (part 1) of the image processing apparatus.

  As shown in FIG. 1, the image processing apparatus 1 includes a multi-value image acquisition unit 101, a binary image generation unit 102, an encoding unit 103, and a first binary multi-value image generation unit 104. The first and second multi-valued image generating means 104 includes a first multi-valued image pixel value determining means 105, a first multi-valued image undetermined pixel determining means 106, a second multi-valued image pixel value determining means 107, Second multi-value image undetermined pixel determining means 108.

  The multi-value image acquisition unit 101 acquires a multi-value image that is an object of image processing. The binary image generation unit 102 binarizes the multilevel image acquired by the multilevel image acquisition unit 101 and generates a binary image. As a binarization method in the binary image generation unit 102, for example, based on a threshold value relating to a predetermined brightness, a pixel above the threshold value is a white pixel, and a pixel less than the threshold value is a black pixel. .

  The first and second multi-valued image generating means 104 is configured to generate the first multi-valued image and the second multi-valued image based on the multi-valued image acquired by the multi-valued image acquiring means 101 and / or the binary image generated by the binary image generating means 102. A binary multi-valued image is generated.

  The first multi-value image pixel value determining means 105 determines the image size of the first multi-value image, temporarily fills the pixel values of the first multi-value image with the same value (for example, black pixel value), A binary image related to a position corresponding to a pixel of a multi-value image is specified, and it is determined whether or not one pixel value (for example, a black pixel value) of the binary image exists in the specified binary image. If it is determined that one pixel value of the binary image exists in the specified binary image, the multi-value image related to the position corresponding to the position where the one pixel value exists in the binary image is specified. Then, the pixel value of the pixel of the first multi-value image is set based on the pixel value in the specified multi-value image (original image). As will be described later, the second multi-value image pixel value determining means 107 determines the image size of the second multi-value image, but the first multi-value image pixel value determining means 105 determines the first multi-value image pixel value determining means 105. And the image size of the second multi-valued image determined by the second multi-valued image pixel value determining means 107 are the same image size. In the present embodiment, for simplification of description, the image size is set to half the size of the original image (the resolution may be half).

  The first multi-valued image undetermined pixel determining means 106 calculates the pixel value of the pixel of the first multi-valued image not set with a value near the pixel of the first multi-valued image set with the value. It sets using the pixel value of the pixel of the 1st multi-valued image to which the value was set in the vicinity.

  The second multi-value image pixel value determining means 107 determines the image size of the second multi-value image, temporarily fills the pixel value of the second multi-value image with the same value (for example, white pixel value), A binary image related to a position corresponding to a pixel of a multi-valued image is specified, and it is determined whether or not the other pixel value (for example, white pixel value) of the binary image exists in the specified binary image. When it is determined that the other pixel value of the binary image exists in the specified binary image, the multi-value image related to the position corresponding to the position where the other pixel value exists in the binary image is specified. Then, the pixel value of the pixel of the second multi-value image is set based on the pixel value in the specified multi-value image (original image). As described above, the image size of the second multi-value image determined by the second multi-value image pixel value determining unit 107 is the image of the first multi-value image determined by the first multi-value image pixel value determining unit 105. The image size is the same as the size.

  The second multi-valued image undetermined pixel determining means 108 calculates the pixel value of the pixel of the second multi-valued image not set with a value near the pixel of the second multi-valued image with the value set. It sets using the pixel value of the pixel of the 2nd multi-valued image to which the value was set in the vicinity.

  The encoding means 103 is suitable for the first multi-value image and the second multi-value image, the first multi-value image and the second multi-value image generated by the first and second multi-value image generation means 104. Compression-encoding using the method. The encoding unit 103 compresses and encodes the binary image generated by the binary image generation unit 102 by a method suitable for the binary image.

  Hereinafter, an example of the position of the binary image corresponding to one pixel of the first multi-valued image and the original image is shown in FIG. FIG. 3 is a diagram illustrating an example of the positions of the binary image and the original image corresponding to one pixel of the first multi-valued image.

  As described above, in the embodiment of the present invention, the resolution of the first multi-valued image is one half of the resolution of the binary image and the original image. Therefore, as shown in FIG. The binary image corresponding to the position of one pixel and the pixel of the original image correspond to 2 × 2 pixels that are relatively in the same position. The first multi-valued image pixel value determining unit 105 specifies a binary image related to the position corresponding to the pixel of the first multi-valued image whose pixel value is determined by the method shown in FIG. Note that the second multi-value image pixel value determining unit 107 also relates to the position corresponding to the pixel of the second multi-value image for determining the pixel value by the same process or method as the first multi-value image pixel value determining unit 105. Identify binary images.

  Hereinafter, an example of the calculation of the pixel value of the first multi-valued image is shown in FIG. FIG. 4 is a conceptual diagram illustrating an example of calculation of pixel values of the first multi-valued image.

  As shown in FIG. 3, the first multi-value image pixel value determining unit 105 specifies the binary image related to the position corresponding to the pixel of the first multi-value image for determining the pixel value. It is determined whether or not there is a black pixel in 2 × 2 pixels of the image. When the first multi-value image pixel value determining unit 105 determines that a black pixel exists, the first multi-value image pixel value determining unit 105 acquires a pixel value of the original image corresponding to the position of the black pixel included in the 2 × 2 pixels, and For example, the average value is determined as the pixel value of the corresponding pixel of the first multi-value image.

  For example, when 3 black pixels are included in 2 × 2 pixels of the binary image related to the position corresponding to the pixel of the first multi-value image for determining the pixel value, the first multi-value image pixel value is determined. The means 105 determines, for example, the average value of the pixel values of the original image corresponding to the positions of the three black pixels as the pixel value of the corresponding pixel of the first multi-value image.

  In addition, when no black pixel is included in 2 × 2 pixels of the binary image related to the position corresponding to the pixel of the first multi-value image for determining the pixel value, the first multi-value image pixel The value determining unit 105 determines that the pixel value of the corresponding pixel of the first multi-value image is undecided. Hereinafter, a pixel whose pixel value is determined is referred to as a determined pixel, and a pixel whose pixel value is not determined is referred to as a determined pixel.

  The first multi-value image pixel value determining unit 105 performs the above-described processing for determining the pixel values of the first multi-value image on all the first multi-value images. Note that the second multi-value image pixel value determining unit 107 also determines the pixel value of the second multi-value image by the same process or method as the first multi-value image pixel value determining unit 105. However, when the second multi-value image pixel value determining means 107 specifies a binary image related to the position corresponding to the pixel of the second multi-value image for determining the pixel value, 2 × 2 pixels of the specified binary image It is determined whether or not there is a white pixel, and if it is determined that a white pixel exists, the pixel value of the original image corresponding to the position of the white pixel included in the 2 × 2 pixel is acquired, and the acquired For example, the average value of the pixel values is determined as the pixel value of the corresponding pixel of the second multi-valued image.

  An example of the configuration of the first multi-valued image undetermined pixel determining unit 106 is shown in FIG. FIG. 5 is a configuration diagram of the first multi-valued image undetermined pixel determining means.

  As shown in FIG. 5, the first multi-valued image undetermined pixel determining unit 106 includes an in-block region setting unit 111, an in-block determined / undetermined pixel counting unit 112, and a pixel value setting unit 113.

  The in-block area setting unit 111 sets (determines) a block size of several pixels on the first multi-valued image and / or enlarges the set block size. For example, the in-block area setting unit 111 first sets the block size to 2 × 2 pixels based on a predetermined value or the like, and expands the block size to 4 × 4 pixels as required. The block size is finally expanded to 8 × 8 pixels which is a predetermined upper limit in response to a request or the like.

  The in-block area setting unit 111 may set the block size to 8 × 8 pixels from the beginning without performing the block size enlargement process.

  The in-block determined / undecided pixel counting unit 112 performs counting related to the determined and undecided pixels in the block having the block size set by the in-block region setting unit 111, and both the determined and undecided pixels are included in the block. It is determined whether or not it is included. In addition, when the determined / undecided pixel counting unit 112 in the block determines that both the determined pixel and the undecided pixel are included in the block, the average value of the determined pixels in the block is obtained.

  The pixel value setting unit 113 determines (sets) the average value of the pixel values of the determined pixels in the block obtained by the intra-block determined / undecided pixel counting unit 112 as the pixel value of the determined pixels in the block. When the pixel value is determined by the pixel value setting unit 113, the undecided pixel is treated as a determined pixel thereafter.

  The configuration of the second multi-valued image undetermined pixel determining unit 108 and the processing by the second multi-valued image undetermined pixel determining unit 108 are the same as the configuration of the first multi-valued image undetermined pixel determining unit 106 and the first multi-valued image undetermined pixel determining unit 108. This is the same as the processing by the determined pixel determining means 106.

  Hereinafter, an example of smoothing of the boundary undetermined pixels by the average within the block by the first multi-valued image undetermined pixel determining means 106 is shown in FIG. FIG. 6 is a diagram illustrating an example of smoothing of the boundary undetermined pixels by the intra-block average.

  As shown in FIG. 6A, the in-block area setting unit 111 first sets the block size to, for example, a size of 2 × 2 pixels. The in-block determined / undecided pixel counting means 112 executes counting related to the determined pixels and the undecided pixels in the block having the block size of 2 × 2 pixels set by the in-block region setting means 111, and determines the determined pixels and It is determined whether or not both undecided pixels are included. If the determined / undecided pixel counting means 112 in the block determines that both the determined pixel and the determined pixel are included in the block having the block size of 2 × 2 pixels, the determined pixel in the block having the block size of 2 × 2 pixels Of the pixel values ((8 + 2) / 2 = 5 in the example of FIG. 6A). The pixel value setting unit 113 determines the average value (5 in the example of FIG. 6A) of the determined pixels obtained by the determined / undecided pixel counting unit 112 in the block as the pixel value of the determined pixels in the block. (Set).

  The first multi-valued image undetermined pixel determining unit 106 performs smoothing of the boundary undetermined pixels by the above-described average within the block with the block size of 2 × 2 pixels on the entire first multi-valued image, for example, an in-block region. The setting unit 111 is requested to increase the block size.

  The intra-block area setting unit 111 that has received the request enlarges the block size, for example, sets the block size to a size of 4 × 4 pixels, as shown in FIG. 6B. The intra-block determined / undecided pixel counting unit 112 performs counting related to the determined pixels and the undecided pixels in the block having a block size of 4 × 4 pixels set by the intra-block region setting unit 111, and determines the determined pixels and It is determined whether or not both undecided pixels are included. If the determined / undecided pixel counting means 112 in the block determines that both the determined pixel and the undecided pixel are included in the block having the block size of 4 × 4 pixels, the determined pixel in the block having the block size of 4 × 4 pixels is determined. (8 + 5 + 2 + 5 + 3 + 3 + 3 + 3 + 7 + 4 + 8 + 9) / 12 = 5 in the example of FIG. 6B. The pixel value setting unit 113 determines the average value (5 in the example of FIG. 6B) of the determined pixels obtained by the determined / undecided pixel counting unit 112 in the block as the pixel value of the determined pixels in the block. (Set).

  The first multi-valued image undetermined pixel determining means 106 performs the smoothing of the boundary undetermined pixels by the block average with the block size of 4 × 4 pixels described above on the entire first multi-valued image.

  Similarly, as shown in FIG. 6C, the first multi-valued image undetermined pixel determining unit 106 performs first smoothing of the boundary undetermined pixels by the average within the block with a block size of 8 × 8 pixels, for example. Perform on the entire multi-valued image. FIG. 6D shows an example of the first multi-valued image after the smoothing processing of the boundary undetermined pixels by the average within the block with the block size of 8 × 8 pixels.

  In addition, the block size is increased stepwise, and the boundary undecided pixel smoothing process is not recursively performed by the average within the block, but the boundary undecided pixel is smoothed by the average within the block with the block size of 8 × 8 pixels from the beginning. The conversion may be performed on the entire first multi-valued image. By doing so, it is not necessary to recursively perform the smoothing processing of the boundary undetermined pixels by the average in the block, and the processing becomes faster.

  Note that there is a possibility that an undecided pixel exists even after the smoothing processing of the boundary undetermined pixel by the average in the block with the block size of 8 × 8 pixels, and the undecided pixel includes the first multi-value image pixel value. The pixel value that is uniformly filled as a provisional value by the determining unit 105 remains.

  The smoothing process of the boundary undetermined pixels by the average within the block by the second multi-valued image undetermined pixel determining means 108 is also the smoothing process of the boundary undetermined pixels by the average within the block by the first multi-value image undetermined pixel determining means 106 described above. It is the same.

  The first and second multi-value image generation means 104 generates a first multi-value image and a second multi-value image in which the boundary between the determined pixel and the undecided pixel is smoothly converted by the above-described processing. A smooth change in the boundary between the determined pixel and the determined pixel is advantageous for compression encoding performed in the encoding unit 103 and the like, and is useful for reducing the file size and improving the image quality. In the case of compressing by JPEG method at the time of compression encoding, there is no problem in the compression efficiency even if the processing is finished up to 8 × 8 pixels. This is because the block size is set to 8 × 8 pixels in the JPEG method, and the fluctuation of the pixel value inside the block of the set block size has a dominant influence on the file size. This is because even if it changes, there is almost no influence on the file size. Further, if the undecided pixels are present in a block size of 8 × 8 pixels, the inside of the block has the same color, which is advantageous as a file size.

  The first multi-value image and the second multi-value image generated by the first and second multi-value image generation means 104 are suitable for the first multi-value image and the second multi-value image by the encoding means 103. Compression-encoded in the manner. For example, as compression encoding suitable for the first multi-value image and the second multi-value image, JPEG compression or JPEG 2000 method is effective.

  The encoding unit 103 compresses and encodes the binary image generated by the binary image generation unit 102 by a method suitable for the binary image. For example, an MMR (Modified Modified Read) method, a JBIG (Joint Bi-level Image Experts Group) method, a JBIG2 method, and the like are effective as compression encoding suitable for a binary image.

  The total size of the first multi-valued image, the second multi-valued image, and the binary image compressed and encoded by the encoding unit 103 is much smaller than the original image to be processed. . For example, the image processing apparatus 1 converts the first multi-value image, the second multi-value image, and the binary image that have been compression-encoded by the encoding means 103 into a JPM (JPEG 2000 multi-layer) format or the like. Put them together into a single file and save it in a reproducible format.

  As shown in an embodiment described later, when reproducing the format as an image, the image processing device 1 decodes (decodes) three types of compression-encoded images, and based on the binary image, Whether to display the pixel value of the first multi-valued image or the pixel value of the second multi-valued image is switched. For example, when the pixel of the binary image is a black pixel, the image processing apparatus 1 displays the pixel value of the first multi-value image, and when the pixel of the binary image is a white pixel, the second multi-value Displays the pixel value of the image.

  Hereinafter, each process mentioned above is demonstrated using a flowchart. FIG. 7 is a flowchart (part 1) illustrating image processing in the image processing apparatus.

  In step S <b> 10, the multi-value image acquisition unit 101 acquires a multi-value image (original image) that is a target of image processing.

  Progressing to step S11 following step S10, the binary image generation unit 102 binarizes the multilevel image acquired by the multilevel image acquisition unit 101 to generate a binary image.

  Progressing to step S12 following step S11, the first multi-valued image pixel value determining means 105 determines the image size of the first multi-valued image, and sets the pixel value of the first multi-valued image to the same value (for example, black pixel). The binary image related to the position corresponding to the pixel of the first multi-valued image is specified, and one pixel value (for example, a black pixel) of the binary image is specified in the specified binary image. Value) exists, and if it is determined that one pixel value of the binary image exists in the specified binary image, the pixel value in the binary image exists at a position where the pixel value exists. A multi-value image related to the corresponding position is specified, and the pixel value of the pixel of the first multi-value image is set based on the pixel value in the specified multi-value image (original image).

  Details of the first multi-value image pixel value determining process (the process of step S12) by the first multi-value image pixel value determining means 105 are shown in FIG.

  Progressing to step S13 following step S12, the second multi-value image pixel value determining means 107 determines the image size of the second multi-value image, and sets the pixel value of the second multi-value image to the same value (for example, white pixel). The binary image related to the position corresponding to the pixel of the second multi-valued image is specified, and the other pixel value (for example, white pixel) of the binary image is specified in the specified binary image. Value) exists, and if it is determined that the other pixel value of the binary image exists in the specified binary image, the pixel value is located at the position where the other pixel value exists in the binary image. A multi-value image related to the corresponding position is specified, and the pixel value of the pixel of the second multi-value image is set based on the pixel value in the specified multi-value image (original image).

  As described above, the image size of the second multi-value image determined by the second multi-value image pixel value determining unit 107 is the image of the first multi-value image determined by the first multi-value image pixel value determining unit 105. The image size is the same as the size.

  Proceeding to step S14 following step S13, the first multi-valued image undetermined pixel determining means 106 is a first multi-value not set with a value in the vicinity of the determined pixel of the first multi-valued image with the value set. The pixel value of the undecided pixel of the image is set using the pixel value of the determined pixel in the vicinity of the undecided pixel.

  Details of the boundary-undecided pixel smoothing process (step S14) of the first multi-valued image of the first multi-valued image undetermined pixel determining means 106 are shown in FIG. 9 to be described later.

  Proceeding to step S15 following step S14, the second multi-valued image undetermined pixel determining means 108 is a second multi-value in which a value is not set near the determined pixel of the second multi-valued image in which the value is set. The pixel value of the undecided pixel of the image is set using the pixel value of the determined pixel in the vicinity of the undecided pixel.

  Progressing to step S16 following step S15, the encoding unit 103 converts the first multilevel image and the second multilevel image generated by the first and second multilevel image generation unit 104 into the first multilevel image. The image is compressed and encoded by a method suitable for the image and the second multi-valued image, and the binary image generated by the binary image generating means 102 is compression-encoded by a method suitable for the binary image, and the processing is terminated.

  Hereinafter, an example of the pixel value determination process of the first multi-value image by the first multi-value image pixel value determination means 105 is shown in FIG. FIG. 8 is a flowchart illustrating an example of pixel value determination processing of the first multi-valued image.

  In step S20, the first multi-valued image pixel value determining unit 105 determines the image size of the first multi-valued image. Here, as described above, the image size of the first multi-value image determined by the first multi-value image pixel value determining unit 105 is the same as that of the second multi-value image determined by the second multi-value image pixel value determining unit 107. It is the same size as the image size, and in the embodiment of the present invention, it is half the size of the original image (the resolution is half).

  Progressing to step S21 following step S20, the first multi-value image pixel value determining means 105 temporarily fills all pixel values of the first multi-value image with the same value (single color). Progressing to step S22 following step S21, the first multi-valued image pixel value determining means 105 specifies (determines) a binary image related to a position corresponding to the pixel of the first multi-valued image.

  Progressing to step S23 following step S22, the first multi-value image pixel value determining means 105 determines whether or not a black pixel value exists in the specified binary image. If the first multi-value image pixel value determining unit 105 determines that there is a black pixel in the specified binary image (YES in step S23), the first multi-value image pixel value determining unit 105 proceeds to step S24 and determines that there is no black pixel value (step S23). (NO in S23), the process proceeds to step S25.

  In step S24, the first multi-valued image pixel value determining unit 105 specifies a multi-value image related to the position corresponding to the position where the black pixel exists, and sets the pixel value in the specified multi-value image (original image). Based on this, the pixel value of the pixel of the first multi-valued image is set (determined).

  In step S25, the first multi-valued image pixel value determining unit 105 determines whether or not the process for determining the pixel values for all the pixels of the first multi-valued image has been executed, and determines that it has been executed (step S25). If YES in S25, the pixel value determination process of the first multi-valued image is finished and if it is determined that it has not been executed (NO in Step S25), the first target of the pixel value determination process of the first multi-valued image is determined. The pixels of the multi-valued image are shifted based on a predetermined method, and the process proceeds to step S22.

  Hereinafter, an example of the boundary undecided pixel smoothing process of the first multivalued image by the first multivalued image undetermined pixel determining means 106 is shown in FIG. FIG. 9 is a flowchart illustrating an example of the boundary undecided pixel smoothing process of the first multi-valued image.

  In step S30, the intra-block area setting unit 111 sets a block size of several pixels square for the first multi-valued image. For example, the in-block area setting unit 111 first sets the block size to a size of 2 × 2 pixels.

  Proceeding to step S31 following step S30, the in-block determined / undecided pixel counting means 112 executes counting related to the determined and undecided pixels in the block having the block size set by the in-block area setting means 111 in step S30. .

  Progressing to step S32 following step S31, the in-block determined / undecided pixel counting means 112 has already decided within the block of the block size set by the in-block area setting means 111 in step S30 based on the count executed in step S31. It is determined whether both the pixel and the pending pixel are included. If the determined / undecided pixel counting unit 112 in the block determines that both the determined pixel and the undecided pixel are included in the block having the block size set by the in-block region setting unit 111 in step S30 (YES in step S32), Proceeding to step S33, if it is determined that neither the decided pixel nor the pending pixel is included (NO in step S32), the process proceeds to step S35.

  In step S33, the in-block determined / undecided pixel counting means 112 calculates an average value of the pixel values of the determined pixels in the block. Progressing to step S34 following step S33, the pixel value setting means 113 determines (sets) the average value of the pixel values calculated by the intra-block determined / undecided pixel counting means 112 in step S33 as the pixel value of the undecided pixels.

  In step S35, the first multi-valued image undetermined pixel determining unit 106 performs boundary undetermined pixel smoothing processing based on the block size set by the in-block region setting unit 111 in step S30 on all regions of the first multi-valued image. It is determined whether it has been performed. If the first multi-valued image undetermined pixel determining means 106 determines that the operation has been performed for all the regions (YES in step S35), the process proceeds to step S36, and determines that the operation has not been performed for all the regions (step S35). NO), the process proceeds to step S31.

  In step S36, the in-block area setting unit 111 enlarges the block size. Proceeding to step S37 following step S36, it is determined whether or not the block size enlarged by the intra-block area setting unit 111 exceeds a prescribed size (for example, a size of 8 × 8 pixels). When determining that the block size exceeds the specified size (YES in step S37), the in-block region setting unit 111 ends the boundary undecided pixel smoothing process and determines that the block size does not exceed the specified size (step S37). NO), the process proceeds to step S31.

  One of the features of the present invention is that the image processing apparatus 1 executes a process for suppressing the fluctuation of the boundary portion of the binary image. For example, the boundary undecided pixel smoothing process described above corresponds to a process for controlling the variation. The image processing apparatus 1 suppresses a change in the boundary portion of the binary image, thereby suppressing deterioration in image quality (color change in the boundary portion such as a character peripheral portion) when compressed by the JPEG method or the like, Can be reduced.

  Another feature of the present invention is that the image processing apparatus 1 holds the first multi-value image and the second multi-value image at the same resolution. For example, in the above-mentioned Patent Document 1 and the like, characters and non-characters are separated, characters are represented by a single color image, and non-characters are represented by a multi-value image. In such a system, characters and non-characters are represented. If it is judged accurately and not separated, the image quality will be greatly affected. For example, in the method of Patent Document 1 or the like, if a part of a photograph that should be non-character is erroneously determined to be non-character, only the erroneously determined part is reproduced (displayed) in a single color, and an image is displayed. This creates a great sense of incongruity. In addition, it is extremely difficult to completely determine whether a character is a non-character. As a result, depending on the image, the image quality is significantly degraded, and the stability of image processing is not high.

  On the other hand, in the present invention, regardless of whether the binary image is color-reproduced by the image processing apparatus 1 as the first multi-value image or the second multi-value image, the first multi-value image, the second multi-value image, Are of the same resolution, the deterioration in image quality is suppressed, and the stability as image processing is high. That is, an image with stable image quality can be provided and the file size can be reduced without separating characters and non-characters. In the present invention, since the image processing apparatus 1 holds the binary image at the same resolution as the original image, the outline of the character can be reproduced without blurring, and the image quality of the character is good.

  In the second embodiment, another example of the configuration of the image processing apparatus 1 and a smoothing process for a boundary-determined pixel will be described. In the second embodiment, differences from the first embodiment will be mainly described.

  First, the basic concept in the present embodiment will be described with reference to FIGS. FIG. 10 is a diagram (part 1) for explaining the basic concept of the present embodiment. Moreover, FIG. 11 is a figure (the 2) for demonstrating the fundamental view in a present Example. Moreover, FIG. 12 is a figure (the 3) for demonstrating the fundamental view in a present Example. Moreover, FIG. 13 is a figure (the 4) for demonstrating the basic view in a present Example.

  As shown in FIG. 10, in the original image, a portion reproduced with the color (pixel value) of the first multi-valued image and a portion reproduced with the color (pixel value) of the second multi-valued image are: It is changing continuously. However, there is a boundary between the portion reproduced with the color (pixel value) of the first multi-valued image and the portion reproduced with the color (pixel value) of the second multi-valued image in the character portion of the original image. When the character is displayed, when the character is displayed, for example, the color of the background (the first multi-valued image or the second multi-valued image) is mixed and displayed on a part of the character, and the outline of the character is blurred. There was a problem.

  Therefore, in the present embodiment, after the image processing apparatus 1 generates, for example, the first multi-value image and the second multi-value image, as shown in FIG. 11, based on the original image and the binary image. As shown in FIG. 12, by correcting the color, as shown in FIG. 13, when the image is reproduced, the color change at the boundary is made clear and the outline of the character is clearly displayed. Can do. However, if the image processing apparatus 1 or the like performs correction as shown in FIG. 12 to a place where a gentle color change such as a photographic part instead of a character part may be performed, an unnatural contour is generated when the image is reproduced. Therefore, as will be described later, a region to be corrected is selected and a correction process is executed.

  Hereinafter, another example of the configuration of the image processing apparatus 1 is shown in FIG. FIG. 14 is a configuration diagram (part 2) of the image processing apparatus.

  As shown in FIG. 14, the image processing apparatus 1 includes a multi-value image acquisition unit 101, a binary image generation unit 102, an encoding unit 103, a first and second multi-value image generation unit 104, and boundary pixels. The first and second multi-value image generation means 104 include a first multi-value image pixel value determination means 105, a first multi-value image, and a detection means 131, an edge detection means 132, and a pixel value correction means 133. An undetermined pixel determining unit 106, a second multi-valued image pixel value determining unit 107, and a second multi-valued image undetermined pixel determining unit 108 are included.

  The boundary pixel detection unit 131 detects a boundary predetermined pixel in the vicinity of an undecided pixel for which no pixel value is set from among the predetermined pixels for which a pixel value is set. For example, the boundary pixel detection unit 131 detects, as a boundary predetermined pixel, a predetermined pixel having a predetermined pixel within a range of one pixel centered on the predetermined pixel from among the predetermined pixels for which the pixel value is set. Among the determined pixels for which values have been set, a determined pixel having a determined pixel in the range of two pixels centering on the determined pixel is detected as a boundary determined pixel. In the following description, for simplification of description, the boundary pixel detection unit 131 will be described assuming that a predetermined pixel having a predetermined pixel within a range of one pixel centered on the predetermined pixel is detected as a boundary predetermined pixel.

The edge detection unit 132 applies, for example, to the boundary predetermined pixels.
1 1 1 -1 0 1
0 0 0 -1 0 1
-1-1-1 -1 0 1
And the like, the edge of the filter value is determined to be an edge when the sum of the squares of the obtained filter values is larger than a predetermined value. Judge and detect edges. Note that when the original image (the first multi-valued image and / or the second multi-valued image) is a color image, the edge detecting unit 132 performs edge detection filtering for each color component to detect an edge.

  Note that, as shown in FIG. 15 and the like which will be described later, for example, when the pixel value of the first multi-valued image (second multi-valued image) subjected to the edge detection filter is an undecided pixel, the edge detecting unit 132 The filter value is obtained using the pixel value of the second multi-value image (first multi-value image) at the corresponding position. In addition, the edge detection unit 132 has been described to perform the edge detection process on the boundary-determined pixels of the first multi-valued image and / or the second multi-valued image. Processing may be performed. However, in the following, for simplification of description, it is assumed that the edge detection unit 132 performs edge detection processing on the boundary determined pixels of the first multi-value image and / or the second multi-value image.

  The pixel value correcting unit 133 corrects the pixel value of the boundary determined pixel detected as the edge using the pixel value of the determined pixel that is not in the vicinity of the determined pixel, that is, is not the boundary determined pixel. The pixel value correcting unit 133 corrects the pixel value of the boundary determined pixel detected as the edge with an average value of the pixel value of the determined pixel that is not in the vicinity of the determined pixel and the pixel value of the boundary determined pixel. It may be. However, for simplification of description below, the pixel value correcting unit 133 is described as correcting the pixel value of the boundary determined pixel detected as an edge using the pixel value of the determined pixel that is not in the vicinity of the determined pixel. I do.

  The concept of an example of edge detection in the edge detection unit 132 is shown in FIG. FIG. 15 is a conceptual diagram illustrating an example of edge detection.

As illustrated in FIG. 15, the edge detection unit 132 is, for example, one of edge detection filters with respect to the boundary-determined pixel (the pixel e of the first multi-valued image in the example of FIG. 15).
-1 0 1
-1 0 1
Is first applied to obtain a filter value (-a + C-d + F-g + i in the example of FIG. 15).

  In FIG. 15, uppercase alphabetic characters represent the determined pixels and the pixel values of the determined pixels in the second multivalued image, and lowercase letters represent the determined pixels and the pixel values of the determined pixels in the first multivalued image. “X” represents an undecided pixel.

Further, as described above, the edge detection unit 132 is the other edge detection filter with respect to the boundary-determined pixel (for example, the pixel e of the first multi-valued image) 1 1 1
0 0 0
-1-1-1
To obtain a filter value (for example, a + b + C−g−i).

  The edge detection unit 132 obtains the square sum of the obtained filter values, determines that the edge is an edge when the square sum of the filter values is larger than a predetermined value, and detects an edge.

  By detecting the edge by the edge detection unit 132 and correcting the pixel value in the pixel value correction unit 133 only for the detected edge portion, the gentle color change can be maintained. If you want to make the color change at the boundary clear, you can make the color change clear.

  The concept of an example of pixel value correction (replacement) in the pixel value correction unit 133 is shown in FIG. FIG. 16 is a conceptual diagram of an example of pixel value correction (replacement).

  As shown in FIG. 16, the pixel value correcting unit 133 replaces the pixel value of the boundary-determined pixel whose edge has been detected by using the pixel value of the predetermined pixel that is not in the vicinity of the undecided pixel, that is, is not the boundary-determined pixel. ,to correct.

  By correcting the pixel value by the pixel value correcting means 133, as shown in FIGS. 12 and 13, when reproducing the image, the color change of the boundary portion is made clear and the outline of the character is clearly displayed. To be able to.

  Hereinafter, the process in Example 2 is demonstrated using a flowchart. FIG. 17 is a flowchart (part 2) illustrating image processing in the image processing apparatus.

  Note that steps S40 to S43 shown in FIG. 17 are the same as the processes of steps S10 to S13 shown in FIG. Also, the processing from step S46 to step S48 shown in FIG. 17 is the same as the processing from step S14 to step S16 shown in FIG.

  In step S44, the boundary pixel detection unit 131, the edge detection unit 132, and the pixel value correction unit 133 perform the above-described boundary determination pixel smoothing process on the first multi-valued image. The details of the boundary-settled pixel smoothing process (the process of step S44) for the first multi-valued image by the boundary pixel detecting unit 131, the edge detecting unit 132, and the pixel value correcting unit 133 are shown in FIG.

  In step S45 following step S44, the boundary pixel detection unit 131, the edge detection unit 132, and the pixel value correction unit 133 perform the above-described boundary boundary smoothing process on the second multi-valued image. .

  Hereinafter, an example of the smoothing process of the boundary-determined pixels for the first multi-valued image by the boundary pixel detecting unit 131, the edge detecting unit 132, and the pixel value correcting unit 133 is shown in FIG. FIG. 18 is a flowchart illustrating an example of the smoothing process for the boundary-determined pixels for the first multi-valued image.

  In step S50, the boundary pixel detection unit 131 detects a boundary predetermined pixel in the vicinity of an undecided pixel for which no pixel value is set from among the predetermined pixels for which a pixel value is set in the first multi-valued image.

  Progressing to step S51 following step S50, the edge detection means 132 performs edge detection filtering on the boundary-determined pixels detected in step S50, and obtains the square sum of the obtained filter values.

  Progressing to step S52 following step S51, the edge detection means 132 determines the boundary determined pixels detected in step S50 according to whether or not the square sum of the filter values obtained in step S51 is greater than a predetermined value. It is determined whether or not is an edge. If the edge detection unit 132 determines that the boundary determined pixel detected in step S50 is an edge (YES in step S52), the edge detection unit 132 proceeds to step S53, and determines that the boundary determined pixel detected in step S50 is not an edge (step S52). NO), the process proceeds to step S55.

  In step S53, the pixel value correcting unit 133 searches for a determined pixel (outside boundary determined pixel) that is not in the vicinity of the determined pixel, that is, is not a boundary determined pixel. Progressing to step S54 following step S53, the pixel value correcting means 133 searches the pixel value of the boundary determined pixel determined to be an edge in step S52 in step S53, and the detected pixel value of the determined pixel outside the boundary. Replace with.

  Progressing to step S55 following step S54, the image processing apparatus 1 determines whether or not the boundary-determined pixel smoothing process has been performed on the entire region of the first multi-valued image, and determines that it has been performed (step S54). If YES in S55, the boundary-determined pixel smoothing process is terminated, and if it is determined that the boundary-determined pixel smoothing process is not being executed (NO in Step S55), a region of the first multi-value image to be processed in the boundary-determined pixel smoothing process is determined in advance. Based on the determined method, the process proceeds to step S50.

  By performing the boundary-determined pixel smoothing process as described above, the pixel change in the vicinity of the edge portion becomes gentle, and the compression efficiency at the time of compression encoding is improved. Further, the boundary-determined pixel smoothing process is useful for reducing the file size. For example, in the process shown in FIG. 18, the boundary determined pixel smoothing is performed such that the pixel values of the determined pixels near the boundary are replaced with the pixel values of the determined pixels outside the boundary without performing the processes of step S51 and step S52. Processing may be performed. In this way, in the boundary-determined pixel smoothing process that does not perform edge detection, the file size is further reduced, but the color change at the boundary portion where the color change is small is emphasized and reproduced in the original original image. It may change slightly compared to the original image.

  By performing the processing as shown in the second embodiment, when the pixel value changes rapidly at the boundary portion such as a character portion among the boundary portions between the first multi-value image and the second multi-value image. By reducing the influence of the color mixed in the boundary (see, for example, FIG. 12), the outline of the character can be clearly reproduced (see, for example, FIG. 13). Further, when the pixel value is gently changed in the photograph portion or the like in the boundary portion between the first multi-value image and the second multi-value image, the pixel value replacement (or averaging) processing is performed. Therefore, a smooth color change can be reproduced as it is.

  In the embodiment described above, the original image (or multi-valued image) is mainly divided into three layers (first multi-valued image, second multi-valued image, and binary image), and for each, The processing and configuration for compression encoding have been described. In the third embodiment, the processing and configuration for image reproduction will be mainly described.

  FIG. 19 is a configuration diagram (part 3) of the image processing apparatus. The configuration of the image processing apparatus 1 shown in FIG. 19 is different from the configuration of the image processing apparatus 1 shown in FIG. 2 of the first embodiment or the configuration of the image processing apparatus 1 shown in FIG. , A configuration that is further added (included).

  As shown in FIG. 19, the image processing apparatus 1 includes a first multi-value image expansion unit 141, a second multi-value image expansion unit 142, a binary image expansion unit 143, and a binary image pixel value determination unit 144. And corresponding pixel value determining means 145.

  The first multi-valued image decompressing unit 141 decodes (decompresses) the first multi-valued image generated by the first and second multi-valued image generating unit 104 and encoded by the encoding unit 103.

  The second multi-level image expansion unit 142 decodes (decompresses) the second multi-level image generated by the first and second multi-level image generation unit 104 and encoded by the encoding unit 103.

  The binary image expansion unit 143 decodes (decompresses) the binary image generated by the binary image generation unit 102 and encoded by the encoding unit 103.

  The binary image pixel value determination unit 144 determines whether each pixel value of the binary image decoded by the binary image expansion unit 143 is white or black, and passes the determination result to the corresponding pixel value determination unit 145.

  The corresponding pixel value determining unit 145 is decoded by the first multi-valued image decompressing unit 141 at a position corresponding to the pixel position of the binary image based on the determination result received from the binary image pixel value determining unit 144. The pixel value of the first multi-valued image or the pixel value of the second multi-valued image decoded by the second multi-valued image decompressing means 142 is determined as the pixel value of the pixel of the binary image and displayed. For example, when the determination result received from the binary image pixel value determination unit 144 is black, the corresponding pixel value determination unit 145 has a first multi-value image expansion unit 141 at a position corresponding to the pixel position of the binary image. The pixel value of the first multi-valued image decoded in is determined as the pixel value of the pixel of the binary image and displayed.

  The image processing apparatus 1 performs the above-described processing on all the pixels of the binary image and reproduces (displays) the image.

  In the embodiment described above, for example, as shown in FIGS. 2 and 5 of the first embodiment, FIG. 14 of the second embodiment, FIG. 19 of the third embodiment, etc., each configuration of the image processing apparatus 1 according to the present invention is configured. However, in the present embodiment, an example in which each of the above-described components is implemented as software in the image processing apparatus 1 (or information processing apparatus) is shown.

  FIG. 20 is a configuration diagram (part 4) of the image processing apparatus. As shown in FIG. 20, the image processing apparatus 1 includes a CPU (Central Processing Unit) 401, a memory 402, a hard disk 403, an input / display device 404, a drive device 405, an interface device 406, and a reading device. 408 and a printing apparatus 409.

  The input / display device 404 includes an operation panel or the like, and is used for inputting various operation signals to the image processing device 1 and displaying various information by the image processing device 1. The interface device 406 is an interface that connects the image processing apparatus 1 to a network or the like.

  Each functional configuration of the image processing apparatus 1 in the embodiment described above or a program corresponding to each process (hereinafter referred to as an image processing program) is installed in the image processing apparatus 1 from the beginning, or is recorded on an SD memory card or the like, for example. It is provided to the image processing apparatus 1 by the medium 407 or downloaded through the network. The recording medium 407 is set in the drive device 405, and the image processing program is installed in the hard disk 403 from the recording medium 407 via the drive device 405.

  The memory 402 reads and stores an image processing program or the like from the hard disk 403 when the image processing apparatus 1 is activated, for example. The CPU 401 executes processing according to an image processing program or the like read and stored in the memory 402, stores the processing result of the image processing in the hard disk 403, displays it on the input / display device 404 as necessary, and prints Printing on the device 408.

  The hard disk 403 stores image processing results, image data, image processing programs, and the like. The reading device 408 is a scanner or the like, for example, and reads set paper or the like and stores image data or the like in the hard disk 403. Further, as described above, the printing apparatus 409 prints the processing result of image processing, for example, in response to a request.

  Note that the above-described image processing program may be mounted (or installed) on an information processing apparatus such as a PC (Personal Computer) so that the information processing apparatus performs the above-described image processing. When the image processing program is mounted on a PC, for example, the input / display device 404 shown in FIG. 20 is divided into an input device and a display device. For example, the input device includes a keyboard and a mouse. The display device is composed of a display or the like. Of course, the information processing apparatus does not include the reading device 408 or the printing device 409 as a configuration.

  The image processing program installed on the PC is created by a PC user or the like using an input device, for example, and the original image stored in the hard disk 403 or the like is a processing target, and the processing result is displayed on a display or the like.

  As described above, according to the present invention, the file size can be reduced without performing the determination of characters and non-characters. Further, according to the present invention, it is possible to suppress the color change at the boundary. Furthermore, according to the present invention, the file size can be reduced while clearly reproducing the outline of characters and the like.

  According to the present invention, it is possible to suppress image quality deterioration and efficiently reduce the file size without performing determination of characters and non-characters.

  The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to such specific embodiments, and various modifications can be made within the scope of the gist of the present invention described in the claims.・ Change is possible.

It is a conceptual diagram which shows the basic process in a present Example. It is a block diagram (the 1) of an image processing apparatus. It is a figure which shows an example of the position of the binary image corresponded to 1 pixel of a 1st multi-value image, and an original image. It is a conceptual diagram which shows an example of calculation of the pixel value of a 1st multi-value image. It is a block diagram of a 1st multi-value image undetermined pixel determination means. It is a figure which shows an example of the smoothing of the boundary undetermined pixel by the average in a block. 3 is a flowchart (part 1) illustrating image processing in the image processing apparatus. It is a flowchart which shows an example of the pixel value determination process of a 1st multi-value image. It is a flowchart which shows an example of the boundary undecided pixel smoothing process of a 1st multi-value image. It is FIG. (1) for demonstrating the basic view in a present Example. It is FIG. (2) for demonstrating the basic view in a present Example. It is FIG. (The 3) for demonstrating the basic view in a present Example. It is FIG. (4) for demonstrating the basic view in a present Example. It is a block diagram (the 2) of an image processing apparatus. It is a conceptual diagram which shows an example of edge detection. It is a conceptual diagram of an example of correction | amendment (replacement) of a pixel value. 7 is a flowchart (part 2) illustrating image processing in the image processing apparatus. It is a flowchart which shows an example of the smoothing process of the boundary predetermined pixel with respect to a 1st multi-value image. It is a block diagram (the 3) of an image processing apparatus. It is a block diagram (the 4) of an image processing apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image processing apparatus 101 Multi-valued image acquisition means 102 Binary image acquisition means 103 Coding means 104 First, binary multi-value image generation means 105 First multi-value image pixel value determination means 106 First multi-value image undecided pixel determination Means 107 Second multi-valued image pixel value determining means 108 Second multi-valued image undetermined pixel determining means 111 In-block region setting means 112 In-block determined / undetermined pixel counting means 113 Pixel value setting means 131 Boundary pixel detecting means 132 Edge detection Means 133 Pixel value correction means 141 First image decompression means 142 Second image decompression means 143 Binary image decompression means 144 Binary image pixel value examination means 145 Corresponding pixel value determination means 401 CPU
402 Memory 403 Hard Disk 404 Input / Display Device 405 Drive Device 406 Interface Device 407 Recording Medium 408 Reading Device 409 Printing Device

Claims (24)

An image processing apparatus for processing an image,
Multi-value image acquisition means for acquiring a multi-value image;
Binary image generating means for generating a binary image from the multi-valued image;
Multi-value image generation means for generating a first multi-value image and a second multi-value image based on the multi-value image and the binary image;
Have
The multi-value image generating means
If one pixel value of the binary image exists in the binary image at a position corresponding to the pixel position of the first multi-valued image, this corresponds to the position where one pixel value of the binary image exists. First multi-value image pixel value setting means for setting a pixel value of a pixel of the first multi-value image based on a pixel value in the multi-value image at a position;
If the other pixel value of the binary image exists in the binary image at a position corresponding to the pixel position of the second multi-valued image, this corresponds to the position where the other pixel value of the binary image exists. Second multi-value image pixel value setting means for setting a pixel value of a pixel of the second multi-value image based on a pixel value in the multi-value image at a position;
The pixel value of the undecided pixel in the first multi-valued image in which the value is not set near the decided pixel in the first multi-valued image in which the value is set, and the pixel value of the decided pixel in the vicinity of the undecided pixel First multi-value image pixel non-set pixel setting means for setting using,
The pixel value of the undecided pixel in the second multi-valued image that has not been set, the pixel value of the determined pixel in the vicinity of the undecided pixel in the vicinity of the determined pixel in the second multi-level image in which the value has been set Second multi-value image pixel non-set pixel setting means for setting using
An image processing apparatus comprising:   2. The image processing apparatus according to claim 1, further comprising encoding means for encoding an image.   The image processing apparatus according to claim 1, wherein the first multi-value image and the second multi-value image have the same resolution.   4. The image processing apparatus according to claim 1, wherein resolutions of the first multi-value image and the second multi-value image are lower than the resolution of the multi-value image. 5. The first multi-value image pixel non-set pixel setting means includes:
First block area setting means for setting a block area of a predetermined size for the first multi-valued image;
A first counter that counts whether or not both a determined pixel for which a pixel value is set and an undecided pixel for which a pixel value is not set exist in the block area set by the first block area setting means. In-block determined / undecided pixel counting means,
Have
The second multi-value image pixel non-set pixel setting means includes:
A second in-block area setting means for setting a block area of a predetermined size for the second multi-valued image;
A second counter that counts whether or not both a determined pixel having a pixel value set and an undecided pixel having no pixel value set exist in the block area set by the second block area setting means. In-block determined / undecided pixel counting means,
The image processing apparatus according to claim 1, further comprising: The first multi-value image pixel non-set pixel setting means includes:
A first pixel value setting unit that sets the pixel value of the undecided pixel using the determined pixel in the block area set in the first block area setting unit;
The second multi-value image pixel non-set pixel setting means includes:
The second pixel value setting means for setting the pixel value of the undecided pixel using the determined pixel in the block area set by the second block area setting means. Image processing apparatus.   The first multi-value image pixel non-set pixel setting means or the second multi-value image pixel non-set pixel setting means sets the pixel value by the block area unit of the predetermined size in steps of the block area unit of the predetermined size. The image processing apparatus according to claim 5, wherein the image processing apparatus is recursively performed on the first multi-valued image or the second multi-valued image while being enlarged.   The first multi-value image pixel non-set pixel setting means or the second multi-value image pixel non-set pixel setting means gradually increases the block area unit of the predetermined size, and finally the block of the predetermined size The image processing apparatus according to claim 7, wherein the area unit is 8 × 8 pixels.   The image processing apparatus according to claim 5, wherein the block area of the predetermined size is 8 × 8 pixels. Boundary pixel detection means for detecting boundary determined pixels in the vicinity of undecided pixels for which pixel values are not set from among the determined pixels for which pixel values are set;
Pixel value correcting means for correcting the pixel value of the boundary determined pixel using a pixel value of another determined pixel that is not in the vicinity of the determined pixel;
The image processing apparatus according to claim 1, further comprising: An edge detection unit that detects an edge of the boundary-determined pixel detected by the boundary pixel detection unit;
The image processing apparatus according to claim 10, wherein the pixel value correcting unit corrects a pixel value for the boundary-determined pixel detected as an edge by the edge detecting unit. An image processing method in an image processing apparatus for processing an image, the image processing apparatus comprising:
A multi-valued image acquisition stage for acquiring a multi-valued image;
A binary image generation step of generating a binary image from the multi-valued image;
Based on the multi-value image and the binary image, a multi-value image generation step for generating a first multi-value image and a second multi-value image;
Have
The multi-value image generation step includes
If one pixel value of the binary image exists in the binary image at a position corresponding to the pixel position of the first multi-valued image, this corresponds to the position where one pixel value of the binary image exists. A first multi-value image pixel value setting step of setting a pixel value of a pixel of the first multi-value image based on a pixel value in the multi-value image at a position;
If the other pixel value of the binary image exists in the binary image at a position corresponding to the pixel position of the second multi-valued image, this corresponds to the position where the other pixel value of the binary image exists. A second multi-value image pixel value setting step for setting a pixel value of a pixel of the second multi-value image based on a pixel value in the multi-value image at a position;
The pixel value of the undecided pixel in the first multi-valued image in which the value is not set near the decided pixel in the first multi-valued image in which the value is set, and the pixel value of the decided pixel in the vicinity of the undecided pixel A first multi-value image pixel non-set pixel setting stage to be set using
The pixel value of the undecided pixel in the second multi-valued image that has not been set, the pixel value of the determined pixel in the vicinity of the undecided pixel in the vicinity of the determined pixel in the second multi-level image in which the value has been set A second multi-value image pixel non-set pixel setting stage to be set using
An image processing method comprising:   The image processing method according to claim 12, further comprising an encoding step of encoding an image.   The image processing method according to claim 12 or 13, wherein the first multi-valued image and the second multi-valued image have the same resolution.   The image processing method according to claim 12, wherein the resolution of the first multi-valued image and the second multi-valued image is lower than the resolution of the multi-valued image. The first multi-value image pixel non-set pixel setting step includes:
A first block area setting step for setting a block area of a predetermined size for the first multi-valued image;
First counting whether or not both a determined pixel having a pixel value and an undecided pixel having no pixel value are present in the block area set in the first block area setting step. In-block determined / undecided pixel counting stage,
Have
The second multi-value image pixel non-set pixel setting step includes:
A second block area setting step for setting a block area of a predetermined size for the second multi-valued image;
A second counter that counts whether or not both a determined pixel for which a pixel value is set and an undecided pixel for which a pixel value is not set exist in the block area set in the second block area setting step. In-block determined / undecided pixel counting stage,
16. The image processing method according to claim 12, further comprising: The first multi-value image pixel non-set pixel setting step includes:
A first pixel value setting step of setting the pixel value of the undecided pixel using the determined pixel in the block region set in the first block region setting step;
The second multi-value image pixel non-set pixel setting step includes:
17. The second pixel value setting step of setting the pixel value of the undecided pixel by using the determined pixel in the block region set in the second block inner region setting step. Image processing method.   In the first multi-value image pixel non-set pixel setting step or the second multi-value image pixel non-set pixel setting step, the pixel value is set in the block region unit of the predetermined size in the block region unit of the predetermined size. The image processing method according to claim 16 or 17, wherein the image processing method is recursively performed on the first multi-valued image or the second multi-valued image while being enlarged.   In the first multi-value image pixel non-set pixel setting step or the second multi-value image pixel non-set pixel setting step, the block region unit of the predetermined size is increased step by step, and finally the block of the predetermined size is set. The image processing method according to claim 18, wherein the area unit is 8 × 8 pixels.   18. The image processing method according to claim 16, wherein the block area having the predetermined size is 8 × 8 pixels. A boundary pixel detection stage for detecting a boundary predetermined pixel in the vicinity of an undecided pixel for which a pixel value is not set from among the predetermined pixels for which a pixel value is set;
A pixel value correction step of correcting the pixel value of the boundary predetermined pixel using a pixel value of another predetermined pixel not in the vicinity of the predetermined pixel;
The image processing method according to claim 12, further comprising: An edge detection step of performing edge detection on the boundary-determined pixels detected in the boundary pixel detection step;
The image processing method according to claim 21, wherein the pixel value correcting step corrects a pixel value of the boundary-determined pixel detected as an edge in the edge detecting step. Computer
Multi-value image acquisition means for acquiring a multi-value image;
Binary image generating means for generating a binary image from the multi-valued image;
Multi-value image generation means for generating a first multi-value image and a second multi-value image based on the multi-value image and the binary image;
Have
The multi-value image generating means
If one pixel value of the binary image exists in the binary image at a position corresponding to the pixel position of the first multi-valued image, this corresponds to the position where one pixel value of the binary image exists. First multi-value image pixel value setting means for setting a pixel value of a pixel of the first multi-value image based on a pixel value in the multi-value image at a position;
If the other pixel value of the binary image exists in the binary image at a position corresponding to the pixel position of the second multi-valued image, this corresponds to the position where the other pixel value of the binary image exists. Second multi-value image pixel value setting means for setting a pixel value of a pixel of the second multi-value image based on a pixel value in the multi-value image at a position;
The pixel value of the undecided pixel in the first multi-valued image in which the value is not set near the decided pixel in the first multi-valued image in which the value is set, and the pixel value of the decided pixel in the vicinity of the undecided pixel First multi-value image pixel non-set pixel setting means for setting using,
The pixel value of the undecided pixel in the second multi-valued image that has not been set, the pixel value of the determined pixel in the vicinity of the undecided pixel in the vicinity of the determined pixel in the second multi-level image in which the value has been set Second multi-value image pixel non-set pixel setting means for setting using
An image processing program comprising:   A computer-readable recording medium on which the image processing program according to claim 23 is recorded.

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