JP2008219326A - Image processing device and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image processing device which can improve image quality after an image is outlined even when the input image is a binary image. <P>SOLUTION: An image processing program 4 has a magnification unit 40 which carries out magnification of the binary image, and an outlining unit 42 which outlines the magnified image, and operates on the image processing device 10. The magnification unit 40 cuts out a partial image of characters, etc. included in the binary image of a first resolution, extracts similar partial images, calculates a center of gravity for respective similar partial images, creates a partial image of a second resolution based on the extracted respective similar partial images and the calculated center of gravity, arranges the created partial image on the image of the second resolution, and creates a magnified binary image. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image processing apparatus that converts a bitmap image into line drawing information and a program thereof.

  In general, a technique for inputting a raster image, outlining a character portion of the image, and facilitating reuse (for example, editing) of the image is well known. In such a technique, for example, by converting a character image into an outline, an image having no image quality degradation can be obtained even when the image is enlarged.

  Outline creation is a method of representing an outline shape of an object that can be represented by binary information, such as characters, by approximating it with a curve like a Bezier. In such a method, when binarizing an input raster image, the higher the binarization resolution, the better the image quality after outline conversion. However, there is a problem that the calculation load increases as the resolution increases.

  Patent Document 1 discloses a technique for reducing the outlining load while maintaining image quality by binarizing at a low resolution when the character is large and binarizing at a high resolution when the character is small. Has been.

JP 2006-253892 A

  By the way, if the resolution conversion process is performed before the binarization process, if the format of the input image is a binary image, it is difficult to obtain an image quality that is higher than the image quality when the input image is outlined using the resolution of the input image. Met.

  The present invention has been made from the above-described background, and an object of the present invention is to provide an image processing apparatus capable of improving the image quality after being outlined even when the input image is a binary image.

  In order to achieve the above object, an image processing apparatus according to the present invention includes an image enlarging unit for enlarging a binary image and an outlining unit for outlining an image enlarged by the image enlarging unit. According to the present invention, even when the input image is a binary image, it is possible to improve the image quality after outline conversion.

  Preferably, the image enlarging means includes a partial image extracting means for extracting a similar partial image from a binary image at a first resolution, a partial image extracted by the partial image extracting means, and a first resolution. A partial image generating means for generating a partial image having a second resolution higher than the first resolution based on the phase of the partial image image calculated with higher accuracy than one pixel in the image; and extracting by the partial image extracting means And an arrangement unit that arranges the partial image generated by the partial image generation unit at a position in the second resolution image calculated based on the position of the partial image. According to the present invention, it is possible to generate an enlarged image with higher quality than when enlarging one low-resolution partial image.

  Preferably, the image enlarging means includes a multi-value conversion means for converting a binary image into a multi-value, a resolution conversion means for converting the resolution of the image multi-valued by the multi-value conversion means, and the resolution conversion. Binarizing means for binarizing the image whose resolution has been converted by the means.

  Preferably, the image processing apparatus further includes an enlargement factor calculating unit that calculates an enlargement factor based on the resolution of the read image, and the image enlarging unit enlarges the image based on the enlargement factor calculated by the enlargement factor calculating unit. According to the present invention, a high-quality enlarged image can be generated even when the resolution at the time of printing is unknown.

  Preferably, the enlargement ratio calculating means calculates the enlargement ratio based on a ratio between the resolution of the read image and the resolution of the print image. According to the present invention, it is possible to compensate for missing information due to a difference in resolution between reading an image and printing.

  Preferably, the enlargement ratio calculating means sets the enlargement ratio to 1 or more. According to the present invention, it is possible to prevent the quality of an enlarged image from being deteriorated compared to an image before enlargement.

  Preferably, the enlargement ratio calculating means sets the enlargement ratio to 16 or less. According to the present invention, it is possible to prevent the enlargement processing load from increasing while maintaining the quality of the enlarged image.

  Preferably, the enlargement factor calculating means calculates the enlargement factor so that the number of pixels of the image is equal to or less than a predetermined value. According to the present invention, it is possible to prevent the data amount of the enlarged image from increasing.

  Preferably, the apparatus further includes data amount determination means for determining the data amount of the image outlined by the outline forming means. According to the present invention, it is possible to prevent the data amount of the enlarged image from increasing.

  Preferably, when the data amount determining unit determines that the image data amount exceeds a predetermined value, the enlargement ratio is determined based on the data amount of the image outlined by the outline forming unit and the predetermined data amount. The image processing apparatus further includes an enlargement factor correcting unit for correcting, and the image enlarging unit enlarges the image based on the enlargement factor corrected by the enlargement factor correcting unit. According to the present invention, the amount of image data after outline processing can be controlled.

  Preferably, when the data amount determining unit determines that the image data amount exceeds a predetermined value, the outlining process is performed based on the data amount of the image outlined by the outline forming unit and the predetermined data amount. The image forming apparatus further includes an outlining parameter correction unit that corrects the parameters in the above, and the outlining unit enlarges the image based on the atlining parameter corrected by the outlining parameter correction unit. According to the present invention, the amount of image data after outline processing can be controlled.

  A program according to the present invention is placed in an image processing apparatus including a computer, and an image enlarging step for enlarging a binary image and an outline forming step for outlining the enlarged image are performed on the computer of the image processing apparatus. Let it run. According to the present invention, even when the input image is a binary image, it is possible to improve the image quality after outline conversion.

  According to the image processing apparatus of the present invention, even when the input image is a binary image, the image quality after the outline can be improved.

First, the outline of the present invention will be described.
FIG. 1 is a diagram illustrating a relationship between resolution conversion processing and image quality after outline processing.
FIG. 1A is a diagram illustrating an ideal outline, and FIG. 1B is a diagram illustrating a result obtained by outlining a low-resolution image. Here, the broken line shown in FIG. 1B is the obtained result, and the rectangle represents one pixel. As illustrated in FIGS. 1A and 1B, when a corner is outlined from a low resolution image, the corner is locally rounded, so the result obtained is a rounded outline and turn into.

  FIG. 1C is a diagram illustrating a result obtained from an image having a higher resolution than that shown in FIG. As illustrated in FIG. 1C, when the resolution is high, it is possible to make the resulting outline a shape close to an ideal outline.

For example, there are the following two techniques for increasing the resolution.
The first high resolution method is to convert an input binary image into a multi-value. In this method, for example, the pixel value 0 is converted to 0, and the pixel value 1 is converted to 255. The converted multi-valued image is enlarged using, for example, a method such as linear interpolation or cubic convolution, and the enlarged image is binarized by threshold processing.

  The second high resolution technique applies a super-resolution method. In this method, for example, a magnified image is generated by correcting and enlarging a positional shift of a plurality of low resolution images and further averaging. For this reason, it is possible to generate an enlarged image with higher quality than the enlarged image generated from one image.

FIG. 2 is a diagram for explaining high resolution processing by the super-resolution method.
As shown in FIG. 2A, in the high resolution processing by the super-resolution method, characters appearing a plurality of times in a one-page document or a document composed of a plurality of pages are extracted. When such a plurality of identical characters are read by a reading device such as a scanner, they are often read in different phases with respect to the center of gravity of the characters. For this reason, the phases of the extracted characters are shifted from each other.

  As shown in FIG. 2B, the phase of each character is calculated from, for example, the center of gravity of the character and the relative position between the calculated center of gravity and the sampling grid point. Further, in the super-resolution method, as shown in FIG. 2C, a high-resolution character image is generated based on the calculated phase and each extracted character image.

  Note that the target of high resolution processing is not limited to characters, but may be partial images having the same shape, such as graphics. In this case, partial images that appear multiple times in the input image are extracted, the phase of each partial image is calculated, and a high-resolution partial image is generated based on the calculated phase and each extracted partial image. Is done.

  As the enlargement ratio is increased, the quality of the generated image often saturates at a certain enlargement ratio. Such an enlargement rate is also called a saturation enlargement rate.

FIG. 3 is a diagram illustrating the relationship between the enlargement ratio and the data amount of the generated image.
In FIG. 3, the vertical axis represents the same paper image scanned at 200 dpi and 600 dpi, subjected to multi-value conversion processing (0 to 255) for each scanned image, and then enlarged using cubic convolution. This is the file size when an image binarized as a threshold is outlined and converted to SVG (Scalable Vector Graphics) format. The horizontal axis is the magnification.

  As shown in FIG. 3, the data amount is saturated at a certain enlargement ratio. That is, the image quality is also saturated. In this example, the saturation enlargement ratio P is, for example, 12 to 16 regardless of the scan resolution.

  Therefore, in the high resolution processing, it is necessary to select an appropriate enlargement ratio or resolution. Here, an enlargement ratio necessary for filling the gap between the resolution S0 at the time of image reading and the resolution S1 at the time of printing is defined as a necessary enlargement ratio Q. When the resolution S1 at the time of printing is larger than the resolution S0 at the time of image reading, it is considered that information is missing at the time of image reading. Therefore, the necessary enlargement ratio is obtained from Q = S1 / S0.

  The resolution S1 at the time of printing may be set to a fixed value in advance. For example, when it is considered that a sheet printed by a 600 dpi printer has been scanned, the resolution S1 is set to 600. Also, for example, it is assumed that the resolution of RIP (Raster Image Processor) in CTP (Computer To Plate) and image setter is at most about 2400 dpi, so when print data is generated, the resolution S1 is set to 2400. The

Therefore, if the enlargement factor actually used is U, the enlargement factor U can be obtained from the following equation.
Magnification rate U = min (P, Q)

Further, an enlargement ratio R that provides an appropriate calculation load may be set in advance. In this case, the enlargement ratio U is obtained from the following equation.
Magnification rate U = min (P, Q, R)

FIG. 4 is a diagram illustrating an image obtained by outlining a binary image. FIG. 4A illustrates an image obtained by outlining a scanned image as it is, and FIG. ) Is a diagram exemplifying an image obtained by performing outline conversion after performing high resolution processing on a scanned image.
In this example, the scan resolution is 200 dpi, and the high resolution processing is to enlarge a 200 dpi scan image to 600 dpi three times. As illustrated in FIG. 4, the image shown in FIG. 4B is more natural than the image shown in FIG. 4A, and the quality of the image shown in FIG. ) Higher than the image quality shown.

Next, the image processing apparatus 10 according to the embodiment of the present invention will be specifically described.
FIG. 5 is a diagram showing a hardware configuration of the image processing apparatus 10 according to the embodiment of the present invention, centering on the control apparatus 12.
As shown in FIG. 5, the image processing apparatus 10 includes a control device 12 including a CPU 14 and a memory 16, a communication device 18 that performs data communication with an external computer via a network, and a storage device such as a hard disk drive. 20 and a display device such as a liquid crystal display and a user interface (UI) device 22 including a keyboard and a pointing device.

  The image processing apparatus 10 is a general-purpose computer in which, for example, an image processing program 4 described later is installed, and acquires and acquires binary image data via the communication device 18, the storage device 20, the storage medium 24, or the like. Image processing is performed on the processed image. The image processing apparatus 10 acquires, for example, bitmap-format image data optically read by a scanner function of a printer device (not shown) or a scanner device, and read and transmitted.

FIG. 6 is a diagram showing a functional configuration of the image processing program 4 executed by the control device 12 of the image processing apparatus 10 according to the first embodiment of the present invention.
As shown in FIG. 6, the image processing program 4 includes an enlarging unit 40 and an outlining unit 42. With such a configuration, the image processing program 4 enlarges the binary image and outlines the enlarged image.

  For example, the image processing program 4 is supplied to the control device 12 via the communication device 18, loaded into the memory 16, and specifically using hardware on an OS (not shown) operating on the control device 12. Executed. The image processing program 4 may be stored in a storage medium 24 such as FD, CD, or DVD and supplied to the image processing apparatus 10. The following programs are also supplied and executed in the same manner. Further, all or some of the functions of the image processing program 4 may be realized by hardware such as an ASIC (Application Specific Integrated Circuit) provided in the image processing apparatus 10.

  In the image processing program 4, the enlargement unit 40 receives a binary image and performs an enlargement process on the binary image at a predetermined enlargement rate to generate an enlarged binary image. The enlargement ratio may be stored in advance in at least one of the memory 16 and the storage device 20, may be input via the UI device 22, or may be transmitted via the communication device 18. The enlargement unit 40 outputs the generated enlarged binary image to the outliner 42. The enlargement unit 40 will be described in detail later.

The outline forming unit 42 outlines the enlarged binary image and generates an output image. The output image is represented by vector information or outline information. Note that the algorithm for outline processing is not particularly limited, and may be one disclosed in Patent Document 1, for example. In this case, the parameters a, α ₁ , θ ₁ , θ ₂ , θ ₃ , θ ₄ , θ _{5 and the} like of the algorithm may be set in advance.

FIG. 7 is a diagram illustrating a detailed functional configuration of the enlargement unit 40 of the image processing program 4.
As shown in FIG. 7, the enlargement unit 40 includes a partial image cutout unit 400, a similar partial image extraction unit 402, a centroid calculation unit 404, a high resolution partial image generation unit 406, a position calculation unit 408, and a high resolution partial image arrangement unit 410. Have

  In the enlarging unit 40, the partial image cutout unit 400 is a binary input image (first resolution) having a predetermined resolution (first resolution) read by the scanner device or the like via the communication device 18, the storage device 20, or the storage medium 24. (Binary image) is received, and partial images such as characters and graphics included in the binary image are cut out and output to the similar partial image extraction unit 402. The first resolution is, for example, 200 dpi. The binary image may be a one-page document or a document composed of a plurality of pages.

  For example, the partial image cutout unit 400 may cut a block of continuous black pixels (for example, black pixels connected in the vicinity of 8) from a binary image as one partial image, and estimate a character string and a character interval. The partial image may be cut out by estimating one partial image region. Further, for example, the partial image cutout unit 400 may cut out a partial image specified by an external OCR (Optical Character Reader) or the like. The partial image cutting method is not particularly limited.

  The similar partial image extraction unit 402 receives the partial images cut out by the partial image cutout unit 400, extracts similar partial images, and outputs them to the centroid calculation unit 404 and the high resolution partial image generation unit 406. More specifically, the similar partial image extraction unit 402 identifies the first partial image from the plurality of clipped partial images, and the first partial image and one or more similar to the first partial image The second partial image is extracted. In this way, the similar partial image extraction unit 402 extracts similar partial images from the binary image with the first resolution.

  For example, the similar partial image extraction unit 402 determines whether or not these partial images are similar by performing pattern matching between the first partial image and the second partial image. In this case, the similar partial image extraction unit 402 performs pattern matching between the partial images.

  For example, the similar partial image extraction unit 402 may treat one partial image data as one vector data and perform clustering to extract a partial image similar to the partial image. In this case, the similar partial image extraction unit 402 has a distance (for example, Euclidean distance) between vector data representing the partial image and vector data representing the partial image to be determined is less than a predetermined value (that is, two vectors). When the data distance is short), it is determined that the partial image is similar to the partial image to be determined. A similar determination method is not particularly limited.

  The centroid calculation unit 404 calculates the centroid of each partial image received from the similar partial image extraction unit 402, and outputs the calculated centroid value to the high-resolution partial image generation unit 406. The centroid calculating unit 404 calculates the centroid with higher accuracy than one pixel in the first resolution.

  The centroid calculation unit 404 calculates the phase of each partial image based on the relative position between the calculated centroid and the sampling grid point, and outputs the calculated phase to the high-resolution partial image generation unit 406. Good. For example, the center-of-gravity calculation unit 404 may calculate the center of the partial image based on the width and height of the partial image, or may calculate the center. In this case, the center-of-gravity calculation unit 404 outputs the center of the calculated partial image.

  Based on each partial image extracted by the similar partial image extraction unit 402 and the phase of each partial image calculated with higher accuracy than one pixel at the first resolution, the high-resolution partial image generation unit 406 A partial image having a second resolution higher than the first resolution is generated. Here, the second resolution is calculated based on the enlargement ratio. For example, when the first resolution is 200 dpi and the enlargement ratio is 3, the second resolution is 600 dpi.

  Specifically, the high-resolution partial image generation unit 406 calculates the phase of the partial image based on the relative position between the centroid of each partial image calculated by the centroid calculation unit 404 and the sampling grid point, and the similar partial image A partial image is generated based on the similar partial images received from the extraction unit 402 and the phase of each partial image. When the phase of the partial image is calculated by the gravity center calculation unit 404 and input to the high resolution partial image generation unit 406, the high resolution partial image generation unit 406 may use this phase.

Note that the high-resolution partial image generation unit 406 may further perform resolution conversion processing on the generated partial image to generate a partial image having the second resolution. This resolution conversion process may be an enlargement process or a reduction process.
The partial image generation processing by the high resolution partial image generation unit 406 will be described in detail later.

  The position calculation unit 408 receives partial image position data of a partial image cut out from the binary image having the first resolution by the partial image cutout unit 400, and corresponds to the partial image position based on the position of the partial image. The position of the partial image in the enlarged binary image having the second resolution is calculated. The position calculation unit 408 outputs the calculated position to the high resolution partial image arrangement unit 410.

  The high-resolution partial image arrangement unit 410 generates a position in the enlarged binary image with the second resolution calculated by the position calculation unit 408 based on the position of the partial image extracted with the first resolution, and generates a high-resolution partial image. The partial image having the second resolution generated by the unit 406 and corresponding to the position is received, and the partial image having the second resolution is arranged at the position of the enlarged binary image. The high-resolution partial image arrangement unit 410 arranges the partial images of the second resolution corresponding to the partial images included in the binary image of the first resolution in the enlarged binary image, and generates an enlarged binary image To do. The high resolution partial image arrangement unit 410 outputs the enlarged binary image data to the outline forming unit 42.

FIG. 8 is a diagram illustrating high-resolution partial image generation processing by the high-resolution partial image generation unit 406.
FIG. 8A shows the sampling grid of the input image and the position of the center of gravity of the partial image at the first resolution. In FIG. 8A, the rectangle indicated by the arrow a represents the sampling grid of the input image, and the broken line intersection indicated by the arrow b represents the barycentric position of the partial image. In this example, description will be made using four sampling grids of the input image. As shown in FIG. 8B, the high-resolution partial image generation unit 406 moves the phases of the four sampling grids based on the center of gravity of the partial image.

  FIG. 8C and FIG. 8D are diagrams for explaining a method for setting a sampling grid having a second resolution higher than the first resolution. In FIG. 8C, the circled number indicated by the arrow c illustrates the value of the partial image data at the first resolution. Here, the partial image data is shown such that the circled numbers are represented on the grid points of the sampling grid at the first resolution. In FIG. 8D, a thick line indicated by an arrow d represents a sampling grid of a high-resolution partial image at the second resolution.

  When the phase of the four sampling grids at the first resolution is moved, the high-resolution partial image generation unit 406 sets the sampling grid at the second resolution as shown in FIG. As shown in D), the phase of the sampling grating at the second resolution is moved based on the center of gravity of the partial image.

  FIG. 8E is a diagram for explaining a method for calculating the value of the partial image data at the second resolution. In FIG. 8E, bold circle numbers indicated by arrows e exemplify values of partial image data at the second resolution. Here, the partial image data at the second resolution is shown such that bold circle numbers are represented on the grid points of the sampling grid at the second resolution.

  Based on the phase of each partial image at the first resolution, the high-resolution partial image generation unit 406 interpolates the pixel value of the partial image at the second resolution from the pixel value of each partial image. In this example, the high-resolution partial image generation unit 406 applies the nearest neighbor interpolation method to interpolate the pixel values of the partial image at the second resolution. That is, the high-resolution partial image generation unit 406 selects the sampling grid point at the second resolution among the four values of the partial image data at the first resolution (in this example, circled numbers “1” to “4”). Is selected as the value of the partial image data at the second resolution. The interpolation method is not particularly limited, and other methods (for example, a linear interpolation method) may be applied.

FIG. 9 is a flowchart of the image enlargement process (S10) by the enlargement unit 40.
As shown in FIG. 9, in step 100 (S <b> 100), the partial image cutout unit 400 of the enlargement unit 40 cuts out a partial image from the binary input image and outputs it to the similar partial image extraction unit 402.

In step 102 (S102), the similar partial image extraction unit 402 extracts a similar partial image from the partial images cut out by the partial image cutout unit 400 at the first resolution.
In step 104 (S104), the centroid calculation unit 404 calculates the centroid of each partial image extracted by the similar partial image extraction unit 402 with higher accuracy than one pixel in the first resolution.

  In step 106 (S106), the high-resolution partial image generation unit 406 calculates the phase of each partial image based on the centroid of each partial image calculated by the centroid calculation unit 404 and extracts it by the similar partial image extraction unit 402. A partial image having the second resolution is generated based on each similar partial image and the phase of the similar partial image.

  In step 108 (S108), the position calculation unit 408 calculates the position of each partial image in the enlarged binary image based on the position of each partial image included in the binary input image having the first resolution.

In step 110 (S110), the high-resolution partial image placement unit 410 has a second resolution corresponding to each position in the enlarged binary image calculated based on the position of the partial image extracted at the first resolution. Arrange partial images.
In step 112 (S112), the high-resolution partial image arrangement unit 410 outputs the generated enlarged binary image data to the outliner 42.

FIG. 10 is a flowchart of the overall operation (S20) of image processing by the image processing program 4.
As shown in FIG. 10, in step 200 (S200), the enlargement unit 40 of the image processing program 4 accepts a binary input image. The enlargement unit 40 performs image enlargement processing (S10; FIG. 9) on the binary image to generate an enlarged binary image.

  In step 202 (S202), the outline forming unit 42 outlines the enlarged binary image and generates an output image represented by vector information or the like. The outliner 42 outputs the generated output image data. The outline forming unit 42 may transmit the output image data to an external computer (not shown) via the communication device 18 or may store the output image data in the storage device 20 or the storage medium 24.

Next, an image processing apparatus 10 according to the second embodiment of the present invention will be described.
The image processing apparatus 10 according to the present embodiment is different from the image processing apparatus 10 according to the first embodiment in that the enlargement ratio is calculated based on input parameters.

FIG. 11 is a diagram showing a functional configuration of the image processing program 5 executed by the control device 12 of the image processing apparatus 10 according to the second embodiment of the present invention.
As illustrated in FIG. 11, the image processing program 5 has a configuration in which an enlargement ratio calculation unit 50 is added to the image processing program 4 (FIG. 6). 11 that are substantially the same as those shown in FIG. 6 are denoted by the same reference numerals.

  In the image processing program 5, the enlargement ratio calculation unit 50 receives the resolution (read resolution) S 0 of the input read image, calculates the enlargement ratio based on the read resolution S 0, and sends the calculated enlargement ratio to the enlargement unit 40. Output. More specifically, the enlargement ratio calculation unit 50 calculates the enlargement ratio based on the ratio between the reading resolution S0 and the resolution (print resolution) S1 of the print image. For example, the enlargement factor calculation unit 50 calculates the enlargement factor according to the following equation.

  Magnification factor Q = max (S1 / S0, 1) (1)

  As described above, when S1 / S0 is smaller than 1, the enlargement ratio calculation unit 50 sets the enlargement ratio to 1. That is, the enlargement ratio calculation unit 50 sets the enlargement ratio to 1 or more. The enlargement ratio calculation unit 50 may use an input value as the print resolution S1, or may use a preset fixed value (for example, 600 dpi, 2400 dpi, etc.).

Further, the enlargement factor calculating unit 50 may calculate the enlargement factor using any one of the following formulas using the saturation enlargement factor P.
Magnification rate P = fixed value (for example, 12) (2)
Magnification rate U = min (P, Q) (3)

  As described above, since the saturation enlargement ratio P is considered to be 16 or less, the enlargement ratio calculator 50 may set the enlargement ratio to 16 or less.

FIG. 12 is a diagram showing a flowchart of the overall operation (S30) of image processing by the image processing program 5. Of the processes shown in FIG. 12, the same reference numerals are assigned to the processes that are substantially the same as those shown in FIG.
As shown in FIG. 12, when a binary image is received in the process of S200, in step 300 (S300), the enlargement rate calculation unit 50 of the image processing program 5 calculates the enlargement rate and Output.

  The enlarging unit 40 performs an image enlarging process (S10; FIG. 9) on the input binary image using the calculated enlarging rate to generate an enlarged binary image. Further, the enlarged binary image is outlined by the process of S202.

Next, an image processing apparatus 10 according to a third embodiment of the present invention will be described.
The image processing apparatus 10 according to the present embodiment relates to the second embodiment in that the enlargement ratio is further calculated based on the maximum image size (for example, the data amount, the number of pixels, etc.) of the enlarged binary image. Different from the image processing apparatus 10.

FIG. 13 is a diagram showing a functional configuration of the image processing program 6 executed by the control device 12 of the image processing apparatus 10 according to the third embodiment of the present invention. Of the components shown in FIG. 13, components substantially the same as those shown in FIG. 11 are denoted by the same reference numerals.
As illustrated in FIG. 13, in the image processing program 6, the enlargement ratio calculation unit 60 further receives an input related to the maximum image size K, and calculates the enlargement ratio based further on the maximum image size K.

  In the present embodiment, the enlargement ratio calculation unit 60 calculates the enlargement ratio so that the data amount (or the number of pixels) of the image after enlargement is equal to or less than K. More specifically, R = K / T, where R is an enlargement factor such that the image after enlargement is K or less, and T is the size of the input image. Therefore, the enlargement factor calculation unit 60 calculates the enlargement factor according to the following equation.

  Magnification rate U = min (P, Q, R) (4)

Next, an image processing apparatus 10 according to a fourth embodiment of the present invention will be described.
The image processing apparatus 10 according to the present embodiment is different from the image processing apparatus 10 according to the first to third embodiments in that the enlargement ratio is calculated based on the data amount of the output image.

FIG. 14 is a diagram showing a functional configuration of the image processing program 7 executed by the control device 12 of the image processing apparatus 10 according to the fourth embodiment of the present invention.
As illustrated in FIG. 14, the image processing program 7 has a configuration in which an enlargement ratio correction unit 70 and a data amount determination unit 72 are added to the image processing program 4 (FIG. 6). 14 that are substantially the same as those shown in FIG. 6 are denoted by the same reference numerals.

  In the image processing program 7, the data amount determination unit 72 determines the data amount of the output image. More specifically, the data amount determination unit 72 determines whether or not the data amount of the output image generated by the outliner 42 is equal to or less than a desired data amount. When the data amount of the output image exceeds the desired data amount, the data amount determination unit 72 outputs a signal for correcting the enlargement rate to the enlargement rate correction unit 70. The desired data amount may be stored in advance in at least one of the memory 16 and the storage device 20, may be input via the UI device 22, or transmitted via the communication device 18. Also good.

  When the enlargement rate correction unit 70 receives a signal from the data amount determination unit 72 that the output image data amount exceeds the desired data amount, the enlargement rate correction unit 70 calculates the enlargement rate based on the output image data amount and the desired data amount. Correction is performed, and the corrected enlargement ratio is output to the enlargement unit 40. More specifically, the enlargement ratio correction unit 70 corrects the enlargement ratio by applying a nonlinear optimization method such as a Newton method based on the difference between the data amount of the output image and the desired data amount. Note that the method applied to the correction is not particularly limited, and a steepest descent method, a gradient method, or the like may be used.

  When the enlargement factor is corrected by the enlargement factor correction unit 70, the enlargement unit 40 enlarges the binary image based on the corrected enlargement factor and outputs the enlarged binary image to the outliner 42.

FIG. 15 is a diagram showing a flowchart of the overall operation (S40) of image processing by the image processing program 7. Note that, among the processes shown in FIG. 15, substantially the same processes as those shown in FIG. 10 are denoted by the same reference numerals.
As shown in FIG. 15, when a binary image is received in the process of S200, an image enlargement process (S10; FIG. 9) is executed by the enlargement unit 40, and in the process of S202, the enlarged binary image is converted into an outline unit. An output image is generated by being outlined by 42.

  In step 400 (S400), the data amount determination unit 72 determines whether or not the data amount of the output image generated by the outline forming unit 42 is equal to or less than a desired data amount. If the data amount of the output image is less than or equal to the desired data amount, the image processing program 7 ends the process, and otherwise proceeds to the process of S402.

  In step 402 (S402), the enlargement ratio correction unit 70 corrects the enlargement ratio based on the data amount of the output image and the desired data amount. When the enlargement ratio is corrected, the image processing program 7 returns to the image enlargement process (S10).

Next, an image processing apparatus 10 according to a fifth embodiment of the present invention will be described.
The image processing apparatus 10 according to the present embodiment is different from the image processing apparatus 10 according to the fourth embodiment in that the parameters used in the outlining are corrected based on the data amount of the output image.

FIG. 16 is a diagram showing a functional configuration of the image processing program 8 executed by the control device 12 of the image processing apparatus 10 according to the fifth embodiment of the present invention.
As shown in FIG. 16, the image processing program 8 has a configuration in which the enlargement factor correction unit 70 of the image processing program 7 (FIG. 14) is replaced with an outline coefficient correction unit 80. Note that, among the components shown in FIG. 16, the same components as those shown in FIG. 14 are denoted by the same reference numerals.

In the image processing program 8, when the outlining coefficient correction unit 80 receives a signal indicating that the data amount of the output image exceeds the desired data amount from the data amount determination unit 72, the data amount of the output image and the desired data amount Based on the above, the outlining parameter is corrected, and the corrected outlining parameter is output to the outlining unit. More specifically, the outline factor correction unit 80 corrects the enlargement ratio by applying a nonlinear optimization method such as Newton's method based on the difference between the data amount of the output image and the desired data amount. Here, the outline parameter to be corrected is, for example, the above-described θ ₅ or the like.

  When the outlining parameter is corrected by the outlining coefficient correction unit 80, the outlining unit 42 outlines the enlarged binary image based on the corrected outlining parameter, and generates an output image.

FIG. 17 is a diagram illustrating a flowchart of the overall operation (S50) of image processing by the image processing program 8. Note that, among the processes shown in FIG. 17, substantially the same processes as those shown in FIG. 15 are denoted by the same reference numerals.
As illustrated in FIG. 17, when it is determined in step S400 that the output image data amount exceeds the desired data amount, in step 500 (S500), the outlining coefficient correction unit 80 determines the output image data amount. And outlining parameters are corrected based on the desired amount of data. When the outlining parameter is corrected, the image processing program 8 returns to the process of S202.

Next, an image processing apparatus 10 according to a sixth embodiment of the present invention will be described.
The image processing apparatus 10 according to the present embodiment is the image processing apparatus according to the first embodiment to the fifth embodiment in that a resolution conversion process is performed on the multi-valued image after the binary image is multi-valued. Different from 10.

FIG. 18 is a diagram showing a detailed functional configuration of the enlargement unit 40 of the image processing program in the sixth embodiment of the present invention.
As illustrated in FIG. 18, the enlargement unit 40 includes a multi-value conversion unit 420, a resolution conversion unit 422, and a binarization unit 424.

  In the enlargement unit 40, the multi-value conversion unit 420 receives a binary input image, performs multi-value conversion processing (gradation number increase processing) on the input image, converts the input image into a multi-value image, and converts the multi-value image into the multi-value image. The data is output to the resolution conversion unit 422. For example, the multilevel conversion unit 420 converts the pixel value 0 to 0 and the pixel value 1 to 255 for each pixel of the input image.

  The resolution conversion unit 422 converts the resolution of the multi-value image multi-valued by the multi-value conversion unit 420 based on a predetermined enlargement ratio. The resolution conversion unit 422 enlarges the multi-valued image using a technique such as linear interpolation or cubic convolution, for example.

  The binarization unit 424 binarizes the multi-value image whose resolution is converted by the resolution conversion unit 422 and generates an enlarged binary image. For example, the binarization unit 424 binarizes the multi-valued image using the pixel value 128 as a threshold value.

It is a figure which shows the relationship between the resolution conversion process and the image quality after outline-izing. It is a figure explaining the high resolution process by a super-resolution system. It is a figure which illustrates the relationship between an enlargement rate and the data amount of the produced | generated image. FIG. 4A illustrates an image obtained by outlining a binary image. FIG. 4A illustrates an image obtained by outlining a scanned image as it is, and FIG. 4B illustrates a scan. It is a figure which illustrates the image obtained by performing the high resolution process with respect to the performed image, and making it outline. It is a figure which shows the hardware constitutions of the image processing apparatus 10 which concerns on embodiment of this invention centering on the control apparatus 12. FIG. It is a figure which shows the function structure of the image processing program 4 performed by the control apparatus 12 of the image processing apparatus 10 which concerns on the 1st Embodiment of this invention. 3 is a diagram illustrating a detailed functional configuration of an enlargement unit 40 of the image processing program 4. FIG. It is a figure explaining the production | generation process of the high resolution partial image by the high resolution partial image generation part 406. FIG. It is a figure which shows the flowchart of the image expansion process (S10) by the expansion part 40. FIG. It is a figure which shows the flowchart of the whole operation | movement (S20) of the image processing by the image processing program 4. It is a figure which shows the function structure of the image processing program 5 performed by the control apparatus 12 of the image processing apparatus 10 which concerns on the 2nd Embodiment of this invention. It is a figure which shows the flowchart of the whole operation | movement (S30) of the image processing by the image processing program 5. It is a figure which shows the function structure of the image processing program 6 performed by the control apparatus 12 of the image processing apparatus 10 which concerns on the 3rd Embodiment of this invention. It is a figure which shows the function structure of the image processing program 7 performed by the control apparatus 12 of the image processing apparatus 10 which concerns on the 4th Embodiment of this invention. It is a figure which shows the flowchart of the whole operation | movement (S40) of the image processing by the image processing program 7. It is a figure which shows the function structure of the image processing program 8 performed by the control apparatus 12 of the image processing apparatus 10 which concerns on the 5th Embodiment of this invention. It is a figure which shows the flowchart of the whole operation | movement (S50) of the image processing by the image processing program 8. It is a figure which shows the detailed functional structure of the expansion part 40 of the image processing program in the 6th Embodiment of this invention.

Explanation of symbols

4 Image Processing Program 5 Image Processing Program 6 Image Processing Program 7 Image Processing Program 8 Image Processing Program 10 Image Processing Device 12 Control Device 14 CPU
16 memory 18 communication device 20 storage device 22 UI device 40 enlargement unit 42 outline conversion unit 50 enlargement rate calculation unit 60 enlargement rate calculation unit 70 enlargement rate correction unit 72 data amount determination unit 80 outline conversion coefficient correction unit 400 partial image cutout unit 402 Similar partial image extraction unit 404 Center of gravity calculation unit 406 High resolution partial image generation unit 408 Position calculation unit 410 High resolution partial image arrangement unit 420 Multi-value conversion unit 422 Resolution conversion unit 424 Binarization unit

Claims (12)

Image enlarging means for enlarging a binary image;
An image processing apparatus comprising: an outline forming unit configured to outline an image enlarged by the image enlargement unit. The image enlargement means includes
Partial image extraction means for extracting a similar partial image from a binary image at a first resolution;
Based on the partial image extracted by the partial image extraction means and the phase of the partial image image calculated with higher accuracy than one pixel at the first resolution, the portion having the second resolution higher than the first resolution Partial image generation means for generating an image;
An arrangement unit that arranges the partial image generated by the partial image generation unit at a position in an image of the second resolution calculated based on the position of the partial image extracted by the partial image extraction unit. The image processing apparatus according to 1. The image enlargement means includes
A multi-value quantization means for multi-value a binary image;
Resolution conversion means for converting the resolution of an image multi-valued by the multi-value conversion means;
The image processing apparatus according to claim 1, further comprising: binarization means for binarizing an image whose resolution has been converted by the resolution conversion means. It further has an enlargement ratio calculating means for calculating an enlargement ratio based on the resolution of the read image,
The image processing apparatus according to claim 1, wherein the image enlargement unit enlarges an image based on the enlargement rate calculated by the enlargement rate calculation unit. The image processing apparatus according to claim 4, wherein the enlargement ratio calculating unit calculates the enlargement ratio based on a ratio between the resolution of the read image and the resolution of the print image. The image processing apparatus according to claim 4, wherein the enlargement ratio calculating unit sets the enlargement ratio to 1 or more. The image processing apparatus according to claim 4, wherein the enlargement ratio calculating unit sets the enlargement ratio to 16 or less. The image processing apparatus according to claim 4, wherein the enlargement ratio calculating unit calculates the enlargement ratio so that the number of pixels of the image is equal to or less than a predetermined value. The image processing apparatus according to claim 1, further comprising a data amount determination unit that determines a data amount of the image outlined by the outline conversion unit. An enlargement ratio that corrects the enlargement ratio based on the data amount of the image outlined by the outliner and the predetermined data amount when the data amount determiner determines that the image data amount exceeds a predetermined value It further has a correction means,
The image processing apparatus according to claim 9, wherein the image enlargement unit enlarges an image based on the enlargement rate corrected by the enlargement rate correction unit. When the data amount determining unit determines that the image data amount exceeds a predetermined value, the parameter in the outline processing is corrected based on the data amount of the image outlined by the outline generating unit and the predetermined data amount. Further comprising an outlining parameter correction means for
The image processing apparatus according to claim 9 or 10, wherein the outliner enlarges an image based on the outline parameter corrected by the outline parameter corrector. Place it on an image processing device, including a computer,
An image enlargement step for enlarging the binary image;
A program for causing a computer of the image processing apparatus to execute an outline step for outlining the enlarged image.

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