JP2007228611A - Image processor, image processing method and computer-readable recording medium stored with program for making computer execute the same method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently achieve input density correction, density correction interlocked with density notch, and write density correction. <P>SOLUTION: Input density correction by an input density correction part 103 and density correction by a density correction part 106 and write density correction by a write control block 110 are each controlled independently, in response to the operation of a user. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image processing apparatus that optically reads image data of an original by an image reading unit such as a scanner and writes the read image data onto a recording sheet by a writing unit such as a printer. The present invention relates to an image processing apparatus, an image processing method, and a recording medium that can efficiently perform density correction and writing density correction linked to the recording medium.

  2. Description of the Related Art Conventionally, an apparatus having an image reading unit such as a copy, a scanner, and a facsimile, and an apparatus having a printing unit such as a printer have been widely used. Has also appeared.

  These devices employ various density conversion methods, and more specifically, input density correction that corrects density characteristics depending on the image reading unit by expanding the signal level of the image read by the image reading unit. Technology (hereinafter referred to as “input density correction”), density correction technology in the electrical domain that increases or decreases the print density in conjunction with the density notch operation by the user (hereinafter “density correction linked to the density notch”) And a correction technique (hereinafter referred to as “writing density correction”) for adjusting the component level in the printing unit.

  For example, Japanese Patent Laid-Open No. 9-224155 provides density conversion means for converting the density of image data into a digital signal according to different conversion methods, and density conversion means according to the detection result of the density distribution range of the image data. An image processing apparatus configured to convert the image is disclosed.

  This prior art is a technology that makes it easy to handle originals with various features, such as originals with dark backgrounds, originals with thin text, graphs on graph paper, photographs, drawings, etc. This corresponds to the input density correction. Note that the input density correction and the density correction linked to the density notch are normally integrated and made, and the writing density correction is not based on a user operation.

  However, this conventional technique is merely for performing input density correction in the image input section, and does not perform density correction linked to the density notch or write density correction in the printing section. However, a good image output is not always obtained.

  For example, when a multifunction machine employing this conventional technique operates as a printer rather than as a copy, image data that does not pass through the image reading unit is printed by the printing unit. The density is not corrected. Further, when such a multi-function peripheral operates as a copy, even if the background stain is eliminated by the input density correction, the output image may become unintended due to the light emission characteristics in the printing unit.

  For these reasons, in printers, copiers, scanners, facsimiles or multifunction devices, how to efficiently perform input density correction, density correction linked to density notches, and writing density correction, in other words, density correction. It is extremely important to optimize the system.

  The present invention has been made to solve the above-described problems (problems) of the prior art, and is an image processing apparatus capable of efficiently performing input density correction, density correction linked to a density notch, and writing density correction. An object of the present invention is to provide an image processing method and a computer-readable recording medium on which a program for causing a computer to execute the method is recorded.

  In order to solve the above-described problems and achieve the object, an image processing apparatus according to a first aspect of the present invention optically reads image data of a document by an image reading unit, and records the read image data by a writing unit. In the image processing apparatus for writing to the image processing apparatus, a first density correction unit that corrects density characteristics depending on the image reading unit, a second density correction unit that corrects reproduction characteristics of document density, and a density that depends on the writing unit. And a third density correction unit that corrects the characteristics; and a control unit that independently controls the first density correction unit, the second density correction unit, and the third density correction unit. .

  According to the first aspect of the present invention, the correction of the density characteristic depending on the image reading unit, the correction of the reproduction characteristic of the original density, and the correction of the density characteristic depending on the writing unit are controlled independently. It is possible to efficiently perform density correction, density correction linked with density notch, and writing density correction.

  According to a second aspect of the present invention, in the image processing apparatus according to the first aspect of the present invention, the control means performs a data correction according to a density level and a switching means for switching a filter coefficient according to an input density of the image data. Data correction means and dot correction means for correcting formation of writing dots are provided.

  According to the second aspect of the present invention, the filter coefficient is switched according to the input density of the image data, and the data correction according to the density level and the correction of the writing dot formation are performed. Gradation reproduction can be performed.

  According to a third aspect of the present invention, there is provided an image processing apparatus for optically reading image data of an original by an image reading unit and correcting the density of the read image data. The density depends on the image reading unit. First density correction means for correcting the characteristics, second density correction means for correcting the reproduction characteristics of the original density, and control means for independently controlling the first density correction means and the second density correction means. , Provided.

  According to the third aspect of the present invention, since the correction of the density characteristic depending on the image reading unit and the correction of the reproduction characteristic of the original density are controlled independently, the input density correction and the density correction linked to the density notch are performed. Can be performed efficiently.

  According to a fourth aspect of the present invention, in the image processing apparatus according to the third aspect of the present invention, the control means performs a data correction according to a density level and a switching means for switching a filter coefficient according to an input density of the image data. And a data correction means.

  According to the invention of claim 4, since the filter coefficient is switched according to the input density of the image data and the data correction is performed according to the density level, gradation reproduction is performed over a wide range from the low density part to the high density part. be able to.

  According to a fifth aspect of the present invention, there is provided an image processing apparatus according to a fifth aspect, wherein the image processing apparatus writes image data onto a recording sheet by a writing unit, and the third density correcting unit corrects density characteristics depending on the writing unit. And a control means for controlling the density correction means.

  According to the fifth aspect of the present invention, since the density characteristic depending on the writing unit is corrected and controlled, the writing density correction can be performed efficiently.

  An image processing apparatus according to a sixth aspect of the present invention is the image processing apparatus according to the fifth aspect, wherein the control means includes dot correction means for correcting formation of a writing dot.

  According to the sixth aspect of the present invention, since the formation of the writing dot is corrected, it is possible to reproduce the gradation of a sharp character or image.

  According to a seventh aspect of the present invention, in the image processing apparatus according to the second or fourth aspect of the present invention, the switching means is divided into a low density portion, a high density portion, and an intermediate area based on a predetermined threshold value, and is independent of each other. And a selection means for setting a correction coefficient and selecting a density range selection signal.

  According to the seventh aspect of the present invention, the density range selection signal is selected by dividing the low density area, the high density area, and the intermediate area based on a predetermined threshold value, and independently setting the correction coefficient. Therefore, image data having different feature amounts such as a low-density character image and a high-density solid image can be made into a uniform output image.

  An image processing apparatus according to an eighth aspect of the present invention is the image processing apparatus according to the second or fourth aspect, wherein the data correction unit arbitrarily sets a signal different from the image data and adds or subtracts the signal. A key reproduction process is performed.

  According to the eighth aspect of the present invention, the tone reproduction process is performed after arbitrarily setting and adding or subtracting a signal different from the image data. Can be improved.

  According to a ninth aspect of the present invention, in the image processing apparatus according to the second or sixth aspect of the present invention, the dot correction means performs two-dimensional data correction of adjacent pixels based on a pixel arrangement. .

  According to the ninth aspect of the invention, since the data correction of the adjacent pixels is performed two-dimensionally based on the pixel arrangement, the dot that can faithfully reproduce the electrical output signal in consideration of the characteristics of the writing unit. The shape can be corrected.

  An image processing apparatus according to a tenth aspect of the present invention is the image processing apparatus according to the first, third, or fifth aspect, further comprising image quality selection means for selecting a type of image quality processing, wherein the control means is selected by the image quality selection means. The first density correction unit, the second density correction unit, and / or the third density correction unit are independently controlled based on the type of image quality processing performed.

  According to the tenth aspect of the present invention, the type of image quality processing is selected, and the first density correction unit, the second density correction unit and / or the third density correction unit is selected based on the selected type of image quality processing. Therefore, it is possible to perform various density corrections only by selecting the image quality.

  An image processing apparatus according to an eleventh aspect of the present invention is the image processing apparatus according to the tenth aspect of the present invention, wherein the image quality selection means includes a grouping means for grouping processing content settings and a setting grouped by the grouping means. And assigning means for arbitrarily assigning the procedure.

  According to the eleventh aspect of the invention, since the setting of processing contents is grouped and the grouped setting procedure is arbitrarily assigned, desired image quality can be reproduced with a simple procedure for the operator. .

  An image processing apparatus according to a twelfth aspect of the invention according to the eleventh aspect, wherein the arbitrarily assigning means arbitrarily selects a mode for normal use from a plurality of existing image quality modes; Correction means for correcting the image quality characteristics, means for changing the correction value of the image quality characteristics corrected by the correction means to an arbitrary value, and means for storing the correction value of the changed image quality characteristics Features.

  According to the twelfth aspect of the present invention, image quality parameters such as density characteristics and filter characteristics are provided as a set in advance as an image quality mode, and a user can select a necessary mode or use it as a reference for correction. The operability seen from the user can be greatly improved.

  The image processing apparatus according to a thirteenth aspect is the invention according to the eleventh aspect, wherein the means for arbitrarily assigning means for arbitrarily setting a mode for normal use from a plurality of existing image quality modes; A correction unit that corrects the image reading characteristic; a unit that changes the correction value of the image reading characteristic corrected by the correction unit to an arbitrary value; and a unit that stores the correction value of the changed image reading characteristic. It is characterized by that.

  According to the invention of claim 13, image quality parameters such as density characteristics and filter characteristics are provided as a set in advance as an image quality mode, and a user can select a necessary mode or use it as a reference for correction. The operability seen from the user can be greatly improved.

  The image processing apparatus according to a fourteenth aspect is the image processing apparatus according to the eleventh aspect, wherein the arbitrarily assigning means arbitrarily sets a mode for normal use from among a plurality of existing image quality modes; Correction means for correcting pixel generation characteristics; means for changing a correction value of the pixel generation characteristics corrected by the correction means to an arbitrary value; and means for storing the correction value of the changed pixel generation characteristics. It is characterized by that.

  According to the fourteenth aspect of the present invention, image quality parameters such as density characteristics and filter characteristics are provided as a set in advance as an image quality mode, and a user can select a necessary mode or use it as a correction reference. The operability seen from the user can be greatly improved.

  In the image processing apparatus according to claim 15, in the invention according to claim 11, the means for arbitrarily assigning is a means for arbitrarily setting a mode for normal use from a plurality of existing image quality modes, Correction means for correcting the image quality characteristics, means for changing the correction value of the image quality characteristics corrected by the correction means relative to a value once set, and the correction value of the changed image quality characteristics And means for storing.

  According to the fifteenth aspect of the present invention, image quality parameters such as density characteristics and filter characteristics are provided as a set in advance as an image quality mode, a necessary mode can be selected or used by a user as a reference for correction, and In particular, when performing corrections when changes to settings are required, each adjustment value can be adjusted by increasing or decreasing the current setting value, greatly improving operability from the user's perspective. it can.

  An image processing apparatus according to a sixteenth aspect is the image processing apparatus according to the eleventh aspect, wherein the arbitrarily assigning means arbitrarily sets a mode for normal use from a plurality of existing image quality modes; Correction means for correcting the image reading characteristics; means for changing the correction value of the image reading characteristics corrected by the correcting means relative to a temporarily set value; and And a means for storing the correction value.

  According to the invention of claim 16, image quality parameters such as density characteristics and filter characteristics are provided as a set in advance as an image quality mode, a necessary mode can be selected or used by a user as a correction reference, and In particular, when performing corrections when changes to settings are required, each adjustment value can be adjusted by increasing or decreasing the current setting value, greatly improving operability from the user's perspective. it can.

  The image processing apparatus according to claim 17 is the image processing apparatus according to claim 11, wherein the means for arbitrarily assigning is a means for arbitrarily setting a mode for normal use from a plurality of existing image quality modes; Correction means for correcting pixel generation characteristics; means for changing a correction value of the pixel generation characteristics corrected by the correction means relative to a temporarily set value; and And a means for storing the correction value.

  According to the invention of claim 17, image quality parameters such as density characteristics and filter characteristics are provided as a set in advance as an image quality mode, a necessary mode can be selected, or a user can use it as a reference for correction, and In particular, when performing corrections when changes to settings are required, each adjustment value can be adjusted by increasing or decreasing the current setting value, greatly improving operability from the user's perspective. it can.

  The image processing method according to claim 18 is an image processing method in which image data of an original is optically read by an image reading unit, and the read image data is written on a recording sheet by a writing unit. A first density correction step for correcting density characteristics depending on the density, a second density correction step for correcting reproduction characteristics of the original density, and a third density correction process for correcting density characteristics depending on the writing unit. And a control step of independently controlling corrections by the first density correction step, the second density correction step, and the third density correction step.

  According to the eighteenth aspect of the present invention, the correction of the density characteristic depending on the image reading unit, the correction of the reproduction characteristic of the original density and the correction of the density characteristic depending on the writing unit are controlled independently. It is possible to efficiently perform density correction, density correction linked with density notch, and writing density correction.

  The image processing method according to the invention of claim 19 is the image processing method according to claim 18, wherein the control step performs a switching step of switching a filter coefficient according to the input density of the image data, and performs data correction according to the density level. It includes a data correction step and a dot correction step for correcting the formation of writing dots.

  According to the nineteenth aspect of the present invention, the filter coefficient is switched according to the input density of the image data, and the data correction according to the density level and the correction of the writing dot formation are performed. Gradation reproduction can be performed.

  An image processing method according to a twentieth aspect of the present invention is an image processing method for optically reading image data of a document by an image reading unit and correcting the density of the read image data. The density depends on the image reading unit. The first density correction process for correcting the characteristics, the second density correction process for correcting the reproduction characteristics of the original density, and the correction by the first density correction process and the second density correction process are independently controlled. And a control process.

  According to the twentieth aspect of the invention, the correction of the density characteristic depending on the image reading unit and the correction of the reproduction characteristic of the original density are controlled independently, so that the input density correction and the density correction linked with the density notch are performed. Can be performed efficiently.

  According to a twenty-first aspect of the present invention, in the image processing method according to the first aspect of the invention, the control step performs a switching step of switching a filter coefficient according to an input density of the image data, and performs data correction according to the density level. And a data correction step.

  According to the twenty-first aspect of the present invention, since the filter coefficient is switched according to the input density of the image data and the data correction is performed according to the density level, gradation reproduction is performed over a wide range from the low density portion to the high density portion. be able to.

  An image processing method according to a twenty-second aspect of the present invention is the image processing method in which image data is written on a recording sheet by a writing unit, and a third density correction step for correcting density characteristics depending on the writing unit, And a control step of independently controlling the density correction step.

  According to the twenty-second aspect of the present invention, the density characteristic depending on the writing unit is corrected and controlled, so that the writing density correction can be performed efficiently.

  An image processing method according to a twenty-third aspect of the present invention is the image processing method according to the twenty-second aspect, characterized in that the control step includes a dot correction step of correcting formation of writing dots.

  According to the twenty-third aspect of the present invention, since the formation of the writing dot is corrected, it is possible to reproduce the gradation of a sharp character or image.

  The image processing method according to a twenty-fourth aspect of the present invention is the image processing method according to the nineteenth or twenty-first aspect, wherein the switching step is divided into a low density portion, a high density portion, and an intermediate area based on a predetermined threshold value. And a correction step of selecting a density range selection signal.

  According to the twenty-fourth aspect of the present invention, the density range selection signal is selected by dividing the low density part, the high density part, and the intermediate area based on a predetermined threshold value, and setting the correction coefficient independently of each other. Therefore, image data having different feature amounts such as a low-density character image and a high-density solid image can be made into a uniform output image.

  The image processing method according to the invention of claim 25 is the image processing method according to claim 19 or 21, wherein the data correction step arbitrarily sets a signal different from the image data, adds or subtracts, and A key reproduction process is performed.

  According to the invention of claim 25, since the tone reproduction process is performed after arbitrarily setting a signal different from the image data and adding or subtracting it, the continuity in the uniform image in the low density portion is performed. Can be improved.

  An image processing method according to a twenty-sixth aspect of the present invention is the image processing method according to the nineteenth or twenty-third aspect, wherein the dot correction step performs two-dimensional data correction of adjacent pixels based on a pixel array. .

  According to the twenty-sixth aspect of the present invention, since the data correction of the adjacent pixels is performed two-dimensionally based on the pixel arrangement, the dot that can faithfully reproduce the electrical output signal in consideration of the characteristics of the writing unit. The shape can be corrected.

  An image processing method according to a twenty-seventh aspect of the present invention is the image processing method according to the eighteenth, twentieth or twenty-second aspect of the present invention, further comprising an image quality selection step of selecting a type of image quality processing, and the control step is selected by the image quality selection step. The correction by the first density correction process, the second density correction process and / or the third density correction process is independently controlled based on the type of the image quality processing performed.

  According to the twenty-seventh aspect of the present invention, the type of image quality processing is selected, and the first density correction step, the second density correction step, and / or the third density correction step is performed based on the selected type of image quality processing. Therefore, various density corrections can be performed only by selecting the image quality.

  The image processing method according to a twenty-eighth aspect of the present invention is the image processing method according to the twenty-seventh aspect of the present invention, wherein the image quality selecting step includes a grouping step for grouping processing content settings and a grouping by the grouping step And an assigning step for arbitrarily assigning the procedure.

  According to the twenty-eighth aspect of the present invention, since the setting of processing contents is grouped and the grouped setting procedure is arbitrarily assigned, desired image quality can be reproduced with a simple procedure for the operator. .

  A recording medium according to the invention of claim 29 records a program for causing a computer to execute the method according to any one of claims 18 to 28, so that the program can be read by a machine. The operation according to any one of claims 18 to 28 can be realized by a computer.

  An image processing system according to a thirty-third aspect of the invention is an image processing system in which image data of an original is optically read by an image reading unit, and the read image data is written on a recording sheet by a writing unit. A first density correction unit that corrects density characteristics depending on the density, a second density correction unit that corrects reproduction characteristics of document density, and a third density correction unit that corrects density characteristics that depend on the writing unit. And a control means for independently controlling the first density correction means, the second density correction means, and the third density correction means.

  According to the invention of claim 30, the correction of the density characteristic depending on the image reading unit, the correction of the reproduction characteristic of the original density and the correction of the density characteristic depending on the writing unit are controlled independently. It is possible to efficiently perform density correction, density correction linked with density notch, and writing density correction.

  According to the first aspect of the present invention, the correction of the density characteristic depending on the image reading unit, the correction of the reproduction characteristic of the original density, and the correction of the density characteristic depending on the writing unit are controlled independently. There is an effect that an image processing apparatus capable of efficiently performing the correction, the density correction linked to the density notch, and the writing density correction can be obtained.

  According to the second aspect of the present invention, the filter coefficient is switched according to the input density of the image data, and the data correction according to the density level and the correction of the writing dot formation are performed. Therefore, from the low density part to the high density part. There is an effect that an image processing apparatus capable of reproducing gradations over a wide range can be obtained.

  According to the third aspect of the present invention, the correction of the density characteristic depending on the image reading unit and the correction of the original density reproduction characteristic are independently controlled. There is an effect that an image processing apparatus capable of performing correction efficiently can be obtained.

  According to the invention of claim 4, since the filter coefficient is switched according to the input density of the image data and the data correction is performed according to the density level, gradation reproduction is performed over a wide range from the low density part to the high density part. There is an effect that an image processing apparatus capable of performing the operation is obtained.

  According to the fifth aspect of the present invention, since the density characteristic depending on the writing section is corrected and controlled, an image processing apparatus capable of performing the writing density correction efficiently can be obtained.

  According to the sixth aspect of the present invention, since it is configured to correct the formation of writing dots, it is possible to obtain an image processing apparatus that can reproduce gradations of sharp characters and images.

  According to the seventh aspect of the present invention, it is configured to divide into a low density part, a high density part, and an intermediate area based on a predetermined threshold value, independently set a correction coefficient, and select a density range selection signal. Therefore, there is an effect that an image processing apparatus capable of obtaining image data having different feature amounts such as a low-density character image and a high-density solid image as a uniform output image can be obtained.

  According to the invention of claim 8, since the gradation reproduction process is performed after arbitrarily setting a signal different from the image data and adding or subtracting the signal, the continuous reproduction in the uniform image of the low density portion is performed. It is possible to obtain an image processing apparatus capable of improving the performance.

  According to the ninth aspect of the present invention, since data correction of adjacent pixels is performed two-dimensionally based on the pixel arrangement, the electrical output signal can be faithfully reproduced in consideration of the characteristics of the writing unit. There is an effect that an image processing apparatus capable of correcting the shape of the dots can be obtained.

  According to the invention of claim 10, the type of image quality processing is selected, and the first density correction means, the second density correction means and / or the third density correction is selected based on the selected type of image quality processing. Since the means is controlled independently, there is an effect that an image processing apparatus capable of performing various density corrections only by selecting the image quality can be obtained.

  According to the eleventh aspect of the present invention, since the processing content settings are grouped and the grouped setting procedures are arbitrarily assigned, it is possible to reproduce desired image quality with a simple procedure for the operator. There is an effect that a possible image processing apparatus is obtained.

  According to the twelfth aspect, a mode for normal use can be arbitrarily selected from a plurality of existing image quality modes, the image quality characteristic can be changed to an arbitrary correction value, and correction of the changed image quality characteristic can be performed. Since the configuration is such that the value can be stored, the user can greatly improve the operability by selecting a necessary mode or using it as a reference for correction.

  According to the thirteenth aspect, a mode for normal use can be arbitrarily selected from a plurality of existing image quality modes, the image reading characteristic can be changed to an arbitrary correction value, and the changed image reading characteristic can be changed. Therefore, the user can greatly improve the operability by selecting a necessary mode or using it as a reference for correction.

  According to the fourteenth aspect, a mode for normal use can be arbitrarily selected from a plurality of existing image quality modes, the pixel generation characteristic can be changed to an arbitrary correction value, and the changed pixel generation characteristic can be changed. Therefore, the user can greatly improve the operability by selecting a necessary mode or using it as a reference for correction.

  According to the fifteenth aspect, a mode for normal use is arbitrarily set from a plurality of existing image quality modes, and the correction of the image quality characteristics is made relative to the correction value once set. And the correction value of the changed image quality characteristic can be saved, so that the user can select a necessary mode or use it as a reference for correction, When correction is made when the contents need to be changed, each adjustment value can be adjusted by increasing or decreasing the value with respect to the current set value, and the operability from the viewpoint of the user can be greatly improved.

  According to the sixteenth aspect, a mode for normal use is arbitrarily set from among a plurality of existing image quality modes, and correction of image reading characteristics is made relative to a correction value that has been set once. And the correction value of the changed image reading characteristic can be stored. Therefore, the user selects a necessary mode or used by the user as a reference for correction, and in particular, When correction is made when the setting contents need to be changed, each adjustment value can be adjusted by increasing / decreasing the value with respect to the current setting value, and the operability from the viewpoint of the user can be greatly improved.

  According to the seventeenth aspect, a mode for normal use is arbitrarily set from among a plurality of existing image quality modes, and pixel generation characteristics are corrected relative to a correction value once set. And the correction value of the changed pixel generation characteristic can be stored, so that the user can select a necessary mode or use it as a reference for correction, and in particular, When correction is made when the setting contents need to be changed, each adjustment value can be adjusted by increasing / decreasing the value with respect to the current setting value, and the operability from the viewpoint of the user can be greatly improved.

  According to the invention of claim 18, since the density characteristic correction dependent on the image reading unit, the original density reproduction characteristic correction and the density characteristic correction dependent on the writing unit are controlled independently, There is an effect that it is possible to obtain an image processing method capable of efficiently performing input density correction, density correction linked with density notch, and writing density correction.

  According to the nineteenth aspect of the present invention, the filter coefficient is switched according to the input density of the image data, and the data correction according to the density level and the correction of the writing dot formation are performed. Therefore, from the low density part to the high density part. There is an effect that an image processing method capable of performing gradation reproduction over a wide range can be obtained.

  According to the twentieth aspect of the present invention, the correction of the density characteristic depending on the image reading unit and the correction of the reproduction characteristic of the original density are controlled independently, so that the density linked with the input density correction and the density notch is controlled. There is an effect that an image processing method capable of performing correction efficiently can be obtained.

  According to the twenty-first aspect of the present invention, the filter coefficient is switched according to the input density of the image data, and the data correction is performed according to the density level, so that gradation reproduction can be performed over a wide range from the low density portion to the high density portion. There is an effect that an image processing method that can be performed is obtained.

  According to the twenty-second aspect of the present invention, since the density characteristic depending on the writing unit is corrected and controlled, an image processing method capable of efficiently performing the writing density correction is obtained.

  According to the twenty-third aspect of the present invention, since it is configured to correct the formation of writing dots, an image processing method capable of reproducing gradation of sharp characters and images can be obtained.

  According to a twenty-fourth aspect of the present invention, a configuration is provided in which a correction coefficient is set independently for each of a low density part, a high density part and an intermediate area based on a predetermined threshold value, and a density range selection signal is selected. Therefore, there is an effect that an image processing method capable of obtaining image data having different feature amounts such as a low-density character image and a high-density solid image as a uniform output image can be obtained.

  According to the invention of claim 25, since the gradation reproduction processing is performed after arbitrarily setting a signal different from the image data and adding or subtracting it, the continuous reproduction in the uniform image of the low density portion is performed. It is possible to obtain an image processing method capable of improving the performance.

  According to the invention of claim 26, since the data correction of the adjacent pixels is performed two-dimensionally based on the pixel arrangement, the electrical output signal can be faithfully reproduced in consideration of the characteristics of the writing unit. There is an effect that an image processing method capable of correcting the shape of the dots can be obtained.

  According to the twenty-seventh aspect of the present invention, the type of image quality processing is selected, and the first density correction step, the second density correction step, and / or the third density correction is performed based on the selected type of image quality processing. Since the process correction is controlled independently, an image processing method capable of performing various density corrections only by selecting an image quality can be obtained.

  According to the invention of claim 28, since the setting of processing contents is grouped and the grouped setting procedure is arbitrarily assigned, desired image quality can be reproduced with a simple procedure for the operator. There is an effect that a possible image processing method can be obtained.

  A recording medium according to the invention of claim 29 records a program for causing a computer to execute the method according to any one of claims 18 to 28, so that the program can be read by a machine. Thus, the recording medium capable of realizing the operation according to any one of claims 18 to 28 by a computer is obtained.

  According to the invention of claim 30, since the density characteristic correction dependent on the image reading unit, the original density reproduction characteristic correction and the density characteristic correction dependent on the writing unit are controlled independently, There is an effect that an image processing system capable of efficiently performing input density correction, density correction linked with density notch, and writing density correction can be obtained.

Exemplary embodiments of an image processing apparatus, an image processing method, and a computer-readable recording medium storing a program that causes a computer to execute the method will be described below in detail with reference to the accompanying drawings. . Embodiments 1 and 2 shown below show a case where the present invention is applied to a multifunction machine, and Embodiment 3 shows a case where the present invention is applied to a scanner.
(Embodiment 1)
FIG. 1 is a block diagram illustrating a configuration of the multifunction peripheral according to the first embodiment. The MFP 100 shown in FIG. 1 corrects density characteristics depending on image reading (input density correction), document density reproduction characteristics (density correction linked to density notches), and density characteristics dependent on writing units (writing). This is a multi-function machine that is configured to perform optimum density correction by controlling density correction independently.

  That is, in the conventional multifunction peripheral, the input density correction and the density correction linked to the density notch are normally handled as one body. However, in the multifunction peripheral according to the first embodiment, these density corrections can be independently controlled. I am doing so. In the conventional multifunction peripheral, the user controls the writing density correction independently. However, in the multifunction peripheral according to the first embodiment, the user can actively change the writing density correction. Yes.

  For this reason, for example, it is possible to form an image having a desired density in conjunction with the density notch while removing stains on the background of the document, and to form a sharp image corresponding to the document type.

  As shown in the figure, the MFP 100 includes a document reading unit 101, a shading correction unit 102, an input density correction unit 103, a main scanning electric scaling unit 104, a spatial filter processing unit 105, and a density correction. Unit 106, gradation processing unit 107, matrix RAM 108, video path control unit 109, write control block 110, write unit 111, external application 112, external APL interface (I / F) 113, memory An interface (I / F) 114, a memory control unit 115, a printer page memory 116, a RAM 117, a ROM 118, a CPU 119, an operation unit 120, and a system bus 121 are included.

  The document reading unit 101 is a scanner that optically reads a document placed on a document table (not shown). Specifically, the document reading unit 101 reads a document density as reflected light of a light source, and uses an image pickup device such as a CCD as an electrical signal. And an analog signal into a digital signal.

  The shading correction unit 102 is a processing unit that corrects the density unevenness of the light source and the optical system included in the electrical signal after the digital signal conversion. Specifically, the shading correction unit 102 reads a white plate serving as a density reference in advance before reading a document, This read signal is stored in the memory, and correction is performed between the reference data and the read data in dot units for each read position in the main scanning direction.

  The input density correction unit 103 is a processing unit that performs density characteristic correction (input density correction) depending on the document reading unit 101. The input density correction unit 103 converts the shading-corrected digital signal having linear characteristics with respect to the reflectance with respect to the document density. Convert to linear characteristics.

  Specifically, the reading characteristics of the document reading unit 101 (scanner) are measured in advance, and a conversion table having the opposite characteristics is downloaded to the RAM 117, and the input density correction unit 103 performs density linearity by γ correction. To correct data. In addition to the linear density conversion, the input density correction unit 103 enhances the correction effect by correcting the low density part and conversely reducing the level.

  The main scanning electric zooming unit 104 is a processing unit that performs an electric zooming process in the main scanning direction, and performs enlargement and reduction for each line read by the CCD. Specifically, by using the convolution method, the scaling process is performed while maintaining the MTF in the reading optical system, and the resolution of the image data is maintained. In the sub-scanning direction, the scaling process is performed by mechanical control.

  The spatial filter processing unit 105 is a processing unit that performs preprocessing for gradation processing and extraction of feature amounts using the density adaptation processing unit 105a and the isolated point detection / correction processing unit 105b, and includes an MTF correction function and a smoothing function. , An edge line segment detection function, and a variation threshold setting function. The spatial filter processing unit 105 outputs filtered image data and a variation threshold for binarization calculated from the peripheral conditions.

  The density correction unit 106 is a processing unit that performs density correction in conjunction with the image data output from the spatial filter processing unit 105 and the fluctuation threshold value, and corrects the read original density and the reproduction density corresponding to the density notch. Perform the conversion.

  The density correction unit 106 can download arbitrary conversion data in the RAM 117. Specifically, the density correction unit 106 downloads image data and the same data for the variation threshold as a rule. Different data can be downloaded to intentionally change the characteristics.

  The gradation processing unit 107 is a processing unit that converts density data per pixel into area gradation and converts it into writing characteristics. Simple multi-value conversion, binarization, dither processing, error diffusion processing, It is formed by phase control or the like. Note that the conversion to area gradation means that the quantization threshold value is dispersed within a certain region, and this threshold value distribution is performed by downloading an arbitrary value to the matrix RAM 108 and switching the RAM access means in accordance with the processing mode. Choose an appropriate quantization.

  The writing control block 110 is a processing block that performs line image edge correction as a smoothing process, and includes a pixel correction unit 110a, a density conversion unit 110b, and a PWM modulation unit 110c.

  Prior to the PWM modulation process, the pixel correction unit 110a and the density conversion unit 110b perform a density conversion process in consideration of a rising characteristic with respect to an electric signal of an image forming process in order to improve the dot reproduction characteristic.

  The PWM modulation unit 110c is a processing unit that performs pulse width modulation for the writing laser. Specifically, the phase modulation in the gradation processing unit 107 and the phase control in the smoothing process by the pixel correction unit 110a are PWM modulated. By linking with, gradation reproduction with smooth dot aggregation and dispersion is performed.

  The writing unit 111 is a processing unit that reproduces an image on a transfer sheet by image formation, transfer, and fixing on a photoconductor with a laser. In the present embodiment, a laser printer is used as the writing system. However, when a developing method such as ink jet is used, the configurations of the PWM modulation unit 110c and the writing unit 111 are different. However, the same applies to smoothing and density conversion control for dot reproduction.

  Here, in this multifunction device 100, the operation unit performs density correction of the read original by the input density correction unit 103, density correction by the density correction unit 106, setting of gradation processing by the gradation processing unit 107, and density conversion of the writing control block. It can be controlled independently by operation from 120.

  Specifically, the processing mode can be selected on the operation unit 120 according to the type of original such as a picture-based original or a character-based original, and the density according to the original density of a thin original or a dark original. Correction parameters can be set and changed. In actual system control, the operation mode of the operation unit 120 is stored in the RAM 117 via the CPU 119 and the system bus 121, and the storage content of the RAM 117 is set in each function unit.

  The video path control unit 109 is a mechanism for performing path control of the flow of each image signal, and the physical configuration is combined into one, but is logically divided and controlled. Specifically, the video path control unit 109 controls the signal of the scanner system that is a read image. When the A / D conversion level after the CCD reading is 8 bits, the video bit control unit 109 uses the bit width as it is. Perform path control.

  The video path control unit 109 also performs path control via the external APL interface (I / F) 113 to the scanner application as the external application (external application) 112.

  Further, the video path control unit 109 controls the data path after the image quality processing. In this image quality processing, the video path control unit 109 converts the bit width into a binary / multi-value bit width and performs control so as to adapt to the bus width. Although the input / output signal of the external application 112 is also controlled, the facsimile transmission / reception and the print output request from the personal computer are composed of binary images.

  The video path control unit 109 also controls data storage or data reading in the printer page memory 116 via the memory interface (I / F) 114 that performs compression / decompression and the memory control unit 115. At this time, data transfer is performed with a bit configuration that matches the write characteristics.

  The external APLI / F 113 controls an interface signal with an externally connected external application (application unit), and transmits a facsimile, a print request from a personal computer, an image output request as a scanner, or an output from the personal computer by facsimile. Perform path control.

  Next, scanner γ correction and read original density correction shown in FIG. 1 will be described. FIG. 2 is an explanatory diagram for explaining the scanner γ correction and the density correction of the read original. FIG. 2A shows the scanner γ correction, and FIG. 2B shows the density correction of the read original. The conversion table is shown.

  A density characteristic 201 shown in FIG. 6A shows the conversion characteristic of image data after shading correction with respect to the original density, but is not a linear curve as is apparent from FIG. Looking at this density characteristic 201, it rises abruptly in the low density part, but is saturated in the electrical signal in the high density part, which is a general characteristic of Exp (γ).

  In order to change this to a density linear signal, the signal is converted into a density linear space by multiplying the conversion characteristic of Exp (1 / γ) shown as a curve 202 in the figure. This increases the dynamic range of the density signal.

  Further, in the output density correction, in consideration of the influence of the γ characteristic on the writing process process reaction, the conversion table shown in FIG. 4B for changing the density is downloaded to the RAM 117 and multiplied by the characteristic value. Specifically, this conversion table is replaced as a lookup table while referring to the data.

  As shown in FIG. 5B, several types of conversion tables for density correction are prepared, from an upwardly convex curve 203 to a downwardly convex curve 204. The upwardly convex curve 203 has a low density. The curve 204 convex downward shows the characteristic of skipping the low density portion corresponding to the background. The data can be set to any value in consideration of the mode and density notch.

  Consideration of the influence of the writing characteristic is necessary in the case of copying, but in the case of facsimile transmission, since the writing characteristic of the output system is unknown, there is no choice but to set a data linear or density linear characteristic. Also in this copy, the dot reproduction characteristics of the writing system are mainly used for density conversion correction of the read original by transferring density linear conversion to the density converting unit 110b of the writing control block 110.

  In order to give a degree of freedom of density reproducibility and gradation reproducibility, the conversion parameter is given arbitraryness when downloaded to the RAM 117. The target RAM 117 relates to scanner γ correction, density correction for image data, density correction for fluctuation threshold, setting of quantization threshold for dithering and error diffusion processing, code data for smoothing processing, density conversion γ for writing control Thus, the data download from the CPU 119 and the lookup table switching means are common.

  Next, access from the CPU 119 to the RAM 117 shown in FIG. 1 and switching of table reference will be described. FIG. 3 is a diagram showing access from the CPU 119 to the RAM 117 shown in FIG. 1 and switching of table reference. The RAM size can be arbitrarily set, and the address space only needs to be the number of gradations per pixel of the input image. For example, in a system that performs A / D conversion of CCD data with 8 bits, the address space is 8 bits.

  As shown in the figure, in the CPU access mode for data download, the address bus from the CPU 119 is connected to the address to the RAM 117, and the data from the CPU 119 is written to the data input terminal of the RAM 117.

  The RAM 117 downloads the reference data in the write mode. In this embodiment, an example of a synchronous RAM synchronized with a clock (CLK) is shown, but the switching method between the CPU mode and the data reference mode is the same even in the case of an asynchronous RAM.

  In the normal image processing mode, the switch 310 is controlled, the converted input image is connected to the address terminal to the RAM 117, and the switch 311 is controlled to set the RAM 117 to the read mode. . As a result, the conversion table value stored at the address corresponding to the input data is calculated as the output of the RAM 117. With the configuration of the RAM 117, the circuit configuration can be reduced and the calculation processing time can be reduced, and the data can be arbitrarily specified.

  Next, detailed configurations of the density correction unit 106 and the gradation processing unit 107 illustrated in FIG. 1 will be described. FIG. 4 is a block diagram showing detailed configurations of the density correction unit 106 and the gradation processing unit 107 shown in FIG.

  As shown in the figure, there are three reference RAMs as lookup tables, which are shown as RAM 401, RAM 402, and RAM 403 in the figure. Here, the RAM 401 is a correction table for the density conversion γ 411 for the variation threshold, the RAM 402 is a correction table for the density conversion γ 412 for the image data, and the RAM 403 is a dither and error diffusion threshold matrix RAM.

  Here, a path for binary processing and a path for multi-value processing are configured, and each image processing of fluctuation binarization 413, leading pixel control 414, and binary filter 415 is performed for simple binarization processing.

  The dither processing 416 and the error diffusion processing 417 are performed by a common circuit for both binary and multi-value. Specifically, binary / multi-value processing is performed by switching the data contents of the RAM 403 and address / access control. Switching.

  Regarding the multilevel level conversion 418 and the multilevel error diffusion processing 417, phase information for dot formation is added by the phase control 419 and 420 according to the density distribution before and after the main scanning direction together with the density processing. For example, in the case of ternarization, 2 bits are assigned to the signal level, and the states of 00, 01, 10, and 11 can be set. Normally, this is quaternarized, but if 00 is set to white, 11 is set to black, and both 01 and 10 have a PWM pulse width of 50% duty, the density level is ternary. Even with the same 50% duty, 01 turns on the laser in the right half of the dot formation area in the right phase, and 10 turns on the laser in the left half of the dot formation area in the left phase. In this way, the phase and density are defined in conjunction with the PWM modulation unit 110c, and processing is negotiated. For multi-value processing, simple edge detection in the main scanning direction is performed, and simple multi-value and multi-value error diffusion processing are selected based on line segment edge information.

  Next, the use of binary dither matrix download when the RAM 403 shown in FIG. 4 is configured with an address space of 8 bits will be described. FIG. 5 is a diagram for explaining a download usage situation of the binary dither matrix 501 when the RAM 403 shown in FIG. 4 is configured with an address space of 8 bits.

  As shown in the figure, the binary dither matrix size 501 can be set in an arbitrary combination of 4, 6, 8, 16 pixels in the main scanning direction and 4, 6, 8, 16 pixels in the sub scanning direction. Specifically, the combination and the pattern data are selected according to the number of necessary lines and the state of image line thinning. Note that the access to the RAM 403 is not a sequential access but a seek based on a two-dimensional array in order to simplify the operation, so that the configuration in terms of control becomes simple.

  Next, the case where the RAM 403 shown in FIG. 4 is accessed for the multi-value dither matrix will be described. FIG. 6 is an explanatory diagram for explaining a case where the RAM 403 shown in FIG. 4 is accessed for a multi-value dither matrix. Note that the matrix size is 4 × 4, 6 × 6, and 8 × 8, and ternarization is performed per pixel.

  Although the matrix size access is a two-dimensional array, the number of addresses in the main scanning direction needs to be twice as many. In the case of the 4 × 4 matrix 601 shown in FIG. 5A, 2 addresses for each pixel are assigned in the main scanning direction, and 8 addresses are referred to. Further, the pixel A internally refers to the threshold values A0 and A1, so that each matrix-corresponding pixel performs a comparison operation with two threshold values.

  In the case of the left pulse, a threshold value having a magnitude relationship of A0 <A1 is set. In the case of the right pulse, on the contrary, the threshold value is set in a relationship of A0> A1. If the pixel A is smaller than A0 and A1, 00 is assigned as the quantization result. If the pixel A is larger than both A0 and A1, 11 codes are assigned as the laser lighting time over the entire pulse region.

  When there are quantized pixels between A0 and A1, the codes assigned to the right pulse (right phase) and the left pulse (left phase) are different. If the right pulse series is assigned, 01 is the quantization code, and if the left pulse series is assigned, 10 is the quantization code.

  A pulse code is generated with the same definition in each of the matrix pixels of the matrix 602 shown in FIG. 5B and the matrix 603 shown in FIG. Basically, it is realized by downloading the threshold array to the RAM in consideration of phase generation.

  Next, binary and multilevel error diffusion processing will be described. FIG. 7 is an explanatory diagram for explaining binary and multilevel error diffusion processing. A quantization threshold for the product-sum result of the input image and the peripheral error is selected from a fixed value and a variation threshold. The N-value conversion unit 702 converts the output of the addition operation unit 701 into N-values based on the fluctuation threshold value 703. The difference between the output pixel after the N-value conversion and the output of the addition operation unit 701 is calculated by the error calculation unit 704. After delaying this by the error memory 705, the value weighted by the error weighting product-sum unit 706 is added. The unit 701 adds the input pixel.

  Further, as shown in FIG. 5A, in order to reduce the “roughness” of the low density portion, the comparator 707 compares the input pixel value with a predetermined value, generates correction data 708, and inputs it. Added a mode to add arbitrary data to the data. Thereby, addition or subtraction can be arbitrarily set together with the value. Although the addition operation using an adder is used here, subtraction is performed by setting a complement indicating minus as data.

  In this way, by adding arbitrary data, generating regular textures, and adding data equivalent to noise for concentrating dots, effective dots in the writing system can be amplified.

  Further, when using a variation threshold value, a threshold value to be repeated for each block is set in the RAM 403. FIG. 5B shows an example of setting the threshold value 710 of the 8 × 8 variation region in the case of binary values, and the texture is reduced by varying the threshold value 710 within the block. Further, by mixing the fixed value and the variation value of the threshold value in the 8 × 8 matrix region, the balance between edge storage and gradation reproducibility can be adjusted.

  In the case of multi-value, a plurality of threshold values are provided for one pixel of the corresponding matrix, and the quantization code is changed. Note that the phase is rearranged separately in the state of the variable density distribution in the main scanning direction. For the error product-sum operation, a coefficient of 2 lines × 5 pixels using a 1-line FIFO is shown, but this is only an example, and the matrix size and coefficient distribution can be changed.

  Next, switching of threshold values for quantization (variation threshold value, fixed threshold value) will be described. FIG. 8 is a diagram illustrating threshold switching (variation threshold, fixed threshold) for quantization. Here, the threshold value is switched via the system bus 121 according to the mode setting.

  Specifically, with respect to the fluctuation threshold value 801, in the case of error diffusion, the threshold value for referring to the set value in the RAM 403 at the address control and multi-value levels in the main scanning and sub-scanning directions is controlled. In the case of simple binarization, a threshold value set by the spatial filter processing unit 105 and subjected to density correction is used.

  The fixed threshold value 802 is not a value fixed in hardware, but a value set in the register via the CPU 119 is used as a fixed value, and the fixed value itself can be changed according to the mode and image characteristics. The change threshold 801 and the fixed threshold 802 are switched by the switching unit 803 and supplied to the comparison unit 804.

  Next, the configuration of the spatial filter processing unit 105 shown in FIG. 1 will be described. FIG. 9 is a diagram illustrating a configuration of the spatial filter processing unit 105 illustrated in FIG. 1. As shown in the figure, a two-dimensional image matrix 901 is formed by using a plurality of line memories 902, and correction of the frequency characteristic of the image and extraction of the feature amount from the density characteristic are performed in this two-dimensional space.

  The MTF correction 903 has a configuration in which the MTF correction coefficient and the correction intensity can be freely set independently for main scanning and sub-scanning in order to correct MTF deterioration in the optical system, and is widely applicable to processing modes, read originals, and types of optical systems. It is possible.

  The isolated point detection 904 detects background noise and document noise in which generation degradation is expected. Specifically, the isolated point detection 904 detects the regularity of pixel arrangement, and is a complete isolated point or a low-density halftone document. And the target pixel is narrowed down.

  In the isolated point removal 905, it is possible to select whether the detected isolated point is completely removed or replaced with the average value of the surrounding pixels, and the noise component is deleted. The thinning / thickening processing 906 is performed independently of the main and sub, and the main / sub balance of the line density reproducibility is adjusted in conjunction with the MTF correction coefficient.

  A smoothing process 907 extracts surrounding information for removing a moire component generated by a halftone original and aliasing distortion at the time of A / D conversion and for setting a variation threshold. The edge detection 908 detects edge line segments of horizontal, vertical, and left / right diagonal components, and generates a switching signal for adapting filter processing and a control signal for selecting a variation threshold.

  The selector 909 selects the MTF-corrected video path for the edge component of the filter-corrected image, and selects the smoothed video path for the non-edge component. The variation threshold setting 910 for simple binarization sets a threshold for each pixel by a smooth image signal, an edge signal, or the like.

  Next, switching control related to density data for MTF correction will be described. FIG. 10 is an explanatory diagram of switching control related to density data for MTF correction. MTF correction processing is performed on the target pixel. At this time, the correction coefficient and the magnification coefficient are switched in the range of each density level depending on the density level.

  Regarding the selection of the density level, an upper threshold 1001 and a lower threshold 1002 are set. Control is performed independently in the density range below the lower threshold (LOWER), the density range above the upper threshold (UPPER), and the intermediate density range (MIDDLE) existing between them. The coefficient 1003 and the intensity magnification 1004 are also set in the low density, intermediate density, and high density ranges, and the filter processing is adapted so that stable gradation reproduction is achieved within the entire density range.

  Regarding the addition of the MTF correction term to the target pixel, the coefficient intensity is added with the setting of the fine adjustment coefficient 1005 in addition to the selection based on the correction coefficient and the intensity magnification. This is a fine adjustment function for performing very weak MTF correction.

  The low density portion selects the weak MTF correction that is finely set, and performs medium MTF correction in the middle density range. In the high density range, the entire density range is stably reproduced with the setting that weak MTF correction is made to ensure the uniformity of the solid density portion but the fine adjustment coefficient is not selected. Together with the edge separation function of the filter unit, the MTF coefficient is further adapted by edge / non-edge.

  Next, threshold setting will be described. FIG. 11 is a diagram illustrating a configuration relating to setting of a threshold value. As shown in the figure, the smoothed image signal is compared with an upper limit value and a lower limit value set in the register in level determination 1101. For use in the noise and density stable region, the smoothed signal is defined by the respective limit values, and each smoothed signal is replaced by the lower limit value when it is equal to or lower than the lower limit value and with the upper limit value when equal to or higher than the upper limit value. A smoothed signal is used as it is for a signal existing between both limit values. In the select 1102, it is selected whether to use a fixed value set in the register by the edge signal or a smoothing signal.

  In the case of a complete variation threshold value that follows the background density, a fixed threshold value is set as the variation threshold value for the non-edge portion, and a smoothing processing signal is set as the variation threshold value for the edge portion.

  When separating and reproducing a high density edge and a low density edge, a two-stage threshold value is set, the edge portion is set to a fixed value, and the non-edge portion is set to a smoothing processing system signal. Basically, the fixed threshold value functions as a binarization threshold value for the high density edge, and the lower limit set value for the smooth data functions as a binarization threshold value for the low density edge.

  Next, detection of isolated points will be described. FIG. 12 is a diagram illustrating a configuration for detecting an isolated point. Here, in order to detect the isolated state from the surroundings, the target pixel (the central pixel of the matrix) and the outer periphery of the 5 × 5 image matrix 1201, the 7 × 7 image matrix 1202, or the 9 × 9 image matrix 1203 are used. This pixel is regarded as an isolated point when it is completely separated from the other pixel.

  Here, at the same magnification, a 7 × 7 matrix size is used, and isolated points up to a maximum size of 4 × 4 can be detected. In the case of reduction, the interval between the isolated point pixel and the surrounding pixels is also reduced. Therefore, in order to detect 4 × 4 isolated point pixels with 50% reduction, the pixel size is set to a 5 × 5 matrix size. What is necessary is to detect a 2 × 2 mass.

  Conversely, in the case of enlargement of 200% or more, the 4 × 4 isolated point pixels on the original are also enlarged, and cannot be detected unless expanded to a 9 × 9 matrix size, and isolated points remain during enlargement. The matrix size for isolated point detection is switched by changing the kmx value in conjunction with the scaling factor.

  Further, only the detection of isolated points based on the conditions of surrounding pixels within a 5 × 5 or 9 × 9 matrix size also deletes a low-density dither pattern that is useful information in the document. In order to eliminate such a problem, a restriction by comparison with the threshold of kbth and a restriction by state transition are added, and only a true isolated point is detected.

  In the figure, whether or not the pixel of interest is a white background or an isolated point is indicated by a value of T1, T1 = 1 if it is a white background or an isolated point, and T1 = 0 otherwise.

  In the threshold determination 1204, whether or not the target pixel is a white pixel is indicated by T2, and if it is smaller than the threshold, T2 = 1 is white, and if it is equal to or greater than the threshold, T2 = 0 is non-white. . A white background and an isolated point are distinguished by this T2.

  For the determination of the state transition, T1 and T2, the number of continuous white pixels and the size of the isolated point are counted and used as the conditions for the state transition 1250. Although the state of the pixel is indicated by the value of state, the target pixel is intuitively PAPER, which is a region 1206 in which white pixels are widely continuous, or DOT 1207 where the target pixel is an isolated point, or the target pixel is a picture or character Alternatively, a transition is made between PICT, which is a region where low density halftone dots or white pixels are not widely continuous. The state starts with PAPER.

  Next, correction processing for detected isolated points will be described. FIG. 13 is a diagram illustrating a configuration related to correction processing for detected isolated points. As shown in the figure, the detection result of the isolated point is indicated by result, and correction processing is performed on the image data mtfo after MTF correction via the intensity calculation 1301 and the selection unit 1302. Here, this mtfo is emphasized, the isolated points are enhanced, and if this process is repeated multiple times (taking grandchild copy), the generation deteriorates and the low-quality output that makes black spots stand out. Become.

  For isolated points, MTF emphasis is not performed, and the surroundings are smoothed or replaced with a white level. The isolated point removal processing is switched on / off by kmod, and the correction level for processing is switched by ktj. In this case, forced conversion to the white level is set to the maximum removal intensity, and the correction level is weakened to 1/32, 1/8, 1/2 of mtfo.

  Next, the configuration of the video flow will be described. FIG. 14 is a diagram showing a configuration of a video flow. Since the read image is subjected to filter processing such as shading correction, scanner γ correction, electrical scaling, and MTF correction, so far, the original state of the read image is set as an image signal of the scanner system.

  In the image quality processing 1403, density correction and gradation processing are performed via the video path control 1401 shown in the figure. Multi-value processing and binary processing are performed by forming density according to the writing characteristics of the image signal in accordance with the area gradation in consideration of the output to paper for both density and gradation.

  The video path control 1402 handles data after the image quality processing 1403, and mainly binarized data. The VCU I / F 1404 is a general term for signal conversion to a writing system, and performs data format conversion.

  In the normal path from reading to writing, the video path control 1401 and 1402 performs video path control with the external application (APL) and the image memory unit (IMU) 1405 through the respective I / F control modules. The IMU 1405 includes a scanner buffer memory and a printer buffer memory, and external APL units include a facsimile, a printer, a scanner, and the like.

  A path SA from the video path control 1401 to the APL output 1406 is for the scanner APL, and multivalued image data is handled. A facsimile (FAX) from the image quality processing 1403 to the APL output 1406 handles a binary image with a FAX transmission signal. As for PA from the APL input 1407, a binary image is handled by the printer application.

  Next, a video control system will be described. FIG. 15 is a system diagram showing a video control system. The read image signal “S” shown in the figure indicates image data that has undergone processing up to shading correction, scaling, and filtering. Further, “A” indicates an I / F terminal with an external application, “MS” indicates a scanner buffer memory, and “MP” indicates each module of the printer buffer memory. Further, “P” indicates a writing unit after PWM modulation, and “synthesis (G)” indicates image synthesis of the read image and the memory accumulated image.

  As shown in the figure, the video path is switched by each selector (sel1 to sel6). Regarding the parallel operation of the multi-value processing and the binary processing, the dither RAM and the error diffusion processing FIFO memory in the image quality processing have only one system in order to simplify the circuit configuration. Therefore, physically, binary error diffusion and multi-value error diffusion cannot be simultaneously processed, but apparently parallel processing is performed by time division processing.

  In order not to let the operator operating the machine realize the length of processing time, after reading all the documents of multiple jobs first and storing them in the MS, the image quality processing is specialized for binary and multi-value. Reproduce the optimal image and share the circuit resources in a time-sharing manner.

  Describing the time-division parallel operation of binary processing and multi-value processing, a multi-valued error diffusion process is performed on a read original and five copies are output, and a job in which a different original is subjected to binary error diffusion processing and facsimile transmission is almost divided. There are two ways to deal with the same request.

  One of them is to store document read images for two jobs in the MS, and the other is to store only images for multilevel error diffusion processing in the MS, and there is a request for binary error diffusion processing in the middle. In this case, the processing circuit is opened for binary error diffusion processing.

  In the first method, binary error diffusion processing is performed after multilevel error diffusion is finished, and during that time, the read image is stored in a different area from the accumulated image for MS multilevel error diffusion processing. become.

  Specifically, first, an original for copying five copies is read, and image data is stored in the memory through a route of S → 1 → sel3 → MS. Next, the same document data is read from this MS five times, and five copies are output for P. The route is MS → 9 → 10 → sel5 → image quality processing → 3 → sel2 → 13 → P. In the image quality processing, density conversion and multilevel error diffusion processing are performed.

  While printing out, the optical reading means is open and a job for facsimile transmission can be accepted. A facsimile original is read, and image data is stored in a route of S → 1 → sel3 → MS. The video path does not collide in reading from the MS and storing in the MS, and all the image data read in any job is accumulated in the MS.

  After the five copies have been output, the original image for facsimile transmission is read from the MS and subjected to binary error diffusion processing. Specifically, facsimile transmission is performed through a route of MS → 9 → 10 → sel5 → image quality processing → 3 → sel1 → 12 → A → M / B → F. “M / B” means a motherboard, which is a physical module on which a plurality of application units are mounted, and “F” means a facsimile unit.

  The other interrupt means reads out the accumulated data from the MS and interrupts the copy output if the facsimile transmission original is read while the five copies are being output. Since the image data is stored in advance in the MS, it is not necessary to read the original again.

  The facsimile document is transmitted by facsimile via a route of S → 1 → sel5 → image quality processing → 3 → sel1 → 12 → A → M / B → F. After this facsimile transmission is completed, image data is read from the MS and multi-value error diffusion processing is performed in order to perform the remaining copy output again.

  Also, the route of the fusion process of external applications will be described. In this case, the operation of the fusion process of the three applications that outputs original data for reading a document to the scanner application (SA) and directly transmits the document data received from the personal computer as the printer application (PA) to the facsimile application (F). I will show you.

  An original reading signal is output to the scanner application through a route of S → 1 → sel1 → 12 → A → M / B → SA. The path connection is switched by the physical switch on the M / B even while the document is being read, and the facsimile transmission from the PA is performed through the path of PA → M / B → F.

  If the scanner application unit is being used by another device and data cannot be transferred immediately, it is temporarily stored in the MS, and after acquiring the unit, the MS → 9 → 10 → 4 → sel1 → 12 → A → The image data for the scanner application is transferred along the route of M / B → SA. In this case, although the unit function is operating for the three applications, the reading means (S) and the writing means (P) are in an open state, so that a normal copy can be taken.

  In the case of outputting in binary copy, the image processing result is temporarily stored in MP, and the necessary number of copies for P are read from the memory. Image quality processing → 3 → sel3 → MP, MP → 9 → 10 → 4 → sel2 → 13 → P.

  In the case of an output operation using the printer buffer memory, the reading means is open, and the next job can be read to store the image data in the MS or MP buffer memory.

  Next, the configuration of the APL input will be described. FIG. 16 is a diagram showing the configuration of the APL input. As shown in the figure, the APL input control block is an IF block for taking image data synchronized with a clock asynchronous with the system clock into the apparatus.

  In the input mask function 1601, the outside of the effective image area from the APL is masked to the white side, and in the image inversion function, the white pixel is input at the high level and the black pixel is set to the low level according to the I / F specification with the APL Enter by level. In this device, white is defined as the low level and black is defined as the high level, so the level of the image is inverted.

  The write control 1602 of the FIFO 1603 transfers 7015-bit image data with 600 dpi writing on the A4 width maximum transfer paper size of 297 mm. Since binary image data is defined by 8-bit parallel transfer, a 1K × 8-bit FIFO memory is used.

  Write reset (xwrst) and write enable (xweb) of the FIFO 1603 are generated from the line synchronization signal XARLSYNC from the external application using XARCLK supplied from the external application as a reference clock. XARLSYNC has an assert period of 1 clock width.

  A read control function 1604 of the FIFO 1603 is to generate a control signal and specify a data format. The generation of the control signal is based on the line synchronization signal XARLSYNC in the image processing apparatus, and the FIFO read reset (xrrst) and read enable (xreb) are synchronized with the system clock.

  Data format designation is facsimile reception, input data from the printer application is 8-parameter binary image data (8bit / 8dot), and output data to the IMU is converted to serial data (1bit / 1dot). Also, format conversion of output data to the writing system (VCU) is not performed (8 bits / 8 dots), and data to the IMU is S / P converted. The read data from the FIFO is converted into serial data bit by bit by the shift register, and lower bits not used are set to zero.

  Next, the configuration of the APL output will be described. FIG. 17 is a diagram showing the configuration of the APL output. The APL output control block is an I / F block for outputting image data processed inside the apparatus, and an output gate conversion 1701 (only in the main scanning direction, no shift operation) for cutting out a read image, data format conversion 1703 and black and white inversion 1702 are performed.

  The format conversion 1703 can select four types of formats for the output data. (1) Through output (without format conversion) is used for multi-value output of scanner read data and serial output of binary images. (2) The 6-bit output can be set by white masking and outputting other than the upper 6 bits of the 8-bit data, and setting the 6-bit data to the MSB side or the LSB side of the 8-bit bus. (3) 4-bit output can be output by white masking other than the upper 4 bits of 8-bit data, and whether the 4-bit data is brought to the MSB side or the LSB side of the 8-bit bus can be set. (4) The binary 8-bit parallel output is a 8-bit packing of a binary image (when binary data is transferred using only the MSB of an 8-bit bus), and is packed with MSB first.

  The MSB / LSB inversion function 1704 switches the LSB of the 8-bit data bus from the MSB to the MSB, and from the MSB to the LSB in order, 1-bit 2-value, 4-bit multi-value, 6-bit multi-value, 8-bit multi-value, 8-bit 2 It can be set in any case of value packing.

  A gate (effective image range defining signal) conversion 1701 converts the main scanning gate length to a specified length, can be set in a range of 0 to 8191 dots, can be turned on / off, and is mainly a scanner. This is used when an image is cut out using an application. Cutting out in the main scanning direction is used in combination with a shift function of a variable magnification block.

  The scanner reading gate is performed at the maximum original size, the output position front end position after scaling is calculated, the front end of the output image is aligned with the front end of the LGATE (main scanning direction effective image range) by the shift operation, and then the main gate conversion is performed. The gate width is adjusted to the scanning length.

  In the sub-scanning direction, the sub-scan gate length is set in the timing control unit, and the correspondence to the format is that the LGATE length after conversion is specified in units of one dot, and the LGATE length is converted for the selected format. . The conversion method is as follows: 1) In the case of 8-bit multi-value or 1-bit binary serial, the set LGATE length is kept. 2) In the case of 8-bit binary image parallel (8 para), the setting is made. Convert to the length of LGATE ÷ 8. If there is a remainder, set it to the raised length.

  The output timing adjustment 1705 outputs the output data to the APL and the gate signal in synchronization with the rising edge of the output clock (XAWCLK) to the APL. Various clocks are generated in the clock generation module and directly output to the I / F unit. As for the type of this clock, in the case of 8-bit multi-value and 1-bit binary serial, a clock having the same phase and the same frequency as the system clock is output, and in the case of 8-bit binary parallel, the system clock divided by 8 is output. .

  Next, the configuration of the write system output will be described. FIG. 18 is a diagram showing the configuration of the write system output. Write output control outputs image data processed inside the apparatus, and controls output switching 1803 between image data after printer masking, gate signal output timing adjustment 1801 and through data 1802 from the APL input. .

  The timing adjustment 1801 outputs the output data to the VCU and the gate signal in synchronization with the rising edge of the output clock (XPCLK) to the VCU. Various clocks are generated in the clock generation module and directly output to the I / F unit.

  As for the type of this clock, in the case of 4-bit t multilevel, a clock with the same phase as the system clock and divided by 2 is output. In the case of 8-bit binary, a clock having the same phase as the system clock and divided by 8 is output.

  The gate data defining the output data and the effective image range is synchronized with the divided clock XPCLK, but a deviation of a maximum of 8 clk (system clock) is caused by the phase difference with respect to the period of the line synchronization signal XPLSYNC to the VCU. In the VCU output block, processing is performed at the rising edge of the system clock clk, timing adjustment is performed with the inverted clock xclk, and output to the I / F is synchronized with XPCLK.

  Next, the data structure will be described. FIG. 19 is a structural diagram showing a data structure. The data bus to the write system (VCU) consists of 8 bits and is indicated by xpde [2: 0], se, xpdo [2: 0], and so. This is applied to density information and phase information, and is based on bit assignment to 4-bit multivalue. The eight signal lines having different densities and phases are assigned bits in accordance with the data format.

  The data format consists of (a) 4-bit multi-value, (b) 2-bit multi-value, (c) 2-value, and (d) 8-bit multi-value. The data format is converted by parallel transfer, 2-bit multivalued parallel transfer of 4 pixels at once, 2-valued 8-pixel parallel transfer, and 8-bit multivalued serial transfer.

  As shown in FIG. 4A, for 4-bit multivalue, xpde [2: 0] contains even pixel density information, se contains even pixel phase information or additional density information, and xpdo [2: 0] The density information of the odd pixels is distributed to, and the phase information or additional density information of the odd pixels is allocated to so.

  As shown in FIG. 4B, the 2-bit multivalue is expressed as a ternary density when phase information is included, and a quaternary density when the phase is fixed. 1st pixel to xpde [2: 1], 2nd pixel to [xpde [0], se], 3rd pixel to xpdo [2: 1], 4th pixel to [xpdo [0], so] To each.

  As shown in the figure (c), the binary mode is in the order of xpde [2], xpde [1], xpde [0], se, xpdo [2], xpde [1], xpde [0], and so Eight pieces of pixel information are arranged and converted into parallel data for an 8-bit data bus.

  As shown in FIG. 4D, the 8-bit t multi-value indicates that the 8-bit density information of each pixel corresponds to the bus width of [xpde [2: 0], se, xpdo [2: 0], so]. , MSB is assigned the most significant bit of the density signal.

  Next, the smoothing function will be described. FIG. 20 is a diagram illustrating the configuration of the smoothing function. In the image matrix unit 2001, 13-pixel delay data is created in the main scanning direction from 9-line data, and a 9-line × 13-pixel two-dimensional matrix is created. The matrix data is accessed at the same time, and each binary / multilevel conversion process is performed. Only the edge processing of the edge processing unit 2007 does not require a two-dimensional image matrix and performs processing with data on one line.

  The code generation and RAM jaggy correction unit 2002 performs pattern matching using image matrix arrangement data. 12-bit code data is generated by matching and input to the RAM address. This RAM is a RAM for image correction, and outputs image correction data corresponding to the input code. The correction data is downloaded separately to the RAM.

  The isolated point correction unit 2003 detects an isolated point by pattern matching within a 9 × 13 image region including the target pixel. Pixels corresponding to isolated points are removed by mask processing, or pixels are added around the two-dimensional range to form a set of non-isolated pixels. Note that it is possible to switch modes whether to mask or not to add pixels around. In the case of an isolated dot, the dot may or may not be reproduced depending on the process conditions of the writing system, and density unevenness occurs in the uniform input density region, resulting in image quality deterioration. The dot density is increased to the extent that the dots can be reproduced stably or not at all.

  The error diffusion enhancement unit 2004 smoothes the texture with a bandpass filter that holds a line drawing, and generates a phase signal based on the pixels in the main scanning direction.

  The dither smoothing unit 2005 performs low-pass filter processing of 5 × 5 or 9 × 9 on the binary dither pattern, and converts it into a pseudo multi-value signal. The two-dot processing unit 2006 performs averaging between adjacent pixels on the pseudo-multi-valued signal to generate phase information. Data converted from these binary values to multi-values is selected by the selector 2008. The image path selection is switched depending on the mode. In any case, it is converted into 6-bit data having a density of 4 bits and a phase of 2 bits.

  The isolated point correction is a target for determining whether or not the center pixel is the target pixel and is an isolated point within the range of the 9 × 13 image matrix. The connection with surrounding pixels is determined by pattern matching to be an isolated point. In the dither smoothing and dot averaging, the smoothing unit applies 5 × 5, 7 × 7, and 9 × 9 smoothing filters to the 9-line × 13-pixel image matrix 2001.

  Although the input data is a 1-bit binary signal, high frequency signal components are removed by this smoothing filter. The smoothed pixels are averaged between the EVEN and ODD pixels in the main scanning direction. The value is an average value, but distinguishes the phase signal. The EVEN pixel is set to the right phase and the ODD pixel is set to the left phase to form 2-dot image data. The phase data is output as it is, but the density data is subjected to level conversion to convert the data to a 4-bit width.

  Next, the configuration of the write control unit will be described. FIG. 21 is a diagram illustrating the configuration of the write control unit. The input from the video path control unit 109 to the writing system is either a direct image read by the scanner, an image stored in the memory module, or an input image from the external application 112. The pixel clock of each unit and the write clock corresponding to the pixel density are not synchronized, and the speed conversion of the write clock and the read clock to the RAM is performed using, for example, a speed conversion FIFO memory 2101 having a 2-port RAM configuration. Do it.

  The image data read by the writing clock is subjected to data conversion by the smoothing module 2102 and the multi-value processing system 2103. The smoothing module 2102 converts the binary image into multilevel data, and the multilevel processing system 2103 performs phase signal conversion processing.

  After conversion to multi-value data, density levels are converted in consideration of density reproduction characteristics of the image forming process by using a plurality of density conversion tables 2104. The data of the density conversion table 2104 is downloaded from the CPU 119 and executed in parallel with various characteristics. A selector 2105 selects necessary data from the conversion result according to the processing mode.

  When the process has changed, the printer, the facsimile reception, the copy output from the scanner reading, the character-based original, the copy original, the photo original, etc. Therefore, the value of the density conversion table is finely controlled. The power and phase of an LD (laser diode) are controlled by PM modulation and PWM modulation to control on / off of the LD, and a latent image is created on the image forming unit.

  Next, the configuration of the memory module will be described. FIG. 22 is a diagram illustrating a configuration of the memory module. The memory I / F unit 2201 shown in FIG. The module has a work memory area (work area) 2202 and a memory area (memory bank) 2203 for storage. The work area 2202 is configured by a RAM, and the storage area 2203 is configured by a RAM and a non-electronic memory such as an HDD, MO, CD-RW, or DVD.

  In the work area 2202, the input / output image bitmap is developed. The address control unit 2204 can develop the input image and the output image independently on an arbitrary memory address. For example, a bitmap developed from a stored image and an input image are combined, two images are aggregated, the image is rotated, and a print pattern such as a date is added to the input image.

  For storage in the memory bank 2203, data compression 2205 is performed via the address control unit 2210 in order to increase the storage capacity. Basically, data encoding is performed by reversible conversion, but irreversible conversion is also possible within a range where image quality degradation does not appear visually in a reproduced image.

  Data is stored in the memory bank 2203 by the storage memory write control 2206. In this case, ID information is added to the image data, and the properties (input system, processing mode, etc.) of the input image are specified.

  Image data is expanded into a bitmap by a storage memory read control 2207 and data decompression 2208. Although the property information may be directly reflected in the pit map, it is basically used for the parameter setting adaptation instruction to the write control unit. Used for density conversion table switching control.

  Next, an example of the density conversion table will be described. FIG. 23 is a diagram illustrating an example of the density conversion table. Note that data linear characteristics may be used as long as the binary level is reproduced. As the contents of the conversion table, linear data is downloaded and input level = output level.

  As shown in FIG. 6A, when the scanner γ correction in the reading system at the time of copying is optimized by reading original density correction 2301, or the process γ of the image forming unit is linear with respect to the input signal. If you have it, you can adapt. When emphasizing tone reproduction of image content, conversion to density linear data is necessary to correct process linearity.

  FIGS. 5B and 5C show density conversion tables 2302 and 2303 that are linear in density, and the balance of the image contents can be achieved, for example, when characters and patterns are mixed in the image and the linearity of the process can be assured. To reproduce, download a conversion table with intermediate characteristics between data linear and density linear.

  The contents of the conversion table also depend on dot formation. In general, an isolated point of one dot is difficult to reproduce, and density reproduction is good in a state where a lot of lines and dots are dense. The conversion table requires various values depending on the modulation method of LD control and image processing for gradation reproduction.

  Next, an example of the aggregation function will be described. FIG. 24 is a diagram illustrating an example of the aggregation function 2401. Here, a case is shown in which four originals A, B, C, and D are read, and each image is reduced and collected on one transfer sheet. Assume that A and D are originals mainly composed of characters, B is a pattern original, and D is a character and pattern mixed original.

  A and D are read into the memory module by setting the character mode, B is read in the photo mode, and D is read in the character / photo mode. The scanner γ characteristic, the filter characteristic for MTF correction, and the density correction γ characteristic are different. Further, in the image formation on the transfer paper, the density conversion γ characteristics in the writing control unit are different depending on the emphasis on resolution, gradation, and balance.

  The storage in the memory module is performed by changing the parameters of the image processing type except for the characteristics of the writing control, but the necessary writing characteristics are added to the properties for the stored image in the memory module. A density conversion characteristic necessary for the character mode or an assumed density conversion characteristic is added.

  The accumulated images are collected in the work memory, and the data is output to the writing control through the video path control. The density conversion unit switches at least three types of density conversion tables. At the time of integration development, the image switching address in the main scanning and sub-scanning directions is extracted from the property information, and counter control is performed.

  It is also possible to fix the writing conversion table to the mixed original reproduction table and replace the contents of the read original density conversion table with the emphasis direction for characters and patterns.

As described above, in the first embodiment, the input density correction by the input density correction unit 103, the density correction by the density correction unit 106, and the write density correction in the write control block 110 are independently performed in response to a user operation. Since it is configured to be controllable, density correction can be performed in an optimal combination for the entire multifunction device.
(Embodiment 2)
In the first embodiment, since the user can control the input density correction, the density correction linked to the density notch, and the writing density correction completely independently, the options related to the density correction for the user are diversified, and the user frequently There is a risk that test printing must be repeated.

  Therefore, in the second embodiment, a combination of input density correction, density correction linked with density notch, and writing density correction is registered in the operation unit, and an optimum print output suitable for the type of document and the characteristic situation is obtained. A multifunctional machine that can be obtained will be described. Since the configuration other than the operation unit 120 of the multifunction peripheral according to the second embodiment is the same as that shown in FIG. 1, the description thereof is omitted here.

  FIG. 25 is a diagram showing an example of an operation screen 2500 provided in the operation unit 120 shown in FIG. As shown in FIG. 6A, on this operation screen 2500, “background removal” 2501, “aggregation” 2502, “initial setting” 2503, “image quality 1” 2504, “image quality 2” 2505, “density notch” Each input key 2506 is provided.

  "Skin removal" 2501 switches the background tracking level in the reading system within a predetermined setting, and sets whether to completely skip the background portion or leave a signal with a somewhat low density level. Controls the setting of the threshold level for signal deletion after tracking. The table of the scanner γ is also switched.

  “Aggregation” 2502 sets ON / OFF of the image aggregation processing to the memory, and the aggregation method is set by “initial setting”. For example, it is set that two read originals are consolidated on one transfer sheet, or four sheets are consolidated on one transfer sheet.

  “Image quality 1” 2504 and “image quality 2” 2505 are selection modes for certain image processing, such as “character mode” and “photo mode”, “character / photo mode”, and “special manuscript mode”. The processing mode is not fixed.

  The processing mode is set by “initial setting” 2503. Only the frequently used mode is displayed on the operation unit, and the mode to be used occasionally is selected by “initial setting” 2503. At this time, only the simple and frequently used settings are displayed without displaying an unnecessary mode. Even when the density notch is switched, the reading table is switched to the corresponding set value.

  What is assigned to “image quality 1” 2504 and “image quality 2” 2505 is arbitrarily selected in “initial setting” 2503. For example, as shown in FIG. 6B, image quality modes are prepared in advance from setting 1 to setting N, and the mode frequently used by the operator is assigned to “image quality 1” 2504 and “image quality 2” 2505.

  When setting 1 to setting N are displayed on the operation unit, the range of selection is wider and it is possible to cope with many users. However, when there are not so many modes to be used, the operability is reduced and the effect is reduced. thin.

  The selection range includes setting 1 to setting N, and adapts whether to display on the surface according to the use frequency according to the use environment. Settings 1 to N are supplied in advance so that they can be handled in most use environments. However, if a special mode is desired, an arbitrary mode is created.

  In “Initial setting” 2503, setting contents can be arbitrarily grouped and modes can be registered. As shown in FIG. 6C, if various parameters are grouped for each setting, desired parameter setting values 2507 are combined, and the newly created “setting” is set to “image quality 1” 2504, the use environment It is possible to perform customized image quality processing.

  FIG. 26 is an explanatory diagram for explaining the density correction by the operation screen of the operation unit 120. As shown in FIG. 6A, in this multifunction device, in principle, the input density correction 2601, the density correction 2603 linked to the density notch, and the writing density correction 2604 are independently controlled from the operation screen of the operation unit 2601. Can do.

  Specifically, the input density correction is performed by selecting one of the curves s1 to s4 shown in FIG. 5B, and in the case of a character document, any one of N1 to N4 shown in FIG. Is selected to perform density correction linked to the density notch, and in the case of a photographic original, any one of the curves N1 to N4 shown in FIG. Can be done. Further, writing density conversion can be performed by selecting any one of the curves p1 to P4 shown in FIG.

  However, since it is not easy to select these parameters as an optimum combination, for example, the parameters s1, N2, and p3 are set as “image quality 1” 2504 by the “initial setting” 2500 shown in FIG. Thus, only by indicating “image quality 1” 2504 on the display screen, the corresponding input density correction 2602, density correction 2603 linked to the density notch, and writing density correction 2604 can be performed.

As described above, in the second embodiment, the combination of the input density correction by the input density correction unit 103, the density correction by the density correction unit 106, and the write density correction in the write control block 110 is registered in the operation unit 120. Thus, a desired output image can be obtained with an extremely simple operation.
(Embodiment 3)
Next, an embodiment in which user operability is further improved will be described with reference to FIG. In the present embodiment, it is not very easy for a general user to select the above-mentioned parameters as an optimal combination. Therefore, image quality parameters such as density characteristics and filter characteristics are collected as a group in advance as an image quality mode. , Keep offering. Since the user can use a necessary mode as a template for selecting or customizing, this embodiment is an embodiment in which operability from the viewpoint of the user is greatly improved. From the viewpoint of improving the operability for the user, a mode in which maintenance is performed for the mode used by the user is adjusted by a professional service person, etc., and the mode used by the user is restored after the adjustment. preferable. In this embodiment, the absolute value of each adjustment value is adjusted especially when adjustments are made in a maintenance mode by a service person or the like when it is necessary to change the setting contents of the device used by the user. It is the Example about the method to do.

  FIG. 27 shows an example of an operation screen according to the present invention. (a) and (b) Two types of operation screens, operation screens 2700 and 2720 are shown. On the operation screen 2700 of (a), “display unit 2701”, “background removal 2702”, “aggregation 2703”, “initial setting 2704”, “image quality 1” 2705, “image quality 2” 2706, “density notch 2707”. "," Numeric keypad 2708, "" clear / stop (C / S) 2709 ", and" start (START) 2710 "input keys are provided.

  Further, on the operation screen 2720 of (b), a lighting display by “image quality 2725” and LED 2726 is provided instead of “image quality 1” 2705 and “image quality 2” 2706 of (a). On the operation screen 2720 in (b), whether “image quality 1” 2705 or “image quality 2” 2706 on the operation screen 2700 in (a) is selected is distinguished by turning on / off the LED 2726. For example, the lighting of the LED 2726 is assigned as “image quality 1”, and the turning off of the LED 2726 is assigned as “image quality 2”. The “background removal 2702” key can switch the background tracking level in the reading system within a predetermined setting, and can select whether to completely eliminate the background or to leave a somewhat low density background. Controls the setting of the threshold level for signal deletion after tracking, and also switches the table of the scanner γ. An “aggregation” key 2703 is used to select OFF / ON of image aggregation processing to the memory, and an aggregation method is set by an “initial setting” key 2704. For example, it is possible to select such that two read originals are aggregated on one transfer sheet and four are aggregated on one transfer sheet.

  “Image quality 1” 2705 and “image quality 2” 2706 select an image processing mode. For example, there are “character mode” and “photo mode”, “character / photo mode”, and “special manuscript mode”, but the processing mode is not particularly fixed. The processing mode is also set with the “initial setting” key 2704, and only the frequently used mode is displayed on the operation units 2700 and 2720. The mode which is not used frequently is selected with the “initial setting” key 2704 at the time of use. This is because operability is better when the extra mode is not displayed. Also, when the density notch 2707 is switched, the reading table is switched to the corresponding set value.

  Next, the setting of “image quality mode” will be described. What is assigned to “image quality 1” and “image quality 2” is arbitrarily selected by an “initial setting” key 2704. (C) and (f) show examples of “image quality modes” 2740 and 2780 when the “initial setting” key 2704 is pressed. (C) shows a method of selecting from a pre-provided mode and an arbitrarily settable registration mode, and (f) is a selection from the pre-provided mode, and if fine adjustment is necessary, the image quality after selection It is an example which shows the case where it performs regarding a setting. Hereinafter, these examples will be described.

  In the selection relating to “image quality mode”, for example, “character image quality 1” 2741, “character image quality 2” 2742, and “character image quality 3” 2743 are prepared in advance as modes suitable for “character document”. “Photo quality 1” 2744, “Photo quality 2” 2745, “Photo quality 3” 2746 are prepared as suitable modes, and for other general-purpose originals, a mode suitable for “special originals”. “Special Document 1” 2747, “Special Document 2” 2748, and “Special Document 3” 2749 are prepared. The operator assigns “image quality 1” and “image quality 2” to modes that the operator frequently uses.

  Displaying many modes corresponding to each image quality on the operation unit widens the range of selection and can accommodate many users, but there are not so many modes that are practically used, so operability is reduced. And not very useful. The selection range includes a plurality of modes for text-based, photo-based, and special manuscripts, and whether to display according to the usage frequency is changed according to the usage environment.

  In (C), selection means for “registered image quality” 2739 is provided within the range of image quality modes that can be selected by “initial setting”. "Character image quality 1" 2741 through "Special manuscript 3" 2749 are provided in advance and can be handled in most use environments. However, if you want to set a very special mode, create an arbitrary mode. . Regarding “registered image quality” 2739, the setting contents are arbitrarily grouped by the operation item “initial setting” 2704, and the mode is registered. For each setting, various parameters are grouped and desired parameter setting values are assigned in combination. If the newly created “registered image quality” 2739 is set to “image quality 1”, it operates as an image processing apparatus that performs image quality processing specialized for the use environment.

  Next, (d) and (e) show the display screens 2750 and 2760 regarding the parameter setting method. When the procedure for setting the registered image quality 2739 is performed according to “(a) or (b) initial setting”, the display screen 2750 of (d) is displayed on the display unit of (a) or (b). A display screen 2750 shows modules that can be controlled as image quality parameters. Items related to density correction, items related to MTF correction, etc. 2751, 2752, 2753, 2754, 2755, 2756, and 2757 are displayed as optional setting targets. When an item to be set is instructed on the display screen 2750, another screen is displayed to display control target items related to image quality. Thereby, it can set arbitrarily. (e) shows an example of a setting screen for MTF correction. The main scanning coefficient 2761, the intensity magnification 2762, and the like are shown, and the current set value 2763 and the settable range 2764 are displayed, so that the set value can be determined in detail. The input of the set value can be either an absolute value of a parameter or an input of a relative value. In the case of relative value input, the range from “strong” to “weak” is divided, and the selected relative value is converted to the absolute value of the parameter by the CPU.

  (f) shows operation screens 2780 and 2790 that are provided for fine adjustment on the user side based on the currently provided mode. By selecting “Select image quality” 2791 or “Custom image quality” 2792, it is determined whether to select from the existing modes or to make adjustments based on the existing modes.

  “Select image quality” 2791 is used to input an instruction for allocating the existing mode to “image quality 1” or “image quality 2” between “character image quality 1” 2781 and “special document 3” 2789.

  When fine-tuning to make user-specific changes to the existing mode once assigned to "image quality 1", select the "custom image quality" 2792 mode for "image quality 1" and select "image quality 1" The parameter corresponding to the group including “” is displayed in the “current setting value” 2763 of (e), and the user can perform fine adjustment as a changeable target.

  Although it is possible to create a completely new "Registered image quality", this is not the target of selection equivalent to the existing mode, but is assigned to the operation unit of "Image quality 1" and "Image quality 2" This is image quality adjusting means used for subsequent fine adjustment.

  Next, FIG. 28 shows a configuration for storing image quality parameters. A fixed setting value and a fluctuating setting value relating to the image quality mode are stored and managed separately in the ROM area and the nonvolatile memory area.

  FIG. 28A mainly shows a configuration in the case of using “registered image quality” 2739 as a mode for selecting “image quality 1” or “image quality 2”, and FIG. 28B shows “image quality 1”. Alternatively, a configuration in the case where fine adjustment is performed after assigning an existing mode to “image quality 2” is shown.

   In the configuration of (a), the image quality parameters for the existing modes from “character document 1” to “special document 3” are stored in the ROM 2800 and supplied to the system. For example, a setting value for “character image quality 1” is stored in address A 2801 of ROM 2800, and a setting value for “special document 3” is stored in address N 2802. On the other hand, regarding “image quality 1” 2830 and “image quality 2” 2831 to be changed in the normal process, the information is stored in the area of the corresponding nonvolatile memory 2820. Similarly, for the “registered image quality” 2740 for which all characteristic values are to be changed, the parameter is stored in the bb number 2821 in the nonvolatile memory area 2820. The information of “image quality 1” 2830 and “image quality 2” 2831 stored in the nonvolatile memory 2820 is not the characteristic parameter itself, but is stored in the ROM 2800 of the selected image quality mode or stored in the nonvolatile memory. Only the destination address is stored in aa address 2822 and ab value 2823. As a result, the amount of memory used can be reduced.

  In actual operation, when “image quality 1” 2705 is selected on the operation unit 2700, the setting content (reference destination address) in the corresponding nonvolatile memory 2820 is referred to, and the ROM 2800 indicated by the reference destination address or The image quality parameter stored at the address in the nonvolatile memory 2820 is downloaded to the work RAM of the system, and the system operation is performed.

  In the configuration of FIG. 28B, the existing image quality modes from “character image quality 1” to “special document 3” supplied by the ROM 2800 are assigned to “image quality 1” 2830 and “image quality 2” 2831 on the operation unit. Then, all the parameters of the supply mode stored in the ROM 2800 are copied to the nonvolatile memory 2820, or only the storage address in the ROM 2800 is stored in the nonvolatile memory 2820.

  When performing “customization” on “image quality 1” 2830 or “image quality 2” 2831 after the initial setting, if all image quality parameters are copied, the contents of the change are overwritten on each parameter, and then again. The change result is stored at the same address in the nonvolatile memory 2820.

  On the other hand, if the reference ROM address ab value is stored, only the change difference due to “customization” is stored in the nonvolatile memory together with the ROM address 2823 as additional information. When the MTF coefficient is changed, the change parameter and the change amount are stored in the nonvolatile memory 2020.

When the mode is initialized, the finely adjusted change information stored in the nonvolatile memory 2820 is deleted.
(Embodiment 4)
Next, another embodiment in which user operability is further improved will be described with reference to FIG. This embodiment is also an embodiment in which the operability from the viewpoint of the user is greatly improved as in the above-described embodiment. From the viewpoint of improving the operability of the user, as in the above-described embodiment, a mode in which maintenance is performed in the mode used by the user is adjusted by a professional service person, and the user is again adjusted after the adjustment. It is preferable to return to the mode used. In this embodiment, especially when the user needs to change the setting contents of the device, the adjustment value is set to the current setting when adjustment is performed in a maintenance mode by a service person or the like. It is an Example about the method of adjusting by increasing / decreasing a value with respect to a value.

  FIG. 29 shows another example of the operation screen.

  On the operation screen 2900 of FIG. 29A, a “display unit 2901”, “background removal 2902”, “consolidation 2903”, “initial setting 2904”, “character 2905”, “photo 2906”, “density notch 2907” are displayed. "," Numeric keypad 2908, "" clear / stop (C / S) 2909 ", and" START (START) 2910 "input keys are displayed. The “background removal” key 2902 can switch the background tracking level in the reading system within a predetermined setting, and can select whether to completely remove the background or leave a somewhat low density background. it can. Controls the setting of the threshold level for signal deletion after tracking, and also switches the table of the scanner γ.

  An “aggregation” key 2903 sets OFF / ON of the image aggregation processing to the memory, and an aggregation method is set by an “initial setting” key 2904. For example, it is possible to select the aggregation of two read originals on one transfer sheet and the consolidation of four sheets on one transfer sheet.

  A “character” key 2905 and a “photograph” key 2906 select an image processing mode suitable for a document. For example, there are “character mode” and “photo mode”, “character / photo mode”, “special manuscript mode”, etc. However, the processing mode is not particularly fixed. The processing mode is also set with the “initial setting” key 2904, and only the frequently used mode is displayed on the operation unit 2900. The mode which is not used frequently is selected with the “initial setting” key 2904 at the time of use. This is because operability is better when the extra mode is not displayed. Also, when the density notch is switched, the reading table is switched to the corresponding set value.

  What is assigned to “text” and “photo” is arbitrarily selected by an “initial setting” key 2904. FIG. 5B shows a method of adjusting the image quality for selecting and customizing the image quality according to “initial setting” 2904.

  In the item for setting “character” 2921 or “photo” 2922 on the operation unit, “character original 1” mode and “photo original 1” which are also displayed on the initial setting screen as initial values at the time of factory shipment. Each mode is set. This is a document mode set by the manufacturer that many users would generally use.

  In many cases, it can be used by the user as it is, but there are different requirements and items to be adjusted.

  In such a case, as one method, an image quality mode prepared in advance by the manufacturer based on the experience requested in the market so far can be selected from the “initial setting” screen 2930. However, if the user's request still cannot be met, it is necessary to make an adjustment for customization based on the mode provided by the manufacturer closest to the user's request.

  When selecting from among the image quality modes provided in the “initial setting” 2930, for example, “character original 1” 2931, “character original 2” 2932, and “character original 3” 2933 are modes suitable for “character original”. "Photo Original 1" 2934, "Photo Original 2" 2935, and "Photo Original 3" 2935 are prepared as modes suitable for "photo original", and for other general-purpose originals As a mode suitable for “special document”, “special document 1” 2937, “special document 2” 2938, and “special document 3” 2939 are prepared. A mode frequently used by the operator is assigned to “character” 2905 and “photo” 2906 on the operation unit 2910. However, it is not always necessary to assign a mode corresponding to “character document” to “character” 2905.

  If many modes corresponding to each image quality that can be selected on the initial setting screen are displayed on the operation unit 2910, the selection range becomes wider and it can correspond to many users, but it is substantially used. Since there are not many modes to perform, the operability is reduced and it is not very useful. The selection range has a plurality of modes for text-based, photo-based, and special manuscripts, and whether to display on the front surface is changed according to the usage environment.

  Next, adjustment items and adjustment means displayed for image quality adjustment will be described. A display unit 2950 shows adjustment items and adjustment means displayed for image quality adjustment. First, the reference for image quality adjustment is selected from the image quality selection list in the initial setting 2903 in “image quality mode selection”. For example, when customizing to suit the user's preference based on “character document 2” 2932, “character document 2” 2932 is selected in “image quality mode selection” 2951. The selection means can be selected by returning to the initial screen 2910 or by adding a serial number to the image quality list of the initial setting 2930 and selecting the number.

  An adjustment item 2952 for image quality adjustment is an item to be displayed such as “read density correction” 2953, for example, and a fine adjustment is performed by inputting a relative value as an adjustment value. For example, when “character document 2” 2932 is selected as a reference, each adjustment item 2952 displays the content provided in the initial setting 2930 as an adjustment value “0”. It is based on the mode provided by the initial setting 2930, not an absolute value. The operator performs a relative increase (for example, +1) or a decrease (for example, -1) with respect to this reference. For example, “Sharpness adjustment: Low density part” 2959 of “Text Document 2” 2932 is adjusted to be stronger (+1), stronger (+2), or weaker (−1) than the manufacturer's set value. I do. Regarding the display of the adjustment amount, the image quality mode selected by “image quality mode selection” is initially set to “0” in any mode. Even when “character document 1” 2931 is selected, for example, the adjustment amount of “writing density adjustment: solid portion” 2954 is “0”. Although the absolute standard of “writing density adjustment: solid portion” 2954 set in “character original 1” 2931 and “character original 2” 2932 is different, it is not necessary for the user to be aware of the absolute amount, and the mode is selected. Since it is sufficient to use the adjusted time as a reference for the adjustment amount, “0” is displayed. The display of adjustment items on the display unit 2910 changes in conjunction with the selected image quality mode. Although there are a plurality of adjustment items 2952, they are not effective in the image quality mode provided in all initial settings, and therefore invalid adjustment items are not displayed.

  Examples of image quality adjustment are shown in FIGS. 30 (a) and 30 (b). (A) is the case where the reference image quality mode is “character original 1” 2931, and (b) is the case where “photo original 2” 2932 is selected.

  In the setting of “character document 1” 2931, there is no item corresponding to the adjustment item “sharpness adjustment: software” 2957 in FIG. In the case of a text document, the main content is a request for sharpening the line drawing, and adjustment items for softening the line drawing are unnecessary. For this reason, “Sharpness adjustment: software” 2957 is not displayed on the display unit 2950 when “character document 1” 2931 is selected. For example, in order to make fine adjustment so that “read density correction” 2953 in the displayed adjustment items is darker than the current level, the value of the adjustment value 2970 is changed from “0” to +1.

  In the case of “Photo Original 2” 2935 in (b), since it is an image quality mode that requires smooth gradation reproduction, adjustment items not related to smoothness cannot be set. Therefore, the display unit 2950 does not display the adjustment items such as “sharpness adjustment: line drawing part (sharp)” 2955. The adjustment value is changed relative to the standard adjustment value “0” of “Photo Document 2” 2035.

  An example of each image quality mode provided initially is shown in FIG. This is an example in which an initial set value is provided in each of a mode corresponding to a text original, a mode corresponding to a photo original, and a mode corresponding to a special original. Three initial set values are displayed for each mode, but the present invention is not limited to this, and can be increased or decreased if necessary.

For example, the contents of the character mode 3100 include “character original 1” 3101 that faithfully reproduces the original, particularly “character original 2” 3102 that clearly reproduces text characters, and “character original that clearly reproduces pencil characters” 3 "3103 etc. The contents of the photo mode 3120 include “Photo Original 1” 3121 that faithfully reproduces the gradation of a printed matter such as a gravure, “Photo Original 2” 3122 that faithfully reproduces the gradation of a silver salt photograph, and a map and the like. For example, “photo original 3” 3123 for discriminating color use. The contents of the special mode 3130 include “special manuscript 1” 3131 that reproduces only the character content by removing the background portion of the car vehicle inspection certificate, and “special manuscript 2” 3132 that reproduces a color character manuscript such as bank transfer paper clearly. “Special Document 3” 3233 which improves the density reproduction of a document in which the flat density portion is not uniform as in the dot printer output image.
(Embodiment 4)
In the first and second embodiments, the case where the present invention is applied to a multifunction peripheral has been described. However, the present invention is not limited to this, and the present invention can also be applied to a single scanner. Therefore, in the third embodiment, a case where the present invention is applied to a single scanner will be described.

  FIG. 32 is a block diagram showing the configuration of the scanner according to the fourth embodiment. The scanner 270 shown in the figure can perform optimum density correction by independently controlling density characteristic correction (input density correction) dependent on image reading and document density reproduction characteristics (density correction linked to density notches). It is configured as follows.

  That is, in the conventional scanner, the input density correction and the density correction linked to the density notch are normally handled as one body. However, the scanner 270 according to the third embodiment can operate and control these density corrections independently. I have to. For this reason, for example, it is possible to capture an image having a desired density in conjunction with the density notch while removing stains on the background of the document.

  As shown in the figure, the scanner 270 is configured in the same manner as the scanner unit of the multifunction peripheral 100 shown in FIG. The interface unit 271 is an interface for transmitting image data to an external computer or application.

  The input density correction unit 103 is a processing unit that performs density characteristic correction (input density correction) depending on the document reading unit 101. The input density correction unit 103 converts the shading-corrected digital signal having linear characteristics with respect to the reflectance with respect to the document density. Convert to linear characteristics.

  The density correction unit 106 is a processing unit that performs density correction in conjunction with the image data output from the spatial filter processing unit 105 and the fluctuation threshold value, and corrects the read original density and the reproduction density corresponding to the density notch. Perform the conversion.

Here, the input density correction unit 103 and the density correction unit 106 can be independently controlled by operating the operation unit 120. In addition, by registering a combination of the input density correction by the input density correction unit 103 and the density correction by the density correction unit 106 in the operation unit 120, a desired output image can be obtained by an extremely simple operation.
(Embodiment 5)
Next, another embodiment of the present invention will be described. FIG. 33 shows an embodiment of the configuration of an image processing system according to the present invention. The image processing system of this embodiment mainly includes an image reading unit 3301, a writing unit 3302, a first density correction unit 3303, a second density correction unit 3304, a third density correction unit 3305, a first and a second. And a control unit 3306 for independently controlling the third density correction units 3303, 3304, and 3305, a system bus 3308, and a video bus control unit 3307. The system bus 3308 connects the image reading unit 3301, the writing unit 3302, the first density correction unit 3303, the second density correction unit 3304, and the third density correction unit 3305 and the control unit 3306. The video bus control unit 3307 controls whether the image read by the image reading unit 3301 is written by the writing unit 3302 or data is exchanged with an external application.

  This system includes a first density correction unit 3303 that performs density characteristic correction (input density correction) depending on image reading, and a second density that corrects document density reproduction characteristics (density correction linked to a density notch). The correction unit 3304 and the third density correction unit 3305 for correcting the density characteristic depending on the writing unit (writing density correction) are independently controlled by the control unit 3306 via the system bus 3308, and each density correction unit is controlled. However, optimal density correction can be performed. As described in the first embodiment, in the conventional composite system, the input density correction and the density correction linked with the density notch are normally handled as one unit, but in the image processing system according to the fifth embodiment, These density corrections can be operated and controlled independently. In the conventional complex system, the user controls the writing density correction independently. However, in the image processing system according to the fifth embodiment, the user actively uses the control unit 3306 for the writing density correction. Can be changed.

  In the first to fifth embodiments, the case where the present invention is applied to a multifunction machine and a scanner has been described. However, the present invention is not limited to this, and the present invention can also be applied to a printer. Specifically, by providing the printer with the write control block 110 shown in FIG. 1, the user can change the write density correction of the printer.

  As described above, according to the first aspect of the present invention, the correction of the density characteristic depending on the image reading unit, the correction of the reproduction characteristic of the original density, and the correction of the density characteristic depending on the writing unit are controlled independently. Since it is configured, it is possible to obtain an image processing apparatus capable of efficiently performing input density correction, density correction linked with density notches, and writing density correction.

  According to the second aspect of the present invention, the filter coefficient is switched according to the input density of the image data, and the data correction according to the density level and the correction of the writing dot formation are performed. Therefore, from the low density part to the high density part. There is an effect that an image processing apparatus capable of reproducing gradations over a wide range can be obtained.

  According to the third aspect of the present invention, the correction of the density characteristic depending on the image reading unit and the correction of the original density reproduction characteristic are independently controlled. There is an effect that an image processing apparatus capable of performing correction efficiently can be obtained.

  According to the invention of claim 4, since the filter coefficient is switched according to the input density of the image data and the data correction is performed according to the density level, gradation reproduction is performed over a wide range from the low density part to the high density part. There is an effect that an image processing apparatus capable of performing the operation is obtained.

  According to the fifth aspect of the present invention, since the density characteristic depending on the writing section is corrected and controlled, an image processing apparatus capable of performing the writing density correction efficiently can be obtained.

  According to the sixth aspect of the present invention, since it is configured to correct the formation of writing dots, it is possible to obtain an image processing apparatus that can reproduce gradations of sharp characters and images.

  According to the seventh aspect of the present invention, it is configured to divide into a low density part, a high density part, and an intermediate area based on a predetermined threshold value, independently set a correction coefficient, and select a density range selection signal. Therefore, there is an effect that an image processing apparatus capable of obtaining image data having different feature amounts such as a low-density character image and a high-density solid image as a uniform output image can be obtained.

  According to the invention of claim 8, since the gradation reproduction process is performed after arbitrarily setting a signal different from the image data and adding or subtracting the signal, the continuous reproduction in the uniform image of the low density portion is performed. It is possible to obtain an image processing apparatus capable of improving the performance.

  According to the ninth aspect of the present invention, since data correction of adjacent pixels is performed two-dimensionally based on the pixel arrangement, the electrical output signal can be faithfully reproduced in consideration of the characteristics of the writing unit. There is an effect that an image processing apparatus capable of correcting the shape of the dots can be obtained.

  According to the invention of claim 10, the type of image quality processing is selected, and the first density correction means, the second density correction means and / or the third density correction is selected based on the selected type of image quality processing. Since the means is controlled independently, there is an effect that an image processing apparatus capable of performing various density corrections only by selecting the image quality can be obtained.

  According to the eleventh aspect of the present invention, since the processing content settings are grouped and the grouped setting procedures are arbitrarily assigned, it is possible to reproduce desired image quality with a simple procedure for the operator. There is an effect that a possible image processing apparatus is obtained.

  According to the twelfth aspect, a mode for normal use can be arbitrarily selected from a plurality of existing image quality modes, the image quality characteristic can be changed to an arbitrary correction value, and correction of the changed image quality characteristic can be performed. Since the configuration is such that the value can be stored, the user can greatly improve the operability by selecting a necessary mode or using it as a reference for correction.

  According to the thirteenth aspect, a mode for normal use can be arbitrarily selected from a plurality of existing image quality modes, the image reading characteristic can be changed to an arbitrary correction value, and the changed image reading characteristic can be changed. Therefore, the user can greatly improve the operability by selecting a necessary mode or using it as a reference for correction.

  According to the fourteenth aspect, a mode for normal use can be arbitrarily selected from a plurality of existing image quality modes, the pixel generation characteristic can be changed to an arbitrary correction value, and the changed pixel generation characteristic can be changed. Therefore, the user can greatly improve the operability by selecting a necessary mode or using it as a reference for correction.

  According to the fifteenth aspect, a mode for normal use is arbitrarily set from a plurality of existing image quality modes, and the correction of the image quality characteristics is made relative to the correction value once set. And the correction value of the changed image quality characteristic can be saved, so that the user can select a necessary mode or use it as a reference for correction, When correction is made when the contents need to be changed, each adjustment value can be adjusted by increasing or decreasing the value with respect to the current set value, and the operability from the viewpoint of the user can be greatly improved.

  According to the sixteenth aspect, a mode for normal use is arbitrarily set from among a plurality of existing image quality modes, and correction of image reading characteristics is made relative to a correction value that has been set once. And the correction value of the changed image reading characteristic can be stored. Therefore, the user selects a necessary mode or used by the user as a reference for correction, and in particular, When correction is made when the setting contents need to be changed, each adjustment value can be adjusted by increasing / decreasing the value with respect to the current setting value, and the operability from the viewpoint of the user can be greatly improved.

  According to the seventeenth aspect, a mode for normal use is arbitrarily set from among a plurality of existing image quality modes, and pixel generation characteristics are corrected relative to a correction value once set. And the correction value of the changed pixel generation characteristic can be stored, so that the user can select a necessary mode or use it as a reference for correction, and in particular, When correction is made when the setting contents need to be changed, each adjustment value can be adjusted by increasing / decreasing the value with respect to the current setting value, and the operability from the viewpoint of the user can be greatly improved.

  According to the invention of claim 18, since the density characteristic correction dependent on the image reading unit, the original density reproduction characteristic correction and the density characteristic correction dependent on the writing unit are controlled independently, There is an effect that it is possible to obtain an image processing method capable of efficiently performing input density correction, density correction linked with density notch, and writing density correction.

  According to the nineteenth aspect of the present invention, the filter coefficient is switched according to the input density of the image data, and the data correction according to the density level and the correction of the writing dot formation are performed. Therefore, from the low density part to the high density part. There is an effect that an image processing method capable of performing gradation reproduction over a wide range can be obtained.

  According to the twentieth aspect of the present invention, the correction of the density characteristic depending on the image reading unit and the correction of the reproduction characteristic of the original density are controlled independently, so that the density linked with the input density correction and the density notch is controlled. There is an effect that an image processing method capable of performing correction efficiently can be obtained.

  According to the twenty-first aspect of the present invention, the filter coefficient is switched according to the input density of the image data, and the data correction is performed according to the density level, so that gradation reproduction can be performed over a wide range from the low density portion to the high density portion. There is an effect that an image processing method that can be performed is obtained.

  According to the twenty-second aspect of the present invention, since the density characteristic depending on the writing unit is corrected and controlled, an image processing method capable of efficiently performing the writing density correction is obtained.

  According to the twenty-third aspect of the present invention, since it is configured to correct the formation of writing dots, an image processing method capable of reproducing gradation of sharp characters and images can be obtained.

  According to a twenty-fourth aspect of the present invention, a configuration is provided in which a correction coefficient is set independently for each of a low density part, a high density part and an intermediate area based on a predetermined threshold value, and a density range selection signal is selected. Therefore, there is an effect that an image processing method capable of obtaining image data having different feature amounts such as a low-density character image and a high-density solid image as a uniform output image can be obtained.

  According to the invention of claim 25, since the gradation reproduction processing is performed after arbitrarily setting a signal different from the image data and adding or subtracting it, the continuous reproduction in the uniform image of the low density portion is performed. It is possible to obtain an image processing method capable of improving the performance.

  According to the invention of claim 26, since the data correction of the adjacent pixels is performed two-dimensionally based on the pixel arrangement, the electrical output signal can be faithfully reproduced in consideration of the characteristics of the writing unit. There is an effect that an image processing method capable of correcting the shape of the dots can be obtained.

  According to the twenty-seventh aspect of the present invention, the type of image quality processing is selected, and the first density correction step, the second density correction step, and / or the third density correction is performed based on the selected type of image quality processing. Since the process correction is controlled independently, an image processing method capable of performing various density corrections only by selecting an image quality can be obtained.

  According to the invention of claim 28, since the setting of processing contents is grouped and the grouped setting procedure is arbitrarily assigned, desired image quality can be reproduced with a simple procedure for the operator. There is an effect that a possible image processing method can be obtained.

  A recording medium according to the invention of claim 29 records a program for causing a computer to execute the method according to any one of claims 18 to 28, so that the program can be read by a machine. Thus, the recording medium capable of realizing the operation according to any one of claims 18 to 28 by a computer is obtained.

  According to the invention of claim 30, since the density characteristic correction dependent on the image reading unit, the original density reproduction characteristic correction and the density characteristic correction dependent on the writing unit are controlled independently, There is an effect that an image processing system capable of efficiently performing input density correction, density correction linked with density notch, and writing density correction can be obtained.

1 is a block diagram illustrating a configuration of a multifunction machine according to Embodiment 1 of the present invention. It is explanatory drawing for demonstrating scanner (gamma) correction | amendment and density correction of the reading original. It is a figure which shows the access from CPU to the RAM shown in FIG. 1, and switching of a table reference. FIG. 2 is a block diagram illustrating detailed configurations of a density correction unit 106 and a gradation processing unit 107 illustrated in FIG. 1. FIG. 5 is a diagram for explaining a download use situation of a binary dither matrix when the RAM shown in FIG. 4 is configured with an address space of 8 bits. FIG. 5 is an explanatory diagram for explaining a case where the RAM shown in FIG. 4 is accessed for a multi-value dither matrix. It is explanatory drawing for demonstrating a binary and multi-value error diffusion process. It is a figure which shows the switching (variation threshold value, fixed threshold value) of the threshold value for quantization. It is a figure which shows the structure of the spatial filter process part shown in FIG. It is explanatory drawing of the switching control regarding the density data of MTF correction. It is a figure which shows the structure which concerns on the setting of a threshold value. It is a figure which shows the structure of the detection of an isolated point. It is a figure which shows the structure which concerns on the correction process of the detected isolated point. It is a figure which shows the structure of a video flow. It is a systematic diagram which shows the system | strain of video control. It is a figure which shows the structure of an APL input. It is a figure which shows the structure of an APL output. It is a figure which shows the structure of a write-system output. It is a structural diagram which shows a data structure. It is a figure which shows the structure of a smoothing function. It is a figure which shows the structure of a write-control part. It is a figure which shows the structure of a memory module. It is a figure which shows an example of a density | concentration conversion table. It is a figure which shows an example of an aggregation function. 10 is a diagram illustrating an example of an operation screen provided in an operation unit according to Embodiment 2. FIG. It is explanatory drawing for demonstrating the density correction by the operation screen of an operation part. FIG. 10 is a diagram illustrating an example of an operation screen provided in an operation unit according to Embodiment 3. FIG. 10 is a diagram illustrating an example of an operation screen provided in an operation unit according to Embodiment 3. FIG. 10 is a diagram illustrating an example of an operation screen provided in an operation unit according to Embodiment 3. FIG. 10 is a diagram illustrating an example of an operation screen provided in an operation unit according to Embodiment 3. FIG. 10 is a diagram illustrating an example of an operation screen provided in an operation unit according to Embodiment 3. 6 is a block diagram illustrating a configuration of a scanner according to Embodiment 3. FIG. It is a block diagram which shows the structure of the system which concerns on Embodiment 5 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 MFP 101 Original reading part 102 Shading correction part 103 Input density correction part 104 Main scanning electric scaling part 105 Spatial filter processing part 107 Gradation processing part 108 Matrix RAM
109 Video path control unit 110 Write control block 110a Pixel correction unit 110b Density conversion unit 110c PWM modulation unit 111 Write unit 112 External application 113 External APLI / F unit 114 Memory I / F
115 Memory Control Unit 116 Printer Page Memory 117 RAM
118 ROM
119 CPU
120 Operation unit

Claims (30)

In an image processing apparatus that optically reads image data of a document by an image reading unit and writes the read image data on a recording sheet by a writing unit.
First density correction means for correcting density characteristics depending on the image reading unit;
Second density correction means for correcting the reproduction characteristics of the original density;
Third density correction means for correcting density characteristics depending on the writing unit;
Control means for independently controlling the first density correction means, the second density correction means and the third density correction means;
An image processing apparatus comprising:   The control unit includes a switching unit that switches a filter coefficient according to the input density of the image data, a data correction unit that performs data correction according to a density level, and a dot correction unit that corrects formation of a writing dot. The image processing apparatus according to claim 1. In an image processing apparatus for optically reading image data of a document by an image reading unit and correcting the density of the read image data,
First density correction means for correcting density characteristics depending on the image reading unit;
Second density correction means for correcting the reproduction characteristics of the original density;
Control means for independently controlling the first density correction means and the second density correction means;
An image processing apparatus comprising:   The image processing apparatus according to claim 3, wherein the control unit includes a switching unit that switches a filter coefficient according to an input density of the image data, and a data correction unit that performs data correction according to a density level. . In an image processing apparatus that writes image data onto a recording sheet by a writing unit,
Third density correction means for correcting density characteristics depending on the writing unit;
Control means for independently controlling the third density correction means;
An image processing apparatus comprising:   The image processing apparatus according to claim 5, wherein the control unit includes a dot correction unit that corrects formation of a writing dot.   The switching unit includes a selection unit that divides a low density part, a high density part, and an intermediate area based on a predetermined threshold, sets a correction coefficient independently, and selects a density range selection signal. The image processing apparatus according to claim 2 or 4.   The image processing apparatus according to claim 2, wherein the data correction unit arbitrarily sets a signal different from the image data, adds or subtracts the signal, and then performs gradation reproduction processing.   The image processing apparatus according to claim 2, wherein the dot correction unit performs data correction of adjacent pixels two-dimensionally based on a pixel arrangement.   Image quality selecting means for selecting the type of image quality processing is further provided, and the control means is configured to select the first density correction means, the second density correction means, and / or The image processing apparatus according to claim 1, wherein the third density correction unit is independently controlled.   11. The image quality selecting means comprises grouping means for grouping setting of processing contents, and assigning means for arbitrarily assigning setting procedures grouped by the grouping means. The image processing apparatus described. The arbitrarily assigning means is:
Means for arbitrarily selecting a mode for normal use from a plurality of existing image quality modes;
Correction means for correcting image quality characteristics;
Means for changing the correction value of the image quality characteristic corrected by the correction means to an arbitrary value;
12. The image processing apparatus according to claim 11, further comprising means for storing the changed correction value of the image quality characteristic. The arbitrarily assigning means is:
A means for arbitrarily setting a mode for normal use from a plurality of existing image quality modes,
Correction means for correcting image reading characteristics;
Means for changing the correction value of the image reading characteristic to be corrected by the correction means to an arbitrary value;
12. The image processing apparatus according to claim 11, further comprising means for storing the changed correction value of the image reading characteristic. The arbitrarily assigning means is:
A means for arbitrarily setting a mode for normal use from a plurality of existing image quality modes,
Correction means for correcting pixel generation characteristics;
Means for changing the correction value of the pixel generation characteristic corrected by the correction means to an arbitrary value;
12. The image processing apparatus according to claim 11, further comprising means for storing the corrected pixel generation characteristic correction value. The arbitrarily assigning means is:
A means for arbitrarily setting a mode for normal use from a plurality of existing image quality modes,
Correction means for correcting image quality characteristics;
Means for relatively changing the correction value of the image quality characteristic to be corrected by the correction means with respect to a value once set;
12. The image processing apparatus according to claim 11, further comprising means for storing the changed correction value of the image quality characteristic. The arbitrarily assigning means is:
A means for arbitrarily setting a mode for normal use from a plurality of existing image quality modes,
Correction means for correcting image reading characteristics;
Means for relatively changing the correction value of the image reading characteristic to be corrected by the correction means with respect to a value once set;
12. The image processing apparatus according to claim 11, further comprising means for storing the changed correction value of the image reading characteristic. The arbitrarily assigning means is:
A means for arbitrarily setting a mode for normal use from a plurality of existing image quality modes,
Correction means for correcting pixel generation characteristics;
Means for relatively changing the correction value of the pixel generation characteristic to be corrected by the correction means with respect to a temporarily set value;
12. The image processing apparatus according to claim 11, further comprising means for storing the corrected pixel generation characteristic correction value. In an image processing method for optically reading image data of a document by an image reading unit and writing the read image data on a recording sheet by a writing unit,
A first density correction step for correcting density characteristics depending on the image reading unit;
A second density correction step for correcting the reproduction characteristics of the original density;
A third density correction step for correcting density characteristics depending on the writing unit;
A control step for independently controlling correction by the first density correction step, the second density correction step, and the third density correction step;
An image processing method comprising:   The control step includes a switching step of switching a filter coefficient according to the input density of the image data, a data correction step of performing data correction according to the density level, and a dot correction step of correcting the formation of writing dots. The image processing method according to claim 18. In an image processing method for optically reading image data of a document by an image reading unit and correcting the density of the read image data,
A first density correction step for correcting density characteristics depending on the image reading unit;
A second density correction step for correcting the reproduction characteristics of the original density;
A control step for independently controlling correction by the first density correction step and the second density correction step;
An image processing method comprising:   21. The image processing method according to claim 20, wherein the control step includes a switching step of switching a filter coefficient according to an input density of the image data, and a data correction step of performing data correction according to the density level. . In an image processing method for writing image data on a recording sheet by a writing unit,
A third density correction step for correcting density characteristics depending on the writing unit;
A control step for independently controlling the third density correction step;
An image processing method comprising:   23. The image processing method according to claim 22, wherein the control step includes a dot correction step of correcting formation of writing dots.   The switching step includes a selection step of dividing a low density portion, a high density portion, and an intermediate area based on a predetermined threshold value, setting a correction coefficient independently, and selecting a density range selection signal. The image processing method according to claim 19 or 21.   The image processing method according to claim 19 or 21, wherein in the data correction step, a tone reproduction process is performed after arbitrarily setting a signal different from the image data and adding or subtracting the signal.   The image processing method according to claim 19 or 23, wherein the dot correction step performs data correction of adjacent pixels two-dimensionally based on a pixel arrangement.   An image quality selection step for selecting a type of image quality processing is further included, and the control step includes the first density correction step, the second density correction step, and / or the process based on the type of image quality processing selected in the image quality selection step. 23. The image processing method according to claim 18, 20 or 22, wherein the correction in the third density correction step is independently controlled.   28. The image quality selecting step includes a grouping step for grouping setting of processing contents, and an assigning step for arbitrarily assigning the setting procedure grouped by the grouping step. The image processing method as described.   A computer-readable recording medium having recorded thereon a program for causing a computer to execute the method according to any one of claims 18 to 28. In an image processing system for optically reading image data of a document by an image reading unit and writing the read image data on a recording sheet by a writing unit,
First density correction means for correcting density characteristics depending on the image reading unit;
Second density correction means for correcting the reproduction characteristics of the original density;
Third density correction means for correcting density characteristics depending on the writing unit;
Control means for independently controlling the first density correction means, the second density correction means and the third density correction means;
An image processing system comprising:

Images