JP4003439B2 - Image forming apparatus and image forming method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image forming apparatus and an image forming method, and more particularly to an image forming apparatus and an image forming method for acquiring an optimal image by selecting a plurality of ground color removal processes according to a print mode.
[0002]
[Prior art]
Color copiers often have a mixture of color printing and black and white printing. Here, high-quality output results can be acquired by performing black-and-white printing-specific image processing on black-and-white printing, and color printing-specific image processing on color printing.
[0003]
Such image processing includes a ground color removal process of detecting the ground color level of the ground color and the background, and removing the ground color and the background based on the detected ground color level. There is processing.
[0004]
One is a pre-scan (rough scan performed at a high speed in advance before the original image is read) to detect the ground color level of the entire surface of the document, and the ground color removal amount is determined based on the detected ground color level. This is a process for setting and removing the ground color when the document is scanned again. The process of detecting the ground color by this prescan (hereinafter referred to as prescan ground color removal process) can accurately detect the ground color of the document, thereby enabling ground color removal processing giving priority to image quality.
[0005]
The other is to detect the ground color level from the acquired sampling area by using the image data on the line at the leading edge of the original to be scanned first as the sampling area. In this process, the ground color removal amount is set based on the ground color level, and the ground color is removed from the entire surface of the document in one scan. The ground color detection process (hereinafter referred to as speed priority ground color removal process) in this single scan improves the productivity and the FCOT (Fast Copy Output Time), so that the ground color removal process prioritizes speed. Is possible.
[0006]
[Problems to be solved by the invention]
However, in the prescan background color removal process, there is a problem that the time for performing the scan twice decreases the productivity and the FCOT. Further, in the speed priority ground color removal process, only the leading edge portion of the document is used as a sampling region.
[0007]
Therefore, the present invention selects a pre-scan ground color removal process that prioritizes image quality over color printing, or selects a speed priority ground color removal process that prioritizes speed over black and white printing. An object of the present invention is to provide an image forming apparatus and an image forming method capable of selecting an optimum ground color removal process according to necessity.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the invention of claim 1 is an image forming apparatus for copying an original image in any of a plurality of color processing modes including black and white processing and full color processing, and reading means for reading the original image; A first ground color removing unit that removes the ground color of the original image read again by the reading unit according to the ground color level detected based on the entire surface of the original image read by the reading unit; A second ground color removing unit that removes the ground color of the document image in accordance with the ground color level detected based on a minute unit of the original image, and the first color when the color processing mode is the full color processing. And a ground color removal selection means for selecting the second ground color removal means when the color processing mode is the monochrome processing.
[0009]
According to a second aspect of the present invention, any one of a plurality of color processing modes including black and white processing, full color processing, and automatic color processing for automatically selecting either the black and white processing or the full color processing according to an original image. In the image forming apparatus for copying the original image, the original read again by the reading means according to the reading means for reading the original image and the ground color level detected based on the entire surface of the original image read by the reading means. A first ground color removing means for removing the ground color of the image; and a second ground color removing means for removing the ground color of the document image according to a ground color level detected based on a minute unit of the document image read by the reading means. And a color image discriminating unit that discriminates whether or not the original image read by the reading unit is a color image, and the color processing mode is the color self-determining unit. In the case of processing, the color image discrimination means determines the color image of the document image, the first ground color removal means detects the ground color level based on the entire surface of the document image, and the second ground color removal. The background color level based on the minute unit of the original image is simultaneously detected by the means, and when the color image determining means determines that the original is not a color image, the second background color removing means is applied to the original image. When the background image is removed and the color image determining unit determines that the image is a color image, the original image is read again, and the read background image is subjected to background color removal by the first background color removing unit. It is characterized by that.
[0010]
According to a third aspect of the present invention, in the image forming method for copying an original image in any of a plurality of color processing modes including black and white processing and full color processing, the reading means reads the original image, and the ground color removal selecting means is When the color processing mode is the full color processing, the background color of the original image read again by the reading unit is removed according to the ground color level detected based on the entire surface of the original image read by the reading unit. 1 ground color removing means is selected, and when the color processing mode is black and white processing, the ground color of the original image is determined according to the ground color level detected based on a minute unit of the original image read by the reading means. The second ground color removing means for removing the color is selected.
[0011]
According to a fourth aspect of the present invention, any one of a plurality of color processing modes including black and white processing, full color processing, and automatic color processing that automatically selects either the black and white processing or the full color processing according to a document image. In the image forming method for copying a document image with the above, when the reading unit reads the document image and the color processing mode is the automatic color processing, the document image read by the reading unit by the color image determination unit is a color image. And the first ground color removing unit detects the ground color level based on the entire surface of the document image, and the second ground color removing unit detects the ground color level based on the minute unit of the document image. When the color image determining means determines that the image is not a color image, the second background color removing means detects the background based on the entire surface of the detected original image. Depending on the level, when the background color of the document image is removed and the color image determination unit determines that the image is a color image, the document image is read again, and the first background color removal unit detects the detected color. According to the background color level based on a minute unit of the document image, the background color of the re-read document image is removed.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of an image forming apparatus and an image forming method according to the present invention will be described below in detail with reference to the accompanying drawings.
[0019]
FIG. 1 is a block diagram showing a basic configuration of an image forming apparatus according to the present invention.
[0020]
As shown in FIG. 1, an image forming apparatus according to the present invention includes an image input unit 101 that performs image input processing, a front-stage correction processing unit 102, a front-stage color space conversion unit 103, an image processing unit 104, and a rear-stage color space conversion unit 105. , A post-stage correction processing unit 106, and an image output unit 107.
[0021]
Here, the image input unit 101 includes a sensor or the like for reading an original, and in this embodiment, a three-line CCD that separates and reads the three primary colors R (red), G (green), and B (blue). It is comprised as a sensor and is equipped with the reading part which reads each color (R, G, B). Here, the three-line CCD sensor is a CCD in which each color R, G, B is linearly arranged for each color, and these are arranged in parallel at predetermined intervals along the sub-scanning direction.
[0022]
The pre-correction processing unit 102 performs shading correction, gap correction, and the like on the input image data of each color R, G, B from the 3-line CCD sensor of the image input unit 101. Here, the shading correction is correction so that the white level that fluctuates along the sub-scanning direction is constant in the input image data. The gap correction is to make correction so that the timing of reading the same part on the original differs for each color in the 3-line CCD.
[0023]
The pre-stage color space conversion unit 103 converts the input image data of each color R, G, B from the image input unit 101 into L * (Elster), a * (Aester), and b * (Biester).
[0024]
Further, the image processing unit 104 performs ground color removal processing, scaling processing, and spatial filter correction processing on the image data of each color L *, a *, and b * from the previous color space conversion unit 103.
[0025]
Further, the post-stage color space conversion unit 105 outputs C (cyan), M (magenta), Y (yellow), and K (black) image data for each color L *, a *, and b * from the image processing unit 104. ).
[0026]
Further, the post-stage correction processing unit 106 performs output tone correction and the like on each color (C, M, Y, K) output from the post-stage color space conversion unit 105 and outputs it to the image output unit 107.
[0027]
Next, the ground color removal process performed by the image processing unit 104 will be described.
[0028]
FIG. 2 is a block diagram showing the processing procedure of ground color detection and ground color removal in the image processing unit 104.
[0029]
As shown in FIG. 2, the L *, a *, and b * system image data is input to the minute area background color detection unit 204 and the entire background color detection unit 205 in the image processing unit 104. The micro area ground color detection unit 204 performs ground color detection on a micro area of the input L *, a *, and b * image data, and the entire surface ground color detection unit 205 receives the input L *, a *. The background color detection is performed on the entire surface of the b * system image data. In parallel with the ground color detection, the image data of L *, a *, b * series is subjected to enlargement / reduction processing in the enlargement / reduction unit 201, and subjected to spatial filter correction processing in the spatial filter unit 202. The color is input to the color removal unit 203. Here, the ground color level of the L *, a *, and b * system image data detected by the minute region ground color detecting unit 204 and the entire surface ground color detecting unit 205 is input to the ground color removing unit 203.
[0030]
Then, the ground color removing unit 203, to which the L *, a *, b * system image data and the ground color level of the L *, a *, b * system image data are input, receives the L *, a *, b *. Based on the ground color level of the system image data, ground color removal is performed on the L *, a *, and b * system image data.
[0031]
Here, there are two kinds of processing as processing for detecting the ground color of the image data and the ground color level of the background and removing the ground color and the background based on the detected ground color level (hereinafter referred to as ground color removal processing). is there.
[0032]
One is a pre-scan (rough scan performed at a high speed in advance before the original image is read) to detect the ground color level of the entire surface of the document, and the ground color removal amount is determined based on the detected ground color level. This is a pre-scanning ground color removal process for performing ground color removal when setting and scanning the document again.
[0033]
In the ground color detection and ground color removal processing procedure as shown in FIG. 2, the ground color level is detected from the image data read by the prescan in the entire ground color detection unit 205, and the detected ground color level is the ground color removal. When the image data input to the unit 203 is temporarily stored and read in the second scan is input to the ground color removal unit 203, the image data is based on the ground color level temporarily stored in the ground color removal unit 203. Remove the ground color.
[0034]
This pre-scanning ground color removal processing can accurately detect the ground color of the document, thereby enabling ground color removal processing giving priority to image quality. However, productivity and FCOT are reduced when the scan is performed twice.
[0035]
The other is that the image data on the line at the leading edge of the original to be scanned first after scanning is used as a sampling area, the ground color level is detected from the acquired sampling area, and the ground color level is detected based on the detected ground color level. This is a speed-priority ground color removal process in which a color removal amount is set and ground color removal is performed on the entire surface of the document in one scan.
[0036]
In the ground color detection and ground color removal processing procedure as shown in FIG. 2, the ground color level is detected for each line from the image data of the original read by the micro area ground color detection unit 204, and the detected ground color is detected. The level is input to the ground color removal unit 203 for each line, and background color removal is performed for each line on the image data read by the scan input to the ground color removal unit 203.
[0037]
This speed priority ground color removal process improves the productivity and FCOT, thereby enabling the ground color removal process to prioritize speed. However, since only the leading edge of the document is used as a sampling area, there is a problem such as erroneous detection of the ground color.
[0038]
Therefore, the image forming apparatus according to the present invention selects a pre-scan ground color removal process that prioritizes image quality for color printing, or selects a speed-priority ground color removal process that prioritizes speed for monochrome printing. be able to.
[0039]
FIG. 3 is a view showing an example of a “ground color removal setting” screen 301 displayed on the display screen included in the image forming apparatus according to the present invention.
[0040]
In this embodiment, an image forming apparatus according to the present invention has a function called a color mode for performing color printing and a function called a monochrome mode for performing monochrome printing, and a prescan ground color removal process for each of the color mode and the monochrome mode. Alternatively, speed priority ground color removal processing can be set.
[0041]
The user operates a “main menu” screen (not shown) of the display screen included in the image forming apparatus according to the present invention to display a “ground color removal setting” screen 301 as shown in FIG. Display. Here, a “color mode” button 302, a “monochrome mode” button 303, and a “return” button 304 are displayed on the “background color removal setting” screen 301.
[0042]
Then, by operating (for example, pressing) the “color mode” button 302 or the “monochrome mode” button 303, a “background color removal process selection” screen 401 as shown in FIG. 4 is displayed. Further, by operating the “return” button 304 or the like, it is possible to return to the “main menu” screen.
[0043]
FIG. 4 is a view showing an example of a “background color removal process selection” screen 401 displayed on the display screen included in the image forming apparatus according to the present invention.
[0044]
As shown in FIG. 4, the “background color removal process selection” screen 401 includes a “pre-scan background color removal process” button 402, a “speed priority ground color removal process” button 403, a “cancel” button 404, and “return”. A button 405 is displayed.
[0045]
For example, when the “background color removal selection” screen 401 is displayed by operating the “color mode” button 302 displayed on the “background color removal setting” screen 301 shown in FIG. If a pre-scan ground color removal process that prioritizes image quality is to be performed, the “pre-scan ground color removal process” button 402 is operated, for example, to the control unit provided in the image forming apparatus according to the present invention “pre-color mode pre-color processing”. The information “perform scan ground color removal processing” is set, and the “pre-scan ground color removal processing” button 402 changes to a highlighted display as shown in FIG. Further, by operating the “pre-scan ground color removal process” button 402 that is highlighted, the pre-scan ground color removal process can be canceled in the color mode, and the “return” button 405 is operated. By doing so, it is possible to return to the “background color removal setting” screen 301. The same applies to the “speed priority ground color removal process” button 403.
[0046]
By operating the “cancel” button 404, the ground color removal processing method selected on the “background color removal processing selection” screen 401 becomes invalid, and the “ground color removal setting” screen 301 is displayed again. For example, even if the “pre-scan ground color removal process” button 402 is operated and the “pre-scan ground color removal process” button 402 changes to highlighted display, if the “cancel” button 404 is operated, The “removal processing” button 402 changes to gray display, and the “ground color removal setting” screen 301 is displayed again.
[0047]
The image forming apparatus according to the present invention performs color printing on a document to be printed in addition to the color mode for performing color printing and the monochrome mode for performing monochrome printing. If the document is detected as a black and white document, it further has a function called a color automatic mode for performing black and white printing. When the automatic color mode is executed, parallel processing is performed in which color printing and monochrome printing are processed in parallel.
[0048]
In this automatic color mode, a prescan ground color removal process or a speed priority ground color removal process can be set for each of color printing and monochrome printing.
[0049]
Here, also in the color automatic mode, by operating the “background color removal setting” screen 301 shown in FIG. 3 and the “background color removal processing selection” screen 401 shown in FIG. A pre-scan background color removal process or a speed priority background color removal process can be selected.
[0050]
FIG. 5 is a block diagram showing a configuration in which the image forming apparatus according to the present invention has a color automatic mode function.
[0051]
As shown in FIG. 5, the configuration in which the image forming apparatus according to the present invention has a color automatic mode function includes an image input unit 501 that performs image input processing, a front-stage correction processing unit 502, a front-stage color space conversion unit 503, a color Document detection unit 504, background color detection unit 505, color image processing unit 506, color image background color removal unit 507, monochrome image processing unit 508, monochrome image background color removal unit 509, subsequent color space conversion unit 510, and subsequent correction processing unit 511, an image storage unit 512, and an image output unit 513.
[0052]
Here, the image input unit 501, the pre-stage correction processing unit 502, the pre-stage color space conversion unit 503, the post-stage color space conversion unit 510, the post-stage correction processing unit 511, and the image output unit 513 have the same functions as those shown in FIG. It comprises.
[0053]
The color original detection unit 504 determines whether the image data of L *, a *, and b * is a color image.
[0054]
The ground color detection unit 505 includes the micro area ground color detection unit 204 and the entire background color detection unit 205 shown in FIG. 2, and the micro area ground color detection unit 204 and the entire background color detection unit 205 are input. Ground color detection is performed on the image data converted into the L *, a *, and b * systems, and the detected ground color level is input to the color image ground color removal unit 507 and the monochrome image ground color removal unit 509. The
[0055]
The color image processing unit 506 includes an enlargement / reduction unit 201 and a spatial filter unit 202, and performs scaling processing and spatial filter correction processing on the input L *, a *, and b * system image data, respectively. Do.
[0056]
Further, when the L *, a *, and b * system image data from the color image processing unit 506 and the ground color level from the ground color detection unit 505 are input, the color image ground color removing unit 507 receives the ground color. Based on the level, the ground color is removed from the L *, a *, and b * image data.
[0057]
Also, the black and white image processing unit 508 receives L * image data from L *, a *, and b * system image data. The black and white image processing unit 508 includes an enlargement / reduction unit 201 and performs a scaling process on the L * image data.
[0058]
Further, when the L * image data from the monochrome image processing unit 508 and the ground color level from the ground color detection unit 505 are input, the monochrome image ground color removing unit 509 receives the L * based on the ground color level. The background color is removed from the image data. In this embodiment, L * image data is input to the monochrome image processing unit 508. However, the present invention can be applied even if a * image data or b * image data is input.
[0059]
Further, the image storage unit 512 temporarily stores the color image subjected to the ground color removal by the color image ground color removal unit 507 and the monochrome image subjected to the ground color removal by the monochrome image ground color removal unit 509.
[0060]
Here, in the color automatic mode, the prescan ground color removal process or the speed priority ground color removal process can be set for each of color printing and monochrome printing.
[0061]
Next, the processing procedure for selecting the ground color removal processing in the color automatic mode will be described with reference to the flowchart of FIG. In this embodiment, the pre-scanning ground color removal process is selected for color printing, and the speed priority ground color removal process is selected for monochrome printing.
[0062]
The first scan is started (step S601), the entire background color detection unit 205 detects the background color of the entire image data read in the first scan, and the minute area background color detection unit 204 performs the first time. The background color detection is performed for each line from the image data read in the scan (step S602), and the black and white image data subjected to the black and white image processing is performed on the image data read in the first scan. Then, speed priority ground color removal processing is performed based on the ground color level detected by the minute region ground color detection unit 204 (step S603), and color document detection is performed (step S604).
[0063]
When the determination result of color original detection is a black and white original (NO in step S605), a black and white image subjected to speed priority ground color removal processing is output (step S606), and the processing procedure ends.
[0064]
If the color document detection determination result is a color document (YES in step S605), the second scan is started (step S607), and color image processing is performed on the image data read in the second scan. Then, pre-scan ground color removal processing is performed on the color image data subjected to color image processing based on the ground color level detected by the entire ground color detection unit 205 (step S608), and the color subjected to the pre-scan ground color removal processing is performed. An image is output (step S609), and the processing procedure ends.
[0065]
Furthermore, when speed priority ground color removal processing is set in color printing in the color automatic mode, a color image can be output in one scan, optimal ground color removal processing according to the user's needs is performed, and No extra scanning is required.
[0066]
That is, by setting the ground color removal processing for color printing and monochrome printing in the color automatic mode, processing according to the needs of the user in color printing and monochrome printing becomes possible.
As described above, according to the present invention, the pre-scanning ground color removal process that prioritizes image quality over color printing is selected, or the speed-priority ground color removal process that prioritizes speed over monochrome printing is selected. Thus, there is an effect that it is possible to select an optimum ground color removal process according to the user's needs.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a basic configuration of an image forming apparatus according to the present invention.
FIG. 2 is a block diagram showing a ground color detection and ground color removal processing procedure in the image processing unit 104;
FIG. 3 is a diagram showing an example of a “ground color removal setting” screen 301 displayed on a display screen included in the image forming apparatus according to the present invention.
FIG. 4 is a view showing an example of a “background color removal process selection” screen 401 displayed on a display screen included in the image forming apparatus according to the present invention.
FIG. 5 is a block diagram illustrating a configuration in which the image forming apparatus according to the present invention has a function of a color automatic mode.
FIG. 6 is a flowchart showing a processing procedure for selecting a ground color removal process in the color automatic mode.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 101 Image input part 102 Pre-stage correction process part 103 Pre-stage color space conversion part 104 Image process part 105 Post-stage color space conversion part 106 Post-stage correction process part 107 Image output part 201 Enlargement / reduction part 202 Spatial filter part 203 Ground color removal part 204 Micro area Ground color detection unit 205 Whole surface color detection unit 301 “Background color removal setting” screen 302 “Color mode” button 303 “Monochrome mode” button 304 “Return” button 401 “Background color removal processing selection” screen 402 “Prescan ground color” “Removal processing” button 403 “Speed priority ground color removal processing” button 404 “Cancel” button 405 “Return” button 501 Image input unit 502 Previous stage correction processing unit 503 Previous stage color space conversion unit 504 Color document detection unit 505 Ground color detection unit 506 Color image processing unit 507 Color image ground color removal unit 508 Black and white image processing unit 509 White Image ground color removing unit 510 subsequent color space conversion unit 511 subsequent correction processing unit 512 the image storage unit 513 an image output unit

Claims (4)

In an image forming apparatus for copying a document image in any of a plurality of color processing modes including black and white processing and full color processing,
Reading means for reading the document image;
First ground color removing means for removing the ground color of the original image read again by the reading means according to the ground color level detected based on the entire surface of the original image read by the reading means;
A second ground color removing unit that removes the ground color of the document image according to a ground color level detected based on a minute unit of the document image read by the reading unit;
When the color processing mode is the full color processing, the first ground color removing unit is selected, and when the color processing mode is the monochrome processing, the second ground color removing unit is selected. An image forming apparatus comprising: Image forming apparatus for copying a document image in any of a plurality of color processing modes including monochrome processing, full-color processing, and automatic color processing for automatically selecting either monochrome processing or full-color processing according to the document image In
Reading means for reading the document image;
First ground color removing means for removing the ground color of the original image read again by the reading means according to the ground color level detected based on the entire surface of the original image read by the reading means;
A second ground color removing unit that removes the ground color of the document image according to a ground color level detected based on a minute unit of the document image read by the reading unit;
Color image discrimination means for discriminating whether or not the document image read by the reading means is a color image,
When the color processing mode is the automatic color processing, the color image discrimination unit determines a color image for the document image, and the first ground color removal unit detects a ground color level based on the entire surface of the document image. And simultaneously detecting the ground color level based on the minute unit of the original image by the second ground color removing means,
If the color image determining means determines that the image is not a color image, the document image is subjected to ground color removal by the second ground color removing means,
When the color image determining means determines that the image is a color image, the original image is read again, and the read background image is subjected to ground color removal by the first ground color removing means. Forming equipment. In an image forming method for copying an original image in any of a plurality of color processing modes including black and white processing and full color processing,
Reading means reads the original image,
The ground color removal selection means is
When the color processing mode is the full color processing, a first color for removing the ground color of the original image read again by the reading means according to the ground color level detected based on the entire surface of the original image read by the reading means. Select the ground color removal method,
When the color processing mode is the monochrome processing, a second ground color removing unit that removes the ground color of the document image according to a ground color level detected based on a minute unit of the document image read by the reading unit. An image forming method comprising: selecting an image. Image forming method for copying document image in any of a plurality of color processing modes including monochrome processing, full color processing, and automatic color processing for automatically selecting either monochrome processing or full color processing according to document image In
Reading means reads the original image,
When the color processing mode is the automatic color processing, the color image determining unit determines whether or not the document image read by the reading unit is a color image, and the first ground color removing unit determines whether the document image is a color image. The ground color level based on the entire surface is detected, and the second ground color removing means detects the ground color level based on the minute unit of the document image,
When the color image determining unit determines that the image is not a color image, the second background color removing unit removes the background color of the document image according to the detected background color level based on the entire surface of the document image. ,
When the color image determining unit determines that the image is a color image, the document image is read again, and the first background color removing unit reads the document image according to the background color level based on the detected minute unit of the document image. An image forming method comprising removing a ground color from a document image read again.

Images