JP2000270220A - Image processor, image processing method, and computer readable medium recorded with program to be executed by computer and read by the computer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve image quality by suppressing deterioration in image quality such as dirt on background and blurred image caused by a floating original in the case of using an automatic document feeder ADF through revision of a parameter of image processing. SOLUTION: A system controller (discrimination means) 220 uses an ADF 120 to discriminate whether or not image data are received. An image processing unit (revision means) 200 revises a setting value used for respective image processing of an RGB smoothing filter 202, a background elimination circuit 203 and an edge emphasis filter 206 on the basis of the discrimination result.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image processing apparatus used in a color digital copying machine, a color scanner, and the like having a function of automatically conveying a document using an automatic document feeder (hereinafter, referred to as ADF). The present invention relates to an image processing method and a computer-readable recording medium storing a program for causing a computer to execute the method. More specifically, an image processing apparatus capable of minimizing background contamination and image quality deterioration due to floating of an original when using the ADF,
The present invention relates to an image processing method and a computer-readable recording medium storing a program for causing a computer to execute the method.

[0002]

2. Description of the Related Art Conventionally, in digital copying machines and the like,
When a non-white paper such as rough paper or newspaper is used as a document and this is copied (image formation), a so-called background removal process of cutting the background density is performed. This background removal processing has been proposed and implemented by various methods. As a typical example, as a first background removal method, the background density is determined by pre-scanning a document set in a scanner, detecting the density of the document, creating a histogram of the density, and obtaining a peak level. As a second method for detecting and removing the background, as a second method for removing the background, the signal before reading by the CCD sensor and performing shading correction is A
A device that removes the background by returning to a reference voltage of a / D converter is known.

However, in the first background removal method, the document must be scanned twice and read, so that the reading process takes time. Further, in the second background removal method, since the signal contains unevenness (distortion) of the optical system, accurate background removal cannot be performed. In order to solve these problems, the following devices have been proposed and disclosed.

[0004] For example, in a "background removing apparatus" disclosed in Japanese Patent Laid-Open No. Hei 6-31359, a pixel value is sampled for each line of an input digital image signal, and the sampled value of each line is calculated. An average value is obtained, and the average value is used as the background density value of the line. The actual background removal amount is obtained by adding a predetermined offset to this average value. As a result, stable background removal is performed without performing prescan.

In the "image processing apparatus" disclosed in Japanese Patent Application Laid-Open No. 7-264409, by using image area separation information and color information from an input digital image signal, the background removal threshold is set to the background density. The background removal amount is switched with high precision by continuously following the level in a plurality of pixel units (block units).

[0006]

However, the use of the technique disclosed in Japanese Patent Application Laid-Open No. 7-264409 as described above makes it possible to achieve very high precision and realize automatic background removal in block units. Since elements influenced by the area separation information and the color information are large, there is a problem in that the background density is simply present in the entire original document or horizontal stripes are generated due to erroneous determination when outputting in black and white.

In the case of Japanese Patent Application Laid-Open No. 6-31359, since the processing is performed in units of lines, the above-described problem does not occur.
When an ADF (automatic document feeder) is used, the document closely adheres to the conveyance belt side with respect to the reading surface, and a gap is generated between the document and the original reading surface, and density fluctuation caused by the floating of the document. Cannot be detected satisfactorily, and as a result, there is a problem that background stains and blurred images are generated and image quality is deteriorated.

Further, as a method for eliminating the floating of the original when the ADF is used, it is possible to make adjustments on the operation unit, but in this case, it is necessary to operate each time, and the operation becomes complicated. I will. Further, it is possible to mount special hardware to avoid the image quality deterioration due to the floating of the original document. However, in this case, the cost is increased, and it is not economical.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and suppresses image quality deterioration such as background contamination and blurred images caused by floating of an original when using an ADF by changing image processing parameters. It aims at improvement.

[0010]

To achieve the above object, an image processing apparatus according to claim 1 is mounted on an image forming apparatus or an image reading apparatus having an automatic document feeder, and receives input image data. In an image processing apparatus that performs image processing such as smoothing filter processing, background removal processing, and edge enhancement processing, a determination unit that determines whether input of image data has been performed using the automatic document feeder, Changing means for changing a set value used for the image processing based on a result of the determination by the determining means.

According to the first aspect of the present invention, the determining means determines the use / non-use state of the automatic document feeder based on, for example, the presence / absence of a document on a document platen. Change the settings used for image processing. Therefore, it is possible to change the set value of the image processing when the ADF is used / not used in consideration of the change in the state of the original on the contact glass (the state of close contact) when the ADF is used / not used, Image quality degradation at the time can be avoided.

According to a second aspect of the present invention, in the image processing apparatus according to the first aspect, the change unit inputs image data using the automatic document feeder by the determination unit. If it is determined that the background removal processing and / or the set value used for the edge enhancement processing is compared with the setting value when the automatic document feeder is not used, the background removal amount is increased, or It is characterized in that the enhancement filter strength is changed so as to increase.

According to the second aspect of the present invention, when it is determined that image data has been input using the automatic document feeder, the background removal amount is increased or the enhancement filter strength is increased. Is changed to Therefore, the background stain caused by the automatic document feeder can be suppressed, and the blurring of the image can be suppressed.

According to a third aspect of the present invention, there is provided the image processing apparatus according to the first or second aspect, wherein the changing means uses the automatic document feeder by the determination means to input image data. If it is determined that the setting has been performed, the set value used in the smoothing filter processing is compared with a set value when the automatic document feeder is not used by −1.
Notch adjustment is performed to change the direction to decrease the smoothness, the set value used in the background removal processing is changed by +1 notch to change the direction to increase the background removal amount, and the set value used in the edge enhancement processing is set to +1 It is characterized in that the notch is adjusted to change the direction in which the degree of emphasis increases.

According to the third aspect of the present invention, when it is determined that image data has been input using the automatic document feeder, enhancement is performed so that the smoothness is reduced and the background removal amount is increased. The filter strength is changed so as to increase. Therefore, the background stain caused by the automatic document feeder can be suppressed, and the blurring of the image can be suppressed.

According to a fourth aspect of the present invention, in the image processing method for performing image processing such as smoothing filter processing, background removal processing, and edge enhancement processing on input image data, an automatic document feeder is used. A determination step of determining whether or not image data has been input, and a change step of changing a set value used for the image processing based on a determination result of the determination step. I do.

According to the fourth aspect of the present invention, the determining step determines the use / non-use state of the automatic document feeder based on, for example, the presence / absence of a document on a document table. Change the settings used for image processing. Therefore, it is possible to change the set value of the image processing when the ADF is used / not used in consideration of the change in the state of the original on the contact glass (the state of close contact) when the ADF is used / not used, Image quality degradation at the time can be avoided.

According to a fifth aspect of the present invention, in the image processing apparatus according to the fourth aspect, the changing step includes:
If it is determined in the determination step that image data has been input using the automatic document feeder, the background removal processing and / or the edge are compared with a set value when the automatic document feeder is not used. The setting value used for the emphasis processing is changed so that the background removal amount is increased or the emphasis filter strength is increased.

According to the fifth aspect of the present invention, when it is determined that image data has been input using the automatic document feeder, the background removal amount is increased or the enhancement filter strength is increased. Is changed to Therefore, the background stain caused by the automatic document feeder can be suppressed, and the blurring of the image can be suppressed.

According to a sixth aspect of the present invention, in the image processing apparatus according to the fourth or fifth aspect, the changing step includes a step of inputting image data using the automatic document feeder in the determining step. If it is determined that
Compared with the setting value when the automatic document feeder is not used, the setting value used in the smoothing filter processing is changed by -1 notch to change the direction in which the smoothness is weakened, and the setting value used in the background removal processing is reduced. The value is changed by +1 notch to increase the background removal amount, and the setting value used in the edge enhancement process is changed by +1 notch to change the direction to increase the degree of enhancement.

According to the sixth aspect of the present invention, when it is determined that image data has been input using the automatic document feeder, enhancement is performed so that the smoothness is reduced and the background removal amount is increased. The filter strength is changed so as to increase. Therefore, the background stain caused by the automatic document feeder can be suppressed, and the blurring of the image can be suppressed.

Further, the storage medium according to the invention of claim 7 is:
By recording a program for causing a computer to execute the method described in any one of claims 4 to 6, the program can be machine-readable, whereby the operations of claims 4 to 6 can be realized by a computer. .

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of an image processing apparatus, an image processing method, and a computer-readable recording medium which records a program for causing a computer to execute the method according to the present invention will be described with reference to a digital copying machine as an example. This will be described in detail with reference to the drawings.

FIG. 1 is an explanatory diagram showing a system configuration of a digital color copying machine according to an embodiment of the present invention.
This digital color copying machine has a laser printer 1 in which functional units based on an electrophotographic process are arranged and finally a color image (or a black and white image) is formed on recording paper.
00 is provided.

This digital color copying machine also transports a plurality of bundles of originals to be copied one by one to an original reading unit and collects the originals.
And an image scanner 1 that optically scans a document conveyed by the ADF 120 and reads the document as a digital image
40, an operation board 160 for displaying various key groups for setting various copy conditions and copy modes, and setting states and operation states of the apparatus, and R, G, B of the original image as in the image scanner 140. An external sensor 170 having a built-in CCD type handy scanner capable of simultaneously detecting each color component.

The laser printer 100 includes a photosensitive drum 101 on which an electrostatic latent image is formed, a transfer drum 102 for adhering a recording paper to the surface and transferring a toner image on the photosensitive drum 101, Writing unit 103 for irradiating light for each pixel according to the
Charger 104 that charges one surface to a predetermined potential
And a developing unit 105 for attaching (developing) toner to the electrostatic latent image formed on the photosensitive drum 101.

Further, the laser printer 100 includes a cleaning unit 106 for removing and collecting unnecessary matters such as residual toner on the photosensitive drum 101 after the transfer, a transfer charger 107 which is turned on when the transfer is performed, and a transfer drum 102.
A separation charger 108 for separating recording paper from the recording paper;
A fixing unit 109 for fixing the toner image on the recording paper by a heating / pressing action, and stacking and storing a plurality of bundles of recording paper;
A paper feed unit 110 that feeds and conveys the paper to and from the transfer drum 102, and a paper discharge tray 111 that stacks the discharged fixed recording paper
And

The writing unit 103 is provided with a laser diode (not shown). A laser drive control plate (not shown) for driving and controlling a laser beam emitted from the laser diode, a polygon mirror 112, and a polygon mirror 112 are provided. This is a box-shaped unit including a rotating polygon motor 113, an f / θ lens 114, a reflection mirror 115, a lens 116, and the like.

The developing unit 105 includes the photosensitive drum 10
A BK developing unit 105BK for black toner and a Y developing unit 105Y for yellow toner, which are arranged at a predetermined distance from one surface.
And a C developing unit 105C for cyan toner and an M developing unit 105M for magenta toner.

The paper supply unit 110 includes a paper supply cassette 117 for storing and storing recording paper of a predetermined size, and a paper supply cassette 11.
The sheet feed roller 118 feeds the uppermost sheet of the recording paper set in the sheet 7 one by one, and a registration roller 119 that conveys the recording sheet while keeping timing with the transfer drum 102 is provided.

The ADF 120 is an image scanner 140
, A document table 121 for holding a large number of documents stacked thereon, a call roller 122 for contacting the uppermost document surface and sending the contacted document to the separation unit, and preventing a large number of sheets from being fed. Roller 123, a pull-out roller 127, and a transport belt 126.

A document presence / absence sensor 128, which is an optical sensor for detecting whether or not a document is loaded, is provided in front of the calling roller 122. A document tip sensor 128 is provided between the separation roller 123 and the pull-out roller 127. An original sensor 124 by an optical sensor for detecting the size is provided with a registration sensor 125 immediately after the pull-out roller 127.
Are arranged respectively.

The image scanner 140 includes a contact glass 141 on which an original is set and an illumination lamp 142.
A number of lens mirrors for illuminating the original, a dichroic prism for splitting incident light into three colors of blue (B), green (G), and red (R) according to the wavelength;
And three three-dimensional charge-coupled device (CCD) image sensors 143.

Next, the operation in the above configuration will be described. The image scanner 140 receives a scanner start signal synchronized with the operation of the laser printer 100, scans a document in the left-right direction (sub-scan direction), and obtains one-color image data for each scan.

The image of the original P is illuminated by the illumination lamp 142, and the reflected light passes through the image forming lens via a number of mirrors and enters the dichroic prism. The dichroic prism splits the incident light into three colors of R, G, and B according to the wavelength.

Each of the three split lights enters a different one-dimensional CCD image sensor 143. Thus, the three CCDs provided in the image scanner 140
The R, G, and B colors of one line in the main scanning direction on the document image are simultaneously read by the image sensor 143. The two-dimensional image of the document is read by sub-scanning of the carriage of the image scanner 140.

When the document is fed by the ADF 120, the rotating call roller 122 comes into contact with the upper surface of the uppermost document, and the contacted document is fed out. The fed document is fed one sheet by the separation roller 124.

The original fed out to a predetermined position is driven by a pull-out roller 127 and a conveyor belt 126 to drive a contact glass 14 of an image scanner 140.
After the document is further conveyed over the top of the contact glass 141, that is, when the leading end of the document reaches the left end of the contact glass 141, the document is stopped. When reading of the document is completed, the transport belt 126 is driven again, the document on the contact glass 141 is discharged, and the next document is sent to the reading position.

The document leading edge sensor 124 is composed of a plurality of sensors arranged at different positions in the main scanning direction (perpendicular to the paper), and the size of the document in the main scanning direction is determined by a combination of the detection states of these sensors. That is, the document width can be detected.

Further, there is provided a pulse generator for outputting a pulse according to the rotation amount of a paper feed motor (not shown).
The control device of the ADF 120 detects the size of the document in the sub-scanning direction, that is, the length of the document, by measuring the time until the document passes through the document leading edge sensor 124. Note that the call roller 122 and the separation roller 123 are driven by a paper feed motor, and the pull-out rollers 127 and the transport belt 126 are driven by a transport motor.

As described above, reproduction of image data read by the image scanner 140 and subjected to predetermined image processing (described later) is performed on the photosensitive drum 101. That is, the color image data is visualized into BK, C, M, and Y by the laser printer 100 for each color, so that a final color copy is obtained.

The details will be described below. Writing unit 10
Reference numeral 3 converts the color image data from the image scanner 140 into an optical signal, performs optical writing corresponding to the original image, and forms an electrostatic latent image on the photosensitive drum 101.

In the standby state, the four developing devices 105
Although all of BK to 105M are in the state of the cutting edge (development inoperative) on the developing sleeve, the order of the developing operation (color image forming order) is BK, C, M, and Y, which will be described below. . The order of development is not limited to this.

When the copying operation is started, reading of the BK image data is started at a predetermined timing by the image scanner 140, and light writing by a laser beam and formation of a latent image are started based on the image data. Hereinafter, the electrostatic latent image based on the BK image data is referred to as a BK latent image. Note that C, M, and Y are handled in the same manner.

In order to enable development from the leading end of the BK latent image, before reaching the leading end of the latent image to the developing position of the BK developing unit 105BK, the BK developing sleeve is rotated to perform developer cutting. The BK latent image is developed with BK toner.

Thereafter, the developing operation of the BK latent image area is continued. When the trailing end of the latent image has passed to the BK developing position, the developer BK of the BK developing sleeve is quickly cut off.
Make the development inoperative. This is completed at least before the leading end of the Y latent image based on the next Y image data arrives.
This cutting is performed by switching the rotation direction of the BK developing sleeve to a direction opposite to that during the developing operation.

The BK toner image formed on the photosensitive drum 101 is transferred onto the surface of a recording paper wound around a transfer drum 102 driven at the same speed as the photosensitive drum 101. Hereinafter, when the transfer drum 102 is in contact with the photosensitive drum 101, the transfer is performed by turning on the transfer charger 107.

The transfer charger 107 sequentially aligns the BK, Y, M, and C toner images to be sequentially formed on the photosensitive drum 101 on the same surface to form a four-color transfer image on the recording paper surface. I do.

On the photosensitive drum 101 side, B
The process proceeds to the Y process after the K process, and the Y latent image is formed by laser light writing using the image data. Y developing device 10
5Y starts rotating the Y developing sleeve after the trailing end of the preceding BK latent image has passed the developing position and before the leading end of the Y latent image has arrived, to perform developer scribing. , Y latent image is developed with Y toner.

Thereafter, the development of the Y latent image area is continued, and when the trailing end of the latent image passes, the ears are cut off on the Y developing sleeve in the same manner as in the BK developing unit 105BK. This is also completed before the leading end of the next Y latent image arrives. In the steps C and M, the operations of reading, latent image formation, and development of each image data are performed in the same manner as the steps BK and Y, and the description of these operations is omitted.

The recording paper is fed from a paper feed cassette 117 by a feed roller 118, for example, and is fed by a registration roller 119 at a timing when it reaches a predetermined position on the surface of the transfer drum 102.

FIG. 2 is a circuit block diagram showing a schematic configuration of the transmission unit in the digital color copying machine of FIG. The operation control of the entire copying machine is controlled by a system controller 220 composed of a microcomputer. The image scanner 140, the laser printer 100, the operation board 160, the image processing unit 200, and the main control unit 230 are connected to the system controller 220 as shown in the figure.

The RGB image signals read by the image scanner 140 are A / D converted and output as 8-bit color information. This image information is output to the laser printer 100 after undergoing various processes in the image processing unit 200.

The image processing unit 200 includes a scanner gamma correction circuit 201, an RGB smoothing filter 202, a background removal circuit 203, a color correction / UCR
/ UCA circuit 204, selector 205, edge enhancement filter 206, printer gamma correction circuit 207,
The gradation processing circuit 208, the image area separation circuit 209, the synchronization control circuit 210, the ACS circuit 211, and the background detection unit 21
And 2.

The synchronization control circuit 210 generates a clock pulse as a reference for control timing, and inputs various synchronization signals for synchronizing signals between the control units. In this embodiment, the main scanning synchronization signal which is the basis of the scanning timing is the polygon mirror 112 of the laser printer 100.
Are synchronized with the start timing of the scanning of the laser beam by the rotation / deflection of.

The scanner gamma correction circuit 201 converts the reflectance linear RGB data read by the image scanner 140 into linear density RGB data. RGB
The smoothing filter 202 performs a smoothing process for suppressing the occurrence of moire caused by a halftone dot document.

The background removal circuit 203 performs a process of skipping (replacement with white) highlight portions of the background of the document. A color correction / UCR / UCA circuit 204 performs color correction for converting image information of each color of RGB into image information of each color of YMC which is a complementary color thereof, and an image signal obtained by synthesizing all image information of input YMC color. Extract the black component contained in the color of, output it as a BK signal,
UCR / UCA processing for removing the black component from the image signals of the remaining colors and adding the YMC component is performed.

The selector 205 selects one of the input Y, M, C, and BK color signals in accordance with an instruction from the system controller 220 and outputs the selected color signal to the next block. The edge emphasis filter 206 performs emphasis processing of the edge information of the character portion or the picture portion.

The printer gamma correction circuit 207 sets a gamma curve according to the printer characteristics so that the density becomes linear including gradation processing. Gradation processing circuit 20
Numeral 8 binarizes the input 8-bit density information or multi-values it. Generally, dither processing is often performed, and an image signal subjected to dither processing is output to the laser printer 100.

The output of the scanner gamma correction circuit 201 is
On the other hand, it is sent to the image area separation circuit 209, the ACS circuit 211, and the background detection unit 212. The image area separation circuit 209 includes a circuit for determining whether an input image is a character part or a picture part, and a circuit for determining whether the image is chromatic or achromatic. Then, the result is sent to each processing block in units of one pixel. In each processing block, processing is switched based on the result of the image area separation circuit 209.

The ACS circuit 211 is provided for the image scanner 1
It is determined whether the original set in 40 is a black-and-white original or a color original, and the result is sent to the system controller 220 at the end of the BK plate scan. The remaining three scans are performed for color documents, and BK for black and white documents.
The operation is completed by scanning.

The background detection unit 212 is provided with the image scanner 1
This is a circuit for detecting the background density of the original set at 40. In the case of a full-color copy, the background density is detected at the time of BK scanning, and the result is used by the system controller 220.
Back to.

The system controller 220 calculates the amount of background removal based on the result, and sets the calculated value in the background removal circuit 203 at the time of CMY plane scanning to perform background removal. BK scan 1 for black and white copy
Since the number of times is only the number of times, the detected background density
Return to 3 directly to remove the background.

FIG. 3 is a block diagram showing a main configuration of a system related to the image processing unit in FIG.
The image processing unit 200 is composed of functional blocks for performing various processes as described above, but here, only the RGB smoothing filter 202, the background removal circuit 203, and the edge emphasis filter 206, which are main parts of the present invention, are described. Is described.

The system controller 220 and the main controller 230 are connected by a serial interface. The parameters of each functional block constituting the image processing unit 200 are all C
The configuration is set by the PU 301.

The CPU 301 reads out the program data stored in the ROM 303, and stores the data under the control thereof in the RAM 302. Also, the main control unit 2
30 is a CPU 301, a RAM 305, and a ROM 30
And exchanges signals with the ADF 120 and the operation board 160, and sends necessary signals to the system controller 220.

When the mode is determined on the operation board 160 and the copy start key is pressed, the parameters for the smoothing filter, the background removal, and the edge enhancement in the designated mode are sent from the CPU 301 to the RGB smoothing filter 20.
2. It is set in the background removal circuit 203 and the edge enhancement filter 206, and each processing is performed according to the parameters.

FIG. 6 shows an example of the smoothing filter processing.
In (a), the vertical axis indicates the weight coefficient of the peripheral pixel, and the coefficient is set such that the target pixel is the strongest and becomes weaker as the distance from the target pixel increases. FIG. 6 shows an example of an actual smoothing filter operation.
(B).

FIG. 7 shows an example of an output curve due to background removal. For example, the conventional example described above (Japanese Unexamined Patent Application Publication No.
As described in Japanese Patent Application Laid-Open No. 64409), if the density below the background density is cut, and if the density higher than that is output at a normal density, a level difference will occur there. Is often used.

Assuming that the input data is Din, the removal amount is SUB, the threshold value is TH, and the gradient is M, SUB = TH × M− (M−1) × Din.

As a result, the output image data Dout becomes Dout = Din-SUB. As is clear from the above equation, the amount of background removal increases as TH increases, and the boundary of density at which background removal is performed increases as TH decreases.

FIG. 8 shows an example of the emphasis filter processing. Here, a method is used in which second derivative is performed on the entire image data, and the result is added to the original image. FIG. 8A shows a result obtained by applying a secondary part, and FIG. 8B shows an example of the emphasis filter processing operation.

Since the set values of the smoothing filter processing, the background removal processing, and the emphasis filter processing related to the present invention need to correspond to the type of the document and the user's preference, adjustment keys are provided on the operation board 160 respectively. Is provided. The smoothing filter processing and the edge emphasis filter processing are performed as adjustment using a “sharp / soft key”, and the background removal processing is performed as adjustment using a “background density adjustment key”.

FIG. 4 shows the operation key 160 on the operation board 160.
FIG. 5A is an enlarged view of a smoothing filter key, FIG. 5B is an enlarged view of an edge emphasis key, and FIG. 5C is an enlarged view of a background removal key. Then, the processing corresponding to each notch is schematically illustrated in FIGS. 6, 7, and 8 described above.

FIG. 5 (a) is for adjusting the degree of smoothing emphasis, and the center notch (notch 3) corresponds to the thick line graph in FIG. 6 (a). When the smoothness is increased (notch 5), the graph becomes almost flat as shown in FIG. When the smoothness is further reduced (notch 1), a graph stands on the vertical axis in FIG. 6A.

FIG. 5B shows the adjustment of the degree of edge enhancement, and the center notch (notch 3) corresponds to the thick line graph in FIG. 8A. When the edge emphasis degree is increased (notch 5), a graph having a large amplitude in FIG. 8A is obtained. When the edge enhancement degree is further reduced (notch 1), FIG.
The graph of (a) has a small amplitude.

FIG. 5C illustrates the adjustment of the background removal amount. The center notch (notch 3) corresponds to the thick line graph in FIG. When the background removal amount is increased (notch 5), TH in FIG. 7 increases and the inclination M decreases. Further reduce the amount of background removal (Notch 1)
7 is a graph that moves in the direction in which TH decreases and the slope M increases in FIG.

Next, control examples of the smoothing filter processing, the background removal processing, and the edge enhancement filter processing when the ADF 120 is used / not used will be described. ADF1
When the document 20 is used or not used, the document detection sensor 12 determines whether a document is set on the document table 121 of the ADF 102.
8, the determination is made by transmitting the information to the CPU 304 of the main control unit 230 as an “ADFON / OFF flag” (see FIG. 3). Then, the signal is sent to the system controller 220.

FIG. 9 is a diagram showing an AD according to an embodiment of the present invention.
It is explanatory drawing which shows the parameter setting example of the image processing at the time of F-OFF (unused), (a) has shown the smoothing filter intensity | strength, (b) the background removal amount, and (c) has shown the emphasis filter intensity, respectively. .

Here, the "ADFON / OFF flag"
Is determined to be OFF (the state in which the original is not mounted on the ADF 120), the smoothing filter strength, the background removal amount, and the emphasis filter strength are respectively set to the notch 3 as shown in FIG.
(Standard notch). As a result, the image can be faithfully reproduced except for the background dirt.

FIG. 10 shows A according to the embodiment of the present invention.
It is explanatory drawing which shows the parameter setting example of the image processing at the time of DF-ON (use), (a) is a smoothing filter intensity | strength,
(B) shows the background removal amount, and (c) shows the enhancement filter strength.

Here, as shown in FIG.
N / OFF flag ”is determined to be ON (the original is mounted on the ADF 120), the smoothing filter strength,
The operation board 16 is used as the background removal amount and the enhancement filter strength.
On 0, notch 3 (standard) is set, but the actually set value is controlled as in the following (1) to (3).

(1) Smoothing filter strength → Notch 2 (Smoothness is reduced by -1 notch with respect to the set value)

(2) Background removal amount → Notch 4 (The removal amount is increased by +1 notch with respect to the set value.)

(3) Emphasis filter strength → Notch 4 (Emphasis is increased by +1 notch with respect to the set value)

That is, as the above three processes, first, by applying a weaker smoothing than usual, if the original on the conveyor belt 126 does not come into close contact with the contact glass 141 surface, and the original is floated, Is generated, data having a low edge degree is left.

Further, by making the background removal amount larger than usual, the background stain due to the floating of the document is not left.
Further, by increasing the degree of edge emphasis, processing is performed on the remaining data to make the edges more prominent.

As a result, not only the removal of the background stain due to the floating of the document on the contact glass 141 when the ADF 120 is used, but also the occurrence of edge blur can be prevented. Similarly, when the smoothing filter strength, the background removal amount, and the emphasis filter strength are all the notch 4 on the operation board 160, when the “ADFON / OFF flag” is ON, the value actually set is as described above. As described above, the smoothing filter strength is decreased by −1 notch, the background removal amount is increased by +1 notch, and the emphasis filter strength is increased by emphasis degree + 1 notch. Therefore, the smoothing filter strength notch 3, the skin strength amount notch 5, and the emphasis filter strength notch 5 Becomes

Here, the image processing operation when the ADF is used / not used will be described with reference to the flowchart shown in FIG. When the operation is started in the figure, it is first determined whether or not the "ADFON / OFF flag" is ON (step S1).

Here, the "ADFON / OFF flag" is set to O
If it is determined to be N, control is performed so that the smoothing filter strength is reduced by -1 notch, the background removal amount is increased by +1 notch, and the enhancement filter strength is increased by +1 notch, as described above (step S2).

On the other hand, in step S1, "ADFON
If the "/ OFF flag" is OFF, as described above, the smoothing filter processing, the background removal processing, and the edge enhancement processing are performed based on the notch set on the operation board 160 (step S3).

The present invention can be realized by software other than the above embodiment. For example, the above-described image processing method is implemented by being programmed, stored in a storage medium, and operated on a computer system.

In the above-described embodiment, each image processing level for image data at the time of manual document setting is set on the operation board 160 (fixed control by external operation), and in the case of document read data by the ADF 120, as described above. Although the set values of the image processing are changed and controlled, the opposite may be applied.

For example, in the case of an apparatus which uses the ADF 120 frequently and usually performs copying by manual setting of a document, fixed control is performed when the ADF 120 is used, and the set value of image processing is changed during manual setting of a document. It can also be controlled.

The image processing method described in the embodiment is realized by executing a prepared program on a computer such as a personal computer or a workstation connected to a digital copying machine via a network or the like. There may be. In this case, the computer can control the operation of the digital copying machine.

This program is recorded on a computer-readable recording medium such as a hard disk, a floppy disk, a CD-ROM, an MO, and a DVD, and is executed by being read from the recording medium by the computer. This program can be distributed via the recording medium and a network such as the Internet.

[0097]

As described above, according to the first aspect of the present invention, the determining means determines whether or not image data has been input using the automatic document feeder, and based on the determination result. Since the changing means changes the set value used for the image processing, the image quality deterioration such as the background stain and the blurred image caused by the floating of the original when the ADF (automatic original feeder) is used is reduced.
By changing the parameters (set values) of the image processing, the image processing can be suppressed and the image processing apparatus can be improved in image quality.

In other words, the setting value of the image processing when the ADF is used / not used is changed in consideration of the change in the state of the original on the contact glass (the state of close contact) when the ADF is used / not used. / It is possible to avoid image quality degradation when not in use.

According to the second aspect of the invention, when it is determined that image data has been input using the automatic document feeder, the background removal amount is increased or the enhancement filter strength is increased. With such a modification, it is possible to obtain an image processing apparatus capable of suppressing background contamination caused by an ADF (automatic document feeder) and suppressing blurring of an image.

According to the third aspect of the present invention, when it is determined that image data has been input using the automatic document feeder, a comparison is made with the set value when the automatic document feeder is not used. The setting value used in the smoothing filter process is changed by -1 notch to change the direction in which the smoothness is weakened, and the setting value used in the background removal process is changed by +1 notch to change the direction to increase the background removal amount. In order to change the setting value used in the emphasis processing by +1 notch to change in the direction in which the degree of emphasis increases, in other words, to adjust the +1 notch or -1 notch to the currently set value, Even when the image quality is adjusted to the user's preference by manual adjustment, the background contamination caused by the ADF (automatic document feeder) can be suppressed while incorporating the user's preference, and
This has the effect of providing an image processing device capable of suppressing blurring of an image.

According to the fourth aspect of the present invention, the determining step determines whether or not image data has been input by using the automatic document feeder. AD to change the set value used for image processing
Image quality degradation such as background contamination or blurred image caused by floating of an original when using an automatic document feeder (F) can be suppressed by changing image processing parameters (set values) to improve image quality. There is an effect that a processing method can be obtained.

According to the fifth aspect of the present invention, when it is determined that image data has been input using the automatic document feeder, the background removal amount is increased or the strength of the enhancement filter is increased. With such a modification, it is possible to obtain an effect that an image processing method capable of suppressing background contamination caused by an ADF (automatic document feeder) and suppressing blurring of an image can be obtained.

According to the sixth aspect of the present invention, when it is determined that image data has been input using the automatic document feeder, the setting value is compared with the set value when the automatic document feeder is not used. The setting value used in the smoothing filter process is changed by -1 notch to change the direction in which the smoothness is weakened, and the setting value used in the background removal process is changed by +1 notch to change the direction to increase the background removal amount. In order to change the setting value used in the emphasis processing by +1 notch to change in the direction in which the degree of emphasis increases, in other words, to adjust the +1 notch or -1 notch to the currently set value, Even when the image quality is adjusted to the user's preference by manual adjustment, the background contamination caused by the ADF (automatic document feeder) can be suppressed while incorporating the user's preference, and
There is an effect that an image processing method in which blurring of an image can be suppressed can be obtained.

According to the invention of claim 7, according to claim 4,
By recording a program for causing a computer to execute the method described in any one of (1) to (6), the program becomes machine-readable, whereby a recording medium capable of realizing the operations of claims 4 to 6 by a computer is obtained. The effect is that it can be done.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a system configuration of a digital color copying machine according to an embodiment of the present invention.

FIG. 2 is a circuit block diagram showing a schematic configuration of a transmission unit in the digital color copying machine of FIG.

FIG. 3 is a block diagram illustrating a main configuration of a system related to the image processing unit in FIG. 2;

FIG. 4 is an explanatory diagram showing an example in which a key for adjusting an image input / output level is provided on an operation board.

5A and 5B are enlarged views of adjustment keys on the operation board in FIG. 4, wherein FIG. 5A is an enlarged view of a smoothing filter key, FIG. 5B is an enlarged view of an edge emphasis key, and FIG.

FIG. 6 is a graph showing an example of a smoothing filter process corresponding to FIG. 5A and an explanatory diagram showing an example of a calculation.

FIG. 7 is a graph showing an example of a background removal process corresponding to FIG. 5C and an explanatory diagram showing an example of calculation.

FIG. 8 is a graph showing an example of edge enhancement filter processing corresponding to FIG. 5B and an explanatory diagram showing an example of calculation.

FIG. 9 is an ADF-OFF according to the embodiment of the present invention.
It is explanatory drawing which shows the example of a parameter setting of the image processing at the time of (not using), (a) shows the smoothing filter intensity | strength, (b) shows the background removal amount, (c) shows the emphasis filter intensity | strength, respectively.

FIG. 10 shows an ADF-ON according to an embodiment of the present invention.
It is explanatory drawing which shows the parameter setting example of the image processing at the time of (use), (a) shows a smoothing filter intensity | strength, (b) shows a background removal amount, (c) shows an emphasis filter intensity | strength, respectively.

FIG. 11 is a flowchart illustrating an example of image processing when an ADF is used / not used according to the embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 laser printer 120 automatic document feeder (ADF) 140 image scanner 160 operation board 200 image processing unit 220 system coat roller 230 main control unit 202 RGB smoothing filter 203 background removal circuit 206 edge emphasis filter circuit 301, 304 CPU

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5B057 AA11 BA02 BA11 BA19 CA01 CA08 CA12 CA16 CB01 CB08 CB12 CB16 CC01 CE03 CE05 CE20 CH18 5C077 LL02 MP08 PP02 PP03 PP25 PP33 PP38 PP42 PP43 PQ08 PQ22 SS01 TT06

Claims (7)

[Claims] 1. An image processing apparatus which is mounted on an image forming apparatus or an image reading apparatus having an automatic document feeder and performs image processing such as smoothing filter processing, background removal processing, and edge enhancement processing on input image data. A determination unit configured to determine whether image data has been input using the automatic document feeder; and a change unit configured to change a set value used in the image processing based on a determination result of the determination unit. Means, and an image processing apparatus. 2. The image forming apparatus according to claim 1, wherein the change unit determines that image data has been input using the automatic document feeder by the determination unit and compares the image data with a set value when the automatic document feeder is not used. 2. The method according to claim 1, wherein a setting value used in the background removal processing and / or the edge enhancement processing is changed so that the background removal amount is increased or the enhancement filter strength is increased. Image processing device. 3. The image processing apparatus according to claim 2, wherein the change unit compares the set value when the automatic document feeder is not used when the determination unit determines that image data has been input using the automatic document feeder. Then, the setting value used in the smoothing filter process is changed by -1 notch to change the direction in which the smoothness is weakened, and the setting value used in the background removal process is adjusted by +1 notch to increase the background removal amount. The image processing apparatus according to claim 1, wherein the setting value used in the edge enhancement processing is changed by +1 notch so as to increase the degree of enhancement. 4. In an image processing method for performing image processing such as smoothing filter processing, background removal processing, and edge enhancement processing on input image data, whether image data has been input using an automatic document feeder. An image processing method, comprising: a determination step of determining whether or not to perform the determination; and a changing step of changing a set value used for the image processing based on a determination result of the determination step. 5. The method according to claim 1, wherein the determining step determines that image data has been input using the automatic document feeder in the determining step, and compares the input data with a set value when the automatic document feeder is not used. The setting value used in the background removal processing and / or the edge enhancement processing is changed so that the background removal amount increases or the enhancement filter strength increases. Image processing method. 6. The change step, when it is determined in the determination step that image data has been input using the automatic document feeder, is compared with a set value when the automatic document feeder is not used. Then, the setting value used in the smoothing filter process is changed by -1 notch to change the direction in which the smoothness is weakened, and the setting value used in the background removal process is adjusted by +1 notch to increase the background removal amount. The image processing method according to claim 4, wherein the setting value used in the edge enhancement processing is changed by +1 notch to increase the degree of enhancement. 7. A computer-readable recording medium on which a program for causing a computer to execute the method according to claim 4 is recorded.