JP4133674B2 - Image processing apparatus, image reading apparatus, and color copying apparatus - Google Patents

Description

  The present invention relates to an image processing apparatus, an image reading apparatus, and a color copying apparatus, and more specifically, determines whether or not an isolated point is included in image data read from a document, and an isolated point is determined in accordance with an output image quality mode. The present invention relates to an image processing apparatus, an image reading apparatus, and a color copying apparatus that perform image processing to be replaced with replacement pixels.

  In recent years, improvement in image processing technology and image forming technology has made it possible to perform image formation so finely that it is difficult to distinguish a copied banknote copied by a color copying machine from an actual banknote. For this reason, a device has been developed that judges special manuscripts that are prohibited from being copied such as banknotes and securities, and prohibits illegal copying in the case of special manuscripts. An image forming apparatus equipped with is also proposed.

  Further, in the case of a general document other than banknotes and securities, there are many copy-prohibited manuscripts that are prohibited from being copied from the standpoint of importance of document contents and confidentiality.

  Conventionally, such a copy-prohibited document is generally stamped with a secret seal, a copy-prohibited mark, etc., and is distinguished from a copy-capable document.

  Also, conventionally, in order to track the origin of a copy, information such as the machine number, serial number, and user ID of the copying machine can be added to the copy as a tracking pattern in a color that is difficult for human eyes to distinguish. Has been done.

  In other words, this method is a method of writing on the entire surface of the image with a certain dot size with a certain inconspicuous color (for example, yellow), and this method is applied to an image forming apparatus such as a copying machine for copying. By adding information to an object, the origin of the copied object can be traced.

  However, there is a problem that the image quality is deteriorated depending on the output mode of the image because the tracking pattern is written on the entire surface of the image with a certain inconspicuous color and a certain dot size. For example, when a document with a tracking pattern is output after color conversion, even if the original document has dots that are inconspicuous, the dots are converted to a different color and the dots stand out. was there.

  In particular, in a two-color mode in which a color other than black is converted to another color (for example, red), an invisible yellow isolated point (tracking pattern) becomes red and the image quality deteriorates.

  Conventionally, a color image processing apparatus has been proposed in which the tracking pattern of the original image data is deleted and forcibly replaced with white dots (see Patent Document 1).

  Conventionally, there has been proposed an image copying apparatus that deletes the tracking pattern of the original image data and forcibly replaces it with a new tracking pattern such as yellow (see Patent Document 2).

  Further, the present applicant has previously proposed an image processing apparatus that detects a tracking pattern and switches image processing (see Patent Document 3).

Japanese Patent Laid-Open No. 5-130376 Japanese Patent Laid-Open No. 11-266366 JP 2002-325180 A

  However, in the prior art described in this publication, it is necessary to improve the image quality by properly removing the tracking pattern.

  That is, in the prior art described in Patent Document 1 and Patent Document 2 described above, since white dots and yellow dots are replaced, it is painted white in a light color background or only white dots can be converted. There was a problem.

  Note that the prior art described in Patent Document 3 is not a technique for deleting a tracking pattern based on a tracking pattern, but a technique for switching image processing, and it is necessary to consider the removal of the tracking pattern as one of the image processing. is there.

Therefore, according to the first aspect of the present invention, when the isolated point of the image data of the document is replaced with a replacement pixel that is another pixel around the isolated point, the isolated point detection means determines whether the image data of the document has yellow color. in whether to detect the isolated point of yellow, replacement means, the concentration difference between the detected said the isolated point replaces pixels exceeds a predetermined value, the pixel replacing only the B image data of the isolated points Replacement eliminates unnecessary pixel replacement of isolated points , maintains continuity with surrounding images, replaces isolated point pixels with good image quality , and yellow isolated point affects B signal Therefore, the pixel to be replaced is set to only B, the RG signal is not affected by the erroneous determination, the erroneous determination of the isolated point is suppressed, and the isolated point pixel is appropriately and in a good image quality state. Replacement And its object is to provide an image processing apparatus for performing image processing for performing.

According to the second aspect of the present invention, when the isolated point of the original image data is replaced with a replacement pixel that is another pixel around the isolated point, the isolated point detection unit determines whether the original image data has yellow color. When the yellow isolated point is detected, and the replacement means has a replacement pixel having the maximum value among a plurality of replacement pixel candidates around the isolated point that is an area including the detected isolated point, which is thinner than the isolated point. only, by replacing only the replacement pixel B image data of the isolated points, to suppress the erroneous determination of the isolated point, performs replacement of the pixel of the isolated point in a good condition suitable image quality, yellow isolated points Affects the B signal, so that the replacement target pixel is only B, the RG signal is not affected by the erroneous determination, the erroneous determination of the isolated point is suppressed, and an appropriate and good image quality state is obtained. Solitary And its object is to provide an image processing apparatus that performs image processing for replacing the pixel of the point.

According to the third aspect of the present invention, when the isolated point of the document image data is replaced with a replacement pixel that is another pixel around the isolated point, the isolated point detection means determines whether the document image data has yellow color. Then, the yellow isolated point is detected, and the replacement means detects the image data having the similar R and G image data values and the B image data of the isolated point among the plurality of replacement pixel candidates around the detected isolated point. by replacing only to suppress the erroneous determination of the isolated point, and converts the pixel state that is not struck the track pattern, since the yellow isolated points affecting the B signal, the replacement target pixel only as B, intended to RG signals, erroneous influence so as not subject to the time of determination, to suppress the erroneous determination of the isolated point, provides a replacement image processing apparatus that performs the pixel of the isolated point in a good state of proper image quality It is.

According to the fourth aspect of the present invention, at least one of the plurality of replacement pixel candidates includes adjacent pixels, so that the replacement target pixel is set with reference to the adjacent image data, and the output pattern of the copy document It is an object of the present invention to provide an image processing apparatus that performs image processing for replacing an isolated point pixel in a state where the influence is prevented and which is appropriate and has good image quality.

In the invention according to claim 5 , the isolated point detecting means detects a tracking pattern which is a set of isolated points including information such as a device number, a manufacturing number, and a user ID of the apparatus as an isolated point. An object of the present invention is to provide an image processing apparatus that replaces pixels with replacement pixels in an appropriate and good image quality state.

The invention according to claim 6 prevents the isolated point from being converted into another color in the two-color mode by replacing the isolated point with a replacement pixel when the image data output mode is the two-color mode. It is another object of the present invention to provide an image processing apparatus that performs image processing for replacing pixels of isolated points with appropriate and good image quality.

According to the seventh aspect of the present invention, the isolated point of the image data of the original obtained by scanning the original and color-separating and reading the image of the original is another pixel around the isolated point by the image processing means. When the pixel is replaced with a replacement pixel, the image processing device according to any one of claims 1 to 7 is mounted as an image processing unit, so that an unnecessary pixel of an isolated point can be replaced with a surrounding image without replacement. An object of the present invention is to provide an image reading apparatus that performs image processing that replaces pixels of isolated points while maintaining continuity and good image quality.

According to an eighth aspect of the present invention, image processing is performed to replace an isolated point of image data of a document with a replacement pixel that is another pixel around the isolated point by the image processing means, and the image data after the image processing is processed. When the image is recorded and output on the basis of the paper, the image processing device according to any one of claims 1 to 7 is mounted as an image processing unit to replace unnecessary pixels of isolated points. It is another object of the present invention to provide an image forming apparatus that records and outputs an image subjected to image processing that replaces isolated point pixels with good image quality while maintaining continuity with peripheral images.

According to the ninth aspect of the present invention, the image reading unit scans the original and color- separates and reads the image of the original and reads the isolated points of the original image data . When performing image processing to be replaced with a replacement pixel, which is another pixel, and recording and outputting an image on paper based on the image data after the image processing by the image forming unit, the image processing unit serves as an image processing unit. By installing the image processing device according to any one of the above, the continuity with the surrounding image is maintained without replacing the unnecessary pixel of the isolated point , and the isolated point pixel is maintained in a good image quality state. An object of the present invention is to provide a copying apparatus that records and outputs an image subjected to image processing for replacement.

According to a tenth aspect of the present invention, there is provided an image processing apparatus according to any one of the first to seventh aspects, wherein the copying apparatus is connected to an external apparatus and receives a print instruction command and image data from the external apparatus. The processing means performs image processing for replacing isolated points of the image data with replacement pixels, and the image forming means records and outputs an image on paper based on the image data after the image processing. Image processing that replaces isolated point pixels with good image quality while maintaining the continuity with surrounding images without replacing unnecessary pixels of isolated points for input image data. An object of the present invention is to provide a copying apparatus that records and outputs the applied image.

An image processing apparatus according to a first aspect of the present invention is an image processing apparatus that replaces an isolated point of image data of a document with a replacement pixel that is another pixel around the isolated point, and the image data of the document has a yellow color. in whether a isolated point detection means for detecting an isolated point of yellow, the concentration difference between the replacement pixel detected isolated point of the isolated point detecting means exceeds a predetermined value, of the isolated point The above object is achieved by providing replacement means for replacing only B image data with replacement pixels.

According to the above configuration, when the isolated point of the image data of the document is replaced with a replacement pixel that is another pixel around the isolated point, the isolated point detection unit determines whether the image data of the document has yellow color, detecting an isolated point of yellow, replacement means, the density difference between the isolated point obtained by the detection is the replacement pixel exceeds a predetermined value, since the isolated point is replaced with the replacement pixel, unnecessary isolated point Pixel replacement can be eliminated, and image processing can be performed to replace isolated point pixels with good image quality while maintaining continuity with surrounding images. Further, since the replacement means replaces only the B image data among the RGB image data of the isolated points as the replacement target data, since the yellow isolated point affects the B signal, the replacement target pixel is only B and the RG signal is It is possible to prevent the influence of erroneous determination, and it is possible to perform image processing that suppresses erroneous determination of isolated points and replaces isolated point pixels in an appropriate and good image quality state.

An image processing apparatus according to a second aspect of the present invention is an image processing apparatus that replaces an isolated point of image data of a document with a replacement pixel that is another pixel around the isolated point, and the image data of the document has a yellow color. Depending on whether or not there is an isolated point detecting means for detecting a yellow isolated point, and the replacement pixel having the maximum value among the plurality of replacement pixel candidates around the isolated point detected by the isolated point detecting means is determined by the isolated point . The above object is achieved by providing replacement means for replacing only the B image data of the isolated point with a replacement pixel only when the image is thin.

According to the above configuration, when the isolated point of the image data of the document is replaced with a replacement pixel that is another pixel around the isolated point, the isolated point detection unit determines whether the image data of the document has yellow color, A yellow isolated point is detected, and the replacement unit replaces the isolated point only when the replacement pixel having the maximum value among the plurality of replacement pixel candidates around the detected isolated point is thinner than the isolated point. Since it is replaced with a pixel, erroneous determination of the isolated point can be suppressed, and image processing for replacing the pixel of the isolated point with appropriate and good image quality can be performed. Further, since the replacement means replaces only the B image data among the RGB image data of the isolated points as the replacement target data, since the yellow isolated point affects the B signal, the replacement target pixel is only B and the RG signal is It is possible to prevent the influence of erroneous determination, and it is possible to perform image processing that suppresses erroneous determination of isolated points and replaces isolated point pixels in an appropriate and good image quality state.

According to a third aspect of the present invention, there is provided an image processing apparatus for replacing an isolated point of image data of a document with a replacement pixel which is another pixel around the isolated point, wherein the image data of the document has a yellow color. An isolated point detecting unit for detecting a yellow isolated point depending on whether or not, and an image having a similar R or G image data value among a plurality of replacement pixel candidates around the isolated point detected by the isolated point detecting unit The above object is achieved by providing replacement means for replacing only the B image data of the isolated point and the data .

According to the above configuration, when the isolated point of the image data of the document is replaced with a replacement pixel that is another pixel around the isolated point, the isolated point detection unit determines whether the image data of the document has yellow color, The yellow isolated point is detected, and the replacement unit replaces the image data having the closest R and G image data values among the plurality of replacement pixel candidates around the detected isolated point , thereby suppressing erroneous determination of the isolated point. It is possible to convert the pixel into a state where the tracking pattern is not applied. Further, since the replacement means replaces only the B image data among the RGB image data of the isolated points as the replacement target data, since the yellow isolated point affects the B signal, the replacement target pixel is only B and the RG signal is It is possible to prevent the influence of erroneous determination, and it is possible to perform image processing that suppresses erroneous determination of isolated points and replaces isolated point pixels in an appropriate and good image quality state.

In each of the above cases, for example, as described in claim 4, the image processing apparatus may include at least one adjacent pixel as the plurality of replacement pixel candidates .

According to the above configuration, since at least one of the plurality of replacement pixel candidates includes adjacent pixels, the replacement target pixel is set with reference to adjacent image data, and is affected by the output pattern of the copy original. Therefore, it is possible to perform image processing for replacing isolated point pixels in an appropriate state with good image quality.

Further, for example, as described in claim 5 , the isolated point detection unit detects a tracking pattern that is a set of isolated points including information such as a device number, a serial number, and a user ID of the device as the isolated point. You may do.

  According to the above configuration, the isolated point detection unit detects a tracking pattern made up of information such as the device number, manufacturing number, and user ID of the apparatus as an isolated point, so that the tracking pattern is appropriately set and the image quality is good. It can be replaced with a replacement pixel in the state.

Further, for example, as described in claim 6, wherein the image processing apparatus, when the output mode of the image data is two-color mode, the isolated point may be replaces with the replacement pixel.

According to the above configuration, when the output mode of the image data is the two-color mode, the isolated point is replaced with a replacement pixel, so that the isolated point is prevented from being converted to another color in the two-color mode. In addition, it is possible to perform image processing that replaces pixels of isolated points with appropriate and good image quality.

An image reading apparatus according to a seventh aspect of the present invention provides an image processing means for detecting isolated points of image data of the original obtained by scanning the original and color-separating and reading the image of the original. An image reading device that replaces a replacement pixel that is a pixel of the image processing device, wherein the image processing device according to any one of claims 1 to 7 is mounted as the image processing means, thereby achieving the above object. ing.

According to the above configuration, an isolated point of the image data of the original obtained by scanning the original and color-separating and reading the image of the original is replaced with a replacement pixel which is another pixel around the isolated point by the image processing unit. Since the image processing apparatus according to any one of claims 1 to 7 is mounted as an image processing unit when replacing the image, the continuity with the surrounding image is obtained without replacing unnecessary pixels of isolated points. The image processing can be performed to replace the pixel of the isolated point with the image quality being good.

An image forming apparatus according to an eighth aspect of the present invention performs image processing in which an isolated point of image data of a document is replaced with a replacement pixel which is another pixel around the isolated point by the image processing means, and the image processing is performed. An image forming apparatus for recording and outputting an image on a sheet based on subsequent image data, wherein the image processing apparatus according to any one of claims 1 to 7 is mounted as the image processing means. The above-mentioned purpose is achieved.

According to the above configuration, the image processing unit performs image processing to replace the isolated point of the image data of the original document with a replacement pixel that is another pixel around the isolated point, and based on the image data after the image processing. Since the image processing apparatus according to any one of claims 1 to 7 is mounted as image processing means when recording and outputting an image on a sheet, the surrounding area can be obtained without replacing unnecessary pixels of isolated points. It is possible to maintain continuity with the image, and to record and output an image subjected to image processing for replacing isolated point pixels with good image quality.

According to a ninth aspect of the present invention, an image reading unit scans an original and color- separates the original image and reads the isolated point of the image data of the original by the image processing unit. A copying apparatus that performs image processing to replace a replacement pixel that is another pixel around a point and records and outputs an image on a sheet based on the image data after the image processing by the image forming unit. As the means, the above object is achieved by mounting the image processing apparatus according to any one of claims 1 to 7.

According to the above configuration, the image reading unit scans the document and color- separates and reads the image of the document and reads the isolated point of the image data of the document by the image processing unit . The image processing unit performs image processing to replace a replacement pixel, and the image forming unit records and outputs an image on a sheet based on the image data after the image processing. because mounting the image processing apparatus according to any one, without replacement of unwanted pixel isolated point, it is possible to maintain continuity with the surrounding image, a good state of the image quality of the pixel of the isolated point An image subjected to image processing for replacement can be recorded and output.

In this case, for example, as described in claim 10 , the copying apparatus is connected to an external apparatus, and receives a print instruction command and image data from the external apparatus, and any one of claims 1-7. The image processing unit, which is an image processing apparatus, performs image processing for replacing isolated points of the image data with replacement pixels, and the image forming unit records and outputs an image on a sheet based on the image data after the image processing. It may be a thing.

According to the above configuration, the copying apparatus is connected to an external apparatus, receives a print instruction command and image data from the external apparatus, and is an image processing means as an image processing apparatus according to any one of claims 1 to 7. Thus, image processing is performed to replace isolated points of image data with replacement pixels, and an image forming unit records and outputs an image on paper based on the image data after the image processing. even for the image data, without performing the replacement of unwanted pixel isolated point, it is possible to maintain the continuity of the peripheral image, the image processing for replacing the pixel of the isolated point in a good state of the image quality The applied image can be recorded and output.

According to the image processing apparatus of the first aspect, when the isolated point of the image data of the document is replaced with a replacement pixel that is another pixel around the isolated point, the isolated point detection unit converts the isolated point into the image data of the document. on whether there is a yellow, detects isolated point of yellow, replacement means, the concentration difference between the detected isolated point is the replacement pixel exceeds a predetermined value, and the replacing pixel the isolated point Since replacement is performed, unnecessary pixel replacement of isolated points can be eliminated, and image processing for replacing isolated point pixels with good image quality while maintaining continuity with surrounding images can be performed. Further, since the replacement means replaces only the B image data among the RGB image data of the isolated points as the replacement target data, since the yellow isolated point affects the B signal, the replacement target pixel is only B and the RG signal is It is possible to prevent the influence of erroneous determination, and it is possible to perform image processing that suppresses erroneous determination of isolated points and replaces isolated point pixels in an appropriate and good image quality state.

According to the image processing apparatus of the second aspect of the invention, when the isolated point of the image data of the document is replaced with a replacement pixel that is another pixel around the isolated point, the isolated point detection unit converts the isolated point into the image data of the document. A yellow isolated point is detected based on whether or not there is yellow, and the replacement unit detects when the maximum replacement pixel among the plurality of replacement pixel candidates around the detected isolated point is thinner than the isolated point. only, since the isolated point is replaced with the replacement pixel, it is possible to suppress erroneous determination of an isolated point, it is possible to perform image processing for replacing the pixel of the isolated point in a good state of proper image quality. Further, since the replacement means replaces only the B image data among the RGB image data of the isolated points as the replacement target data, since the yellow isolated point affects the B signal, the replacement target pixel is only B and the RG signal is It is possible to prevent the influence of erroneous determination, and it is possible to perform image processing that suppresses erroneous determination of isolated points and replaces isolated point pixels in an appropriate and good image quality state.

According to the image processing apparatus of the third aspect of the present invention, when the isolated point of the image data of the document is replaced with a replacement pixel that is another pixel around the isolated point, the isolated point detection unit converts the isolated point into the image data of the document. A yellow isolated point is detected based on whether or not there is yellow, and the replacement unit detects R, G image data values among a plurality of replacement pixel candidates around the isolated point that is an area including the detected isolated point. Therefore, it is possible to suppress erroneous determination of an isolated point and to convert the pixel to a pixel in which the tracking pattern is not printed. Further, since the replacement means replaces only the B image data among the RGB image data of the isolated points as the replacement target data, since the yellow isolated point affects the B signal, the replacement target pixel is only B and the RG signal is It is possible to prevent the influence of erroneous determination, and it is possible to perform image processing that suppresses erroneous determination of isolated points and replaces isolated point pixels in an appropriate and good image quality state.

According to the image processing apparatus of the present invention, since at least one of the plurality of replacement pixel candidates includes adjacent pixels, the replacement target pixel is set with reference to the adjacent image data, and copied. It is possible to prevent the influence of the output pattern of the original, and to perform image processing for replacing isolated point pixels in an appropriate and good image quality state.

According to the image processing apparatus of the fifth aspect , the isolated point detecting means detects a tracking pattern which is a set of isolated points including information such as the device number, serial number, and user ID of the apparatus as an isolated point. As a result, it is possible to replace the tracking pattern with a replacement pixel appropriately and with a good image quality.

According to the image processing apparatus of the sixth aspect of the invention, when the image data output mode is the two-color mode, the isolated point is replaced with the replacement pixel, so that the isolated point is converted into another color in the two-color mode. It is possible to perform image processing that replaces isolated point pixels in an appropriate and good image quality state.

According to the image reading apparatus of the seventh aspect of the present invention, the isolated point of the image data of the original obtained by scanning the original and color-separating and reading the image of the original is detected by the image processing means at the periphery of the isolated point. Since the image processing device according to any one of claims 1 to 7 is mounted as image processing means when replacing with a replacement pixel that is another pixel of the above, an unnecessary pixel of an isolated point is not replaced. Therefore, it is possible to maintain image continuity with surrounding images, and to perform image processing for replacing isolated point pixels with good image quality.

According to the image forming apparatus of the invention described in claim 8 , the image processing unit performs image processing for replacing the isolated point of the image data of the document with a replacement pixel that is another pixel around the isolated point, and Since the image processing apparatus according to any one of claims 1 to 7 is mounted as image processing means when recording and outputting an image on paper based on image data after image processing, an isolated point is unnecessary. Continuity with surrounding images can be maintained without pixel replacement, and an image subjected to image processing for pixel replacement of isolated points can be recorded and output with good image quality.

According to the color copying apparatus of the ninth aspect of the present invention, the image processing unit scans the original with the image reading unit and color-separates and reads the image of the original with the image processing unit. When performing image processing to replace with a replacement pixel that is another pixel around the isolated point and recording and outputting an image on paper based on the image data after the image processing by the image forming unit, as an image processing unit, Since the image processing apparatus according to any one of claims 1 to 7 is mounted, continuity with a peripheral image can be maintained without replacing an unnecessary pixel of an isolated point , and image quality is excellent. In this state, it is possible to record and output an image that has been subjected to image processing for replacing pixels of isolated points.

According to a color copying apparatus of a tenth aspect of the present invention, the copying apparatus is connected to an external device, and receives a print instruction command and image data from the external device, and any one of the first to seventh aspects. Image processing means that is an image processing apparatus performs image processing for replacing isolated points of image data with replacement pixels, and the image forming means records and outputs an image on paper based on the image data after the image processing. Therefore, the image data input from the external device can maintain continuity with the surrounding image without replacing the unnecessary pixels of the isolated points , and the isolated points of the image data with good image quality can be maintained. An image subjected to image processing for pixel replacement can be recorded and output.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In addition, since the Example described below is a suitable Example of this invention, various technically preferable restrictions are attached | subjected, However, The scope of the present invention limits this invention especially in the following description. As long as there is no description of the effect, it is not restricted to these aspects.

  1 to 9 are diagrams showing an embodiment of an image processing apparatus, an image reading apparatus, and a color copying apparatus according to the present invention. FIG. 1 shows an image processing apparatus, an image reading apparatus, and a color copying apparatus according to the present invention. 1 is a block configuration diagram of a digital full-color copying apparatus 1 to which an embodiment is applied.

  In FIG. 1, a digital full-color copying apparatus 1 includes a scanner 100, a color printer 200, a paper feed unit 300, and the like.

  A scanner (image reading means) 100 presses an original G set on a contact glass 101 with a pressure plate 102, and from an illumination lamp 104 which is a light source on a first traveling body 103 disposed under the contact glass 101. The original G is irradiated with light, and the reflected light reflected by the original G is sequentially reflected by the mirror 105 on the first traveling body 103 by the mirrors 107 and 108 on the second traveling body 106, and passed through the lens 109. It enters a line CCD (Charge Coupled Device) sensor 110. The 3-line CCD sensor 110 photoelectrically converts incident light and reads an image on the original G. At this time, in the scanner 100, the first traveling body 103 and the second traveling body 106 move in the sub-scanning direction while main scanning the document as described above, and the document G is subjected to main scanning and sub-scanning. The image of the original G is read, and the 3-line CCD sensor 110 reads the B, G, and R images by color separation for each color.

  The digital full-color copying apparatus 1 performs color conversion processing by an image processing unit (not shown) based on B, G, and R color-separated image signal intensity levels read by the scanner 100 to obtain Bk (black) and C (cyan). ), M (magenta), and Y (yellow) recording color information including recording color information.

  Based on this color image data, the digital full-color copying apparatus 1 forms Bk, C, M, and Y images on an intermediate transfer belt by a color printer (image forming means) 200 and transfers the images onto a transfer sheet. The scanner 100 receives the toner start signal that takes the operation and timing of the color printer 200, moves the first traveling body 103 and the second traveling body 106 in the right direction indicated by arrows, and scans the image of the document G. One color image data is acquired for each scan, and is sent to the color printer 200 each time, and is visualized by the color printer 200 while being superimposed on the intermediate transfer belt, thereby producing a four-color full-color image. Form.

  In the color printer 200, the optical writing unit 201 converts the color image data from the scanner 100 into an optical signal, performs optical writing corresponding to the original image, and forms an electrostatic latent image on the photosensitive drum 202. .

  The optical writing unit 201 includes a laser emitter 203, a light emission drive control unit (not shown) that drives the laser emitter 203, a polygon mirror 204, a rotation motor 205 that rotationally drives the polygon mirror 204, an fθ lens 206, and a reflection mirror 207. Etc. In the optical writing unit 201, the light emission drive control unit controls lighting of the laser light emitter 203 based on the color image data, and emits the modulated laser to the polygon mirror 204. The polygon mirror 204 is rotationally driven by a rotation motor 205 and scans the incident laser on the photosensitive drum 202 via the fθ lens 206 and the reflection mirror 207 and the like, and electrostatic latent image on the photosensitive drum 202. Form an image.

  The photosensitive drum 202 is rotationally driven counterclockwise as indicated by an arrow, and detects the latent image potential on the photosensitive member cleaning unit 211, the charge eliminating lamp 212, the charger 213, and the photosensitive drum 202 around the photosensitive drum 202. A potential sensor 214, a revolver developing device 215, a selected developing device of the revolver developing device 215, a developing density pattern detector 216, an intermediate transfer belt 217, and the like are disposed.

  The revolver developing device 215 includes a Bk developing device 215K, a C developing device 215C, an M developing device 215M, and a revolver rotation driving unit (not shown) that rotates the developing devices 215K to 215M counterclockwise as indicated by arrows. Each of the developing devices 215K to 215M includes a developing sleeve 215KS, 215CS, 215MS, and 215YS that rotates by bringing the ears of the developer into contact with the surface of the photosensitive drum 202 in order to visualize the electrostatic latent image, and the developer. It consists of a developing paddle that rotates to assemble and agitate. In the standby state, the revolver developing device 215 is set at a position where development is performed by the Bk developing device 215K. When the copying operation is started, the scanner 100 starts reading Bk image data from a predetermined timing. Based on the Bk image data, optical writing on the photosensitive drum 202 by laser light and formation of a latent image by the optical writing are started. Hereinafter, the electrostatic latent image based on the Bk image data is referred to as a Bk latent image. For each of the C, M, and Y image data, light writing and latent image formation are similarly performed. In order to enable development from the leading edge of the Bk latent image, before the leading edge of the latent image reaches the developing position of the Bk developing device 215K, the developing sleeve 215KS starts to rotate, and the Bk latent image is transformed with Bk toner. develop. Thereafter, the developing operation of the Bk latent image region is continued. When the trailing edge of the latent image has passed the Bk latent image position, the developing operation of the next color from the developing position by the Bk developing device 215K is promptly performed. The revolver developing device 215 is driven and rotated to the position. The revolver developing device 215 completes this rotating operation at least before the leading edge of the latent image by the next image data arrives.

  When the color printer 200 starts an image forming cycle, the photosensitive drum 202 is rotated counterclockwise as indicated by an arrow in FIG. 1, and the intermediate transfer belt 217 is rotated clockwise by a drive motor (not shown). Rotate to As the intermediate transfer belt 217 rotates, the color printer 200 sequentially forms a Bk toner image, a C toner image, an M toner image, and a Y toner image. , M, and Y are overlaid on the intermediate transfer belt 217 to form a color toner image. The color printer 200 first forms a Bk image as follows. That is, the charger 213 uniformly charges the photosensitive drum 202 to about −700 V with a negative charge by corona discharge, and then the laser emitter 203 performs raster exposure based on the Bk signal. When the raster image is exposed in this way, the charge proportional to the exposure light amount disappears in the exposed portion of the uniformly charged photosensitive drum 202, and an electrostatic latent image is formed.

  The toner in the revolver developing device 215 is negatively charged by stirring with the ferrite carrier, and the Bk developing sleeve 215KS of the revolver developing device 215 is connected to the metal base layer of the photosensitive drum 202 by a power supply circuit (not shown). The negative DC potential and the AC are biased to a superimposed potential. Therefore, toner does not adhere to the portion where the charge of the photosensitive drum 202 remains, and Bk toner is adsorbed to the portion where there is no charge, that is, the exposed portion. A visual image is formed.

  The intermediate transfer belt 217 is stretched around a drive roller 218, a transfer counter roller 219, a cleaning counter roller 220, and a driven roller group, and is rotated by a drive motor (not shown).

  Then, the color printer 200 applies a Bk toner image formed on the photosensitive drum 202 onto the surface of the intermediate transfer belt 217 that is driven at a constant speed in contact with the photosensitive drum 202 (hereinafter referred to as a belt transfer corona discharger). , Referred to as a belt transfer portion). Hereinafter, toner image transfer from the photosensitive drum 202 to the intermediate transfer belt 217 is referred to as belt transfer.

  The color printer 200 cleans some untransferred residual toner on the photosensitive drum 202 by the photosensitive member cleaning unit 211 in preparation for the reuse of the photosensitive drum 202, and collects the toner collected at this time, not shown. The toner is stored in a waste toner tank (not shown) via a pipe.

  The color printer 200 sequentially aligns and transfers the Bk, C, M, and Y toner images sequentially formed on the photosensitive drum 202 on the same surface of the intermediate transfer belt 217, thereby transferring the four-color overlapping belt. An image is formed, and then batch transfer is performed on the transfer paper by a paper transfer corona discharger 222.

  On the photosensitive drum 202 side, the process proceeds to the C image forming process after the Bk image forming process. At a predetermined timing, reading of the C image data by the scanner 100 is started, and the laser based on the C image data is started. A C latent image is formed on the photosensitive drum 202 by optical writing. The C developing device 215C rotates the revolver developing device 215 after the rear end of the previous Bk latent image passes through the developing position and before the front end of the C latent image arrives. The latent image is developed with C toner. Thereafter, the development of the C latent image area is continued, and when the rear end of the latent image passes, the revolver developing device 215 is driven in the same manner as in the previous Bk developing device 215K, and the C developing device 215C is sent out. The M developing unit 215M is positioned at the developing position. This operation is also performed before the leading edge of the next M latent image reaches the developing position. Note that the image data reading process, the latent image forming process, and the developing process are the same as the Bk image process and the C image process described above, and a detailed description thereof will be omitted.

  The belt cleaning device 223 includes an inlet seal, a rubber blade, a discharge coil, an inlet seal, a rubber blade contact / separation mechanism, and the like, and cleans the intermediate transfer belt 217. The belt cleaning device 223 uses the blade contact / separation mechanism to remove the inlet seal and rubber from the intermediate transfer belt surface while transferring the second, third, and fourth color images after the first color Bk image is transferred to the belt. Keep the blades, etc. apart.

  A paper transfer corona discharger (hereinafter referred to as a paper transfer unit) 222 applies a AC + DC or DC component to the transfer paper and the intermediate transfer belt by a corona discharge method, and the superimposed full color toner image on the intermediate transfer belt 217 is obtained. Transfer to transfer paper.

  A plurality of transfer paper cassettes 301 are housed inside the paper feed unit 300, and transfer papers of various sizes are housed in each transfer paper cassette 301. The paper feed unit 300 feeds and conveys a sheet of a designated size from the cassette 301 in the direction of the registration roller pair 224 of the color printer 200 by the paper feed roller 302.

  The digital full-color copying apparatus 1 is provided with a manual paper feed tray 310 for manually feeding OHP paper, cardboard, or the like on the side surface of the color printer 200.

  The digital full-color copying apparatus 1 feeds transfer paper from one of the paper feed trays 301 and 310 and waits at the nip portion of the registration roller pair 224 when image formation is started. Then, when the leading edge of the toner image on the intermediate transfer belt 217 approaches the paper transfer unit 222, the digital full-color copying apparatus 1 drives the registration roller pair 224 so that the leading edge of the transfer paper exactly coincides with the leading edge of the image. Then, alignment between the paper and the image is performed, and the transfer paper is superimposed on the color superimposed image on the intermediate transfer belt 217 and passes over the paper transfer device 222 connected to a positive potential. At this time, the transfer paper is charged with a positive charge by the corona discharge current, and most of the toner image is transferred onto the transfer paper. Subsequently, when the digital full-color copying apparatus 1 passes through a separation static eliminator (not shown) disposed on the left side of the paper transfer unit 222, the digital full color copying machine 1 discharges the transfer paper and peels the transfer paper from the intermediate transfer belt 217. Move to the paper transport belt 225. The digital full-color copying apparatus 1 conveys transfer paper onto which a four-color superimposed toner image has been collectively transferred from the surface of an intermediate transfer belt 217 to a fixing device 226 by a paper conveyance belt 225, and a fixing roller 226A controlled to a predetermined temperature. The toner image is melted and fixed at the nip portion of the pressure roller 226B, sent out of the main body by the discharge roller pair 227, and stacked on the copy tray (not shown) face up.

  The digital full-color copying apparatus 1 cleans the surface of the photosensitive drum 202 after the belt transfer to the intermediate transfer belt 217 with a photosensitive member cleaning unit 211 made up of a brush roller, a rubber blade, etc. Discharge uniformly. Further, the digital full-color copying apparatus 1 cleans the intermediate transfer belt 217 after transferring the toner image onto the transfer paper by pressing the blade again with the blade contact / separation mechanism of the belt cleaning device 223. In the case of repeat copying, the digital full-color copying apparatus 1 performs the operation of the scanner 100 and the image formation on the photosensitive drum 202 for the first color of the second sheet at a predetermined timing following the fourth color image process of the first sheet. Proceeding to the image process, the intermediate transfer belt 217 is moved to the area where the surface has been cleaned by the belt cleaning device 223 following the batch transfer process of the first four-color superimposed image to the transfer paper. The toner image is transferred onto the belt. After that, the same operation as the first sheet is performed.

  When the digital full-color copying apparatus 1 receives print data (image data) together with a print instruction command from a host (external device) such as a personal computer through a LAN (Local Area Network) or a parallel I / F, the print data is color-coded. A digital full-color copying apparatus having a composite function capable of printing out (outputting an image) with the printer 200, transmitting image data of the original G read by the scanner 100 to a remote facsimile apparatus, and printing out the received image data. is there. The digital full-color copying apparatus 1 is connected to a public telephone network via a private branch exchange PBX (not shown), and can communicate with a facsimile communication or a service center management server via the public telephone network.

  The digital full-color copying apparatus 1 has a block configuration as shown in FIG. 2, and includes a main controller 1000, an IC card 1001, a scanner controller 1002, an engine controller 1003, a sorter controller 1004, an editor 1005, and a printer controller 1006. , A FAX controller 1007, a parallel I / F control 1008, a LAN control 1009, a communication control 1010, an operation / display unit 1020, an IPU (Image Processing Unit) 400, and the like.

  The main controller 1000 controls the entire digital full-color copying apparatus 1 and is connected to an IC card 1001 in which an extended function or the like is registered, and performs function expansion according to a program or the like in the IC card 1001. In the main controller 1000, a main motor necessary for paper conveyance and a driver to which various clutches are connected are mounted.

  The operation / display unit 1020 performs display for the operator and function setting input control from the operator.

  The scanner controller 1002 is connected to a scanner 100 and an optional ADF (Auto Document Feeder) 120. The ADF 120 is provided with a conveyance motor 121, a document set detection sensor 122, and the like. A scanner controller 1002 performs control of the scanner 100 and the ADF 120, control of writing a document image into an image memory, control of image formation from the image memory, and the like.

  An engine controller 1003 is provided in the color printer 200 and controls an image forming engine such as charging, exposure, development, paper feeding, transfer, fixing, and transfer paper conveyance.

  The sorter controller 1004 is connected to a sorter 500 that is optional and sorts and places each of the sorters when printing a plurality of copies. The sorter controller 1004 controls the operation of the sorter 500.

  The printer controller 1006 receives and analyzes an image and a command for instructing printing from an external device such as a personal computer via the parallel I / F control 1008 and the LAN control 1009, and develops a bitmap into a state where it can be printed as image data. The color printer 200 is driven via the main controller 1000 to print out the image data.

  The color printer 200 is driven by a mechanism element that performs feeding of the photosensitive drum 202, image exposure by the optical writing unit 201, development, transfer, fixing, and paper discharge as well as feeding from the paper feed tray 301. An electric circuit, a control circuit, various sensors, and the like are provided.

  When there is a facsimile transmission instruction, the FAX controller 1007 drives the scanner 100 and the IPU 400 via the main controller 1000 to read the image of the original, and transmits the image data to the facsimile via the communication control 1010 and the private branch exchange PBX. When the image data is sent to the communication line and received by the facsimile call from the communication line and the image data is received, the color printer 200 is driven via the main controller 1000 to print out the image data.

  The IPU (image processing apparatus) 400 has a circuit block configuration as shown in FIG. 3, and includes a document recognition unit 401, an RGBγ correction unit 402, an RGB filter 403, a color correction unit 404, a scaling unit 405, and an I / F ( Interface) 406, UCR circuit 407, CMYBk filter (displayed as CMYB filter in FIG. 3) 408, CMYBkγ correction unit (displayed as CMYBγ correction unit in FIG. 3) 409, gradation processing unit 410, video control 411, RAM ( A random access memory (Random Access Memory) 412, a CPU (Central Processing Unit) 413, a ROM (Read Only Memory) 414, and I / Fs 415 and 416 are provided.

  R, G, B image data generated by the scanner 100 is input to the document recognition unit 401 via an I / F (interface) 1011.

  The IPU 400 converts the R, G, B image data input to the document recognition unit 401 from the reflectance data (R, G, B data) to the density data (R, G, B data) by the RGBγ correction unit 402 in the next stage. ).

  Based on the density R, G, and B data, the document recognition unit 401 determines whether the image area of the data is a character edge area (edge area of a character or line drawing), a halftone dot area, a low dot number halftone dot area, or a pattern. It is determined whether it is an area (photograph or picture area, non-character area, halftone dot area, and halftone dot area), and the C / P signal and B / C signal are sent through the RGB filter 403 and the I / F 415 Output to the controller 1000.

  Note that the C / P signal is a 2-bit signal, “3” indicates a low linearity dot area, “2” indicates a dot area, “1” indicates a character edge area, and “0”. Indicates a picture area. Further, the B / C signal is a 1-bit signal, H (“1”) indicates an achromatic region, and L (“0”) indicates a chromatic region.

  The C / P signal and B / C signal generated by the document recognition unit 401 include an RGB filter 403, a color correction unit 404, a scaling unit 405, an I / F 406, a UCR circuit 407, a CMYBk filter 408, a CMYBkγ correction 409, and a gradation. The data is provided to the processing unit 410 in cascade in synchronization with the image data.

  The RGB filter 403 is a filter that performs MTF correction on RGB data, and includes a coefficient matrix corresponding to an N × N pixel matrix and logic that multiplies each coefficient by each image data to obtain a weighted average value. When the C / P signal represents “1” (character edge region), the RGB filter 403 uses a coefficient matrix for sharpening processing and represents “0” or “2”, “3” ( In the case of a pattern region, a low line number halftone dot region, or a halftone dot region), a weighted average value is derived using a coefficient matrix for smoothing processing and output to the color correction unit 404. If the smoothing filters here are arranged in descending order of the smoothing amount, they become a low linear number halftone dot region, a halftone dot region, and a pattern region. This is because the halftone dot structure will remain and cause moire unless the smoothness of the halftone dot is increased. Further, the halftone dot having a low number of lines needs to be smoothed more strongly than the halftone dot having a high number of lines. .

  The color correction unit 404 converts the R, G, and B data into C, M, and Y data by a primary masking process or the like, and simultaneously generates Bk data from the RGB common part.

  A scaling unit 405 subjects the image data to enlargement / reduction in the main scanning direction x or equal magnification processing.

  The UCR circuit 407 is for improving the color reproduction of the image data, and generates Bk data by performing UCR (under color removal) processing on the common part of the C, M, Y data input from the color correction unit 404. The C, M, Y, and Bk data are output. The UCR circuit 407 performs skeleton black processing when the C / P signal is other than “1” (character edge region), that is, when it is a character region or a picture region, and the C / P signal is “3” (character edge region). Area), full black processing is performed. Further, the UCR circuit 407 erases C, M, and Y data when the C / P signal is “1” (character edge region) and the B / C signal is “H” (achromatic region). This is because black characters are expressed only by the black component.

  The above processing is performed when the image data is full color. For example, when the color other than black is set to red in the two-color mode, the masking coefficient is set to output only the R component (M, Y) according to the density of the G signal. Set the coefficient to be The UCR circuit 407 converts the Bk component into two colors (red and black) by outputting the red component (M, Y) from the Bk, M, and Y values.

  Further, the output image signal IMG of the UCR circuit 407 is one color among C, M, Y, and Bk at a temporary point, and is a frame sequential one color output. That is, full-color (four-color) data is generated by reading the original four times with the scanner 100. Further, in the case of black and white copying, since only one Bk image formation is required, the scanner 100 only needs to read the original once.

  In other words, if there is a mechanism for determining whether a color document or a black and white document, the number of times of reading depends on the document, so there is no need for the operator to determine whether the document is a color document or a monochrome document according to the document.

  In the digital full-color copying apparatus 1 according to the present embodiment, the B / C signal is a signal that is used to determine whether the color document is a color document or a monochrome document, and the B / C signal is “H” (achromatic region) over the entire document surface. ), The main controller 1000 determines that the document is a monochrome document.

  The CMYBk filter 408 performs smoothing and sharpening using an N × N spatial filter according to the frequency characteristics of the color printer 200 and the C / P signal.

  The CMYBkγ correction 409 changes the γ curve in accordance with the frequency characteristics of the color printer 200 and the C / P signal, and processes the image when the C / P signal is other than “1” (other than the character edge region). A γ curve that is faithfully reproduced is used, and when the C / P signal is “1” (character edge region), the γ curve is raised to enhance the contrast.

  The gradation processing unit 410 performs quantization such as dither processing and error diffusion processing according to the gradation characteristics of the color printer 200 and the C / P signal. That is, the gradation processing unit 410 performs gradation-oriented processing when the C / P signal is other than “1” (other than the character edge area) during Bk image formation, and emphasizes resolution in other cases. Perform the process. In addition, the gradation processing unit 410 performs gradation-oriented processing when the C / P signal is “0” (picture area) during image formation other than Bk, and otherwise emphasizes resolution. Process.

  The IPU 400 outputs the image data subjected to the above processing from the video control 411 having a buffer memory to the color printer 200 in synchronization with the image data writing operation. Information such as the machine number, manufacturing number, and user ID of the apparatus (digital full-color copying apparatus 1) is added to the copy as a tracking pattern (a set of isolated points) in yellow, which is difficult to distinguish with human eyes.

  When the IPU 400 is other than the character area (C / P signal = 1), the smoothing process is performed by the RGB filter 403, the skeleton black process is performed by the UCR circuit 407, and the linear (gradation property) is performed by the CMYBkγ correction 409. ) Is selected, and the CMYBk filter 408 and the gradation processing unit 410 perform processing that emphasizes gradation.

  On the other hand, when the IPU 400 is a character region (C / P signal = 1 and B / C signal = L), the RGB filter 403 performs edge enhancement processing, the UCR circuit 407 performs full black processing, and CMYBkγ correction 409. Then, a curve emphasizing contrast is selected, and the CMYBk filter 408 and the gradation processing unit 410 perform processing emphasizing resolution.

  In addition, the IPU 400 performs black character processing (C / P signal = 1 and B / C signal = H) so that C, M, and Y data are not printed during C, M, and Y image formation excluding Bk. , Prevents the surroundings of black characters from being colored due to misalignment.

  At this time, the IPU 400 may make the RGB filter 403 of the Bk data clearer by performing edge enhancement stronger than in the case of color characters.

  As described above, the IPU 400 performs four types of processing: a pattern, a character edge, a halftone dot, and a low line number halftone dot.

  As shown in FIG. 4, the document recognition unit 401 can show the functional blocks as a recognition processing unit 421 and a tracking pattern processing unit 422. The recognition processing unit 421 and the tracking pattern processing unit 422 include a scanner. R, G, and B image data generated by 100 are input via the I / F 1011, respectively.

  The recognition processing unit 421 performs character edge detection, pattern detection, and chromatic / achromatic detection, and outputs a C / P signal representing a character edge area or a pattern area and a B / C signal representing a chromatic area / achromatic area. appear.

  The additional write pattern processing unit 422 detects and removes the tracking pattern (yellow isolated point) of the input data, and at the same time, synchronizes (positions) with the recognition result (C / P, B / C) of the recognition processing unit 421. Thus, the RGB image data after removal is output.

  As shown in FIG. 5, the tracking pattern processing unit 422 is roughly divided into a tracking pattern determination unit 431 to which RGB data is input, a replacement pixel calculation unit 432 to which B data is input, and a pixel determined as a tracking pattern. Is provided with a tracking pattern replacement unit 433 that replaces the pixel with another neighboring pixel, and the tracking pattern replacement unit 433 controls whether or not the pixel value of the tracking pattern is replaced based on the output mode signal.

  The tracking pattern processing unit 422 removes only B from the RG data without converting it.

  In the following description, it is assumed that when the RGB value increases, it becomes black, and when the RGB value decreases, it becomes white.

  As shown in FIG. 6, the tracking pattern determination unit (isolated point detection means) 431 includes a yellow pixel detection unit 441 and a pattern matching unit 442, and RGB data is input to the yellow pixel detection unit 441. The yellow pixel detection unit 441 determines whether the input RGB data is a yellow pixel or a yellow pixel.

  First, the yellow pixel detection unit 441 determines whether the pixel is a white pixel using the RGB data of the pixel of interest using the following conditional expression (1).

Max {R, G, B} <thw (1)
Here, Max {R, G, B} indicates the maximum value of R, G, B data, and thw is a parameter set in advance.

  Further, the yellow pixel detection unit 441 performs hue determination, and determines whether or not the hue of the target pixel is in the yellow region using the following conditional expressions (2) and (3).

RY hue region boundary determination (2) R-2 × G + B> 0 (2)
YG hue region boundary determination 11 × R-8 × G-3 × B> 0 (3)
Further, the yellow pixel detection unit 441 determines whether the maximum color difference of RGB of the target pixel is larger than the threshold value thy by the following conditional expression (4).

Max {R, G, B} -Min {R, G, B}> thy (4)
Here, Max {} represents the maximum value in {}, and Min {} represents the minimum value in {}.

  The yellow pixel detection unit 441 determines that a pixel that satisfies all the conditions (1) to (4) is a yellow pixel.

  That is, if the yellow pixel detection unit 441 detects a yellow hue dot and detects a yellow hue dot, the above formula need not be satisfied.

  The tracking pattern processing unit 422 uses the result determined by the yellow pixel detection unit 441 to determine the tracking pattern by the pattern matching unit 442 performing pattern matching as shown in FIG.

  In FIG. 7, the pixel marked with “x” is the target pixel, and the pattern matching unit 442 determines that the following condition is met within the range of 7 × 21 pixels, for example, and outputs the tracking pattern.

Tracking pattern = X-marked pixel is not yellow pixel and hatched pixel is not yellow pixel The tracking pattern is a yellow isolated dot, so the pattern matching unit 442 performs yellow and non-yellow pattern matching. This is because the non-yellow is not white and the tracking pattern at the time of color is detected.

  Returning to FIG. 5 again, the replacement pixel calculation unit 432 obtains a pixel value to be replaced for the pixel determined as the tracking pattern by the tracking pattern determination unit 431.

  For example, when considering a matrix having a pixel of interest as a pixel of interest as shown in FIG. 8, the replacement pixel calculation unit 432 sets a replacement pixel value from the replacement pixel candidates indicated by black circles using the following conditional expression (5). Calculate with

Replacement pixel value = Max {B (1,1), B (1,2), B (1,3), B (1,9), B (1,10), B (1,11), B ( 4, 6)} (5)
Max {} represents the maximum value in {}, and B (1, 1) represents B data in the first row and the first column.

  In FIG. 8, the replacement candidate pixels are three consecutive pixels because, when the background pixel is the output of the copying machine, the gradation is expressed in the ratio of presence or absence of dots, so that one dot is dark. This is because we do not know whether to take data or thin data.

  Further, the replacement pixel calculation unit 432 may refer to the RG data when detecting the replacement pixel.

  For example, when the R and G pixels of the target pixel are the replacement pixel candidates R1 and G1, the maximum value of B is selected from the pixels (R−R1 and G−G1) that have a small difference between the target pixel and the replacement pixel candidate. You may make it decide. When the tracking pattern is printed with the Y component, the B signal is affected by the tracking pattern, but RG is relatively unaffected by the tracking pattern, and therefore tends to be data before the tracking pattern is printed.

  The tracking pattern is affected only by B because the spectral characteristics of the Y component are excellent.

  Next, the tracking pattern replacement unit 433 will be described. The tracking pattern replacement unit 433 changes the tracking pattern pixel by replacing the pixel value of the pixel determined as the tracking pattern by the tracking pattern determination unit 431.

  The tracking pattern replacement unit 433 compares the B data value of the target pixel with the B data of the replacement pixel of the replacement pixel calculation unit 432, and replaces the B data of the target pixel when the target pixel value is greater than the predetermined value α. Let it be B data of a pixel. The predetermined value α is “0” or more. The replacement pixel calculation unit 432 and the tracking pattern replacement unit 433 function as replacement means as a whole.

  Here, the reason why the value is smaller than the target pixel is that the purpose is to remove a yellow isolated point, and a larger value is not replaced as a false detection.

  The reason why only the B data is replaced is that, as described above, the tracking pattern has little influence on the RG.

  Furthermore, if the value is larger than the predetermined value α, the replacement is originally not meaningful in terms of data value even if the small data is replaced. This is because there is a possibility of gradation skipping due to this process.

  Next, the operation of this embodiment will be described. The digital full-color copying apparatus 1 reads an image of the original G with the scanner 100 and records and outputs it on a recording sheet with the color printer 200. At this time, if there is a yellow isolated point in the image data of the original G, the isolated point The area is replaced with a replacement pixel having a predetermined density. At this time, if the density difference between the isolated point area and the replacement pixel is larger than a predetermined value α, the isolated point area is replaced with the replacement pixel.

  That is, the digital full-color copying apparatus 1 performs main scanning and sub-scanning on the document G set on the contact glass 101 of the scanner 100 to read an image of the document G, and reads the document G read by the scanner 100. After the image data is subjected to necessary image processing by the IPU 400, it is printed out (image output) by the color printer 200, and the image data of the original G read by the scanner 100 is transmitted to a remote facsimile apparatus.

  When the IPU 400 performs image processing to record and output the image data of the original G read by the scanner 100 on a recording sheet by the color printer 200, the original recognition unit 401 of the IPU 400 determines whether or not there is a yellow isolated point. If there is an isolated point, if the density difference between the isolated point region and the replacement pixel is larger than a predetermined value α, the isolated point region is replaced with the replacement pixel.

  That is, as shown in FIG. 4, the document recognition unit 401 includes a recognition processing unit 421 and a tracking pattern processing unit 422, and the recognition processing unit 421 performs character edge processing on RGB image data input from the scanner 100. Detection, picture detection, and chromatic / achromatic detection are performed to generate a C / P signal representing a character edge area or a picture area and a B / C signal representing a chromatic area / achromatic area.

  The additional write pattern processing unit 422 detects and removes the tracking pattern (yellow isolated point) of the RGB image data input from the scanner 100 and simultaneously removes the recognition result (C / P, B /) of the recognition processing unit 421. The image data of RGB after removal is output in synchronization (position) with C).

  Then, as shown in FIG. 5, the tracking pattern processing unit 422 includes a tracking pattern determination unit 431 to which RGB data is input, a replacement pixel calculation unit 432 to which B data is input, and pixels determined to be a tracking pattern as peripheral elements. A tracking pattern replacement unit 433 that replaces the other pixel is provided. The tracking pattern replacement unit 433 controls whether or not the pixel value of the tracking pattern is replaced based on the output mode signal. Then, the tracking pattern processing unit 422 removes only B from the RG data without converting it.

  As shown in FIG. 6, the tracking pattern determination unit 431 includes a yellow pixel detection unit 441 and a pattern matching unit 442, and the yellow pixel detection unit 441 is based on the conditional expressions (1) to (4). Whether the input RGB data is a yellow pixel or not is determined.

  The pattern matching unit 442 determines the tracking pattern by performing pattern matching as shown in FIG.

  Then, the replacement pixel calculation unit 432 in FIG. 5 applies the pixel determined as the tracking pattern by the tracking pattern determination unit 431 based on the conditional expression (5) in the case of the matrix shown in FIG. Find the pixel value to be replaced.

  Then, the tracking pattern replacement unit 433 changes the tracking pattern pixel by replacing the pixel value with respect to the pixel determined as the tracking pattern by the tracking pattern determination unit 431.

  The tracking pattern replacement unit 433 compares the B data value of the target pixel with the B data of the replacement pixel of the replacement pixel calculation unit 432. If the target pixel value is greater than a predetermined value α of “0” or more, the target pixel value The B data of the pixel is replaced with the B data of the replacement pixel.

  That is, as shown in FIG. 9, the document recognizing unit 401 determines whether the target pixel of the RGB image data is a yellow isolated point (tracking pattern) (step S101). The process proceeds to the next process without performing replacement.

  If the target pixel is a tracking pattern in step S101, the document recognition unit 401 determines whether the pixel value of the target pixel that is the isolated point region is larger than the pixel value obtained by adding the predetermined value α to the pixel value of the replacement pixel. Check, that is, whether or not the density difference between the pixel of the target pixel and the replacement pixel is larger than the predetermined value α (step S102), and the pixel value of the target pixel is a pixel value obtained by adding the predetermined value α to the pixel value of the replacement pixel If it is below, the process proceeds to the next process without replacing the pixels.

  In step S102, when the pixel value of the target pixel that is the isolated point region is larger than the pixel value obtained by adding the predetermined value α to the pixel value of the replacement pixel, the document recognition unit 401 sets the target pixel value to the replacement pixel value. (Step S103), and the process proceeds to the next process.

As described above, when the digital full-color copying apparatus 1 according to the present embodiment replaces the isolated point of the document image data with a predetermined replacement pixel, the tracking pattern determination unit 431 of the tracking pattern processing unit 422 of the IPU 401 performs the document image data processing. A yellow isolated point is detected based on whether or not there is yellow, and if the density difference between the detected isolated point and a predetermined replacement pixel exceeds a predetermined value, the tracking pattern replacement unit 433 detects the isolated point. Is replaced with the replacement pixel.

Therefore, unnecessary pixel replacement of isolated points can be eliminated, and image processing for replacing isolated point pixels with good image quality while maintaining continuity with surrounding images can be performed.

In the digital full-color copying apparatus 1 according to the present embodiment, when the isolated point of the document image data is replaced with a predetermined replacement pixel, the yellow pixel detection unit 441 of the tracking pattern determination unit 431 has yellow color in the document image data. Whether or not the yellow isolated point is detected and the tracking pattern replacement unit 433 determines that the replacement pixel having the maximum value among the plurality of replacement pixel candidates around the detected isolated point is thinner than the isolated point. Only the isolated point is replaced with the replacement pixel.

  Therefore, erroneous determination of isolated points can be suppressed, and image processing for replacing isolated point pixels in an appropriate state with good image quality can be performed.

Further, in the digital full-color copying apparatus 1 according to the present embodiment, when the isolated point of the image data of the document is replaced with a predetermined replacement pixel, the yellow pixel detection unit 441 of the tracking pattern determination unit 431 has yellow color in the document image data. Whether or not a yellow isolated point is detected, and the tracking pattern replacement unit 433 replaces the replacement pixel candidates around the detected isolated point with image data having similar R and G image data values. Yes.

  Therefore, erroneous determination of isolated points can be suppressed, and conversion to pixels in a state where no tracking pattern is applied can be achieved.

  In the digital full-color copying apparatus 1 of this embodiment, at least one of the replacement pixels includes adjacent pixels.

  Therefore, it is possible to prevent the influence of the output pattern of the copy original by setting the pixel to be replaced with reference to the adjacent image data, and the pixel of the isolated point in an appropriate and good image quality state. Image processing for replacement can be performed.

  Furthermore, in the digital full-color copying apparatus 1 of the present embodiment, the tracking pattern replacement unit 433 replaces only B image data among the RGB image data in the isolated point area as replacement target data.

  Therefore, since the yellow isolated point affects the B signal, the replacement target pixel is only B, and the RG signal can be prevented from being affected at the time of erroneous determination. It is possible to perform image processing for replacing pixels of isolated points with appropriate and good image quality.

  Further, in the digital full-color copying apparatus 1 of the present embodiment, the tracking pattern determination unit 431 detects a tracking pattern made up of information such as the machine number, serial number, and user ID of the apparatus as an isolated point.

  Therefore, it is possible to replace the tracking pattern with the replacement pixel appropriately and in a good image quality state.

  Further, the digital full-color copying apparatus 1 according to the present embodiment replaces the isolated point area with the replacement pixel when the image data output mode is the two-color mode.

  Therefore, it is possible to prevent the isolated point region from being converted to another color in the two-color mode, and it is possible to perform image processing that replaces isolated point pixels in an appropriate and good image quality state. .

  The digital copying apparatus full-color copying apparatus 1 according to the present embodiment replaces the isolated point of the image data of the original scanned by scanning the original and color-separating the image of the original with the IPU 401 with a predetermined replacement pixel. At this time, the IPU 401 performs image processing for replacing the isolated point region with a replacement pixel.

  Therefore, it is possible to maintain continuity with the surrounding image without replacing unnecessary pixels in the isolated point region, and to perform image processing for replacing isolated point pixels with good image quality. it can.

  The full-color copying machine 1 of the digital copying apparatus according to the present embodiment performs image processing for replacing isolated points of image data of a document with predetermined replacement pixels by the IPU 401, and an image is processed based on the image data after the image processing. When recording and outputting on a sheet, the IPU 401 performs image processing to replace the isolated point area with a replacement pixel.

  Therefore, it is possible to maintain the continuity with the surrounding image without replacing unnecessary pixels in the isolated point region, and to perform an image processing that performs image processing for replacing isolated point pixels with good image quality. Record output is possible.

  Further, the digital color copying apparatus 1 of the present embodiment uses the scanner 100 to scan an original and color-separate and read the original image. When the color printer 200 records and outputs an image on paper based on the image data after the image processing, the IPU 401 performs the image processing to replace the isolated point area with the replacement pixel. ing.

  Therefore, it is possible to maintain the continuity with the surrounding image without replacing unnecessary pixels in the isolated point region, and to perform an image processing that performs image processing for replacing isolated point pixels with good image quality. Record output is possible.

  Further, the digital copying apparatus 1 of the present embodiment is connected to an external apparatus, receives a print instruction command and image data from the external apparatus, and replaces an isolated point area of the image data with a replacement pixel by the IPU 401. Image processing is performed, and the color printer 200 records and outputs an image on paper based on the image data after the image processing.

  Therefore, it is possible to maintain continuity with the surrounding image without replacing unnecessary pixels in the isolated point area even for image data input from an external device, and the isolated point with good image quality. It is possible to record and output an image that has undergone image processing for replacing the pixels.

  The invention made by the present inventor has been specifically described based on the preferred embodiments. However, the present invention is not limited to the above, and various modifications can be made without departing from the scope of the invention. Needless to say.

  It is determined whether image data read from a document includes a tracking pattern, and an image processing apparatus that performs image processing corresponding to an output image quality mode, an image reading apparatus equipped with the image processing apparatus, a color copying apparatus, and the like. Can be applied.

1 is a schematic front view of a digital full-color copying apparatus to which one embodiment of an image processing apparatus, an image reading apparatus, and a color copying apparatus according to the present invention is applied. FIG. 2 is a block diagram of the main part of the digital full-color copying apparatus in FIG. 1. FIG. 3 is a detailed circuit block configuration diagram of the IPU of FIG. 2. FIG. 4 is a circuit block configuration diagram of a document recognition unit in FIG. 3. The circuit block block diagram of the tracking pattern process part of FIG. FIG. 6 is a circuit block diagram of a tracking pattern determination unit in FIG. 5. Explanatory drawing of the pattern matching process in the pattern matching part of FIG. FIG. 6 is an explanatory diagram of a replacement pixel value calculation process by a replacement pixel calculation unit in FIG. 5. 5 is a flowchart showing tracking pattern detection and replacement processing by the document recognition unit in FIG. 4.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Digital full color copying apparatus G Original 100 Scanner 101 Contact glass 102 Pressure plate 103 1st traveling body 104 Illumination lamp 105 Mirror 106 2nd traveling body 107, 108 Mirror 109 Lens 110 Three-line CCD sensor 120 ADF
121 Conveyor Motor 122 Document Set Detection Sensor 200 Color Printer 201 Optical Writing Unit 202 Photosensitive Drum 203 Laser Emitter 204 Polygon Mirror 205 Rotating Motor 206 fθ Lens 207 Reflecting Mirror 211 Photoconductor Cleaning Unit 212 Static Discharge Lamp 213 Charger 214 Potential Sensor 215 Revolver developing device 215K to 215M Developer 215KS to 215YS Developing sleeve 216 Development density pattern detector 217 Intermediate transfer belt 218 Drive roller 219 Transfer counter roller 220 Cleaning counter roller 221 Belt transfer corona discharger (belt transfer unit)
222 Paper transfer corona discharger 223 Belt cleaning device 224 Registration roller pair 225 Paper transport belt 226 Fixing device 226A Fixing roller 226B Pressure roller 227 Discharge roll pair 300 Paper feed unit 301 Transfer paper cassette 302 Paper feed roller 310 Manual paper feed tray 400 IPU
401 Document Recognition Unit 402 RGBγ Correction Unit 403 RGB Filter 404 Color Correction Unit 405 Scaling Unit 406 I / F
407 UCR circuit 408 CMYBk filter 409 CMYBkγ correction unit 410 gradation processing unit 411 video control 412 RAM
413 CPU
414 ROM
415, 416 I / F
421 Recognition processing unit 422 Tracking pattern processing unit 431 Tracking pattern determination unit 432 Replacement pixel calculation unit 433 Tracking pattern replacement unit 441 Yellow pixel detection unit 442 Pattern matching unit 500 Sorter 1000 Main controller 1001 IC card 1002 Scanner controller 1003 Engine controller 1004 Sorter controller 1005 Editor 1006 Printer controller 1007 FAX controller 1008 Parallel I / F control 1009 LAN control 1010 Communication control 1011 I / F
1012 BR unit 1020 Operation / display unit

Claims (10)

An image processing apparatus that replaces an isolated point of image data of a document with a replacement pixel that is another pixel around the isolated point,
On whether there is a yellow image data of the document, beyond the isolated point detection means for detecting an isolated point of yellow density difference between the replacement pixel detected isolated point of the isolated point detection means the predetermined value An image processing apparatus comprising: a replacement unit that replaces only the B image data of the isolated point with a replacement pixel. An image processing apparatus that replaces an isolated point of image data of a document with a replacement pixel that is another pixel around the isolated point,
An isolated point detecting unit for detecting a yellow isolated point depending on whether or not the image data of the document has yellow , and a maximum value among a plurality of replacement pixel candidates around the isolated point detected by the isolated point detecting unit. An image processing apparatus comprising: a replacement unit that replaces only B image data of an isolated point with a replaced pixel only when the replaced pixel is thinner than the isolated point . An image processing apparatus that replaces an isolated point of image data of a document with a replacement pixel that is another pixel around the isolated point,
Of the plurality of replacement pixel candidates around the isolated point detected by the isolated point detecting unit, the isolated point detecting unit for detecting a yellow isolated point depending on whether or not the image data of the document has yellow , R, An image processing apparatus comprising: image data having a similar G image data value; and replacement means for replacing only B image data of the isolated point . The image processing apparatus, as the plurality of replacement candidate pixel, at least one image processing apparatus according to claim 1 or claim 2, characterized in that it comprises adjacent pixels. Isolated point detection means, as the isolated point, machine number of the device, serial number, claim from claim 1, characterized in that for detecting the tracking pattern is a set of isolated point consisting of information such as the user ID 4 An image processing apparatus according to any one of the above. 5. The image processing according to claim 1, wherein when the output mode of the image data is a two-color mode, the image processing device replaces the isolated point with the replacement pixel. apparatus. An image reading device that replaces an isolated point of image data of the original scanned by scanning the original and color-separating the image of the original with a replacement pixel that is another pixel around the isolated point by the image processing means. An image reading apparatus comprising the image processing apparatus according to claim 1 as the image processing means. The image processing unit performs image processing to replace the isolated point of the image data of the original document with a replacement pixel that is another pixel around the isolated point, and records the image on a sheet based on the image data after the image processing. An image forming apparatus for outputting, wherein the image processing apparatus according to claim 1 is mounted as the image processing means. The image reading unit scans the document and color- separates and reads the image of the document and reads the isolated point of the image data of the document to a replacement pixel that is another pixel around the isolated point by the image processing unit. A copying apparatus that performs replacement image processing and records and outputs an image on paper based on image data after the image processing by the image forming unit, wherein the image processing unit is any one of claims 1 to 7. A color copying apparatus comprising the image processing apparatus according to claim 1. 8. The copying apparatus is connected to an external apparatus, receives a print instruction command and image data from the external apparatus, and is an image processing unit that is an image processing apparatus according to claim 1, wherein the image data 10. A color copying apparatus according to claim 9 , wherein image processing is performed to replace the isolated point with a replacement pixel, and an image is recorded and output on a sheet based on the image data after the image processing by the image forming means.

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