31 results about "Under color removal" patented technology

An image processing method of processing image data includes a color space conversion step of converting an input color signal of image data into an output color signal having cyan (C), magenta (M), and yellow (Y) values; a black generation / under color removal step of converting the CMY values into cyan (C), magenta (M), yellow (Y), and black (K) values by adding a black (K) value and decreasing the CMY values so that portions of cyan (C), magenta (M), and yellow (Y) recording liquids used to form the image data are replaced with a black (K) recording liquid; and a total amount control step of controlling amounts of cyan (C), magenta (M), yellow (Y), and black (K) recording liquids calculated from the CMYK values so that a total amount of the CMYK recording liquids per unit area on a recording medium does not exceed a predetermined total amount limit.

An edge enhancement processing system and method for modifying image data at certain pixel locations to include gray scale image data so as to reduce jaggedness in the image. An adjustable threshold device establishes a binary pixel value for an incoming current gray level pixel in accordance with a thresholding criterion. An operator accessible input to the thresholding device is used by the operator to adjust the threshold value in the thresholding criterion. A current binary pixel formed in accordance with the thresholding criterion and neighboring pixels also so formed in accordance with the thresholding criterion are examined in accordance with predetermined criteria for determining adjustment of the current pixel to a gray scale value to reduce edge jaggedness of the image. Generally, adjustment of the thresholding value is made in instances where under color removal and / or gray component replacement is employed.

The present invention is directed to an improved system and methodology for generating ink / media transforms. A preferred methodology comprises one or more of the following steps: selecting the ink type; selecting the color set; selecting the media type; selecting the ink saturation level; generating a set of “linearization” color samples, or “ramps”; measuring the linearization ramps; generating a set of “target” color samples, or “patches”; measuring the target patches; screening the target patches and generating the boundary surface of a printer's gamut; implementing an under-color removal (UCR) and black generation (BG); and building the Printer Profile, Transforms and ICC Color Profiles.

The present invention provides an image processing apparatus that supplies image signals to an image forming apparatus that forms an image on a recording medium using recording material. The apparatus includes a storage unit that stores a limiting value of a sum of signal levels of image signals output to the image forming apparatus, an input unit that inputs C, M, Y and K signals as image signals, a first comparison unit that compares the limiting value and the sum of the signal levels of the input C, M, Y and K signals, an under color removal unit that replaces a predetermined level of C, M and Y signals with a K signal in an under color removal process When the sum of the signal levels of the input C, M, Y and K signals exceeds the limiting value, a second comparison unit that compares the limiting value and the sum of the signal levels of the C, M, Y and K signals after undergoing the under color removal process, and where the sum after the under color removal process exceeds the limiting value, an adjustment unit that reduces the C, M and Y signals after undergoing the under color removal process at an identical rate so as to reduce the sum after the under color removal process to less than the limiting value.

c, m, and y, which are the primary colors, are calculated from inputted RGB data. Duty limitation is then applied to c, m, and y by means of the limit amount α. c′, m′, and y′, which have been limited by α, are then normalized. The largest limit amount is β when the normalized values are less than 200%. If these values are between 200% and 250%, β+((c″+m″+y″) / 255−2)×2γ is then the largest limit amount, which is β+γ when the values are equal to or more than 250%. C, M, Y, and K are obtained by subjecting c′, m′, and y′ to under color removal and black generation processing. Unless the total of these values exceeds the largest limit amount, C, M, Y, K are outputted as is as the output values C′, M′, Y′, and K′. When the largest limit amount is exceeded, Duty limitation is applied.

A pure rendering intent is used to render text and line art in color imaging systems. A CMY image goes through a one hundred percent under color removal process creating a CMYK image. The CMYK image is processed by a set of clamping tone reproduction curves. The clamping tone reproduction curves shift nearly saturated colors to total saturation. The result is a rendering of text and line art that has improved clarity and legibility.

As the color conversion process for image data of an RGB signal, a color correction section 26 performs a color correction process, and a black generation and under color removal section 27 performs a black generation and under color removal process. In the color conversion process, the color correction section 26 and the black generation and under color removal section 27 are supplied with a halftone frequency recognized by a halftone frequency recognition section 23. The color correction section 26 and the black generation and under color removal section 27 change the process based upon the halftone frequency. As a result, an image processing apparatus is realized in which improved image quality can be produced by an optimum image process that is performed on an image containing a halftone area depending upon the halftone frequency of the halftone area so that image quality is improved.

A segmentation process section classifies signals of pixels in input image data into respective signals of a black text / low density area, a black text / high density area, a color text area, and an area other than a text area. A black generation and under color removal section performs an under color removal process with respect to the signal of the black text / low density area so that an amount of UCR is a middle value (C, M, Y) of signals indicative of color component density levels. Consequently, it is possible to prevent color fringing and a white spot at a time when chromatic aberration occurs in the input image data.

Present invention relates to a color image processing apparatus including an input color chip making unit for making a color chip of the selected color signal as an input color chip, an output color chip making unit for subjecting the selected color signal to the under color removal processing carried out in an UCR processing unit with two or more parameters different from one another, thereby making a color chip of the obtained color signal as an output color chip for each parameter, and a parameter determining unit for selecting among the parameters a parameter which provides the minimum difference between the input color chip and the output color chip, wherein the UCR processing unit subjects the input color signal to the UCR processing by using the parameter selected by the parameter determining unit. With this, a color image desired by a user can be created.

A segmentation process section classifies signals of pixels in input image data into respective signals of a black text / low density area, a black text / high density area, a color text area, and an area other than a text area. A black generation and under color removal section performs an under color removal process with respect to the signal of the black text / low density area so that an amount of UCR is a middle value (C, M, Y) of signals indicative of color component density levels. Consequently, it is possible to prevent color fringing and a white spot at a time when chromatic aberration occurs in the input image data.

An arrangement for sharpening the resolution of printed text in a color printing system is disclosed. An image processing system (1) includes a color conversion apparatus (2) for converting from one color space (RBG) to another color space (CMYK) for display on a color printer (8). The color conversion apparatus (2) includes a near-black correction unit (36) which detects near black-near white and near white-near, black transistions and when such a transition occurs, outputs a full,or deep black color in place of the near-black color.

An apparatus for processing images including a compression-expansion unit, a first under color removing unit, and a second under color removing unit. The compression-expansion unit executes a compression and expansion process on an image data using discrete cosine transform. The first under color removing unit applies the first under color removal process to the image data before the compression and expansion process. The second under color removing unit applies the second under color removal process to the image data after the compression and expansion process.

In a method for improving the color reproducibility of printed matter to be produced by a printing press in proof print produced by a proof press, a look-up table containing converted values of image data over the entire color space with respect to the proof press is created, the look-up table is corrected based on the color of a printing paper for the printing press and a paper exposed area factor in the proofing, and proof print is created by the use of the corrected look-up table. Furthermore, proof printing image data, in which each of levels of monochromatic color gradation of black on the printed matter is represented on the proof print, out of the proof printing image data over the entire color space in a subtractive process resulting from color matching between proof print by the proof press and the printed matter by means of the printing press is corrected in such a manner that a part having a black ink area factor of 100% on the printed matter is represented only with black ink also on the proof print, but that a part other than the part having a black ink area factor of 100% on the printed matter is represented on the proof print by using under color removal, so that the representing characteristics of the black ink on the printed matter are reproduced on the proof print.

This invention is directed to a method capable of performing appropriate under color removal in image original reading. According to this method, under color removal of the original is performed as follows. A printing medium without any printed image is read by primary and complementary color readings. A brightness signal distribution is generated by converting, using a provisional table, each of image data generated by the reading methods. The lowest one of signal levels is selected from each of the distributions. In correspondence with each of the primary and complementary color readings, a conversion table is formed, which converts the image data to make a pixel value corresponding to the selected lowest one of the signal levels to a value representing white. Under color removal of the image data is performed using a corresponding conversion table in accordance with the reading method of the image original.

In a color image processor for converting a RGB input image data into a CMYK image output data, it is determined whether a data format of the input image data is a non-picture image format or a picture image format. For the input image data of the non-picture image format, a color conversion is performed with values of C, M and Y colors made minimum and a value of K color made maximum, when values of all of the R, G and B colors are minimum, and, for the input image data of the picture image format, a color conversion is performed with the values of the C, M and Y colors set to temporary values slightly smaller than the maximum values thereof when values of all of the R, G and B colors are minimum. Final C, M, Y and K colors are obtained by performing the Black-Generation and Under-Color-Removal processing for the temporary values.

In a method for improving the color reproducibility of printed matter to be produced by a printing press in proof print produced by a proof press, a look-up table containing converted values of image data over the entire color space with respect to the proof press is created, the look-up table is corrected based on the color of a printing paper for the printing press and a paper exposed area factor in the proofing, and proof print is created by the use of the corrected look-up table. Furthermore, proof printing image data, in which each of levels of monochromatic color gradation of black on the printed matter is represented on the proof print, out of the proof printing image data over the entire color space in a subtractive process resulting from color matching between proof print by the proof press and the printed matter by means of the printing press is corrected in such a manner that a part having a black ink area factor of 100% on the printed matter is represented only with black ink also on the proof print, but that a part other than the part having a black ink area factor of 100% on the printed matter is represented on the proof print by using under color removal, so that the representing characteristics of the black ink on the printed matter are reproduced on the proof print.

An image processing method of processing image data includes a color space conversion step of converting an input color signal of image data into an output color signal having cyan (C), magenta (M), and yellow (Y) values; a black generation / under color removal step of converting the CMY values into cyan (C), magenta (M), yellow (Y), and black (K) values by adding a black (K) value and decreasing the CMY values so that portions of cyan (C), magenta (M), and yellow (Y) recording liquids used to form the image data are replaced with a black (K) recording liquid; and a total amount control step of controlling amounts of cyan (C), magenta (M), yellow (Y), and black (K) recording liquids calculated from the CMYK values so that a total amount of the CMYK recording liquids per unit area on a recording medium does not exceed a predetermined total amount limit.

The present invention provides a color image processing system for processing drawings at high speed while reproducing color tone with fidelity. The color image processing system includes a digital processor that performs a raster operation on multigradation image data and generates an output image represented by a first plurality of color components. The system also includes a processor which separates the output image data into a second plurality of color components and stores the separated data in a memory. The system includes a reverse color separator which transforms the stored image data back into image data represented by the first plurality of color components and supplies this transformed image data to the digital processor. In a preferred embodiment, the digital processor performs an under color removal / black generation conversion to separate the output image data resulting from the raster operation into cyan, magenta, yellow and black color components. The reverse color separator performs a reverse under color removal / black generation conversion to restore the stored image data to a cyan, magenta, yellow format suitable for use by the digital processor.

In a method for improving the color reproducibility of printed matter to be produced by a printing press in proof print produced by a proof press, a look-up table containing converted values of image data over the entire color space with respect to the proof press is created, the look-up table is corrected based on the color of a printing paper for the printing press and a paper exposed area factor in the proofing, and proof print is created by the use of the corrected look-up table. Furthermore, proof printing image data, in which each of levels of monochromatic color gradation of black on the printed matter is represented on the proof print, out of the proof printing image data over the entire color space in a subtractive process resulting from color matching between proof print by the proof press and the printed matter by means of the printing press is corrected in such a manner that a part having a black ink area factor of 100% on the printed matter is represented only with black ink also on the proof print, but that a part other than the part having a black ink area factor of 100% on the printed matter is represented on the proof print by using under color removal, so that the representing characteristics of the black ink on the printed matter are reproduced on the proof print.

As the color conversion process for image data of an RGB signal, a color correction section 26 performs a color correction process, and a black generation and under color removal section 27 performs a black generation and under color removal process. In the color conversion process, the color correction section 26 and the black generation and under color removal section 27 are supplied with a halftone frequency recognized by a halftone frequency recognition section 23. The color correction section 26 and the black generation and under color removal section 27 change the process based upon the halftone frequency. As a result, an image processing apparatus is realized in which improved image quality can be produced by an optimum image process that is performed on an image containing a halftone area depending upon the halftone frequency of the halftone area so that image quality is improved.

A system and method are provided for determining ink jet printing system parameters by selecting an appropriate linearizing transformation for application to images to be printed on a printing system for a specific substrate. These transformations can be any transformation capable of being applied in graduated increments and having a corresponding incremental visual influence on the printed output. The present invention allows the user to determine multiple parameters for the printer, including for example, tone scale correction, determination of upper ink limits, amount of under color removal, and allows the user to identify the proper ink level for optimum quality of graphics and / or text printing.

c, m, and y, which are the primary colors, are calculated from inputted RGB data. Duty limitation is then applied to c, m, and y by means of the limit amount α. c′, m′, and y′, which have been limited by α, are then normalized. The largest limit amount is β when the normalized values are less than 200%. If these values are between 200% and 250%, β+((c″+m″+y″) / 255−2)×2γ is then the largest limit amount, which is β+γ when the values are equal to or more than 250%. C, M, Y, and K are obtained by subjecting c′, m′, and y′ to under color removal and black generation processing. Unless the total of these values exceeds the largest limit amount, C, M, Y, K are outputted as is as the output values C′, M′, Y′, and K′. When the largest limit amount is exceeded, Duty limitation is applied.

This invention is directed to a method capable of performing appropriate under color removal in image original reading. According to this method, under color removal of the original is performed as follows. A printing medium without any printed image is read by primary and complementary color readings. A brightness signal distribution is generated by converting, using a provisional table, each of image data generated by the reading methods. The lowest one of signal levels is selected from each of the distributions. In correspondence with each of the primary and complementary color readings, a conversion table is formed, which converts the image data to make a pixel value corresponding to the selected lowest one of the signal levels to a value representing white. Under color removal of the image data is performed using a corresponding conversion table in accordance with the reading method of the image original.

An image processing apparatus, which supplies image signals to an image forming apparatus, includes a storage unit that stores a limiting value of a sum of signal levels of output image signals, an input unit that inputs C, M, Y and K signals, a first comparison unit that compares the limiting value and the sum of the signal levels, an under color removal unit that replaces a predetermined level of C, M and Y signals with a K signal in an under color removal process when the sum of the signal levels of the input signals exceeds the limiting value, a second comparison unit that compares the limiting value and the sum after undergoing the under color removal process, and where the sum after the under color removal process exceeds the limiting value, an adjustment unit that reduces the C, M and Y signals after undergoing the under color removal process at an identical rate so as to reduce the sum to less than the limiting value.

As the color conversion process for image data of an RGB signal, a color correction section 26 performs a color correction process, and a black generation and under color removal section 27 performs a black generation and under color removal process. In the color conversion process, the color correction section 26 and the black generation and under color removal section 27 are supplied with a halftone frequency recognized by a halftone frequency recognition section 23 . The color correction section 26 and the black generation and under color removal section 27 change the process based upon the halftone frequency. As a result, an image processing apparatus is realized in which improved image quality can be produced by an optimum image process that is performed on an image containing a halftone area depending upon the halftone frequency of the halftone area so that image quality is improved.

A method of performing color space conversion and under color removal. Pixelated data is first resampled (102) to an efficient word size—typically 8-bits wide. The RGB color format data words are then subtracted from a maximum intensity to yield CMY color format data words. The minimum value of the three intensity words for each pixel is determined and used as an initial black value. A scaled version of the initial black value is then subtracted from each of the four CMYK intensity words (104). The resulting CMYK values are then limited to a range bounded by the maximum and minimum producible intensities for each color.

An image processing method is disclosed for performing an under color removal process and a black recording liquid incorporation process on an input three-color signal, and generating image data for an imaging apparatus that is configured to form a color image on a recording medium using recording liquids of cyan, magenta, yellow, and black. The method includes the steps of regulating a maximum black recording liquid incorporation amount such that glossiness of black realized in an image formed on a glossy recording medium is not degraded, setting the black to be realized by the black recording liquid until reaching the regulated maximum black recording liquid incorporation amount, and setting the black to be realized through addition of a composite of the cyan, magenta, and yellow recording liquids if the black to be realized requires an amount of the black recroding liquid exceeding the regulated maximum black recording liquid incorporation amount.

An image processing method is disclosed for performing an under color removal process and a black recording liquid incorporation process on an input three-color signal, and generating image data for an imaging apparatus that is configured to form a color image on a recording medium using recording liquids of cyan, magenta, yellow, and black. The method includes the steps of regulating a maximum black recording liquid incorporation amount such that glossiness of black realized in an image formed on a glossy recording medium is not degraded, setting the black to be realized by the black recording liquid until reaching the regulated maximum black recording liquid incorporation amount, and setting the black to be realized through addition of a composite of the cyan, magenta, and yellow recording liquids if the black to be realized requires an amount of the black recording liquid exceeding the regulated maximum black recording liquid incorporation amount.