31 results about "Under color removal" patented technology

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.

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.

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.

The color printing control device outputs color material reduction processed data generated by applying a color material reduction process to each pixel of bitmaps converted to color material colors to be used in printing, when it is judged that the color material reduction printing mode is specified. The color material reduction process includes chroma conversion that reduces chroma and under-color removal / black generation that replaces at least a portion of achromatic components generated by overlaying of a plurality of color materials.

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.

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.

Under-color removal of show-through background from a scanned original, so as to retain chromatic highlights of the scanned image of the original. An under-color level defines a value at which signals having a higher luminance than a luminance of the under-color level are converted into white. Before under-color removal, and based on the scanned image of the original, an achromatic color is converted into a color closer to white than the under-color level for an achromatic color closer whose luminance falls in a specified range lower than the luminance of the under-color level; and a chromatic color is converted into a chromatic color having a lower luminance than the luminance of the under-color level for a chromatic color in the specified range. Under-color removal of the converted achromatic and chromatic colors is thereafter applied using the under-color level, by which signal values having a higher luminance than a luminance of the under-color level are converted into white.