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公开(公告)号：DE60302862T2
公开(公告)日：2006-06-22
申请号：DE60302862
申请日：2003-12-16
Applicant: XEROX CORP
Inventor： HAINS CHARLES M , KANG SANG-CHUL
Abstract: The system and method reduces aliasing which is formed by the patterns that are introduced by the halftone screens used in the printer. The system and method provides halftone-specific anti-alias filters for obtaining optimal effective resolution in printed images. A method of reducing aliasing in a digital image includes providing a digital image; selecting a halftone screen for halftoning the digital image, wherein the halftone screen has a directional component associated with it; filtering the digital image with an antialiasing filter, the antialiasing filter having been designed to have a directional frequency response that is optimized for the directional component of the selected halftone screen; and halftoning the filtered digital image.
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公开(公告)号：CA2347205A1
公开(公告)日：2001-11-12
申请号：CA2347205
申请日：2001-05-08
Applicant: XEROX CORP
Inventor： RUMPH DAVID E , LUNG VINCENT C , HAINS CHARLES M
Abstract: This invention is a method of producing a set of TRC's for a color printer 's secondary halftone screens that is correlated with the printer's primary halftone screens. The method makes use of the printer/screen characteristic data that is normally gathered during screen calibration. However, instead of progressing from the data to a normal calibration for the secondary screens, the method goes backward through the data starting with the finished primary screen TRC's. The method insures that for every primary screen density, the closest possible secondary screen density is used when t he same digital value is specified.
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公开(公告)号：DE69322350T2
公开(公告)日：1999-05-20
申请号：DE69322350
申请日：1993-09-22
Applicant: XEROX CORP
Inventor： HAINS CHARLES M
Abstract: A set of halftone screens and a write white xerographic system are used for generating halftone images with a minumum of artifacts. The screens used in a four color printer have at least 64 pixels per pattern and are distributed to create four-centered dots that are at either -14, 0, + 14 or +45 degrees (Figs.11,12,9 and 13). The xerographic process involves charging the photoreceptor (Fig.14A), partially discharging the photoreceptor with a scanning beam to create an image (Fig.14B), and then using toner which adheres to the charged portions of the photoreceptor to create the hard copy (Figs.14C,14D).
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公开(公告)号：DE69411340T2
公开(公告)日：1998-12-17
申请号：DE69411340
申请日：1994-07-19
Applicant: XEROX CORP
Inventor： COLEMAN ROBERT M , TASCA SANDRA E , HANNA THOMAS , GREEN LELAND D , HAINS CHARLES M , CHAI STEPHEN T
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公开(公告)号：DE69309409T2
公开(公告)日：1997-09-18
申请号：DE69309409
申请日：1993-12-03
Applicant: XEROX CORP
Inventor： HAINS CHARLES M
Abstract: A method of quantizing pixel values in an image formed by a plurality of pixels, each pixel representing an optical density of the image at a location within the image, and having an original optical density value selected from one of a set of 'c' original optical density values that has a number of members larger than a desired output set of 'd' optical density values through a process of combined halftoning and cell-to-cell error diffusion. Initially, each pixel is modified with a pro rata portion of an error term epsilon (n) determined for a previous halftone cell, or from the current cell in a previous interaction. A set of modified pixels, corresponding in position to an m x n halftone cell, are processed in accordance with a standard halftoning process, to derive a set of output pixels at one of d optical density levels. The calculated output density is used to address a lookup table (152) having a stored set of empirical density values upon printing the dot represented by a halftone cell with the same count of optical density levels. The empirical density value for the cell returned from the lookup table is compared to a sum of the modified pixel values for the cell. The difference (which represents the difference in gray level input and the actual output) is directed on a weighted basis to the pixels of subsequently processed dots.
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Patent Agency Ranking
公开(公告)号：DE69309409D1
公开(公告)日：1997-05-07
申请号：DE69309409
申请日：1993-12-03
Applicant: XEROX CORP
Inventor： HAINS CHARLES M
Abstract: A method of quantizing pixel values in an image formed by a plurality of pixels, each pixel representing an optical density of the image at a location within the image, and having an original optical density value selected from one of a set of 'c' original optical density values that has a number of members larger than a desired output set of 'd' optical density values through a process of combined halftoning and cell-to-cell error diffusion. Initially, each pixel is modified with a pro rata portion of an error term epsilon (n) determined for a previous halftone cell, or from the current cell in a previous interaction. A set of modified pixels, corresponding in position to an m x n halftone cell, are processed in accordance with a standard halftoning process, to derive a set of output pixels at one of d optical density levels. The calculated output density is used to address a lookup table (152) having a stored set of empirical density values upon printing the dot represented by a halftone cell with the same count of optical density levels. The empirical density value for the cell returned from the lookup table is compared to a sum of the modified pixel values for the cell. The difference (which represents the difference in gray level input and the actual output) is directed on a weighted basis to the pixels of subsequently processed dots.
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公开(公告)号：CA2619131C
公开(公告)日：2013-04-16
申请号：CA2619131
申请日：2008-02-06
Applicant: XEROX CORP
Inventor： HAINS CHARLES M
Abstract: A method of simulating a differential gloss image includes providing a background and a gloss effect image. The gloss effect image is configured for controlling the selective application of first and second halftones to the background image for creation of a differential gloss image when the background image is printed. A mask based on the background image is formed in which regions of mid--tone gray level are accentuated. An edge effect filter may be applied to the gloss effect image to form a filtered gloss effect image. The mask is applied to the filtered gloss effect image to generate a background modified filtered gloss effect image. The background modified filtered gloss effect image is applied to the background image to generate a representation which simulates the differential gloss image.
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公开(公告)号：CA2619131A1
公开(公告)日：2008-08-13
申请号：CA2619131
申请日：2008-02-06
Applicant: XEROX CORP
Inventor： HAINS CHARLES M
Abstract: A method of simulating a differential gloss image includes providing a background and a gloss effect image. The gloss effect image is configured fo r controlling the selective application of first and second halftones to the background image for creation of a differential gloss image when the background image i s printed. A mask based on the background image is formed in which regions of mid--tone gray level are accentuated. An edge effect filter may be applied t o the gloss effect image to form a filtered gloss effect image. The mask is applied to t he filtered gloss effect image to generate a background modified filtered gloss effect image. The background modified filtered gloss effect image is applied to the background image to generate a representation which simulates the differential gloss image.
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公开(公告)号：BRPI0504846A
公开(公告)日：2006-06-27
申请号：BRPI0504846
申请日：2005-10-26
Applicant: XEROX CORP
Inventor： PURDUM CONNIE , LOCE ROBERT P , XU BEILEI , LIEBERMAN DAVID J , MCELVAIN JON S , HAINS CHARLES M , GWALTNEY MARK A
Abstract: Disclosed herein is an image processing method for producing enhanced halftone edges, particularly suited to those edges which only lie upon the background as apposed to those edges which abut other halftone screens. It utilizes a step of defining border pixels and a step of halftoning those border pixels in a different manner than the halftoning applied to the interior region of the tint or image segment. The preferred halftone for the border pixels will be related to the interior halftone by some number of common spatial frequency harmonics. Examples of common-harmonic screening for an edge include, but are not limited to: (a) same screen with different tone reproduction characteristics (boosted edge values); (b) same screen angles and frequencies with a different spot function, possibly phase shifted; (c) a dot screen whose frequency vectors can be generated by the frequency vectors of the interior screen; (d) a line screen whose frequency vectors can be generated by the frequency vectors of the interior screen. This generation process is directed to ensuring that the two screens will be “harmonically matched” where at least one of the fundamental frequency vectors and harmonics of the first screen will equal at least one of the fundamental frequency vectors and harmonics of the second screen.
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公开(公告)号：DE60302862D1
公开(公告)日：2006-01-26
申请号：DE60302862
申请日：2003-12-16
Applicant: XEROX CORP
Inventor： HAINS CHARLES M , KANG SANG-CHUL
Abstract: The system and method reduces aliasing which is formed by the patterns that are introduced by the halftone screens used in the printer. The system and method provides halftone-specific anti-alias filters for obtaining optimal effective resolution in printed images. A method of reducing aliasing in a digital image includes providing a digital image; selecting a halftone screen for halftoning the digital image, wherein the halftone screen has a directional component associated with it; filtering the digital image with an antialiasing filter, the antialiasing filter having been designed to have a directional frequency response that is optimized for the directional component of the selected halftone screen; and halftoning the filtered digital image.
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