Adaptive Dithering Patents (Class 358/3.14)
  • Patent number: 7161712
    Abstract: An apparatus for forming an image includes a photosensitive body, an optical write unit which scans a light beam along a main scan path on a photosensitive body to create a latent image thereon, the light beam having power levels corresponding to multi-level image data, and a shading correction unit which corrects shading along the main scan path by making adjustment to the multi-level image data along the main scan path, and changes the adjustment on a condition-specific basis.
    Type: Grant
    Filed: April 3, 2002
    Date of Patent: January 9, 2007
    Assignee: Ricoh Company, Ltd.
    Inventors: Takayuki Maruta, Minori Uchida
  • Patent number: 7158264
    Abstract: Halftone image data is generated according to a threshold array in which thresholds T up to a given gradation have been determined, and candidate pixels to be blackened are then determined. Then, a low-frequency component extractor extracts low-frequency component data from density image data which simulates the density of the halftone image data corresponding to an output image from an image output apparatus. A particular frequency component divider 70 divides the extracted low-frequency component data into particular frequency component data for intensifying the low-frequency components, and blackening candidate pixels for intensifying the particular frequency components are excluded, thus narrowing down candidate pixels. The positions of thus determined blackening candidate pixels are determined as the positions of thresholds for a next gradation.
    Type: Grant
    Filed: June 11, 2002
    Date of Patent: January 2, 2007
    Assignee: Fuji Photo Film co., Ltd.
    Inventor: Yoshiaki Inoue
  • Patent number: 7145675
    Abstract: A printer system comprises a communication interface and printer components. The communication interface receives a humidity value from a toner cartridge. The printer components control printing operation based on the humidity value. To control printing operation, the printer components may configure a dither matrix based on the humidity value. The toner cartridge comprises a humidity sensor and a communication interface. The humidity sensor detects a humidity level and generates the humidity value to correspond to the humidity level. The communication interface transfers the humidity value from the humidity sensor to the printer system.
    Type: Grant
    Filed: January 16, 2001
    Date of Patent: December 5, 2006
    Assignee: Hewlett-Packard Development Company, L.P.
    Inventor: George H. Kerby
  • Patent number: 7102791
    Abstract: A mask is produced for converting multi-level image data into a halftone image through comparison with a threshold for each pixel. For this purpose, a dot pattern is determined on each of predetermined gray scale levels, and, the mask is created by the dot patterns obtained at the step, where the respective dot patterns are determined independently for every gray scale level.
    Type: Grant
    Filed: March 14, 2002
    Date of Patent: September 5, 2006
    Assignee: Ricoh Company, Ltd.
    Inventors: Masanori Hirano, Satoshi Ohuchi
  • Patent number: 7088473
    Abstract: A system and method for effectively implementing a dither matrix for an electronic printer device may preferably create an improved dither matrix with optimal threshold values for use in a corresponding dither tile. During a matrix populating procedure for assigning tile threshold values for the dither matrix, the dither tile may preferably be embedded within a larger frame area of additional adjacent frame cells. A design entity may then preferably compute various cost functions when the additional boundary cells of the frame area are in place. The embedded dither matrix of the dither tile is thus preferably populated within the foregoing frame area so that various boundary effects may be taken into account when an overall cost function of both the dither tile plus the frame area is calculated.
    Type: Grant
    Filed: January 31, 2002
    Date of Patent: August 8, 2006
    Assignees: Sony Corporation, Sony Electronics Inc.
    Inventor: Ted J. Cooper
  • Patent number: 7085014
    Abstract: A method, apparatus and article of manufacture for providing improved print quality regardless of media smoothness is disclosed. Information regarding the smoothness of media is ascertained and the information about the media smoothness is used in the generation of an output. A selectable halftone screen is used in the print device to provide different halftone screens for different media smoothness. The halftoning screens can be changed depending on the roughness of the media being used. Pre-defined halftone screens may be stored and selected for a range of media smoothness. The selection of the pre-defined halftones may be selected by the operator or may be selected automatically by the print device.
    Type: Grant
    Filed: June 6, 2001
    Date of Patent: August 1, 2006
    Assignee: International Business Machines Corporation
    Inventors: John B. Condon, Joan LaVerne Mitchell, David Joseph Shields
  • Patent number: 7081901
    Abstract: A display system provides stochastic dithering to image data for storage in a frame buffer for display. Dithering is used to reduce the size of the frame buffer and to reduce the complexity of the drive circuitry that is used to display an image. The bit depth of the frame buffer is reduced by spatially dithering image data before it is written into the frame buffer. Stochastic dither patterns (which are uncorrelated) are used to minimize adverse effects of the dither patterns within the displayed image.
    Type: Grant
    Filed: March 31, 2003
    Date of Patent: July 25, 2006
    Assignee: National Semiconductor Corporation
    Inventors: Christopher A. Ludden, Jeffrey A. Small
  • Patent number: 7079290
    Abstract: Apparatus and method for flexible digital halftoning are provided in which novel pattern choices are allowed by not restricting the basic halftone patterns to grow sequentially. Rather, positions in a threshold array allow multiple transitions between on (i.e., printed with toner/ink) and off (not printed) as a function of the input value at the corresponding position. In one embodiment, multiple threshold matrices are employed and the output decision is a vote (e.g., exclusive OR) of the outputs of the individual threshold matrices. In another embodiment, each position contains an arbitrary bit vector to express the output for each input. This flexibility in growing basic halftone patterns allows the number of densities output to be larger than n+1 (where “n” is the number of dots within a basic halftone cell).
    Type: Grant
    Filed: June 6, 2001
    Date of Patent: July 18, 2006
    Assignee: International Business Machines Corporation
    Inventors: James Francis Crossland, Joan LaVerne Mitchell
  • Patent number: 7016073
    Abstract: Utilization of non-printing high-spatial-frequency auxiliary pixels are introduced into the bitmap of halftones utilized in an image to obtain local control of the image development by modification of local average voltage in the development nip. These auxiliary pixels embody frequencies or levels of charge that are past the threshold for printing on the Modulation Transfer Function (MTF) curve, and therefore by themselves result in no toner deposition on the resultant page. These auxiliary pixels will however, position the toner cloud by modulating it and compensate for cleaning field and toner supply effects. This will better position the toner cloud to ensure adequate toner supply to all parts of the image so that the desired printing pixels will print as intended and provide a more faithful rendering of grayscale information in the image.
    Type: Grant
    Filed: July 27, 1999
    Date of Patent: March 21, 2006
    Assignee: Xerox Corporation
    Inventors: Robert J. Meyer, Allen T. Retzlaff, Jr.
  • Patent number: 7012717
    Abstract: This invention is a method of multilevel dither screening in a printer. Plural pixel values are packed into equal sections of a first data word. Corresponding dither values are packed into the equal sections of a second data word. These first and second data words are added in an arithmetic logic unit selectively spilt into the equal sections. Each section of the sum data word is saturated to all 1's. A predetermined number of least significant bits of the saturated sections are truncated. The resulting normalized pixel values are quantized into a limited set of threshold ranges. This dithering process serves to introduce an amount of scattering to the input pixel values to reduce quantization and pixelation artifacts in the final printed product.
    Type: Grant
    Filed: November 15, 2000
    Date of Patent: March 14, 2006
    Assignee: Texas Instruments Incorporated
    Inventor: Venkat V. Easwar
  • Patent number: 7009737
    Abstract: A non-periodic dot output arrangement is taken in the low thickness region, and a periodic dot output arrangement is taken in the intermediate and high thickness region. In addition, error diffusion processing is made for all thickness regions. Small dots are produced in the non-periodic dot arrangement low-thickness region, and dot-concentrated-type dots are produced in the periodic dot arrangement intermediate-and-high-thickness region. Moreover, non-periodic dots are produced in the edge region of the image.
    Type: Grant
    Filed: May 30, 2001
    Date of Patent: March 7, 2006
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventor: Hiroyuki Morimatsu
  • Patent number: 7009731
    Abstract: There is provided an image processing apparatus employing an error diffusion method capable of preventing a pseudo contour attributable to a delayed dot. The image processing apparatus receives an error diffused from a neighboring pixel and corrects a value (an input value of 0 to 1) of a pixel to be processed before it reduces a tone. Then a subtracter calculates an error associated with the tone reduction, which is diffused to a neighboring pixel. Herein, only for an input value of no less than 0.5 an inversion portion multiplies by ?1 an error from a neighboring pixel and an error to a neighboring pixel. Thus a dot can be free of delay to prevent a pseudo contour.
    Type: Grant
    Filed: November 16, 2000
    Date of Patent: March 7, 2006
    Assignee: Minolta Co., Ltd.
    Inventor: Toshitsugu Yamamoto
  • Patent number: 6987588
    Abstract: A method to compensate for dot placement errors includes receiving image data comprising a plurality of pixels, each having at least two states, a first corresponding to depositing no ink and a second corresponding to depositing ink; identifying a stray pixel pattern within the image data, the stray pixel pattern including a stray pixel corresponding to a misplaced dot in a dot pattern; and modifying the image data corresponding to the stray pixel pattern by setting the stray pixel to the first state and changing a second pixel from the first state to the second state.
    Type: Grant
    Filed: June 25, 2001
    Date of Patent: January 17, 2006
    Assignee: Xerox Corporation
    Inventors: Meng Yao, Michael T. Stevens, Mark R. Parker
  • Patent number: 6982799
    Abstract: A printhead controller controls printing of a page by at least one printhead. The printhead controller, in use, receives data, in a compressed format relating to the page to be printed, the data including a page description comprising a bi-level black layer and a contone color layer. The printhead controller extracts from the compressed data relating to the bi-level black layer the contone color layer. Memory is provided for temporary storage of the expanded data. A dithering/compositing unit produces a ditherer page from the data temporally stored in the memory and feeds its out put to the printhead.
    Type: Grant
    Filed: April 24, 2003
    Date of Patent: January 3, 2006
    Assignee: Silverbrook Research PTY LTD
    Inventor: Paul Lapstun
  • Patent number: 6930801
    Abstract: A threshold arrangement capable of reducing a moiré pattern produced by an interference between the output resolution and halftone frequency of an image outputting apparatus is determined. Halftone dot image data is generated by a threshold arrangement determined up to a certain gradation, and low-frequency component data is extracted from the halftone dot image data by an FFT, a LPF, and an IFFT. The position of a threshold where the extracted low-frequency component data is smaller is determined as the position of the threshold for a next gradation. The process of determining the position of the threshold is a process in a real space, and can determine the position of the threshold for the next gradation accurately. The threshold arrangement thus determined minimizes a moiré pattern which is an unwanted low-frequency component in a gradation image that is generated using the threshold arrangement.
    Type: Grant
    Filed: February 5, 2001
    Date of Patent: August 16, 2005
    Assignee: Fuji Photo Film Co., Ltd.
    Inventor: Yoshiaki Inoue
  • Patent number: 6909524
    Abstract: An image processor unit minimizes image-quality degradation that can be caused by the addition of predetermined information to an image and that enables the predetermined information to be added to the image so that embedded information can be accurately extracted. The image processor unit includes an input unit for inputting the image; a plurality of quantization-threshold setting unit, of which occurrence probability distributions are different from one another, for setting quantization thresholds in terms of probability; a control unit for controlling a regularity for selection of the plurality of quantization-threshold setting unit in units of a predetermined image region according to the predetermined information; and a quantizing unit that uses quantization thresholds set by the quantization-threshold setting unit and thereby quantizes the image according to an error diffusion method.
    Type: Grant
    Filed: October 2, 2001
    Date of Patent: June 21, 2005
    Assignee: Canon Kabushiki Kaisha
    Inventor: Nobutaka Miyake
  • Patent number: 6870645
    Abstract: An embodiment of a halftoning method reduces the grainy appearance resulting from overlap of cyan and magenta colorants using a single threshold matrix for both the cyan and the magenta color planes. The cyan color value and the magenta color value for a pixel are summed. If the sum is greater than the maximum possible color value by at least the corresponding matrix threshold value, both cyan and magenta colorants are placed on the pixel. If the sum is not greater than the maximum possible color value by at least the corresponding matrix threshold value, then the smallest of the cyan color value and the magenta color value is compared to the corresponding matrix threshold value. If this smallest color value is greater than the corresponding matrix threshold value, the corresponding colorant is placed on the pixel. Otherwise, the other colorant is placed on the pixel. If the sum is less the maximum possible color value, then the sum is compared to the corresponding matrix threshold value.
    Type: Grant
    Filed: October 3, 2000
    Date of Patent: March 22, 2005
    Assignee: Hewlett-Packard Development Company, L.P.
    Inventors: Morgan T. Schramm, Jay S. Gondek
  • Patent number: 6853467
    Abstract: A method for performing a digital multistage screening of a continuous-tone image with a screen having any desired screen resolution and any desired screen angle, in which the screening is carried out by reading out threshold values and comparing the threshold values read out with the color values of the continuous-tone image. Threshold value matrices are used in which the threshold values represent one or more screen dots of a given screen, with which the desired screen resolution and the desired angle are approximated. While the threshold values are being read out, an error between the coordinates of the desired screen and of the given screen is determined, and the error is compensated for by correcting the read address for the threshold value matrix, as soon as the error exceeds a predefined limiting value. Instead of the threshold value matrices, printing-value matrices can also be used.
    Type: Grant
    Filed: November 8, 2002
    Date of Patent: February 8, 2005
    Assignee: Heidelberger Druckmaschinen AG
    Inventors: Heinrich Wadle, Ludo Kerz
  • Patent number: 6833933
    Abstract: A method of generating a stochastic screen for use in printing a halftone containing image on a surface, where the generated stochastic screen comprises an array of threshold values each of which represents a halftone threshold at which pixels are printed at the corresponding location. The method comprises a) entering a first threshold value into the array and b) for a first halftone level, defining a number of threshold values to be entered into the array and, for each threshold value to be placed, for each of a number of candidate locations in the array, computing a distance function between the candidate location and the locations of threshold values already placed into the array, and placing the threshold value into the array at a location for which the distance function is substantially minimized. The process of step b) is then repeated for each subsequent halftone level.
    Type: Grant
    Filed: May 24, 2000
    Date of Patent: December 21, 2004
    Assignee: Software 2000 Limited
    Inventor: Michael Woods
  • Publication number: 20040252346
    Abstract: A method for generating a dispersed cluster screen defining a stable environment for printing an image is provided. The method initiates with generating a pattern of cluster centroids. Then a cluster growth sequence is defined. Next, a cluster is grown around the cluster centroid according to the cluster growth sequence. A computer readable medium having program instructions for generating a dispersed cluster screen and an image forming device configured to print an image according to a dispersed cluster screen technique are also provided.
    Type: Application
    Filed: May 29, 2003
    Publication date: December 16, 2004
    Inventors: Jincheng Huang, Anoop K. Bhattacharjya
  • Publication number: 20040233477
    Abstract: A method is disclosed for halftoning images either via a direct method or a threshold array construction. The method includes comparing a pattern to an image and calculating a first potential in order to determine a first set of pixels to move; calculating a second potential in order to determine a second set of pixels in which to move the first set of pixels; and then moving pixels in the first set of pixels having high first potentials to pixel locations in the second set of pixels having low second potentials. The method may further include an inner program loop that decreases the number of pixels to move in the first and second sets and iteratively repeats the above steps; and an outer program loop that resets the number of pixels moved in the first and second sets and iteratively repeating the process to further optimize the pattern.
    Type: Application
    Filed: May 21, 2003
    Publication date: November 25, 2004
    Applicant: International Business Machines Corporation
    Inventors: Mikel J. Stanich, Gerhard R. Thompson, Chai Wah Wu
  • Publication number: 20040223189
    Abstract: A method/algorithm enables the rapid development and tuning of multi-level and multi-frequency halftone screens to improve printer performance. The screens are primarily directed to laser printers. The method/algorithm generally involves generating a lattice of points by selecting a plurality of points along an imaginary line whose path extends along a surface of a geometric shape; assigning a dot shape to each of the lattice points; selecting a growth model for each dot shape; quantizing the lattice points and assigned dots to a specified grid of pixels; and generating multi-frequency screens from the lattice of points and associated dots.
    Type: Application
    Filed: May 9, 2003
    Publication date: November 11, 2004
    Inventor: Anoop Bhattacharjya
  • Patent number: 6775032
    Abstract: The present invention is a method and apparatus allowing the application of two or more distinct halftone types in the rendering of a single image. The invention employs a halftone selector of a threshold type, or as an alternative a segmenter type. The halftone selector determines which areas of an image will receive which type of grayscale halftone treatment on a pixel by pixel basis. Examples of various halftone types include stochastic, clustered dot, line screen, and other high addressability types. Each pixel of data is treated by the appropriate halftoner circuit which in response outputs digital data. A controller circuit remaps the digital data into the appropriate width and position signals for a pulse width position modulator, including any other signals as needed for any additional inverter circuitry. The pulse width position modulator generates a video signal which may be inverted by the inverter circuit as responsive to the controller circuit remapping determination.
    Type: Grant
    Filed: February 27, 2001
    Date of Patent: August 10, 2004
    Assignee: Xerox Corporation
    Inventor: Timothy W. Jacobs
  • Patent number: 6771391
    Abstract: A synthesized image is formed by synthesizing a main image and a background mage represented by respective image data items each having n-valued gradation values each having any one of n possible values(n is an integer which is equal to or larger than 3) and defining a density of pixels. A plurality of different data items representative of candidates for the background image are stored as background image data candidates. An arbitrary one of the background image data candidates is set to a background image data item representative of the background image. There is formed a main image data item forming a main image data item representative of the main image, the main image data item having n-valued main image gradation values commonly applied to all valid pixels of the main image, as values of the n-value gradation values.
    Type: Grant
    Filed: January 19, 2000
    Date of Patent: August 3, 2004
    Assignees: Seiko Epson Corporation, King Jim Co., Ltd.
    Inventors: Yoshiharu Konishi, Hitoshi Hayama, Kenichi Tanabe, Hiroshi Ono
  • Patent number: 6765688
    Abstract: A method for generating a secondary image, being a first body of data from an initial document, onto a second body of data from the initial document, to produce a final document. The method includes identifying within the initial document the first and second bodies of data. The initial document is then formatted into an initial digital document file capable of being processed by the document producer into the final document. The first body of data is stored in a computer readable memory as a secondary image data file, and the second body of data is stored in the memory as a primary image data file. The secondary image data file and at least a portion of the primary image data file are then combined in the document producer to generate a digital page of the finished document, which is then generated by the document producer as the final document.
    Type: Grant
    Filed: February 8, 2000
    Date of Patent: July 20, 2004
    Assignee: Hewlett-Packard Development Company, L.P.
    Inventor: Steven J. Claiborne
  • Publication number: 20040136035
    Abstract: A method for generating a screened representation of an image, includes the steps of: (a) generating a first dot of the screened representation, wherein the first dot has a first dot size of at least two microdots; (b) repeating the dot generation step until a first number of the first dots are generated; (c) arranging the first number of dots in a frequency modulated pattern; (d) selecting a second number of second dots out of the first dots, wherein the second number is at most equal to the first number and larger than zero; and (e) enlarging the second dots by adding one or more microdots to each of the second dots.
    Type: Application
    Filed: December 2, 2003
    Publication date: July 15, 2004
    Inventor: Rudi Bartels
  • Publication number: 20040130753
    Abstract: A threshold mask for converting a contone image to a halftone image defines halftone cells that define halftone dots that undergo a growth in population as tone levels increase. After some growth in population, the halftone cells define halftone dots that then grow in size from a first predetermined size as tone levels increase further. During the growth in population, the halftone dots having a second predetermined size are placed into halftone gaps. The second predetermined size is smaller than the first predetermined size. In the simplest implementation, FM screening is used up to a tone level where the FM dither pattern holes begin to become visible. At this point AM screening is applied only to the remaining dot centers (corresponding to those holes) until they reach the stable dot size. Then, the dots are further grown according to the method used outside of the FM regime (e.g. the conventional AM process). In the FM regime, two types of visual disturbances can arise.
    Type: Application
    Filed: January 6, 2003
    Publication date: July 8, 2004
    Inventor: Kenneth R. Crounse
  • Patent number: 6760126
    Abstract: Methods and apparatus for adaptive halftoning for accommodating a mix of high and low visual activity are provided. Accommodations for white gap reduction and variable darkening are provided for print engine imperfections. A method includes the steps of thresholding a selected pixel of a source image to generate a first dithered output signal, L. The selected pixel is also thresholded to generate a second dithered output signal, S. A weighted combination of the first and second dithered output signals is generated in accordance with at least one of an edge activity indicator parameter and a mix suppression parameter. The parameters are calculated from pixel values within a contiguous region of the source image including the selected pixel. The first and second dithered output signals correspond to large and small threshold matrices in one embodiment. The second dithered output signal may be boosted using a variable darkening parameter, &ggr;, to accommodate isolated dot gain problems before being combined.
    Type: Grant
    Filed: June 20, 2000
    Date of Patent: July 6, 2004
    Assignee: Hewlett-Packard Development Company, L.P.
    Inventors: Kong Kritayakirana, Daniel R. Tretter, Qian Lin
  • Publication number: 20040095609
    Abstract: A print engine/controller (10) configured to be coupled with others to drive an ink drop printhead (33). It has an interface (27) at which to receive compressed page data. Image decoders (28, 88) decode compressed image planes image decoders to perform an expansion, in pipeline fashion, for the received compressed page data. A half-toner/compositer (29) composites respective strips of the decoded image planes and sends output to a printhead interface (32). A printhead interface (32) interfaces with the printhead. A synchronization signal generator (89, 90) may output a synchronization signal that is used to synchronize print engine/controllers. One printhead interface (32) preferably acts as master generating the synchronization signal to synchronize all the print engine/controllers to drive the printhead at any one or more of higher speed, higher input resolution, higher outlet resolution or wider format.
    Type: Application
    Filed: November 17, 2003
    Publication date: May 20, 2004
    Applicant: Silverbrook Research Pty Ltd
    Inventors: Simon Robert Walmsley, Paul Lapstun
  • Publication number: 20040095608
    Abstract: A print engine/controller (10) configured to be coupled with others to drive an ink drop printhead (33). It has an interface (27) at which to receive compressed page data. Image decoders (28, 88) decode compressed image planes in the received compressed page data. A half-toner/compositer (29) a half-toner/compositer composites respective strips of the decoded image planes by halftoning a contone layer to a bi-level version and compositing a spot1 bi-level layer over an appropriate halftoned contone layer. A printhead interface (32) interfaces with the printhead. A synchronization signal generator (89,90) outputs a synchronization signal that is used to synchronize print engine/controllers. In some embodiments, one printhead interface (32) acts as master generating the synchronization signal to synchronize all the print engine/controllers to drive the printhead at any one or more of higher speed, higher input resolution, higher outlet resolution or wider format.
    Type: Application
    Filed: November 17, 2003
    Publication date: May 20, 2004
    Applicant: Silverbrook Research Pty Ltd
    Inventors: Simon Robert Walmsley, Paul Lapstun
  • Publication number: 20040095607
    Abstract: A printer with synchronized engine/controllers is disclosed. The printer has a multi-segment printhead. Each engine/controller (10) configured to be coupled with others to drive the printhead (33). Each engine/controller (10) has an interface (27) at which to receive compressed page data. Image decoders (28, 88) decode compressed image planes image decoders to perform an expansion, in pipeline fashion, for the received compressed page data. A half-toner/compositor (29) composites respective strips of the decoded image planes and sends output to a printhead interface (32). A printhead interface (32) interfaces with the printhead. A synchronization signal generator (89, 90) may output a synchronization signal that is used to synchronize print engine/controllers.
    Type: Application
    Filed: November 17, 2003
    Publication date: May 20, 2004
    Applicant: Silverbrook Research Pty Ltd
    Inventors: Simon Robert Walmsley, Paul Lapstun
  • Publication number: 20040090654
    Abstract: In an error diffusion halftoning process a clusters of adjacent pixels can be placed at any arbitrary position of the pixel grid.
    Type: Application
    Filed: September 15, 2003
    Publication date: May 13, 2004
    Inventors: Luc Minnebo, Koen Vande Velde, Paul Delabastita
  • Publication number: 20040061904
    Abstract: The invention provides a procedure that is applicable to various halftoning methods, which minimizes image distortion introduced by the halftoning process. The procedure involves maintaining specific relationships between the halftone pattern and the phase and resolution of the input image. Specifically, that the halftone pattern is designed such that it does not bias tone reproduction with respect to the location of the input image pixels—each input pixel should be given equal weight when filtered by the halftoning process. This suggests a 1 to 1 relationship between each pixel of the input image and the corresponding tone output produced by the halftoning process. The procedure results in improved print quality, manifested by avoidance of certain types of moiré which are commonly associated with halftoning, as well as improved reproduction of edges and image details.
    Type: Application
    Filed: September 18, 2003
    Publication date: April 1, 2004
    Inventor: Brent M. Bradburn
  • Publication number: 20040051902
    Abstract: A determination section (200) determines whether there is a peripheral dot located at an arbitrary distance from a target dot at least in a main scanning direction and in a subscanning direction in a dot image to detect whether space dots surround the target dot. An adder (400) adds an arbitrary amount of additional value m to target dot image data d corresponding to the target dot based on a result of detection by the determination section (200).
    Type: Application
    Filed: May 22, 2003
    Publication date: March 18, 2004
    Inventor: Eiichi Sasaki
  • Patent number: 6671071
    Abstract: A circuit for generating a threshold bias signal for processing n color separations representing a color image includes a threshold bias register which holds and outputs the current threshold bias signal.
    Type: Grant
    Filed: October 19, 1999
    Date of Patent: December 30, 2003
    Assignee: Xerox Corporation
    Inventor: Doron Kletter
  • Patent number: 6667816
    Abstract: In a networked printing environment having at least a number of workstations of users, a management unit maintains logic storage spaces in a memory, each allocated to a respective user. Digital data files sent from a user's workstation for printing contain an identification of the relevant user and are either of a first type or of a second type. The first type is formed by files which must be printed automatically, and the second type is formed by files which must be stored in the logic storage space of the user in the memory and may be printed only on a command from the operator control unit, which command identifies the relevant file. When handling a print job, the management unit checks, whether the job can be performed completely. If this appears not to be the case, the management unit converts the file into a file of the second type and, if necessary, creates a logic storage space for the relevant user and stores the file in the logic storage space of the relevant user.
    Type: Grant
    Filed: March 19, 1999
    Date of Patent: December 23, 2003
    Assignee: Océ-Technologies B.V.
    Inventors: Antonius C. M. Van Buren, Wilhelmus G. J. Volleberg, Johannes F. M. E. Geelen
  • Publication number: 20030210431
    Abstract: A stochastic halftone pattern has been invented which has a narrow band power spectrum due to the incorporation of a dot growth process. The narrow band power spectrum may be matched to the resolution characteristics of specific printers, resulting in smoother printed halftone textures. The spectrum of a halftone pattern may be made anisotropic (angularly dependent), helping to de-couple sets of patterns for color printing with reduced color noise or mottle.
    Type: Application
    Filed: June 16, 2003
    Publication date: November 13, 2003
    Applicant: 3M Innovative Properties Company
    Inventor: Richard L. Rylander
  • Patent number: 6633412
    Abstract: When clustered-dot dithering is employed in laser printers a banding effect sometimes results from the interaction of the dither matrix with non-uniform line spacing in the printer. We have found that we can lessen the effect of this interaction if we change the dither matrix as it moves over the image. We do this by modulating the dither matrix (halftone cell) as a function of the spatial position of the sub-area in the image. Halftone cells can be formed in a variety of patterns (e.g. vertical, horizontal, etc.) but generally their threshold values grow from a minimum value to a maximum value. Our process is to modulate the halftone cell according to a function: f (s, h) where s is the spatial position of the sub-area of the image and h is the halftone cell. We modulate the cell by altering the relative positions of the threshold values in the cell as we move the cell over the image.
    Type: Grant
    Filed: March 26, 1999
    Date of Patent: October 14, 2003
    Assignee: Seiko Epson Corporation
    Inventors: Tsung-Nan Lin, Joseph Shu
  • Patent number: 6608701
    Abstract: A compact rendering processor for processing image data including a multi-bit halftone region generates high addressability pixels. The compact rendering processor includes a tagging sub-processor operating on the image data to identify a target pixel and a neighboring pixel to determine a fill-order. The compact rendering processor also includes a rendering sub-processor that converts the target pixel into a high addressability pixel based upon the fill-order. Optionally, a diffusion sub-processor can be included to diffuse an error resulting from the conversion of the target pixel into a high addressability pixel to other pixels within the image data.
    Type: Grant
    Filed: July 7, 1999
    Date of Patent: August 19, 2003
    Assignee: Xerox Corporation
    Inventors: Robert P. Loce, Michael Branciforte, Fritz F. Ebner, Douglas N. Curry, Yeqing Zhang, Leon C. Williams
  • Patent number: 6606168
    Abstract: A stochastic halftone pattern has been invented which has a narrow band power spectrum due to the incorporation of a dot growth process. The narrow band power spectrum may be matched to the resolution characteristics of specific printers, resulting in smoother printed halftone textures. The spectrum of a halftone pattern may be made anisotropic (angularly dependent), helping to de-couple sets of patterns for color printing with reduced color noise or mottle.
    Type: Grant
    Filed: March 31, 1999
    Date of Patent: August 12, 2003
    Assignee: 3M Innovative Properties Company
    Inventor: Richard L. Rylander
  • Publication number: 20030123093
    Abstract: There is generated a virtual tile set which virtually covers color planes of an original image without any clearance or overlap by combination of Penrose-type virtual tiles to be non-periodically provided on the planes. The respective tiles are subjected to raster conversion in accordance with predetermined gradation levels, thereby generating a raster image. Since the virtual tiles can be laid non-periodically, iteration of the same dot pattern on the raster image can be prevented.
    Type: Application
    Filed: November 12, 2002
    Publication date: July 3, 2003
    Applicant: SEIKO EPSON CORPORATION
    Inventor: Toshiyuki Hattori
  • Publication number: 20030081258
    Abstract: A halftone threshold pattern comprising a clustered-dot ordered array of halftone threshold data is generated (step S1), and an array of halftone threshold data between a plurality of halftone threshold patterns is determined to generate an auxiliary multiple halftone threshold pattern (steps S2, S3). Then, an array of halftone threshold data between a plurality of auxiliary multiple halftone threshold patterns is determined as a dispersed-dot ordered array to generate a multiple halftone threshold pattern (steps S4, S5).
    Type: Application
    Filed: October 7, 2002
    Publication date: May 1, 2003
    Applicant: FUJI PHOTO FILM CO., LTD.
    Inventor: Makoto Sugizaki
  • Patent number: 6552824
    Abstract: A method is described of processing image data of pixels to be rendered. In the method, image data representing a pixel to be rendered is provided. Criteria or tests are established for processing the pixel in accordance with binary error diffusion or multibit error diffusion. In response to examination of the pixel in accordance with the criteria, a decision is made as to whether the pixel is to be rendered in accordance with binary error diffusion or multibit error diffusion. The pixel is then rendered in accordance with the decision.
    Type: Grant
    Filed: December 17, 1998
    Date of Patent: April 22, 2003
    Assignee: Eastman Kodak Company
    Inventors: Gregory Rombola, Dongli Yang
  • Publication number: 20030072036
    Abstract: An inkjet printer comprises a printhead that includes a number of printhead segments that span a print area so that portions of consecutive printhead segments overlap in common print areas. Each printhead segment defines a lead-in area in one common print area and a lead-out area in a consecutive common print area. An interface is configured to receive image data. A memory device stores data relating to characteristics of the printhead. A dithering unit communicates with the interface and the memory device. The dithering unit is configured to generate a lead-in dither matrix associated with the lead-in area and a lead-out dither matrix associated with the lead-out area, to generate lead-in/lead-out dither matrices for each common print area, to generate a variable probability value that is dependent on a scalar value that corresponds to a position along a line spanning each common print area and to interpolate the lead-in/lead-out dither matrices with the variable probability value.
    Type: Application
    Filed: June 19, 2002
    Publication date: April 17, 2003
    Inventors: Kia Silverbrook, Paul Lapstun, Simon Robert Walmsley
  • Patent number: 6545773
    Abstract: Color printheads in a color inkjet printer are in a fixed order in the scanning carriage, which causes the colors to be printed in a different order when the carriage is scanned in an opposite direction. The different print order may result in a perceptible change in hue between passes in bi-directional printing. Depleted shingle masks are substituted for the nominal ones, based on print direction, at the shingle masking stage, to compensate for print-direction-induced hue shift. A look-up table indexed by a composite color tone value providing a depletion probability and a halftoning error diffusion value are used in determining when depleted shingle masks are to be invoked.
    Type: Grant
    Filed: March 1, 1999
    Date of Patent: April 8, 2003
    Assignee: Hewlett-Packard Company
    Inventor: Kevin R Hudson
  • Publication number: 20030053100
    Abstract: A method for performing a digital multistage screening of a half-tone image with a screen having any desired screen resolution and any desired screen angle, in which the screening is carried out by reading out threshold values and comparing the threshold values read out with the color values of the half-tone image. Threshold value matrices are used in which the threshold values represent one or more screen dots of a given screen, with which the desired screen resolution and the desired angle are approximated. While the threshold values are being read out, an error between the coordinates of the desired screen and of the given screen is determined, and the error is compensated for by correcting the read address for the threshold value matrix, as soon as the error exceeds a predefined limiting value. Instead of the threshold value matrices, printing-value matrices can also be used.
    Type: Application
    Filed: November 8, 2002
    Publication date: March 20, 2003
    Inventors: Heinrich Wadle, Ludo Kerz
  • Publication number: 20030048479
    Abstract: The image processing apparatus disclosed performs as follows:
    Type: Application
    Filed: August 8, 2002
    Publication date: March 13, 2003
    Inventor: Tetsushi Hirano
  • Patent number: 6526155
    Abstract: Visible digital watermarks enable a robust tracking method to be associated with one or more input images. Specifically, by modifying a halftone screen within a certain area by setting a gray-scale range within that area to a threshold, and halftoning an input image based on this modified halftone screen, visible watermarks can be embedded into an input image.
    Type: Grant
    Filed: November 24, 1999
    Date of Patent: February 25, 2003
    Assignee: Xerox Corporation
    Inventors: Shen-ge Wang, Keith T. Knox
  • Publication number: 20030035146
    Abstract: A stochastic screening mask is provided for rendering halftone images. A filter controlled force masking method is used to vary the mask patterns from regularity to randomness. Dot size (amplitude), dot number (frequency), and dot shape are modulated integrally at each gray level during the generation of the mask. The single pixel limit for blue noise masking is broken down by this approach. The halftone patterns generated with this method can have visually pleasing blue noise attribute. This new screening method would provide flexible solutions for different types of printing processes.
    Type: Application
    Filed: August 13, 2002
    Publication date: February 20, 2003
    Inventors: Shenbo Yu, Richard G. Comeau, Craig C. Cook, Fred W. Andree
  • Patent number: 6498661
    Abstract: A method, apparatus, article of manufacture for transmitting data to a facsimile presentation device is disclosed. In one embodiment of the invention, the method comprises the steps of receiving a presentation job comprising input data associable with at least one input grayscale value, retrieving at least one of a plurality of threshold matrices, each threshold matrix selected to control a grayscale rendering characteristic of the facsimile presentation device associated with the threshold matrix, applying the grayscale values to the retrieved threshold matrix to rasterize the input data, and transmitting the rasterized input data to the facsimile presentation device. This invention can be practiced in several embodiments, and permits the user to select the threshold matrix according to the presentation device and/or a selected presentation quality.
    Type: Grant
    Filed: March 26, 1999
    Date of Patent: December 24, 2002
    Assignee: International Business Machines Corporation
    Inventors: Craig Duray Brossman, Arianne Therese Hinds, Nenad Rijavec, Mikel J. Stanich, Mark Andrew Stephens, Raymond Glenn Wardell