摘要:
A multiple beam printer system having N laser beams receives print job information from a print host. A rendering application uses a threshold array to generate halftone image data from the print job. The threshold array is defined based on a spot function. The defined screen is non-orthogonal and includes Y pels in a direction that is perpendicular to a scanning direction of the laser beams where Y is an integer multiple of N. A distance between screen dots in pels is preferably equal to an integer multiple of N. The screen dot may be defined by a supercell encompassing two screen dots and having an odd number of pels in a direction that is parallel to the scanning direction. The spot function may include a snap feature that snaps a screen dot to the nearest printer grid pel. The spot function may include scaling to compensate for the distortion of the non-orthogonal screen dot.
摘要:
Provided are a method, system, and program for generating threshold values in a dither matrix. A dither matrix of threshold values is generated. The threshold values in the dither matrix are filtered to generate a filtered dither matrix of filtered dither values by performing for dither values in the dither matrix: determining a region of dither values in the dither matrix that surrounds the value being considered, wherein the dither values in the determined region comprise one of dither values in a first portion of the region within the dither matrix or a wrap around dither value in a second portion of the region that extends beyond the dither matrix; and using an offset value to determine one wrap around dither value, wherein repeated instances of the dither matrix are designed to be applied to an image by forming a tile pattern of the repeated instances of the matrix over the image pattern, and wherein the repeated instances of the matrix in the tile pattern are offset in one direction by the offset value; and performing an operation on the determined dither values in the region to determine a filtered value for the dither value being considered.
摘要:
Techniques for generating dither masks are provided. A dither mask is generated by selecting a sequence of at least three original patterns comprising pixels of at least one of a first color and a second color. At least two patterns are interpolated to generate interpolated patterns in the sequence between the at least three original patterns. If a pattern having at least one specified characteristic exists in the sequence, the steps of interpolating between at least two patterns, and determining if a pattern having at least one specified characteristic exists in the sequence, are repeated. The interpolation is between at least one pattern from each side of the pattern having at least one specified characteristic in the sequence.
摘要:
A method, computer program product and system for detecting and compensating for color misregistration. A black/white edge or a solid color edge on a target may be scanned. A black/white edge may refer to a black image, e.g., black text, on a white surrounding background having a rapid spatial transition from black to white. A solid color edge may refer to a solid color image, e.g., solid color text, on a white surrounding background having a rapid spatial transition from color to white. A curve of gray values versus spatial pixel positions for each color channel, e.g., red, green and blue color channels, may be generated. A misregistration error may then be calculated by calculating the offset between the color channel curves. The misregistration error may then be used to calibrate the scanner to compensate for the detected color misregistration.
摘要:
A method (and system) for changing spatial resolution of an image includes systematically creating an image scaling look-up table including at least one pixel replacement pattern and applying a scaling algorithm to modify the image using the image scaling look-up table, thereby allowing a user to scale binary images with easy control of dot gain, output bit depth and other printer parameters.
摘要:
A method (and system) of multi-bit halftoning includes comparing values of an image to threshold values of a halftone threshold matrix, and generating output values that provide a greater than minimum level of contrast.
摘要:
A method and system for generating halftone tables, using a spot function, subdivides the pixels within the halftone cell of a halftone matrix into a plurality of sub-pixels, determines the value of the spot function corresponding to the position of each of the sub-pixels within the halftone matrix, repeats the subdividing and determining for all of the sub-pixels in the halftone matrix, ranks the values for the entire halftone matrix, normalizes the ranked values, generates a cumulative histogram based upon the normalized values, and stores the cumulative histogram as a halftone table.
摘要:
A digital halftoning technique for controlling a spot function is disclosed. A method for generating a spot for use in halftoning according to the present invention includes defining a spot function that combines two functions selected to provide a predetermined spot shape for use in a halftone cell and scaling the spot function using a scaling function that varies according to a value of a first and second spot function ordinate. Asymmetric modulation of spot functions is used to control the touching of adjacent spots, and to change the shape of the spots with the gray region.
摘要:
A data processing system and method are described for generating a halftone screened image from an input image. A first threshold matrix is generated which, when utilized to halftone a solid gray input image, generates a first halftoned output image which is a plurality of generally solid vertical lines. The first threshold matrix includes a plurality of matrix elements arranged in a plurality of rows and a plurality of columns. A plurality of groups of the matrix elements are shifted within the first threshold matrix to create a second threshold matrix which, when utilized to halftone the solid gray input image, generates a second halftoned output image which is a checkerboard type pattern of alternating black or white blocks. In one embodiment, groups of the plurality of the rows are shifted horizontally over by at least one adjacent column to generate the second matrix.
摘要:
A method and apparatus for matching the print outputs of two printers having different characteristics. For the purpose of laser printing, or more generally for reproduction on any printing device with limited number of printing levels, a color or grayscale image has to be transformed into an array of printing decisions at each pixel of the output image. Sometimes this array is the only available representation of the original image. One may desire to print this array on a printer with different characteristics from the printer for which the array was originally prepared. The method and apparatus solve this problem by generating a printing decision matrix which takes into account the differences between the two printers.