Abstract: Digital halftoning processes for producing a halftone image include, for each pixel in the image: indexing a two-dimensional look up table using a position of the pixel, identifying a threshold value for the pixel from the two-dimensional look up table, creating an index that indexes a three-dimensional lookup table using the threshold value and the position of the pixel, and obtaining an output value for the pixel from the three-dimensional look up table via the index. The digital halftoning processes also produce a halftone representation of the image from output values for corresponding pixels.

Abstract: Methods, systems, and media to calibrate a reprographic system are disclosed. Embodiments of the invention may calibrate a component like scanner and/or printer in response to user input and/or coupling the component to the reprographic system. More specifically, embodiments may generate a curve that describes tone differences between an image scanned by a scanner or an image printed by the printer by comparing the outputs to acceptable tone descriptions for the image. Some embodiments comprise a graphical user interface (GUI) to communicate with the user, allowing the user to select user preference curves to change, for example, the brightness of an image being copied. Some embodiments incorporate network and phone system interfaces to communicate with remote components as well as to receive input from and/or output to other systems via email, facsimile, etc.

Abstract: Provided are a method, system, and program for generating threshold values in a dither matrix. A dither matrix of threshold values is generated.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A method and system obtains a linear combination in accordance with an image processing algorithm using at least one lookup table that is indexed by at least one subset of bits from a set of pixels in an image.

Abstract: 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.

Abstract: A halftone spot function, for determining a shape of a halftone spot as a function of the intensity of an image being printed, is generated by creating one or two line segments forming a part of the shape of the spot function or by creating a number of contour lines that are interpolated to form the function. A halftone spot pattern is generated as a number of supercells, each of which includes a number of halftone spots, each defined within a halftone spot cell by a halftone spot function, with the supercell being defined to include a number of device pixels, each of which is fully inked of left without ink, a number of spot cells in each direction, and offset distance establishing angles of the lines dividing the spot cells from one another.

Abstract: Methods, systems, and media to calibrate a reprographic system are disclosed. Embodiments of the invention may calibrate a component like scanner and/or printer in response to user input and/or coupling the component to the reprographic system. More specifically, embodiments may generate a curve that describes tone differences between an image scanned by a scanner or an image printed by the printer by comparing the outputs to acceptable tone descriptions for the image. Some embodiments comprise a graphical user interface (GUI) to communicate with the user, allowing the user to select user preference curves to change, for example, the brightness of an image being copied. Some embodiments incorporate network and phone system interfaces to communicate with remote components as well as to receive input from and/or output to other systems via email, facsimile, etc.

Abstract: A method and system for providing a halftoned image is disclosed. The method and system comprise scaling the halftoned image by performing pel repetition utilizing an error diffusion algorithm such that artifacts are minimized. According a system and method in accordance with the present invention performs pel repetition using error diffusion technology, so that any resulting “artifacts” are realized as high-frequency image addition, making them much less visible. A system and method in accordance with the present invention provides adjustability in the computational complexity of the scaling, so that quality can be traded off continuously against the amount of processing power required.

Abstract: A method and system embeds an image into two images by performing a digital halftoning process on a Cartesian product of color spaces.

Abstract: 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.