An example system in accordance with an aspect of the present disclosure includes a halftone engine and a gray value engine. The halftone engine is to apply halftoning to an image recursively across a plurality of levels of image scales and spatial resolutions, to generate a pattern that is at least quasi-periodic across the plurality of levels. The gray value engine is to substitute gray values recursively for at least a portion of the halftoning.

Embodiments are disclosed for generating a vector object that comprises a precise circular halftone representation of an input image. A method of precise circular halftone generation includes receiving an input image, dividing the image into a grid comprising a plurality of cells, determining a color of a portion of the input image associated with a first cell, determining a radius of circular halftone elements to represent the color associated with the first cell, and generating a path object representing the portion of the input image using circular halftone elements having the determined radius.

A method for calibrating a printing process by applying a selected adjustment curve to an image input file to produce an output file. The adjustment curve is derived to match a target tonal response curve having a function value for 0 that is non-zero or has a discontinuity between 0 and 10%. The adjustment curve has a basic part selected from limited options and an intersecting highlight part derived using a 1-dimensional function having input parameters selected from limited options. The adjustment curve has a starting point (X1, Y1), a highlight curve part having a first slope at the starting point and a first intersection with the basic curve part at (X2, Y2). The first slope and first intersection are among the input parameters selected from limited options. The basic curve part has a second slope at a midrange point (X3>X2, Y3>Y2).

Embodiments are disclosed for generating a vector object that comprises a precise circular halftone representation of an input image. A method of precise circular halftone generation includes receiving an input image, dividing the image into a grid comprising a plurality of cells, determining a color of a portion of the input image associated with a first cell, determining a radius of circular halftone elements to represent the color associated with the first cell, and generating a path object representing the portion of the input image using circular halftone elements having the determined radius.

For a multi-pass printing, an image of a unit area is printed by M printing scans of M print regions of first and second nozzle arrays. Each of N pieces of column data is printed by a different printing scan. Ejection data for the first nozzle array is generated using a first mask pattern and ejection data for the second nozzle array is generated using a second mask pattern different from the first mask pattern, for each of the N pieces of column data. On that basis, the first mask pattern and the second mask pattern have a complementary relationship in each of the M print regions. Further, in each of the first mask pattern and the second mask pattern, a combination of print regions, of the M print regions, for printing dots at the same position on the print medium has a mutually complementary relationship.

An image forming apparatus includes: a correction unit configured to correct a tone of each pixel in first image data in accordance with an image height on a photosensitive member, and output second image data; a halftone processing unit configured to determine exposed regions of pixels in an image by applying halftone processing to the second image data; and a scanning unit configured to form a latent image by scanning the photosensitive member with light that changes in scanning speed in accordance with an image height based on the exposed regions of the pixels. The scanning unit is further configured to perform partial exposure with respect to the pixels based on the exposed regions of the pixels, the partial exposure exposing partial regions of the pixels to light unlike entire exposure that exposes entire regions of the pixels to light.

A method for manufacturing a security document including a security pattern generation method includes the steps of selecting a bounding region, an image object, and a raster image or a function; cutting the image object into image object partitions; and repeating the image object as a pattern, preferably a lattice pattern, in the bounding region wherein each of the image object partitions of an image object is transformed depending on the position area of the image object in the lattice pattern and the rank of the image object partition.

A system, method, and non-transitory computer readable medium are disclosed for mitigating dot placement errors for a given print job. The method includes processing tone values on a per pixel basis to determine whether to implement plane dependence. Plane independence is implemented if the tone value exceeds a predetermined threshold. The method may be performed on a pixel by pixel basis and/or a print object or region basis. Determining whether to implement plane dependence may involve de-asserting or partially de-asserting a plane dependence component of an executed half-toning instruction between sequentially processed color planes of a printing system.

There is provided an ink-deposition device suitable for depositing ink on a target surface and a printing system comprising the same. In operation in a printing system, the ink-deposition device can convert digital images into ink images on the target surface using pixel-masks and methods as disclosed herein. Advantageously, the ink-deposition device, the printing system comprising it and the methods of using the same can reduce or prevent the occurrence of some undesired ink-formations typically governed by the respective physical and/or chemical properties of the surface and ink being used or mitigate their effect on print quality. Application of the pixel-image mask yields a binary image that exhibits pixel-clusters with stochastically distributed centroids.

An image forming apparatus includes a conversion unit configured to convert image data based on a conversion condition corresponding to a type of halftoning, an image processing unit configured to perform the halftoning, an image forming unit configured to form an image, a measurement unit configured to measure a measuring image, an acquisition unit configured to acquire information related to the number of the sheets on which the measuring images are to be formed, and a controller configured to generate a first conversion condition corresponding to first halftoning based on a result of a first measuring image on a first sheet, and generate a second conversion condition corresponding to second halftoning based on a result of a second measuring image on a second sheet, wherein, based on the information, the controller controls whether to control the number of the first sheets is larger than the number of the second sheets.