A system is disclosed. The system includes at least one physical memory device to store compensation logic and one or more processors coupled with the at least one physical memory device to execute the compensation logic to generate first ink deposition function representing a first output ink amount versus input digital count for each of a plurality of color planes, generate second ink deposition function representing a second output ink amount versus input digital count for each of the plurality of color planes and generate transfer functions for each of the plurality of color planes based on the first ink deposition function and the second ink deposition function, wherein the transfer functions transform input digital counts.

In the print data for a nozzle of a printer, white dots are replaced by pre-ejection pulses. One or more repetitions of the pre-ejection pulses may be inserted into the print data, depending on the actual print speed of the printer, to determine print speed-dependent print data with which the nozzle is activated to print a print image with high print quality.

A printing system is disclosed. The printing system includes at least one physical memory device to store calibration logic and one or more processors coupled with the at least one physical memory device to execute the calibration logic to perform uniformity compensation, including receiving print image measurement data corresponding to primary color markings and secondary color markings printed by pel forming elements, wherein each of the pel forming elements is associated with one of a plurality of primary colors, generating a first set of transfer functions based on the print image measurement data, wherein the first set of transfer functions includes a transfer function for each of the pel forming elements associated with a primary color, generating a second set of transfer functions based on the print image measurement data, wherein the second set of transfer functions includes transfer functions for each of the pel forming elements associated with a plurality of secondary colors, generating a set of inverse transfer functions for each of the pel forming elements based on the first set of transfer functions and the corresponding second set of transfer functions and generating a uniformity compensated halftone design based on the set of inverse transfer functions and a first halftone design.

According to an aspect of the embodiments, in multi-tonal image data in which each of pixels is represented by bit data of M bits (M≥2), reduction processing is performed by applying a mask pattern to the bit data to be thinned out without increasing load of calculation processing.

A method of color image processing for quantizing output includes obtaining an input for an object pixel which is represented by a vector in a first color space. A modified input equal to the input plus a sum of errors from other pixels in a neighborhood of the object pixel is generated. For each color component in the first color space, where corresponding color components of the modified input are located with respect to a preset range is determined. If the modified input's color component is greater than the preset range, then that color component for an output is determined to be on; if less than the preset range, then that color component for the output is determine to be off; and, if within the preset range, then that color component for the output is determined to be unknown. A transformed modified input is mapped to a perceptual color space when any color component of the output is unknown. Colors consistent with color components of the output that have already been determined are also mapped to the perceptual color space. The color in the perceptual color space that lies closest to the transformed modified input is chosen. An output in the first color space having color components on and off is generated consistent with the determinations and/or choices made. Error for the object pixel is then calculated as the difference between the output and the modified input.

Mask entries for each of a plurality of passes over which print fluid drops are to be dispensed for printing an image are generated based on different types of masks and based on image data for the image. Print fluid drop dispensation for a pixel for which the mask entries for a given pass specify repeated print fluid drop dispensation is moved to a mask entry for an adjacent pass that does not specify print fluid drop dispensation for the pixel. Ejection of print fluid to print the image is caused based on the generated mask entries.

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.

An image processing method includes performing first halftone processing and second halftone processing. The second halftone processing is performed, for a second kind of color in advance among a plurality of colors constituting an original image, in units of blocks each consisting of a plurality of pixels that constitute the original image and the second kind of color is converted into an amount of second kind of ink corresponding to the second kind of color among the plurality of inks. The first halftone processing is performed, for the first kind of color, for each pixel that constitutes the original image or each pixel group having a smaller number of pixels than the block and the first kind of color is converted into an amount of first kind of ink corresponding to the first kind of color among the plurality of inks.

In an example implementation, a method of rosette-free printing includes, in a printing device whose color plane misregistration is less than 15 percent of a screen ruling of a halftone screen, printing multiple color planes of a multicolor image using the halftone screen.

A method for correcting tone-level non-uniformities in a digital printing system includes printing a test target having a set of uniform test patches. The printed test target is automatically analyzed to determine tone-level errors as a function of cross-track position for each of the test patches. A tone-level correction function is determined and represented using a set of one-dimensional feature vectors which specifies tone-level corrections as a function of cross-track position, pixel value and time. Corrected image data is determined by using the tone-level correction function to determine a tone-level correction value for each image pixel responsive to the input pixel value, cross-track position and time. The corrected image data is printed using the digital printing system to provide a printed image with reduced tone-level errors.