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.

An image processing apparatus generates image data for an image forming apparatus having a recording head with recording elements in a first direction that forms an image on a recording medium by ejecting ink from the elements toward the medium fed in a second direction perpendicular to the first. The apparatus has an acquiring unit that acquires multi-valued input image data having a uniform tone, a conversion unit that converts the input image data into halftone image data indicating a dot pattern, by using a dither matrix, and a correction processing unit that executes a density unevenness correction process in accordance with properties of each of the elements. The properties of the elements are obtained by reading a chart image formed based on the halftone image data. The dither matrix is a dispersive dither matrix with a size of Sx rows corresponding to the second direction, Sx, a natural number.

A first dot pattern printed according to a result of quantization performed on a multi-valued grayscale value by using a first threshold matrix and a second dot pattern printed according to a result of quantization performed on multi-valued grayscale value by using a second threshold matrix are printed on a print medium in an overlapping manner. In order to generate the threshold matrices, a first initial pattern being a dot pattern corresponding to a first grayscale value and a second initial pattern being a dot pattern corresponding to a second grayscale value lower than the first grayscale value are generated for pixel regions of the first and second threshold matrices. Then, thresholds of the first and second threshold matrices are set such that dot patterns having continuity with the first and second initial patterns are obtained at grayscale values between the first and second grayscale values.

Provided is quantization processing that can reduce color development defect due to dot overlapping and can output an image with reduced granularity when the image is printed by using multiple kinds of colorants. To this end, dot arrangement information for a colorant for which dot arrangement is already determined among multiple kinds of colorants is acquired for a predetermined region of the image, and an evaluation value of each pixel included in the predetermined region is derived based on the arrangement information. In addition, for the predetermined region, a target value for a predetermined colorant for which dot arrangement is yet to be determined is derived based on the image. Then, whether or not to arrange a dot of the predetermined colorant in the predetermined region is determined based on the target value and the evaluation value.

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.

In an example, a method includes accessing an initial prediction of a granularity metric for a halftone pattern. A correction factor to apply to the initial prediction may be determined, the correction factor being determined from a correction factor model defining a relationship between initial predictions of granularity metrics and human perceptions of granularity. The method may further include generating, using processing circuitry, a revised prediction of the granularity metric for the halftone pattern using the correction factor.

A first dot pattern printed according to a result of quantization performed on a multi-valued grayscale value by using a first threshold matrix and a second dot pattern printed according to a result of quantization performed on multi-valued grayscale value by using a second threshold matrix are printed on a print medium in an overlapping manner. In order to generate the threshold matrices, a first initial pattern being a dot pattern corresponding to a first grayscale value and a second initial pattern being a dot pattern corresponding to a second grayscale value lower than the first grayscale value are generated for pixel regions of the first and second threshold matrices. Then, thresholds of the first and second threshold matrices are set such that dot patterns having continuity with the first and second initial patterns are obtained at grayscale values between the first and second grayscale values.

Sharpness of image data in a low-frequency component, which is deceased by an image forming apparatus, is recovered and the recovered image data is converted into halftone image data. Halftone processing includes calculating edge intensity in a local region, dividing the local region into a first pixel group and a second pixel group based on a pixel value of each pixel, determining a distribution order of dots based on a pixel value of each pixel, a threshold value, and the edge intensity such that dots are likely to be distributed to the first pixel group and dots are unlikely to be distributed to the second pixel group, and determining an output value for each pixel in the local region by distributing dots to some pixels included in the local region as much as a number of dots to be output to the local region while referring to the distribution order.

Methods and systems for the in-situ creation of a halftone noise screen layer by layer. Each layer produced is a white noise uniform distributed screen, statistically similar to one generated by a uniform noise function. The generation of each layer, however, is driven by a screen state which is an error based metric on the mean screen threshold. The set of screens produced are not independent of each other; adjacent layers are negatively correlated, while non-adjacent layers are completely uncorrelated. The result of this screen creation is that for any color the variation of coverage across the viewed surface is smaller than the variation produced by randomly generated screen planes. The algorithm is computationally inexpensive and eliminates the need to store multiple screens in memory.

An image processing apparatus capable of improving image quality of binarized image data is provided. The image processing apparatus includes a generation part that generates a binarized image data. The binarized image data comprises a first cell, containing a first dot pattern in which an outside pixel density is higher than an inside pixel density; and a second cell, containing a second dot pattern in which an inside pixel density is higher than an outside pixel density.