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.

Threshold values in a dither matrix according to the present invention are arranged such that in a case where screen processing is executed on a multi-tone image that has a first density, halftone dots are formed at a first screen angle, and in a case where screen processing is executed on a multi-tone image that has a density being higher than a second density that is higher than the first density, halftone dots are formed at a second screen angle that is different from the first screen angle.

There is provided a recording data generating apparatus that generates recording data used for reproducing a gloss of an image by recording inclined structures on a recording medium, the recording data generating apparatus including: a conversion unit that converts gloss data with a first resolution having an inclined structure as one pixel into inclined structure data representing a combination ratio of a predetermined number of kinds of inclined structures; a halftone processing unit that generates N-value quantization data representing one of the predetermined number of kinds of inclined structures by performing a halftone process of the inclined structure data of each pixel with the first resolution, N being equal to the predetermined number of kinds; and a recording data generating unit that generates recording data used for recording one of the predetermined number of kinds of inclined structures for each pixel with the first resolution based on the quantization data.

In an example, a halftone screen is generated. A plurality of amplitude-modulated dot clusters is arranged in correspondence with a grid. Each of the amplitude-modulated dot clusters comprises a plurality of frequency-modulated dots.

An image processing apparatus including: a halftone processing unit configured to generate halftone image data represented by a halftone dot corresponding to a density value by performing halftone processing using a dither matrix for input image data; a phase change processing unit configured to correct a deviation of a laser beam scan line that is used in forming an image in accordance with the input image data on a printing medium by performing phase change processing to shift the phase of a pixel in the halftone image data in a sub scanning direction; and a pseudo high-resolution processing unit configured to convert the halftone image data after the phase change processing into halftone image data with a lower resolution by performing pseudo high-resolution processing, and in the dither matrix, threshold values are arranged so that the number of pixels in the sub scanning direction, which make up the halftone dot, is always even.

An image processing apparatus which performs image processing for print processing, including: a pseudo halftone processing unit configured to perform pseudo halftone processing by dithering with respect to an input image, and generate a halftone image constituted by plural dots, and a threshold matrix holding unit configured to hold a threshold matrix used for the pseudo halftone processing, wherein in the threshold matrix, thresholds are arranged such that the halftone image has a density region in which dots to be formed depending on a density of the input image are not rotational symmetric on a 90 basis, and orientations of the dots differ from each other in the density region.

An image processing apparatus includes a scanner that acquires an image, and a processor that changes areas of a plurality of dot patterns in accordance with gradation values in the image using a plurality of dither matrices, and generates a binary image based on the plurality of dot patterns. A change rate of each of the areas differs from each other. The plurality of dither matrices include a first dither matrix and a second dither matrix. A first change rate of a first area of a plurality of first dot patterns formed based on the first dither matrix and a second change rate of a second area of a plurality of second dot patterns formed based on the second dither matrix differ.

An image processing apparatus which performs image processing for print processing, including: a pseudo halftone processing unit configured to perform pseudo halftone processing by dithering with respect to an input image, and generate a halftone image constituted by plural dots, and a threshold matrix holding unit configured to hold a threshold matrix used for the pseudo halftone processing, wherein in the threshold matrix, thresholds are arranged such that the halftone image has a density region in which dots to be formed depending on a density of the input image are not rotational symmetric on a 90 basis, and orientations of the dots differ from each other in the density region.

An image processing apparatus including: a halftone processing unit configured to generate halftone image data represented by a halftone dot corresponding to a density value by performing halftone processing using a dither matrix for input image data; a phase change processing unit configured to correct a deviation of a laser beam scan line that is used in forming an image in accordance with the input image data on a printing medium by performing phase change processing to shift the phase of a pixel in the halftone image data in a sub scanning direction; and a pseudo high-resolution processing unit configured to convert the halftone image data after the phase change processing into halftone image data with a lower resolution by performing pseudo high-resolution processing, and in the dither matrix, threshold values are arranged so that the number of pixels in the sub scanning direction, which make up the halftone dot, is always even.

An image processing apparatus which performs image processing for print processing, including: a pseudo halftone processing unit configured to perform pseudo halftone processing by dithering with respect to an input image, and generate a halftone image constituted by plural dots, and a threshold matrix holding unit configured to hold a threshold matrix used for the pseudo halftone processing, wherein in the threshold matrix, thresholds are arranged such that the halftone image has a density region in which dots to be formed depending on a density of the input image are not rotational symmetric on a 90 basis, and orientations of the dots differ from each other in the density region.