A frequency adaptive descreening method includes obtaining a scan image of an original document, dividing a region of the scan image by analyzing frequency characteristics of the obtained scan image, estimating a resolution with respect to each of regions resulting from dividing the region according to the analyzed frequency characteristics, and adaptively performing filtering on the regions resulting from dividing the region by using the estimated resolution.

In some examples, a device includes a printing device to generate an image on a substrate from a digital image, and a processor to: receive a scanned image of the image on the substrate, identify a plurality of image portions of the scanned image, identify horizontal color changes across a horizontal portion of the plurality of image portions, identify vertical color changes across a vertical portion of the plurality of image portions, compare the horizontal color changes and vertical color changes to corresponding horizontal color changes and corresponding vertical color changes of the digital image, and measure a presence of color plane misregistration, and the color, direction and magnitude of misregistration based on the comparison.

Systems and methods for replacing cells of an image based on some pre-determined metric are described herein. For example, systems and methods described herein may improve the functioning of a standard imaging system. For example, the systems and methods described herein may be used to post-process existing images in an imaging system based on one or more pre-determined metrics and improve the halftone images according to those pre-determined metrics.

The invention provides an image forming device, which can generate a multi-valued image based on a binary image. An image forming device includes: an image acquisition part for acquiring a binary image; and a multi-valued image generation part generating a multi-valued image including a specific pixel based on pixel values of pixels within a first image region with a first size including the specific pixel and pixel values of pixels within a second image region with a second size different from the first size including the specific pixel in the binary image.

Devices, systems and methods are disclosed for reducing an amount of moiré pattern exhibited by an image having a halftone pattern. Regions of the image including the halftone pattern may be identified and selectively blurred to reduce the amount of moiré pattern visible to a user. The halftone pattern may be detected using digital wavelets to identify high frequency patterns in the image. The halftone pattern may be blurred using a convolution matrix having a weighted average, and a transition band may be used to reduce an intensity of the blur near the edges of the halftone pattern.

Processing a dithered image comprising a grid of pixels including defining an array of pixels corresponding to a sub-region of the image; performing edge detection along the rows and the columns of the array; counting the number of edges detected along the rows of the array to determine the number of horizontal edges in the array; counting the number of edges detected along the columns of the array to determine the number of vertical edges in the array; identifying whether the sub-region is dithered based on the number of horizontal and vertical edges in the array; and selectively processing the corresponding sub-region of the image based on whether or not the sub-region is identified to be dithered. The identification step may also be based on the lengths of segments of similar pixels in the lines of the array.

In an example, a method includes, by one or more processors, acquiring a dot pattern having a distribution of dots. A greyscale image comprising a plurality of pixels each associated with a greyscale value may be derived from the dot pattern. Deriving the greyscale image may comprise, for each pixel, determining the closest dot to the pixel and associating a distance of the closest dot from the pixel with the pixel, and assigning a greyscale value to each pixel, wherein the greyscale value is based on the distance associated with that pixel.

An image processing apparatus includes a halftone processing unit and a multi-level gradation processing unit. The halftone processing unit is configured to perform a halftone process for a target image and generate a binary image corresponding to the target image. The multi-level gradation processing unit is configured to (a) set a target pixel as a dot pixel in the binary image, (b) determine whether a dot exists on plural first periphery pixels with a predetermined first distance from the target pixel and plural second periphery pixels with a predetermined second distance from the target pixel or not, (c) derive a gradation level of the target pixel among predetermined three or more gradation levels on the basis of a number of dots on the plural first periphery pixels and a number of dots on the plural second periphery pixels and thereby generate a multi-level gradation image.

An image processing apparatus includes a halftone processing unit and a multi-level gradation processing unit. The halftone processing unit is configured to perform a halftone process for a target image and generate a binary image corresponding to the target image. The multi-level gradation processing unit is configured to (a) set a target pixel as a dot pixel in the binary image, (b) determine whether a dot exists on plural first periphery pixels with a predetermined first distance from the target pixel and plural second periphery pixels with a predetermined second distance from the target pixel or not, (c) derive a gradation level of the target pixel among predetermined three or more gradation levels on the basis of a number of dots on the plural first periphery pixels and a number of dots on the plural second periphery pixels and thereby generate a multi-level gradation image.

An image processing apparatus includes a reading unit configured to read an image of a document and generate image data, a first binarization unit configured to generate binary image data by performing halftone processing on the image data generated by the reading unit, a smoothing unit configured to perform smoothing processing on a character region of the binary image data, a second binarization unit configured to perform binarization processing on the character region having been subjected to the smoothing processing by the smoothing unit, and a character recognition unit configured to perform character recognition processing on the character region having been subjected to the binarization processing by the second binarization unit.