A non-transitory computer-readable medium stores computer-readable instructions. The instructions, when executed by a processor of an image processing apparatus, perform processes. The processes include registering, in a storage, a candidate color for each of a plurality of divided areas included in image data indicating an image on a sheet. The processes further include identifying, from among a plurality of pixels included in the image data, a target pixel based on a color value of the target pixel. The processes further include replacing the color value of the identified target pixel with a target color when a condition based on the color value of the identified target pixel and a color value of the target color is satisfied.

Provided is an information processing system configured to: receive a plurality of images; select a standard image; search, in extracting partial images for complementing a too bright region/too dark region in the standard image from a reference images, using correction images obtained by subjecting each of the images to multivalued processing for each division of luminance components, for regions having matching shapes of respective regions included in the correction image of the standard image and the correction images of the other images; and complement image portions corresponding to the too bright region and/or too dark region in the correction image of the standard image using image portions, which are matching regions and correspond to appropriately bright regions, to thereby generate a synthetic image. Each image is dividable into at least three values: a too bright region, an appropriately bright region, and a too dark region, and has a relationship in which a boundary luminance between the too bright region and the appropriately bright region aligns with a boundary luminance between the appropriately bright region and the too dark region in a darker image having an adjacency relationship therewith.

An image forming apparatus includes an input unit configured to input image data, an image forming unit configured to form an image on a recording material based on the input image data, a reading unit configured to read the image formed on the recording material, and a control unit configured to, based on the input image data and the image read by the reading unit, acquire a plurality of change amounts from the read image, and determine a type of an abnormal image based on a plurality of the acquired change amounts.

There is provided with an information processing apparatus. A first obtaining unit obtains data of a reference image indicating a target of printing output to be performed by a printing apparatus. A second obtaining unit obtains data of an image printed by the printing apparatus. A correcting unit corrects a local image density difference or the reference image based on a global image density difference between the reference image and the printed image. An evaluating unit evaluates quality of the printed image based on the local image density difference between the corrected reference image and the printed image.

The disclosure relates to an image tone adjustment method, an apparatus thereof, and a computer-readable storage medium. The method includes: fitting overlapping areas to obtain a first correction parameter and a second correction parameter, performing interpolation on each pixel of the target image to obtain a corresponding correction parameter, correcting the target image according to the corresponding correction parameters; fitting an overlapping area between the corrected target image and the first image, and an overlapping area between the corrected target image and the second image to obtain a first RGB three-channel linear transformation parameter and a second RGB three-channel linear transformation parameter, performing linear interpolation on each pixel of the corrected target image to obtain a corresponding RGB three-channel linear transformation parameter, and transforming the corrected target image.

The disclosure relates to an image tone adjustment method, an apparatus thereof, and a computer-readable storage medium. The method includes: fitting overlapping areas to obtain a first correction parameter and a second correction parameter, performing interpolation on each pixel of the target image to obtain a corresponding correction parameter, correcting the target image according to the corresponding correction parameters; fitting an overlapping area between the corrected target image and the first image, and an overlapping area between the corrected target image and the second image to obtain a first RGB three-channel linear transformation parameter and a second RGB three-channel linear transformation parameter, performing linear interpolation on each pixel of the corrected target image to obtain a corresponding RGB three-channel linear transformation parameter, and transforming the corrected target image.

Multi-value image data is sampled for each predetermined pixel range to generate tone information of the pixel range. The generated tone information is stored in a storage unit. Attribute information representing the attribute of a pixel is generated from the multi-value image data, and the generated attribute information is stored in the storage unit. Halftone processing is performed on the multi-value image data based on the tone information and attribute information stored in the storage unit.

Multi-value image data is sampled for each predetermined pixel range to generate tone information of the pixel range. The generated tone information is stored in a storage unit. Attribute information representing the attribute of a pixel is generated from the multi-value image data, and the generated attribute information is stored in the storage unit. Halftone processing is performed on the multi-value image data based on the tone information and attribute information stored in the storage unit.

For preferably reducing show-through in an image obtained by reading an original, an image processing apparatus: stores an index value for each of a plurality of mutually differing degrees of variation; obtains a degree of variation of signal values included in a region of interest of a predetermined size including a pixel of interest included in image data corresponding to the read image; obtains a value indicating a brightness of the region of interest; determines an amount of correction of a value of the pixel of interest using the obtained value and an index value corresponding to the obtained degree of variation; and corrects the value of the pixel of interest using the determined amount of correction.

A terminal device includes a display unit that displays acquired image information, a receiving unit that receives an analysis position of quality unevenness in the image information, and a detection unit that detects pitch information by respectively performing frequency analysis on first and second regions containing the analysis position. The display unit displays the pitch information detected from the first region with respect to pitch information equal to or greater than a predetermined pitch length and displays the pitch information detected from the second region with respect to pitch information less than the predetermined pitch length.