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.

A terminal device includes an acquisition unit that acquires image information of a read-out original, a display unit that displays the image information acquired by the acquisition unit, a detection unit that detects pitch information by performing frequency analysis of the image information displayed by the display unit, and a control unit that controls the image information so as to be enlarged or reduced in accordance with a size of the original and controls to display the pitch information so as to be superimposed on the image information which is enlarged or reduced.

The image forming apparatus including: a controller controlling the image forming unit to form a test image, controlling the measurement unit to measure the test image on the image bearing member, and controlling the transfer unit to transfer the test image to the sheet; a reception unit receiving a user instruction; a second generation unit generating the conversion condition based on the user instruction and the measurement result of the test image, wherein the sample image includes a first sample image, a second sample image, and a third sample image, a color difference between the first and second sample images is smaller than a threshold value, a color difference between the second and third sample images is larger than the threshold value, density of the first sample image is higher than density of the second sample image and density of the third sample image.

A print job is analyzed to determine what page locations can use optional colors and different image quality increase values of different optional colors at the page locations are calculated. Only one of the optional colors is selected, based on which optional color produces the highest print job image quality increase for all of the page locations of the print job. Each individual page of the print job is evaluated to determine if use of the selected optional color increases image quality of the individual page to identify page exceptions. Instructions to mount a selected replaceable printing module corresponding to the selected optional color are displayed, and the print job is printed using the selected replaceable printing module.

The invention provides methods that improve image compression and/or quality within the JPEG process by using a low-pass filter to remove high frequency components from image data, which removes blocking artifacts. Preferred embodiments apply the low-pass filter to the Chroma components after decompression prior to conversion into RGB color space.

An image forming apparatus includes: a raster image processing unit configured to convert original image data into image data for image formation being of a raster image; an image forming unit configured to form an image on a paper sheet; a reading unit configured to generate read image data by reading the image formed on the paper sheet; a monitor setting unit configured to set a monitor setting color and an ideal value for the monitor setting color; a color tone monitoring unit configured to monitor a color tone difference between a value of the read image data in the monitor setting color and the ideal value; and a hardware processor configured to perform control to have color correction performed in the image forming unit, wherein the monitor setting color includes at least one of a primary color, a secondary color, a tertiary color, and a tertiary achromatic color.

Provided are a non-transitory computer-readable storage medium storing a control program for creating a database for use in color calibration and that storing a control program for a judgement based on the database. The control programs cause a computing device to perform the following operations. The database-creating operations include calculating a white-ground color difference using a print medium, and repeating a feedback adjustment of a color correction LUT, to obtain a resulting color accuracy. The operations further include obtaining white-ground color differences and resulting color accuracies for plural paper products of a certain print medium type, to obtain a mathematical relation and create a database. The judgement operations include using the database to calculate an estimated resulting color accuracy from a white-ground color difference calculated using a print medium, and judging whether to perform a feedback adjustment of a color correction LUT based on the estimated resulting color accuracy.

A processor of a printing device automatically raster image processes print data in a print job to produce a first, relatively low resolution, bitmap for printing the print job with the printer's main colors and one or more optional colors. The processor automatically compares the extended gamut of the lower-resolution first bitmap and the main color gamut of the printing engine to identify image quality improvement pixels of the extended gamut that are outside the main color gamut. The processor automatically either raster image processes the print data with the main colors and one of the optional colors, or raster image processes the print data with only the main colors, based on whether the number of image quality improvement pixels of the extended gamut that are outside the main color gamut exceeds a pixel quantity threshold, to produce a second, relatively higher resolution, bitmap.

Provided is an image conversion method that allows for the representation, on a display, the light and shade of a printed image obtained by printing the image on paper. The image conversion method includes a step of acquiring an illumination-light component and a reflectance component from an input image, a step of correcting the illumination-light component in accordance with display luminance information of a print mode in which the input image is to be printed, so that light and shade of the input image displayed on a display come close to light and shade of a printed image obtained by printing the input image in the print mode, and a step of acquiring a combined image by combining the corrected illumination-light component and the reflectance component or the corrected reflectance component.

An image capturing system includes an imager, a detector, and a controller. The imager is configured to move relative to an object to be imaged and capture an image of the object. The detector is configured to detect a predetermined relative position of the object with respect to the imager. The controller is configured to switch from stop supplying a system clock to supplying the system clock based on the detected predetermined relative position. The system clock is used to control a timing to start capturing an image by the imager. After stops supplying the system clock, the controller resumes supplying the system clock to the imager according to a relative movement of the object, based on the detected predetermined relative position.