Abstract: Halftone image data is generated according to a threshold array in which thresholds T up to a given gradation have been determined, and candidate pixels to be blackened are then determined. Then, a low-frequency component extractor extracts low-frequency component data from density image data which simulates the density of the halftone image data corresponding to an output image from an image output apparatus. A particular frequency component divider 70 divides the extracted low-frequency component data into particular frequency component data for intensifying the low-frequency components, and blackening candidate pixels for intensifying the particular frequency components are excluded, thus narrowing down candidate pixels. The positions of thus determined blackening candidate pixels are determined as the positions of thresholds for a next gradation.

Abstract: A threshold array having an array of thresholds for reproducing a gradation with a dot pattern as a clustered pattern of dots each made up of one or more blackening pixels is corrected. At least one non-contact point candidate position to be turned into a non-contact point is determined among contact points of the dots. Then, at least one contact point candidate position to be turned into a contact point is determined among non-contact points of the dots at the given gradation. Thereafter, the threshold array is corrected by switching around a threshold for the non-contact point candidate position and a threshold for the contact point candidate position, whereby the layout of contact points of the dots can be corrected.

Abstract: A mask is produced for converting multi-level image data into a halftone image through comparison with a threshold for each pixel. For this purpose, a dot pattern is determined on each of predetermined gray scale levels, and, the mask is created by the dot patterns obtained at the step, where the respective dot patterns are determined independently for every gray scale level.

Abstract: A printer system comprises a communication interface and printer components. The communication interface receives a humidity value from a toner cartridge. The printer components control printing operation based on the humidity value. To control printing operation, the printer components may configure a dither matrix based on the humidity value. The toner cartridge comprises a humidity sensor and a communication interface. The humidity sensor detects a humidity level and generates the humidity value to correspond to the humidity level. The communication interface transfers the humidity value from the humidity sensor to the printer system.

Abstract: An image processing method and apparatus for improving both gradation and resolution in a screening process. The apparatus comprises an image memory for storing multi-valued image data in pixel units; a pixel data acquiring portion for acquiring image pixel data from the memory; a threshold value matrix constituted by a density area by which dots of a high number of lines are produced and another density area by which dots of a low number of lines are produced; a threshold value data acquiring portion for acquiring from the matrix threshold value data corresponding to image data acquired by the pixel data acquiring portion based upon the image data address; and a comparator for comparing the acquired image data with the acquired threshold value data to thereby output a consequent binary signal.