摘要:
Provided are a method and apparatus for determining error diffusion coefficients. The method includes: (a) setting N groups of error diffusion coefficients (N is a positive integer), in which each group includes a plurality of coefficients; (b) binarizing an image having one gray level value using each of the N groups of error diffusion coefficients; (c) detecting N fit values with respect to N binary-coded images using an evaluation function; (d) determining whether the fit values are detected a predetermined number of times; (e) when a detection number of the fit values does not coincide with the predetermined number of times, reproducing the N groups of error diffusion coefficients according to reproduction rates determined by the N fit values; (f) selecting optional error diffusion coefficients in the reproduced N groups of error diffusion coefficients, and substituting portions of data of selected error diffusion coefficients with each other; and (g) determining the N groups of error diffusion coefficients including the error diffusion coefficients containing substituted data as new error diffusion coefficients, and returning to step (b).
摘要:
An apparatus and method of diffusing a color error which includes modulating a threshold value using a binary error of different color channels, to prevent overlapping of dots of a channel, when a sum of input values of the different color channels is not more than a predetermined value, determining a channel whose color is to be output by comparing a corrected input value of each channel in which an error is diffused and binarizing a color channel by comparing the modulation threshold value with the corrected input value of the determined channel.
摘要:
Provided are a method and apparatus for determining error diffusion coefficients. The method includes: (a) setting N groups of error diffusion coefficients (N is a positive integer), in which each group includes a plurality of coefficients; (b) binarizing an image having one gray level value using each of the N groups of error diffusion coefficients; (c) detecting N fit values with respect to N binary-coded images using an evaluation function; (d) determining whether the fit values are detected a predetermined number of times; (e) when a detection number of the fit values does not coincide with the predetermined number of times, reproducing the N groups of error diffusion coefficients according to reproduction rates determined by the N fit values; (f) selecting optional error diffusion coefficients in the reproduced N groups of error diffusion coefficients, and substituting portions of data of selected error diffusion coefficients with each other; and (g) determining the N groups of error diffusion coefficients including the error diffusion coefficients containing substituted data as new error diffusion coefficients, and returning to step (b).
摘要:
A method of and apparatus for detecting a pixel distance to adjust a threshold value are disclosed. The method and apparatus include determining a first coordinate of a first pixel with reference to a minor pixel for each pixel of an image, and detecting a first pixel distance which corresponds to a distance between the first pixel and the minor pixel by using the determined first coordinate, wherein the first pixel is binarized by adjusting a threshold value based on the detected first pixel distance, and the first coordinate is reset when the binarized first pixel is determined to be the minor pixel.
摘要:
An error diffusion method and apparatus using an area ratio of candidate colors in a CMYKRGBW cube, wherein the candidate colors are determined in response to an input value, and the CMYKRGBW cube is converted into a color space consisting of only four colors so that the candidate colors can be evenly distributed. The color space is then expressed using the area ratio of the candidate colors. Accordingly, it is possible to evenly distribute candidate colors in all gray-scale regions, including a highlight region, thereby obtaining a soft image that does not have a pattern that is strenuous on the eye of an observer.
摘要:
An apparatus and a method for compensating for a defective pixel are provided. The apparatus includes a defective pixel information detecting unit and a halftoning unit. The defective pixel information detecting unit detects whether input continuous gray scale data forms a defective pixel caused by a defective image-forming element and outputs the detected result as defective pixel information. The halftoning unit reflects the defective pixel information in halftoning of the continuous gray scale data using error diffusion. In an image-forming apparatus (such as a printer, an LED etc) reproducing continuous gray scales using a plurality of image-forming elements each forming a limited gray scale, image quality deterioration caused by the defective pixel can be compensated for by performing halftoning in consideration of the defective image-forming element when some of the image-forming elements are defective.
摘要:
An image forming apparatus which provides a plurality of developers that have different densities for each color, and an image forming method thereof. The image forming method may include detecting a remaining amount of a first developer; and forming an image by expressing a gray scale of inputted data according to a multi-bit halftoning process using a second developer that is similar to the first developer in color and higher than the first developer in density if the remaining amount of the first developer is a preset value or less.
摘要:
Disclosed is an error diffusion apparatus with cluster dot. The error diffusion apparatus for performing an error diffusion on a second pixel based on a first pixel includes: a binary processing unit for binarizing a tone value of the first pixel based on a predetermined threshold; a binary error diffusion unit for computing a binary error value based on a difference between the tone value of the first pixel and a binary tone value for the first pixel, and reflecting the binary error value on a tone value of the second pixel applied to the binary processing unit; and a cluster forming unit for deciding whether to form a cluster for the first and second pixels, in reference to a predetermined cluster pattern and a binary tone value of the first pixel. The error diffusing apparatus reduces switching noises generated from the image forming process in pixel unit, and expands the tone value range of an image. In addition, the error diffusing apparatus prevents deteriorations in image quality by limiting the cluster size and restricting the cluster formation in the shadow and highlight areas of an image.
摘要:
An image forming apparatus and an image forming method thereof are provided. An image forming apparatus according to an exemplary embodiment of the present general inventive concept comprises a decoder to decode a compressed image to convert the compressed image into image data, a pure black determining unit to determine whether the image data is pure black by using information of the converted image data, a section classifying unit to classify the image data into a text section and an image section by using a result of the pure black determination, and a color coordinate converter to perform color coordinate conversion on the image section of the classified sections. Therefore, it is possible to improve readability of black text.
摘要:
An image forming apparatus and an image forming method thereof are provided. An image forming apparatus according to an exemplary embodiment of the present general inventive concept comprises a decoder to decode a compressed image to convert the compressed image into image data, a pure black determining unit to determine whether the image data is pure black by using information of the converted image data, a section classifying unit to classify the image data into a text section and an image section by using a result of the pure black determination, and a color coordinate converter to perform color coordinate conversion on the image section of the classified sections. Therefore, it is possible to improve readability of black text.