Abstract: A method and apparatus to generate a preview image. The method of generating the preview image includes classifying data input from an application program by data types, performing a color matching operation that converts a first color signal of the input data into a second color signal used in a printing device according to one or more rendering intents set for the classified data types, and generating the preview image of the input data for which the color matching operation is completed. The preview image is generated based on the color-matched data for the different classified data types. Thus, the preview image appears to be substantially the same image as a document that is printed by an image forming device.

Abstract: A method and apparatus to generate a preview image. The method of generating the preview image includes classifying data input from an application program by data types, performing a color matching operation that converts a first color signal of the input data into a second color signal used in a printing device according to one or more rendering intents set for the classified data types, and generating the preview image of the input data for which the color matching operation is completed. The preview image is generated based on the color-matched data for the different classified data types. Thus, the preview image appears to be substantially the same image as a document that is printed by an image forming device.

Abstract: An apparatus includes an output voltage sensing unit, which senses an output voltage of a laser diode, which has been sampled during a power control period and transmits the sensed output voltage of the laser diode to an output voltage control unit; the output voltage control unit, which obtains an error voltage between a reference voltage and the sensed output voltage of the laser diode and generates a control voltage by proportionally integrating the error voltage; and an optical power compensation unit, which receives the control voltage and generates a compensated control voltage by compensating for an optical power deviation on the photosensitive drum during the printing period.

Abstract: An image processing apparatus and an image processing method that reduce data transmission time by transmitting data between internal memories of a codec without passing through a system memory. Reducing the number of accesses to the system memory increases processing speed, and reduces the load of a main processor, when image data is to be encoded or decoded.

Abstract: An apparatus includes an output voltage sensing unit, which senses an output voltage of a laser diode, which has been sampled during a power control period and transmits the sensed output voltage of the laser diode to an output voltage control unit; the output voltage control unit, which obtains an error voltage between a reference voltage and the sensed output voltage of the laser diode and generates a control voltage by proportionally integrating the error voltage; and an optical power compensation unit, which receives the control voltage and generates a compensated control voltage by compensating for an optical power deviation on the photosensitive drum during the printing period.

Abstract: An apparatus includes an output voltage sensing unit, which senses an output voltage of a laser diode, which has been sampled during a power control period and transmits the sensed output voltage of the laser diode to an output voltage control unit; the output voltage control unit, which obtains an error voltage between a reference voltage and the sensed output voltage of the laser diode and generates a control voltage by proportionally integrating the error voltage; and an optical power compensation unit, which receives the control voltage and generates a compensated control voltage by compensating for an optical power deviation on the photosensitive drum during the printing period.

Abstract: A halftone screen generating method includes growing dot centers into uniform binary patterns in an input image, calculating a main distance of each dot center, forming a screen filter by using the main distance, and generating the halftone screen by using the screen filter to form a binary image. The halftone screen generating method controls cluster dots to have a predetermined main distance, and improve a printing quality by growing dot centers uniformly.

Abstract: Provided are a method and apparatus for determining error diffusion coefficients.

Abstract: A print apparatus including a photoconductive drum, a laser scanning unit (LSU) to scan a surface of the photoconductive drum, and an image processing unit to generate and output dot size information corresponding to externally input image data. The dot size information determines sizes of individual dots on an image to be printed, a memory unit to store dot size compensation values related to a scanning distance of laser beams emitted from the LSU to the surface of the photoconductive drum to the LSU. The compensation values change the dot size information. The apparatus further includes a light intensity difference compensation unit to compensate for the dot size information according to the stored compensation values if the dot size information is received, and a pulse width modulation (PWM) unit to generate and output a pulse signal to control the scanning of the laser beams of the LSU according to the compensated dot size information.

Abstract: A method and apparatus enhances an image quality where original brightness data Xij of a concerned pixel is compared with predetermined brightness levels X1 and X2, which are reference variables to obtain new brightness data Yij, with an enhanced contrast. The method sets initial values of a parameter Vb to calculate the brightness level X1, a parameter Vp to calculate the brightness level X2, the brightness level X1, and the brightness level X2, and compares the brightness data Xij with Vb and Vp. The method resets Vb and Vp according to comparison results and identifies a background area according to the comparison results between the brightness data Xij and parameter X1 or X2, and performs the contrast enhancement on pixels belonging to the background area, and updates the brightness levels X1 and X2 using Vb and Vp when the concerned pixel is the last one in the concerned line.

Abstract: A method of and an apparatus for enhancing digital image quality. Input color data are transformed to obtain brightness data and chrominance data. The transformed brightness data is compared with predetermined brightness levels X1 and X2 on a pixel by pixel basis and the brightness data of each concerned pixel is reset or output without change according to the comparison. The comparison identifies the concerned pixel as belonging to one of a dark area and a light area requiring contrast enhancement and the brightness level of the concerned pixel is adjusted to provide the enhanced contrast. The obtained chrominance data and the reset brightness data are inversely transformed into corresponding color data. The predetermined brightness levels X1 and X2 are adaptively recomputed after a last pixel in a concerned line is considered for contrast enhancement.

Abstract: A halftone screen generating method includes growing dot centers into uniform binary patterns in an input image, calculating a main distance of each dot center, forming a screen filter by using the main distance, and generating the halftone screen by using the screen filter to form a binary image. The halftone screen generating method controls cluster dots to have a predetermined main distance, and improve a printing quality by growing dot centers uniformly.

Abstract: A color halftone screen generating method and a system thereof. The color halftone screen generating method includes determining a dot center of each of a plurality of channels arbitrarily, selecting a predetermined number of applicants in a sequence in which cost values are small for each channel by performing a mask operation for each channel, overlapping the determined dot centers of the channels and computing an overlap cost value using an overlap filter, and output selecting an applicant closest to a position having a minimum overlap cost value among overlap cost values of the applicants. The color halftone screen generating method and system can reduce a pattern of low frequency characteristics generated due to overlapping of color channels and improve quality of a binary output image by uniformly distributing overlapped cluster dots.

Abstract: 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.

Abstract: A method and apparatus for processing halftone by generating a first dot pattern corresponding to a first color and a second dot pattern corresponding to a second color for a video signal having at least two colors is provided. The method includes generating the first dot pattern by halftone processing the video signal using a first screen, and generating the second dot pattern by halftone processing the video signal using a second screen, which has a relationship of complement relative to the first screen.

Abstract: A method and apparatus to generate a preview image. The method of generating the preview image includes classifying data input from an application program by data types, performing a color matching operation that converts a first color signal of the input data into a second color signal used in a printing device according to one or more rendering intents set for the classified data types, and generating the preview image of the input data for which the color matching operation is completed. The preview image is generated based on the color-matched data for the different classified data types. Thus, the preview image appears to be substantially the same image as a document that is printed by an image forming device.

Abstract: Provided is a control system for controlling a plurality of function blocks. The control system includes a plurality of function blocks each including at least one function register; a central processing unit outputting a setting command to set a function register value of at least one of the plurality of function blocks; a setting controller receiving the setting command from the central processing unit to set the at least one function register of at least one of the plurality of function blocks to predetermined setting data according to the setting command; a memory storing the predetermined setting data of the at least one function register; and a bus supporting a data interchanging operation among the central processing unit, the memory, and the setting controller.

Abstract: 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.

Abstract: 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.

Abstract: A print apparatus including a photoconductive drum, a laser scanning unit (LSU) to scan a surface of the photoconductive drum, and an image processing unit to generate and output dot size information corresponding to externally input image data. The dot size information determines sizes of individual dots on an image to be printed, a memory unit to store dot size compensation values related to a scanning distance of laser beams emitted from the LSU to the surface of the photoconductive drum to the LSU. The compensation values change the dot size information. The apparatus further includes a light intensity difference compensation unit to compensate for the dot size information according to the stored compensation values if the dot size information is received, and a pulse width modulation (PWM) unit to generate and output a pulse signal to control the scanning of the laser beams of the LSU according to the compensated dot size information.