Abstract: An apparatus and a method for making a digital color proof of an image on a surface of a receiving substrate, the apparatus including a plurality of application stations for imagewise applying each a specific type of marking particles to the surface of the receiving substrate, the application stations including a first number N1 of first application stations for applying marking particles of a first, dominant color and a second number N2 of one or more second application stations for applying marking particles of a second, non-dominant color, wherein N1 is larger than N2.

Abstract: In the image drawing apparatus, a drawing position last time is stored in advance in a drawing position memory section, and a linear complementing processing section specifies pixels to be complemented from the last drawing position stored in the drawing position memory section and a drawing this time, and calculates semi-transparent rates of the pixels specified. A semi-transparency processing section then calculates pixel values of the pixels to be complemented by using the calculated semi-transparent rates. Therefore, anti-aliasing processing can be carried out at a high speed.

Abstract: A system and method descreen halftone images into a continuous tone image while preserving edge detail and reducing initial image blur. The descreening can be applied to monochrome or color images. Descreening is achieved by first using a low pass filter to form a blurred image of the original, which is used to guide future image filtering, but which further filtering is applied to the original image. The intelligent filtering is provided by a Sigma filter, which can be performed in a single iteration and sized and shaped according to values of the blurred image. The system and method can take a block-oriented approach that performs analysis for an entire block of pixels rather than on individual pixels. This further improves the implementation speed of the process.

Abstract: An image reading apparatus including a light source for illuminating an original, a white member which is illuminated by the light emitted from the light source, a photoelectric converting element for receiving the reflection light from the original and the reflection light from the white member, a memory for storing a reference output of the photoelectric converting element which is obtained by receiving the reflection light from the white member, a shading compensation device for compensating an output of the photoelectric converting element which is obtained by receiving the reflection light from the original in accordance with the reference output, and a rewriting device for rewriting the reference output to be stored in the memory, wherein the rewriting device rewrites the reference output at a timing according to a fluctuation in light amount of the light source.

Abstract: A digital image processing method for adaptively sub-sampling an image to X % of original pixels, includes the steps of generating an edge map of the image; normalizing the edge map to N-bits; applying a shift to the normalized edge map such that X % of the pixels will be ones when the normalized shifted edge map is halftoned using a blue noise halftoning technique; halftoning the edge map using the blue noise halftoning technique to generate a halftone mask; and sub-sampling the image at the pixel locations represented by ones in the halftone mask.

Abstract: In order to efficiently output image data having superior image quality in comparison with that of an image development process dependent on a single development process resource, PDL data based on a plurality of page description languages is received from an external host computer via a host I/F. A CPU determines whether the image information in the PDL data is color image information or monochrome image information. A first development process, which is most suitable for color image information, and a second development process, which is most suitable for monochrome image information, are performed in a parallel manner. The developed color image information and monochrome image information are merged in a frame memory and are output to a color copier.

Abstract: A raster image processing system (20) for producing the appropriate number and set of halftoned color separations for a select output device (24) is disclosed. The raster image processing system (20) includes a processing unit (30), an interpreter (32) and a color combiner (34). The interpreter (32) and color combiner (34) are application processes that are controlled by software running on the processing unit (30). The processing unit (30) identifies the number and set of colorants used to describe input image data and the number and set of halftoned color separations that a select output imaging device (24) is capable of rendering. The interpreter (32) converts the input data describing an image that is composed of “N” colorants into “N” halftoned color separations. The color combiner (34) thereafter converts the N halftoned color separations into “M” halftoned color separations that are ideally suited for the particular output device (24) chosen by a user of the system.

Abstract: Disclosed are two novel techniques for digital color halftoning with green-noise stochastic dither patterns generated by homogeneously distributing minority pixel clusters. The first technique employs error diffusion with output-dependent feedback such that the overlapping of pixels of different colors can be regulated for increased color control. The second technique uses a green-noise mask which is a dither array designed to create green-noise halftone patterns. The green-noise mask is constructed to also regulate the overlapping of different colored pixels. As is the case with monochrome image halftoning, both techniques are tunable, allowing for large clusters in printers with high dot-gain characteristics, and small clusters in printers with low dot-gain characteristics.

Abstract: An image for adjusting a tone curve includes an overall tone curve image including a tone curve of dot gains in a predetermined full scale with respect to all input image gradation values of image data, and an enlarged tone curve image including a tone curve of enlarged dot gains in a full scale, smaller than the predetermined full scale, which represent a highlight area of gradations which is part of the entire tone curve. The user can finely adjust and correct the tone curve in the highlight area while viewing the overall tone curve.

Abstract: A method for representing a digital image in a plurality of image processing states using at least one reference digital image and at least one residual image comprising the steps of manipulating an input digital image using at least one digital image processing enhancement step to form at least one additional digital image in a different image processing state; designating at least one of the digital images to be a reference digital image in a reference image processing state; and determining at least one residual image representing differences between one of the reference digital images and one of the additional digital images, whereby the residual image(s) and the reference digital image(s) can be used to form digital image(s) in different image processing states.

Abstract: A printer has a spreading unit 1 for spreading data sent from an upper apparatus into bit map data, a memory unit 2 for storing the bit map data spread by the spreading unit 1, an extracting unit 3 for extracting a contour-protecting shaped matrix which prevents the disappearance of a contour of an image, and a printing unit 7 which stores template data and a toner consumption saving pattern and which prints dot data of the bit map data based on a shape of the contour-protecting shaped matrix. The extracted matrix data are compared with the template data. When the matrix data corresponds with the template data, a noted pixel positioned in a central portion of the matrix is replaced with the toner consumption saving pattern. Accordingly, numbers of black dots can be decreased in a part of image data to save toner consumption in the printer.

Abstract: An image input device identifies what part of the optical input system needs cleaning when there is dust or other foreign matter in the optical input system. This image input device has an image noise position detector for capturing image data from a scanner, and detecting the main scanning address of noise information corresponding to image noise present in the image data; a focus calculator for calculating focus information around the main scanning address detected by the image noise position detector; focus information storage for storing focus information for each subscanning line; and a foreign matter position determining circuit for determining the location of foreign matter on the scanner based on the focus information stored in the focus information storage.

Abstract: An image forming apparatus adds a plurality of dots of image date in the subscanning direction and starts generating a density from a particular pixel, and switches PWM (Pulse Width Modulation) right and left phases in order to concentrate potentials and to increase a saturation region. It is therefore possible to stabilize image density in a highlight portion and therefore realize high quality images, while reducing banding and image noise.

Abstract: There is provided an image forming apparatus that enables the formation of high-quality multi-level images by ensuring that the size of blocks into which the image is to be divided is specified in accordance with the resolution of the image to be recorded. The apparatus divides input image gradation level data into a plurality of blocks and performs graduated recording by converting the divided image gradation level data into multi-level recording data in accordance with gradation conversion characteristics determined as keyed to relative positions in each of the blocks; the blocks are typically set to a size satisfying the following relation: (55/n)<X/p<(65/n), provided p is an integral multiple of 10; where X is the resolution of the image to be recorded in a given direction and expressed in dpi, p is the length of each block in said given direction and expressed in dots, and n is a natural number.

Abstract: A synthesized image is formed by synthesizing a main image and a background mage represented by respective image data items each having n-valued gradation values each having any one of n possible values(n is an integer which is equal to or larger than 3) and defining a density of pixels. A plurality of different data items representative of candidates for the background image are stored as background image data candidates. An arbitrary one of the background image data candidates is set to a background image data item representative of the background image. There is formed a main image data item forming a main image data item representative of the main image, the main image data item having n-valued main image gradation values commonly applied to all valid pixels of the main image, as values of the n-value gradation values.

Abstract: The exposure control device has a line sensor sensing image data corresponding to a color image recorded in a negative film. The line sensor is exposed using first, second and third exposure times so that image data are obtained for each of the exposure times. Histograms, representing a distribution of pixel values of the each of image data, are generated for each of the exposure times. Regarding each of the histograms, maximum effective values are obtained. A first histogram, in which the maximum effective value is the greatest, is selected. The optimum exposure time is calculated, based on the maximum effective value (Hr2D) of the first histogram and the maximum effective value (Hr1D) of the second histogram which corresponds to image data, obtained by an exposure time which is subsequently shorter than the exposure time of the first histogram.

Abstract: A method for enhancing printing quality to process the picture and textual data in an image properly such that both the picture and textual data can be clearly printed. The inventive method can treat the image data to be printed in a real time fashion and while the entire image data is not required. In the inventive method, the difference of gray level is reallocated by error diffusion method to render the edge more smooth and clear.

Abstract: In a method for operating an engraving member in an electronic engraving machine to engrave printing forms, especially printing cylinders for intaglio printing, a stylus of the engraving member is controlled by an engraving signal and engraves a sequence of cups arranged in a gravure screen in the rotating printing cylinder. The engraving signal is formed by superimposing the image signal representing the tone gradations to be engraved. In order to obtain good quality engraving, the engraving member is heated to a temperature that is close to operating temperature before engraving starts and/or during an interruption of engraving. For this purpose, the engraving member is driven with a periodic signal whose frequency is preferably located inside the ultrasonic range in order to avoid noise disturbances.

Abstract: A de-blocking method and apparatus in which a block classifier determines whether the received decoded image is a planar surface or a complex surface. A first correction value calculator calculates correction values for block boundary pixels using a first filtering coefficient when the decoded image is a planar surface, an interpolator provides first correction values for pixels on the block boundary, and a second correction value calculator calculates second correction values for some block boundary pixels using a second filtering coefficient when the decoded image is a complex surface. A corrector provides a corrected image by correcting the received decoded image using the first correction values when the received decoded image is a planar surface, or using the second correction values when the received decoded image is a complex surface.

Abstract: A method for processing digital images to be displayed, stored, or printed, to eliminate blooming and other artifacts. The system utilizes morphological processes to isolate and modify image structures susceptible to marking process artifacts and then combines the modified image structures with the input image to produce a printable image that may be rendered on a given printer.