Canon Kabushiki Kaisha

Atsushi Ushiroda

Tomokazu Yanai

Hideki Kubo

Hitoshi Fukamachi

Hisashi Ishikawa

Hiroshi Tajika

Norihiro Kawatoko

Yuji Konno

Tetsuya Edamura

Osamu Yamada

Miyuki Fujita

Takayuki Ogasahara

Tetsuhiro Maeda

Katsumi Masaki

Yumi Watanabe

Takahiro Moro

Takafumi Sawaki

Atsuhiko Masuyama

Yoshihito Machida

Ken Onodera

This invention obtains a high-quality output image in which a jaggy or a disconnection of a thin line hardly stands out. An edge detection unit detects whether the pixel of interest is an edge pixel or a non-edge pixel. A screen processing unit performs screen processing for the pixel of interest to determine the output value of the N-level tone. A calculation unit performs filtering processing having a preset visual sense characteristic for an area including the pixel of interest to calculate the target value of the pixel of interest, and corrects the value of the pixel of interest so as to come close to the target value, thereby determining the output value of the N-level tone. The selector selects, according to the detection result by the edge detection unit, either the result from the calculation unit or that from the screen processing unit.

Image processing apparatus and control method for performing screen processing

In order to form a high-quality image, upon execution of multi-pass printing using a printing head with a plurality of nozzles, an image processing apparatus calculates, using a scan duty setting unit (), scan duty data for respective nozzles for each scan of the printing head in accordance with input image data. A halftone processor () generates a dot pattern to be formed by applying N-ary processing. The constraining condition information is set so that the phase of spatial frequencies of a next dot pattern to be generated has an opposite phase relationship in a low frequency region with respect to the already printed dot pattern.

Image processing apparatus, image forming apparatus, and control method thereof for printing based on constraining condition information

The image densities of images formed with a plurality of laser beams on the basis of image data are measured. The quantity of each of the plurality of laser beams is adjusted in accordance with the measurement result.

Image forming apparatus, control method therefor, and program

In order to form a high-quality image, upon execution of multi-pass printing using a printing head with a plurality of nozzles, an image processing apparatus calculates, using a scan duty setting unit, scan duty data for respective nozzles for each scan of the printing head in accordance with input image data. A halftone processor generates a dot pattern to be formed by applying N-ary processing based on predetermined constraining condition information to the calculated scan duty data. A constraining, condition information calculation unit generates constraining condition information to be referred to by the halftone processor at the time of the next scan. The constraining condition information is set so that the phase of a next dot pattern to be generated has an opposite phase relationship in a low frequency region with respect, to the already printed dot pattern.

Image processing apparatus, image forming apparatus, and control method thereof, which form an image by applying N-ary processing

In order to form a high-quality image, upon execution of multi-pass printing using a printing head with a plurality of nozzles, an image processing apparatus calculates, using a scan duty setting unit, scan duty data for respective nozzles for each scan of the printing head in accordance with input image data. A halftone processor generates a dot pattern to be formed by applying N-ary processing based on predetermined constraining condition information to the calculated scan duty data. A constraining condition information calculation unit generates constraining condition information to be referred to by the halftone processor at the time of the next scan. The constraining condition information is set so that the phase of a next dot pattern to be generated has an opposite phase relationship in a low frequency region with respect to the already printed dot pattern.

An image processing method for deciding the quantization data on each image plane of the image data composed of at least first and second image planes includes performing a quantization process for the sum total value of pixel values existing at the same position on the first and second image planes, using a first threshold, to decide a quantized value, and performing an arithmetical operation on the decided quantized value, the pixel value of any one of the first and second image planes and a second threshold, to generate the quantization data on each of the first and second image planes.

Image processing method and image processing apparatus

An image processing method matches the gradations of a first output unit and a second output unit which have different gradation-reproduction ranges. The image processing method sets first-output-unit information on the first output unit, sets output-medium information for use in the second output unit, and finds an output-gradation reproduction curve from the first-output-unit information and the output-medium information.

Image processing method and apparatus, and recording medium used therewith

Disclosed are an image processing apparatus and method in which it is possible to suppress density unevenness in the output of an image forming apparatus in a simple manner. A test image is printed out by a printer (), the printout is read by an image reading processing unit (), and an analyzing processing unit () detects the output characteristic (density unevenness, printing position deviation, etc.) of each of a plurality of print elements possessed by the printhead of the printer. A mask generating processing unit () generates a threshold-value mask which reflects the output characteristics detected by the analyzing processing unit and stores the mask in a mask memory (). A halftoning processing unit () outputs image data to the printer after the image data is subjected to halftoning utilizing the threshold-value map that has been stored in the mask memory.

Image processing apparatus and method for correcting print data so as to reduce density unevenness, and image forming system

An apparatus and method are provided to enable high speed printing of an image with high resolution while suppressing degradation of image quality due to white stripes and density variations. In an ink jet printing apparatus using a multi-pass printing system, the same scan print area is divided at a predetermined pitch and the printing duties of the divided areas determined by the thinning out mask pattern are set to different values. In regard to the same scan print area formed by a plurality of the main scans, the divided areas corresponding to the ends of the print head have their printing duties set smaller than those of the divided areas on the inner side of the ends of the print head.

Ink jet printing apparatus and ink jet printing method for forming an image on a print medium

Image processing method and apparatus for performing halftone conversion

As a thinning pattern which is used in a multipass recording method, plural mask patterns are created according to a printing mode from a pseudo periodic mask arrangement that an arrangement of non-recording pixels and recording pixels becomes visually preferable when binarization is performed at an arbitrary level. Thus, as compared with a mask pattern based on a random number, generation of a repetitive pattern and deterioration of graininess can be lowered, and the number of memories for storing the mask patterns can be reduced.

Image recording apparatus, image recording control method, and storage medium

A color ink-jet head, having plural arrays of nozzles side by side in a main scan direction corresponding to different color inks, is moved to scan reciprocally. In a multi-pass recording for divided recording on an area by scanning at plural times with the head, an ink firstly landed on recording of the area determines a prioritized color influential on the color tone. Moreover, a printing medium is largely covered by the recording of first two passes. A harmful influence on a whole image by the color irregularity can reduced by suppressing the color irregularity in the two passes, therefore, the data recording ratio of the first pass to the area is set smaller than that of the second pass and thereafter. Further, for such the control, a pseudo periodical masking data arranging record prohibiting pixels and record permitting pixels in a visually agreeable state is introduced.

Printing method, printing apparatus and printing system

An image processing apparatus of a digital copying machine, a digital facsimile, or a printer comprises an input unit to input multi-level data; an arithmetic operating circuit for adding error data to the input multi-level data and for calculating error correction data; a selector to select a predetermined dot pattern on the basis of the error correction data; an error calculation circuit to calculate a difference between the representative value for each dot pattern and the error correction data; a storage memory for storing the difference as error data into a memory; and a dot pattern memory in which dot patterns corresponding to a plurality of colors have been stored. The input unit inputs multi-level image data of a plurality of colors and the selector selects the dot pattern whose dot arrangement differs in accordance with the color of the multi-level image data.

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Kawasaki, Japan

Atsushi Ushiroda