Abstract: 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.

Abstract: 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 (105), scan duty data for respective nozzles for each scan of the printing head in accordance with input image data. A halftone processor (108) 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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 (105), scan duty data for respective nozzles for each scan of the printing head in accordance with input image data. A halftone processor (108) 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 (111) generates constraining condition information to be referred to by the halftone processor (108) 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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 (105), scan duty data for respective nozzles for each scan of the printing head in accordance with input image data. A halftone processor (108) 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 (111) generates constraining condition information to be referred to by the halftone processor (108) 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.

Abstract: 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 (105), scan duty data for respective nozzles for each scan of the printing head in accordance with input image data. A halftone processor (108) 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.

Abstract: 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.

Abstract: 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.

Abstract: 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 (13), the printout is read by an image reading processing unit (10), and an analyzing processing unit (17) 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 (11) generates a threshold-value mask which reflects the output characteristics detected by the analyzing processing unit and stores the mask in a mask memory (15). A halftoning processing unit (12) 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: From a first threshold mask having threshold values corresponding to the number of gray levels, which is larger than that of an input image, a second threshold mask having threshold values corresponding to the number of gray levels, which is equal to that of an input image, is generated on the basis of tone reproduction characteristics corresponding to the type of paper used in a printer or the printer state. Using the generated second threshold mask, the number of gray levels of the input image is converted, and the converted image is output to an output apparatus. In this manner, a high-quality image can be output by making halftone conversion corresponding to the tone reproduction characteristics of the output apparatus by a small memory size without decreasing the number of gray levels of the input image.