Abstract: A gamut judging apparatus of the present invention has source color distance calculator 1 that calculates the length of a source color vector connecting a source color as an object to judge whether the source color is in or out of gamut of a device and a center color set in the gamut, gamut distance calculator 3 that calculates a gamut distance between the center color and an intersection at which the source color vector or an extended source color vector intersects a gamut boundary of the device, and a judging section that judges that the source color is out of the gamut of the device when the length of the source color vector is larger than the gamut distance, and judges that the source color is in the gamut of the device when the length of the source color vector is smaller than the gamut distance.

Abstract: A method and apparatus of converting a first color value as determined by first color co-ordinates in a color space defined by color parameters the first color co-ordinates being situated outside a boundary of a predetermined color range situated in the color space, to a second color value determined by second color co-ordinates in the color space, the second color co-ordinates being situated on said boundary of the color range. To this end, the method includes determining, in dependence on the distance of the first color co-ordinates from the boundary, an extended part of the boundary of the color range and establishing the second color co-ordinates on the basis of said extended part of the boundary. In one embodiment, the extended part of the boundary is determined by the boundary part situated between a first and second distance range from the first color co-ordinates and the second color co-ordinates are determined by the average of the color co-ordinates situated in that part of the boundary.

Abstract: A halftone gradation processing method reduces or eliminates the discontinuous gradation reproduction in comparison with conventional error diffusion. A halftone gradation processing method includes obtaining a position and a pixel value of a target pixel in an input image, correcting the pixel value, selecting the closest threshold to the corrected pixel value from among usable thresholds assignable to the pixel value, calculating an error between the corrected pixel value and the selected threshold, and diffusing the error around the target pixel, the pixel value correcting being corrected by the diffused error, and the selected threshold being output to an output device which may handle the assigned thresholds.

Abstract: In a method for processing signals in an electronic engraving machine for engraving printing forms, in particular printing cylinders used for rotogravure, an engraving control signal is obtained by superimposing engraving data, representing tone values between “white” and “black” which are to be engraved, with a periodic screen signal for generating a gravure screen. The engraving control signal guides the lifting movement of the stylus of an engraving element. As a result of the lifting movement of the stylus, a series of cups arranged in the gravure screen is engraved on the printing form. To compensate an incorrect lifting movement of the stylus (rebound effect, lag effect), the engraving data undergo digital filtering before superposition of the gravure screen.

Abstract: Prioritizing a printing system's basic processing resources includes providing a job contention manager (JCM) that adds a first basic job resource to queues of each basic resource which a first video capability requires to perform a first sub-job. The first basic job resources are ready for processing if they are at the top of all of the queues, of all the basic resources, required by the first video capability. The JCM adds a second basic job resource sub-job to queues of each basic resource which a second video capability requires to perform the first sub-job. The second basic job resources, are ready for processing after the first basic job resource, if the first and second basic job resources in the queue are submitted by the same job service and if the second basic job resource is for the same sub-job as the first basic job resource's sub-job.

Abstract: A system for simulating grayscales in a digital printer, such as an ink-jet printer, exploits a modified error diffusion technique. When a datum for a particular pixel in an image is 0, the datum is substituted with a low-level artificial datum such as 4 on a scale from 0 to 255. The addition of the artificial datum in the error diffusion algorithm avoids artifacts caused by the presence of large number of zeros in the error diffusion algorithm.

Abstract: A method for improving the quality of arbitrary digital images with an input pixel window having an input pixel is provided to calculate variation in the pixel window, compare the variation in the pixel window to a predetermined threshold value, and process the input pixel based upon the comparison.

Abstract: By using negative feedback, moiré patterns can be reduced, or virtually eliminated, from input black-and-white or color original images. In particular, by feeding back an image containing the difference between the original input image and the halftone output with possible moiré patterns, and subtracting the low-frequency part of this image from the original input image, a resultant halftone image can be achieved that has reduced moiré patterns.

Abstract: A shading correction apparatus can execute a first method of adding and averaging, in the sub-scanning direction, shading data obtained by reading a white reference plate in the main scanning direction and in the sub-scanning direction to obtain correction data to be used for shading correction and a second method of directly using shading data obtained by reading the white reference plate in the main scanning direction as correction data for shading correction. When the white reference plate is pre-scanned by an image sensor, and the minimum value of the obtained shading data is equal to or smaller than a predetermined value, the first method is selected. When the minimum value exceeds the predetermined value, the second method is selected.