Abstract: A method for calibrating and converting colors of a digital image into printer specific colorant control values is disclosed. This method comprises the steps of calibrating a specific printer of a printer type according to a printer type specific procedure, wherein for each colorant separately a one-dimensional relationship between a printer tone value and a colorant control value is established; profiling the printer type to establish an output profile that defines a relationship between color values in a profile connecting color space and the printer tone values; deriving from the input profile and the output profile a one-dimensional relationship between a black channel and the black printer tone value of the printer; determining if an image color value is to be converted either by using the profiles or by using the one-dimensional relation; converting the image color value and subsequently using the printer calibration relations to obtain the colorant control values.

Abstract: A method for calibrating and converting colors of a digital image into printer specific colorant control values is disclosed. This method comprises the steps of calibrating a specific printer of a printer type according to a printer type specific procedure, wherein for each colorant separately a one-dimensional relationship between a printer tone value and a colorant control value is established; profiling the printer type to establish an output profile that defines a relationship between color values in a profile connecting color space and the printer tone values; deriving from the input profile and the output profile a one-dimensional relationship between a black channel and the black printer tone value of the printer; determining if an image color value is to be converted either by using the profiles or by using the one-dimensional relation; converting the image color value and subsequently using the printer calibration relations to obtain the colorant control values.

Abstract: A method for processing with a document processing system is provided. The method includes generating a sheet assembly by executing a production route model of at least one function leading to a plurality of actions, the sheet assembly including a set of transitions that result from invocation of the plurality of actions, extracting from the sheet assembly a document imposition recipe including a set of imposition descriptions generated by computing transformations and parameters for each transition performed on the sheet assembly, and rendering the imposition descriptions of the document imposition recipe on behalf of at least one source file in order to deliver impositions in a source format describing at least placement of content of pages of the source file and action marks for subsequent displaying of the impositions on a user interface of the document processing system and/or for subsequent processing on the at least one printer and/or an the at least one finisher.

Abstract: A method for processing with a document processing system is provided. The method includes generating a sheet assembly by executing a production route model of at least one function leading to a plurality of actions, the sheet assembly including a set of transitions that result from invocation of the plurality of actions, extracting from the sheet assembly a document imposition recipe including a set of imposition descriptions generated by computing transformations and parameters for each transition performed on the sheet assembly, and rendering the imposition descriptions of the document imposition recipe on behalf of at least one source file in order to deliver impositions in a source format describing at least placement of content of pages of the source file and action marks for subsequent displaying of the impositions on a user interface of the document processing system and/or for subsequent processing on the at least one printer and/or an the at least one finisher.

Abstract: A method for making a color transform for an output device is provided. The color transform represents a correspondence relation between a first and a second color space. Each of the two color spaces involves a number of color channels and the color channels of the second color space control the colorants in the output device. An excess relation for the color channels of the color space associated with the output device is established and only color points in the second color space wherefor a sum of the excess values related to the color point is lower than a predetermined limit, are included in the color transform. This enables to adapt the shape of a color gamut to a behavior of the colorants and enhances the flexibility in making a color transform for various print processes.

Abstract: A method for making a color transform for an output device is provided. The color transform represents a correspondence relation between a first and a second color space. Each of the two color spaces involves a number of color channels and the color channels of the second color space control the colorants in the output device. An excess relation for the color channels of the color space associated with the output device is established and only color points in the second color space wherefor a sum of the excess values related to the color point is lower than a predetermined limit, are included in the color transform. This enables to adapt the shape of a color gamut to a behaviour of the colorants and enhances the flexibility in making a color transform for various print processes.

Abstract: A color management method, wherein a Graphics Processing Unit (GPU) is used for converting colors from a source device color space to an output device color space in accordance with predetermined color profiles of the source and output devices. The method includes the steps of storing, in the GPU, an at least three-dimensional conversion texture that specifies a color conversion table; loading input color data into the GPU; sampling the conversion texture at a position specified by the input color data, thereby to identify output color data; and outputting the output color data.

Abstract: A method of compressing and decompressing digital data that is especially suitable for halftoned image data in which every bit represents the marking of a receiving material by ink or toner is provided. The method is lossless and balances the use of memory, the processing time, the compression factor and the cost of hardware resources. The recurrence of data in halftoned images on which the smaller data size of the compressed data is based, is caused by the use of a halftone dither matrix. Various halftone dither matrices may be used in the halftoned image. The method is adapted to employ the characteristics of a specific halftone dither matrix by applying a dynamic set of offset values, in which an offset value represents a number of words between the current word of digital data and an identical, previously processed word.

Abstract: A method for processing pixels in rasterized image data includes a combination of text and photographic content. Each pixel having a discrete color value, a surround value based on the number of neighboring pixels having the same color value is determined. A division in blocks of two by two pixels is made and a critical number is determined based on the number of surround values lower than a predetermined threshold. This critical number has one of five possible values. Based on this critical number, a discrimination is made between noisy blocks, and flat blocks. The color values of pixels within a noisy block are replaced by an average of the color values of the pixels within the noisy block. For image data rasterized with 600 pixels per inch, this method does not deteriorate the image quality of text nor photographic content. The image data are more apt for lossless compression.

Abstract: A method for processing pixels in rasterized image data includes a combination of text and photographic content. Each pixel having a discrete color value, a surround value based on the number of neighboring pixels having the same color value is determined. A division in blocks of two by two pixels is made and a critical number is determined based on the number of surround values lower than a predetermined threshold. This critical number has one of five possible values. Based on this critical number, a discrimination is made between noisy blocks, and flat blocks. The color values of pixels within a noisy block are replaced by an average of the color values of the pixels within the noisy block. For image data rasterized with 600 pixels per inch, this method does not deteriorate the image quality of text nor photographic content. The image data are more apt for lossless compression.

Abstract: A method compresses a digital continuous tone image of pixels situated on scan lines. The method includes the steps of, for a current pixel to be encoded, said current pixel having an actual pixel value, predicting a predicted pixel value based on pixel values of at least one previously processed pixel from the same image, using a fixed rule, determining a difference parameter based on a difference value of said predicted pixel value and the actual pixel value of said current pixel to be encoded, and inspecting the difference parameter for existence of an uninterrupted series of highest order bits having a value equal to zero, removing at least part of said highest order zero bits, and, if a number of bits within predetermined limits remains, generating a compression code having a predetermined fixed length, said code indicating the number of remaining bits.

Abstract: A method of creating a printable raster image file from a PDL file, including interpreting the PDL file, thereby to create a display list; and applying raster image processing to the display list, thereby to create the printable raster image file in four separation colours (C, M, Y, K), wherein the raster image processing is performed in a Graphics Processing Unit (GPU) having three colour channels (R, G, B) and an alpha channel (A) for transparency, and the three colour channels and the alpha channel are mapped onto the four separation colours (C, M, Y, K).

Abstract: A method of compressing and decompressing digital data that is especially suitable for halftoned image data in which every bit represents the marking of a receiving material by ink or toner is provided. The method is lossless and balances the use of memory, the processing time, the compression factor and the cost of hardware resources. The recurrence of data in halftoned images on which the smaller data size of the compressed data is based, is caused by the use of a halftone dither matrix. Various halftone dither matrices may be used in the halftoned image. The method is adapted to employ the characteristics of a specific halftone dither matrix by applying a dynamic set of offset values, in which an offset value represents a number of words between the current word of digital data and an identical, previously processed word.

Abstract: A color management method, wherein a Graphics Processing Unit (GPU) is used for converting colors from a source device color space to an output device color space in accordance with predetermined color profiles of the source and output devices. The method includes the steps of storing, in the GPU, an at least three-dimensional conversion texture that specifies a color conversion table; loading input color data into the GPU; sampling the conversion texture at a position specified by the input color data, thereby to identify output color data; and outputting the output color data.

Abstract: A method compresses a digital continuous tone image of pixels situated on scan lines. The method includes the steps of, for a current pixel to be encoded, said current pixel having an actual pixel value, predicting a predicted pixel value based on pixel values of at least one previously processed pixel from the same image, using a fixed rule, determining a difference parameter based on a difference value of said predicted pixel value and the actual pixel value of said current pixel to be encoded, and inspecting the difference parameter for existence of an uninterrupted series of highest order bits having a value equal to zero, removing at least part of said highest order zero bits, and, if a number of bits within predetermined limits remains, generating a compression code having a predetermined fixed length, said code indicating the number of remaining bits.

Abstract: A method and apparatus that convert a series of drawing instructions, suitable for assigning pixel values corresponding to the drawing instructions to an image arranged in rows and columns of pixels, to a series of runlengths and corresponding pixel values. A runlength represents the number of successive pixels with mutual identical pixel values while the series of runlengths and pixel values is arranged according to a first order as determined by successive pixel positions. The runlengths of the pixel values (as generated by the drawing instructions) are determined in a second order which is different from the first order. Consequently, the insert positions of these runlengths are determined on the basis of pixel positions which correspond with said determined runlengths.

Abstract: Image data in outline form is automatically converted into a bit map for a reproduction means, using the half bitting effect for more accurate positioning of image boundaries. The pixels are divided up into strips each associated with an effective boundary line position and a half bit pattern by means of which the effective boundary line position can be reached. These strips are so selected that a point within the strip is situated closer to the associated effective boundary line position than to the pixel boundary or to another effective boundary line position. For pixels which are intersected by the outline, a check is made as to whether the outline extends entirely within such a strip and the pixels which satisfy this condition are given a value in accordance with the associated half bit pattern if they are flanked by at least one other pixel satisfying the same condition.

Abstract: Digital image data containing binary pixel values are reproduced, without any loss of detail, by a reproduction unit, such as a laser printer, having a lower base resolution than the resolution of the image data, by subjecting the image data to a resolution conversion, the resolution being reduced in one direction, to a value corresponding to the resolution of the reproduction unit, and enlarged in the remaining direction.

Abstract: Boundaries between colored and uncolored image parts are reproduced on a pixel raster by determining a binary value ("colored" or "uncolored"), proceeding along a boundary, for adjoining pixels intersected by said boundary, said value being determined on the basis of the situation of said pixel with respect to the boundary and a carried-forward correction value. On the basis of the situation of said pixel with respect to the boundary a fractional value is calculated which is then rounded off to a binary pixel value. The rounding-off error made in such cases is processed using a prevention function for preventing allocating such binary values to the boundary pixels that visible bulges are formed on the boundary and is then carried-forward to the next pixel and included in the fractional value thereof. Instances of such prevention functions are described. This procedure gives a better reproduction of lines extending obliquely over the pixel raster.