Abstract: Halftone generating methods and systems convert continuous tone anti-aliased image data to halftone image data using halftoning techniques that efficiently use memory resources. One of a plurality of Holladay counters is selected and the address bits from the selected Holladay counter are output to a look-up table that efficiently stores various halftone screens. Halftone image data is then output. If necessary, the halftone image data is unpacked and replicated as required depending on the resolution requirements of the halftone screen.

Abstract: The invention generates a page description language compliant data stream, that has been pre-designed and pre-processed to create unique and predictable page element ordering, overlay layout, and for splitting large page elements into multiple independent elements. In this way, multiple processors can be used to render the document without merging the data stream.

Abstract: There is disclosed in embodiments methods relating to the compression of printing hints. The method in embodiments generates a first set of image pixels having corresponding printing hints. The printing hints are then adjusted to produce a second set of image pixels processed in such a way that an end printed result is visually equivalent to a printed result using the first set of image pixels thereby reducing the entropy in the printing hints. The method improves the compression ratio of an image using printing hints by adjusting the printing hints of pixels that are zero or fully saturated. The printing hints are adjusted in such a way to reduce the complexity of the printing hints.

Abstract: A toner process control process, which includes substantially predicting an effect of reload error on a developed test patch, generating a developed test patch, sensing color density data from the test patch with a sensor, altering the sensed color density data to compensate for the predicted effect of reload error, and adjusting toner output according to the altered sensed color density data.

Abstract: A toner process control process, which includes substantially predicting an effect of reload error on a developed test patch, generating a developed test patch, sensing color density data from the test patch with a sensor, altering the sensed color density data to compensate for the predicted effect of reload error, and adjusting toner output according to the altered sensed color density data.

Abstract: A method for improving the image quality, which includes substantially predicting an effect of reload error for at least one toner color of a developed image, modulating the color density of at least one pixel of a digital image to compensate for the predicted effect of the reload error, generating the developed image based upon the modulated digital image.

Abstract: A toner control process, which includes substantially determining how reload error will affect a printed image, modulating the color density of a test patch to compensate for reload error prior to printing the test patch, printing the modulated test patch, sensing the digital image, adjusting toner output according to the sensed digital image.

Abstract: A toner control process, which includes substantially determining how reload error will affect a printed image, modulating the color density of a test patch to compensate for reload error prior to printing the test patch, printing the modulated test patch, sensing the digital image, adjusting toner output according to the sensed digital image.

Abstract: A system and method for printer control and color balance calibration. The system and method address the image quality problems of print engine instability, low quality of color balance and contouring from the calibration. The method includes defining combinations of colorants, such as inks or toners that will be used to print images, defining a desired response for the combinations that are to be used and, in real time, iteratively printing CMY halftone color patches, measuring the printed patches via an in situ sensor and iteratively performing color-balance calibration based on the measurements, accumulating corrections until the measurements are within a predetermined proximity of the desired response. The calibration is performed on the halftones while they are in a high quantization resolution form.

Abstract: An apparatus and method that provide consistent output across a plurality of different hard copy output devices which may be included in a system comprising an image data source and a hard copy output device. The image data source supplies image data to a printable image data adjusting apparatus. The image data supplied may be in a device-dependent color space or a device-independent color space. If the image data is in a device-dependent color space, the printable image data adjusting apparatus first converts the image data into device-independent image data and stores it in memory as target image data. If the image data is already device-independent image data, the image data are simply stored in the memory of the printable image data adjusting apparatus as target image data. The printable image data adjusting apparatus then uses the target image data to generate printable image data. The hard copy output device uses the printable image data to generate a hard copy image.

Abstract: A method and apparatus for compressing and decompressing electronic documents, with maximum intradocument independence, and maximum flexibility in optimization of compression modes. The method includes receiving documents containing unknown combinations of a plural data types, including combinations of scanned data, computer rendered data, compressed data and/or rendering tags; dividing the received image into strips of blocks determining from the image itself, which data types are present in each block; compressing data of each data type present in each block with a compression method optimized for its data type. Scanned data may be further segmented into plural scanned data types, where each data type is compressed in said compressing data step with a compression method optimized for said scanned image data type.

Abstract: In an image rendering system, a method of compensating for system performance changes related to image attributes includes rendering a diagnostic image, sensing at least one image quality from the diagnostic image, updating an image attribute compensation tone reproduction curve based on the sensed image quality and rendering an image based on the updated image attribute compensation tone reproduction curve. For example, image attributes include print media type and a halftone screen selection. An image processing system operative to perform the method of compensation includes a set of image attribute compensation tone reproduction curves. Each curve of the set is associated with a particular combination of image attributes. For example, each curve is associated with a particular media type/halftone screen combination.

Abstract: A halftone cell is composed of a plurality of pixel groupings predefined to correspond to optimal tone level gradations. Selected output pixel groupings vary in number, and in shape of subpixels used from other pixel groupings, in order that successive input levels correspond to successive halftone cells defining substantially equal changes in a measured darkness value. Tone level gradations are optimized by purposeful correlation of input levels to output levels, especially where the number of output levels exceeds the number of input levels. During optimization, a calibration sample is produced by the image output device and calibration elements are empirically measured. Darkness change between successive levels is calculated and compared. Where the percentage of darkness change exceeds a desired amount, additional calibration elements are produced until the change calculated between successive levels is substantially the same.

Abstract: Halftone generating methods and systems convert continuous tone anti-aliased image data to halftone image data using halftoning techniques that efficiently use memory resources. One of a plurality of Holladay counters is selected and the address bits from the selected Holladay counter are output to a look-up table that efficiently stores various halftone screens. Halftone image data is then output. If necessary, the halftone image data is unpacked and replicated as required depending on the resolution requirements of the halftone screen.

Abstract: Shifting a page image while it is still in compressed form. The page image is compressed into independent strips that are a full page in the fast scan direction, and a small number of scanlines in the slow scan direction. Then, to shift the page image, whole strips can be deleted in one margin and/or deleted from the other. If the number of scanlines per strip is small enough, the difference in a margin created by the change of one strip will not be apparent. This invention can be used to advantage when it is decided at print time that the output shall be in the form of a saddle-stitched booklet requiring two-up printing, folding and subsequent trimming of the outside edges to uniform alignment. Here, a progressive page shift can be introduced at the printer controller while the images are still compressed, instead of requiring the change to be done to the PostScript Master, which would require reRiPing or decompression, shift and recompression.

Abstract: An improved technique for compressing a color or gray scale pixel map representing a document using an MRC format including a method of segmenting an original pixel map into two planes, and then compressing the data or each plane in an efficient manner. The image is segmented such that pixels that compress well under a lossy compression technique are placed on one plane and pixels that must be compressed losslessly are placed on another plane. Lossy compression is then applied to the lossy pixel plane while lossless compression is applied to the lossless pixel plane.

Abstract: A method and apparatus for compressing and decompressing electronic documents, with maximum intradocument independence, and maximum flexibility in optimization of compression modes. The method includes receiving documents containing unknown combinations of a plural data types, including combinations of scanned data, computer rendered data, compressed data and/or rendering tags; dividing the received image into strips of blocks determining from the image itself, which data types are present in each block; compressing data of each data type present in each block with a compression method optimized for its data type. Scanned data may be further segmented into plural scanned data types, where each data type is compressed in said compressing data step with a compression method optimized for said scanned image data type.

Abstract: A digital image reproducing apparatus, such as a copier, facsimile machine, or a scanner includes a code detector which analyzes a digital representation of an input document, either directly or in memory for visually apparent machine readable code embedded in the background of the document. A decoder operatively connected with the detector analyzes the machine readable code and determines a security code associated with the original document. A control unit compares the security code from the document with a user authorization or security code and, based on the comparison determines whether to allow or disallow the digitized document to be reproduced. If the document is allowed to be reproduced, an image reproducing system, under the control of the control unit, reproduces the document including any image on the document and the low density tinted background containing the machine readable code.

Abstract: The present invention is a method for antialiased rendering (AAR) of an image. First, tagging methods for identifying antialiased pixels were described, the methods being employed separately or in concert with one another. After identifying AAR pixels, a fill order is determined and applied using a fill order algorithm that preferably employs a pixel window that is a subset of the larger window employed for pixel identification.

Abstract: The present invention is a method for antialiased tagging (AAT) applied coincident with an antialiasing operation. First, tagging methods for identifying antialiased pixels are described, the methods being employed separately or in concert with one another and focusing on pixels having a plurality of neighboring pixels that are near the extremes of the range of pixel levels (e.g. saturation and background). After tagging antialiased pixels, a preferred rendering method is optionally determined and is optionally included with the antialiased tagging information. Once tagged, said tag including the preferred rendering method, the pixel data and tag are then passed to a rendering processor and placed into a form suitable for binary printing.