Abstract: An annular window-shaped structuring element is provided for image processing to remove speckles from a scanned image. The window-shaped structuring element is composed of two differently sized squares sharing the same geometric center-point. The pixel to be analyzed with the structuring element is at the center-point. The structuring element is used in a method to remove speckles from binary, grayscale, and/or color images by first eroding the image, detecting speckles relative to other pixels in the image, and removing declared speckles. The method may additionally include a halftoning module to protect halftone images.

Abstract: A digital image processing system for automatically segmenting a set of input image signals into a combination of predetermined classes of imagery, the set of input image signals forming part of a video image generated by an image input terminal. The system includes a classification circuit that receives the set of input image signals and classifies them as a ratio of the predetermined classes of imagery. A plurality of image processing circuits also receives the set of input image signals, each of which is adapted to process a unique class of imagery selected from the predetermined classes of imagery to generate a set of output image signals for that predetermined class of imagery.

Abstract: A process for color graphics image processing, related to detection and segmentation of sweeps, is provided. An input graphics image is transformed into a three-dimensional histogram in an appropriate color space 104 (e.g., CIELUV). Two-dimensional histograms are estimated from the three-dimensional histogram 106. The two-dimensional histograms are processed to detect and segment sweeps 108. Sweep segment information from the processing of the two-dimensional histograms is combined 110. The combined sweep segment information is used to process the input graphics image to identify and segment sweeps 112. Post-processing may be optionally and selectively used to reject false alarms (i.e., areas falsely identified as sweeps) 114.

Abstract: A method and system for image processing, in conjunction with classification of images between natural pictures and synthetic graphics, using SGLD texture (e.g., variance, bias, skewness, and fitness), color discreteness (e.g., R_L, R_U, and R_V normalized histograms), or edge features (e.g., pixels per detected edge, horizontal edges, and vertical edges) is provided. In another embodiment, a picture/graphics classifier using combinations of SGLD texture, color discreteness, and edge features is provided. In still another embodiment, a “soft” image classifier using combinations of two (2) or more SGLD texture, color discreteness, and edge features is provided. The “soft” classifier uses image features to classify areas of an input image in picture, graphics, or fuzzy classes.

Abstract: A method and apparatus for generating highlight color tints for DND printing from full color image information uses complementary halftone screens. Image information that is out of a printing gamut is mapped into the printing gamut and the complementary halftone screens are applied to generate tint information while preserving gradation.

Abstract: An adaptive filtering method and apparatus for descreening a scanned halftoned image representation is disclosed. The apparatus includes an image input subsystem; a processing subsystem for processing halftoned image data provided by the image input subsystem; and software/firmware means operative on the processing subsystem for a) low-pass filtering a halftoned input pixel value provided by the image input subsystem to produce a low-pass filtered pixel value; b) notch-filtering the halftoned input pixel value to produce a notch-filtered pixel value; c) determining a local contrast value for the halftoned input pixel value; and d) producing a descreened output pixel value based on the low-pass filtered pixel value, the notch-filtered pixel value, or a combination of the low-pass filtered pixel value and the notch-filtered pixel value depending on the local contrast value.

Abstract: This invention relates to a method and apparatus for segmenting an image using a combination of image segmentation techniques. More particularly, the invention is directed to an improved image segmentation technique for use in an image processing system that performs at least two distinct image segmentation processes on an image and combines the results to obtain a combined multi-layer representation of the image that can be suitably processed. In a specific example, a block based segmentation technique is performed on an image to generate a MRC (mixed raster content) representation—having foreground, background and selector layers. A pixel based segmentation technique is also performed on the image to generate rendering hints. The MRC representation and the rendering hints are then combined to obtain a four (4) layer representation of the image. The four layer representation is subsequently processed as required by the image processing system, e.g. compressed and stored.

Abstract: A method and system for image processing, in conjunction with classification of images between natural pictures and synthetic graphics, using SGLD texture (e.g., variance, bias, skewness, and fitness), color discreteness (e.g., R_L, R_U, and R_V normalized histograms), or edge features (e.g., pixels per detected edge, horizontal edges, and vertical edges) is provided. In another embodiment, a picture/graphics classifier using combinations of SGLD texture, color discreteness, and edge features is provided. In still another embodiment, a “soft” image classifier using combinations of two (2) or more SGLD texture, color discreteness, and edge features is provided. The “soft” classifier uses image features to classify areas of an input image in picture, graphics, or fuzzy classes.

Abstract: Systems and methods for template matching of multicolored images provide an image conversion process that respectively views two, three or four input color planes through an input observation window. Single plane vectors are obtained that represent the color planes. The obtained single plane vectors are combined into a multi-plane vector that may be used in a look-up table for descreening or resolution enhancement, for example. Various interactions between color planes may be taken into account to provide optimum color space conversion. Additional information obtained by using the multi-plane vector allow performance of image processes with optimized accurate color values.

Abstract: The method and system of this invention predictively encodes and decodes an image signal that has been treated with the Roberts Method. The method and system generates a noise signal that is substantially similar to the noise signal generated during the Roberts Method treatment, calculates a range of values for the original image signal based upon an image signal from a different pixel location, predicts the image signal based upon the range of values and the noise signal and calculates an error signal that is encoded. The decoding method and system operates in reverse of the encoding method and system.

Abstract: A method for processing digital images to be displayed, stored, or printed, to eliminate blooming and other artifacts. The system utilizes morphological processes to isolate and modify image structures susceptible to marking process artifacts and then combines the modified image structures with the input image to produce a printable image that may be rendered on a given printer.

Abstract: A method for processing digital images to be displayed, stored, or printed, to eliminate blooming and other artifacts. The system utilizes morphological processes to isolate and modify image structures susceptible to marking process artifacts and then combines the modified image structures with the input image to produce a printable image that may be rendered on a given printer.

Abstract: The present invention is a method and apparatus to minimize and prevent blooming problems in color image systems. Particular applicability is found where an image on image system is employed. The invention is inserted into the colorant driving signal path of the system. The invention places an averaging circuit in the path of one or more colorant driving signal streams. The averaging circuit produces an average value signal representative of a small area of its respective colorant. A modulator or other signal varying device responsive to the average value signal is placed in the path of yet another but separate colorant driving signal stream. In this manner the separate colorant driving signal is modulated or varied in response to the average neighboring value of a different color thus minimizing and preventing image blooming.

Abstract: A method for calibrating a multi-chip image sensor, and an imaging system having a multi-chip sensor that includes color correction factors generated by such a method. The image sensor is successively controlled to image three different test targets. After imaging each target, a set of correction factors is generated and used to correct image signals generated when imaging the next test target. A first set of correction factors corrects for pixel-to-pixel variations between imaging elements in the array. The second set of correction factors corrects for chip-to-chip variations between chips in the array. The third set of correction factors corrects for array-wide variations compared to a standard color chart.

Abstract: An encoding/compression technique using a combination of predictive coding and run length encoding allows for efficient compression of images produced by error diffusion.

Abstract: The present invention is a method and apparatus for resolution enhancement of gray-scale input images including text and line art, and more particularly to a filtering method and image processing apparatus for enhancement of high contrast line edges found in continuous tone (gray-scale) images without requiring that the input image data include predetermined tag bits to identify region types (e.g., continuous tone or text and line art).

Abstract: The present invention is a method and apparatus for reducing two-color moire often found during the rendering of full color images using halftoning techniques. The invention relies upon the application of a non-periodic halftone operation to the least perceptible color separation (e.g., yellow) so as to prevent the formation of periodic structures due to the interaction of the yellow colorant with one of the other colorants (e.g., cyan or magenta).

Abstract: The present invention is a method and apparatus for generating N-bit per pixel output signals in response to M-bit per pixel image input signals, where M is greater than N. The invention employs a halftone cell threshold memory that stores a single threshold for each cell element. During real-time processing of the video image signals, multiple thresholds are calculated based upon the stored thresholds, and the image signals are compared to the thresholds. The threshold calculation process is simplified by using equally spaced constants and any desired variation from the resulting equally spaced thresholds is accomplished through a remapping of the video image signals using a look-up table. The output of the plurality of comparisons carried out for each halftone cell element is then encoded to produce a digital gray-scale output signal.

Abstract: A method and apparatus for converting the resolution of an input image to a higher resolution that is a noninteger multiple of the input resolution. The method and apparatus employ either an interlocked or noninterlocked clustering arrangement of output pixels in order to assign to each output pixel a reference value determined from the signal levels of the input image. In addition, the method and apparatus include a template-based enhancement filter to further refine modify or alter the assigned signal level prior to its output as a higher resolution image.

Abstract: The present invention is a method and apparatus for detecting the presence of image regions requiring compact dot growth control and controlling the dot growth of such regions when rendered on a printing system. The invention operates to recognize those pixels within a bitmap image that are appropriate for alteration, using a template-based approach, and then alters the exposure pulse of identified pixels during imaging so as to assure a more stable output by a xerographic development system.