Seiko Epson Corporation

Joseph S Shu

Chia-Hsin Li

Anoop Kumar Bhattacharjya

Tsung-Nan Lin

Hakan Ancin

Andrei Pascovici

Changick Kim

Jincheng Huang

Jau-Yuen Chen

Vasudev Bhaskaran

Jack Boyce

Onur Gonen Guleryuz

Jerzy Wieslaw Swic

Dennis Lai Chao

A method having a corresponding apparatus and computer program comprises receiving a mosaic image comprising a plurality of pixels; separating the mosaic image into a plurality of color channels each comprising only the pixels having a corresponding one of a plurality of colors; and processing each color channel of the image data separately, wherein the processing of each of the color channels comprises at least one of compressing the pixels in the color channel, and color processing the pixels in the color channel.

Mosaic image data processing

A method for smoothing artificial discontinuities between image blocks associated with digital data comprises reconstructing a block-based pixel representation of image blocks associated with digital data. If the difference between adjacent image blocks of the block-based pixel representation is less than or equal to a quantization parameter, then the method includes modifying boundary pixel values to define at least one additional frame, and displaying the at least one additional frame and an original frame in an alternating fashion so as to visually achieve smooth block boundaries between the adjacent image blocks. The method may be performed by a suitable device and/or may be embodied in an instruction set executable by such device.

Method and apparatus for video deblocking

A 3-D dot code is embedded in a printed medium using an embedder that embeds data directly into the halftone dots of a selected file that is ready for printing. An extractor extracts the embedded bits by scanning the printed medium and then interprets the embedded data. A bleed-through elimination module in the extractor is able to eliminate adverse affects on the scanned input of the embedded data caused by bleed-through from the print on the opposite side of the page. The extractor may also include a module that compensates for a misaligned scanned input by automatically detecting the rotation and translation, and then registering the image so that the upper-left corner is located in a certain position. This operation expedites subsequent data retrieval, in which data is read by block matching.

3-Dimensional dot code for paper storage

The appearance of edges in an image is improved through precise placement of subpixels within pixel cells that are located on or near edges in an image. Image data is examined to identify a 'target pixel' near the edge of an object that represents the object and is adjacent to a 'background pixel' that represents only background. The target pixel may represent both the object and its background or it may represent the object only. A &#x201c;second pixel&#x201d;, adjacent to the target pixel and representing the object, is also identified. The second pixel may represent both the object and its background or it may represent the object only. The target pixel's location with respect to the second pixel is analyzed to determine the placement of a subpixel within the target pixel cell and the placement of a subpixel within the second pixel cell, such that the edge of the object is well-defined and the density of the object is preserved. A vertical smoothing process can additionally be performed to improve further the appearance of edges in the image. The technique is particularly advantageous for printing a halftoned object represented by pixels that are not saturated.

PWM rendering for color/gray-scale text and graphics for laser printer

A superpattern generator uses a first halftone pattern representing a first gray level and a second halftone pattern representing a second gray level to generate a larger pattern or 'superpattern'. In a preferred implementation, the superpattern generator generates a grid of elements to be used as a template for the superpattern, calculates a distance value representing the 'distance' from the first gray level to a desired gray level T, determines how many elements of the grid represent the first halftone pattern and how many represent the second halftone pattern based on the distance value, superimposes a dither matrix on the grid and assigns values representing the first halftone pattern or the second halftone pattern to pixels within the elements of the grid by examining threshold values in the dither matrix. This process is repeated for various values of Tto generate a set of superpatterns representing a set of gray levels intermediate to the first gray level and the second gray level.

Mixed screen design for multi-mode document

Nozzle scheduling algorithms that provide a unified approach to designing nozzle firing algorithms that incorporate a variety of specifiable nozzle-firing constraints such as print head (nozzle) geometry, nozzle spacing, number of nozzles, head movement (number of passes), ink-media interaction, etc. Such constraints are provided as design rules for a given printer/output medium, and the result is an appropriate nozzle firing algorithm. The design algorithms may be used to generate nozzle firing sequences in a halftone-dependent or halftone-independent manner.

Nozzle scheduling for ink jet printing

A method for reducing block artifacts between image blocks of a decompressed image is provided. The method initiates with selecting a set of pixel positions corresponding to pixels proximate to a border between the image blocks. Then, an amount of additional frames to be inserted when displaying the decompressed image is determined. Next, a pixel value associated with each pixel of the set of pixels proximate to the border is modified for each of the additional frames. Then, an original frame and the additional frames are displayed in an alternating mode such that block artifacts between the image blocks are visually reduced. A computer readable media, an integrated circuit and a device enabled to reduce blocking artifacts are also provided.

A technique is provided that identifies screen and non-screen regions of a projected or displayed image to smooth and selectively remove moir&#xe9; from the screen regions while maintaining sharpness in the non-screen regions. Each pixel in the image is classified as a screen or non-screen pixel and then pixels in a predetermined surrounding area of each pixel are examined to check the classification of that pixel. A low pass filter is applied to pixels in the image, such that, when the low pass filter is applied, a center of the low pass filter is selectively shifted relative to a current pixel based on the examination.

Image artifact removal technique for LCP

A technique is provided that identifies screen and non-screen regions of a projected or displayed image to smooth and selectively remove moir&#xe9; from the screen regions while maintaining sharpness in the non-screen regions. Each pixel in the image is classified as a screen or non-screen pixel and then pixels in a predetermined surrounding area of each pixel are examined to check the classification of that pixel. A low pass filter is applied to pixels in the image, such that, when the low pass filter is applied, one or more pixels covered by the low pass filter are respectively replaced by one or more other pixels covered by the low pass filter based on the examination.

Memory efficient image artifact removal technique for LCP

A dither matrix generator defines a three-dimensional array of pixels referred to as the 'cluster array' in which each pixel is designated based on its value as a 'cluster pixel' or a &#x201c;void pixel&#x201d;. The dither matrix generator also defines a three-dimensional array referred to as the &#x201c;dither matrix,&#x201d; and assigns rank values to the dither matrix in two stages. In the first stage, the dither matrix generator identifies the largest cluster in the cluster array, identifies a cluster pixel located in the largest cluster, assigns a rank value to the element in the dither matrix corresponding to the cluster pixel and removes the cluster pixel from the cluster array. The process is repeated until the cluster array contains no cluster pixels. In the second stage, the dither matrix generator resets the pixels in the cluster array to their initial values, identifies the largest void in the cluster array, identifies a void pixel within the largest void, assigns a rank value to the element in the dither matrix corresponding to the void pixel and inserts a cluster pixel in the location of the void pixel. The process is repeated until the cluster array contains only cluster pixels.

Three dimensional stochastic screen for LCD and video

Color processing architecture and algorithms (CPAA) for color laser printers process and handle incoming RGB image data effectively to achieve high performance, high quality image printing with low memory requirements. CPAA supports a new data structure for faster raster operation processing (ROP) for color laser printers. The CPAA architecture advantageously improves the flow of data through the processing pipeline to provide high speed at higher resolutions, e.g., at 600 and 1200 dpi. An advance quantizer using multilevel dithering flexibly reduces bits to support fast ROP and to enable fast conversion to CMYK data with only a simple look-up table (LUT) operation by a color matching module, while an adaptive filter maintains high image quality.

Color processing architecture and algorithms for color laser printers

When clustered-dot dithering is employed in laser printers a banding effect sometimes results from the interaction of the dither matrix with non-uniform line spacing in the printer. We have found that we can lessen the effect of this interaction if we change the dither matrix as it moves over the image. We do this by modulating the dither matrix (halftone cell) as a function of the spatial position of the sub-area in the image. Halftone cells can be formed in a variety of patterns (e.g. vertical, horizontal, etc.) but generally their threshold values grow from a minimum value to a maximum value. Our process is to modulate the halftone cell according to a function: f (s, h) where s is the spatial position of the sub-area of the image and h is the halftone cell. We modulate the cell by altering the relative positions of the threshold values in the cell as we move the cell over the image. This effectively breaks up the bands of clusters of one size or another and provides a visually uniform image even in lighter tones.

Smoothness enhancement in laser printing through periodic modulation of halftone cell

An apparatus and method for improving a color space transformation between an input device such as a scanner and an output device such as a printer. The color space transformation includes a first three-dimensional look up table that receives color information from the input device and transforms colors specified in an input device color space into colors in a device-independent color space, and a second three-dimensional look up table that receives colors from the first three-dimensional look up table and transforms colors specified in a device-independent color space into colors in an output device color space. The method includes inputting sample images with the input device and outputting those sample images with the output device, identifying areas in the sample images output by the output device where contouring appears, forming a list of colors corresponding to the identified areas, identifying nodes in the second three-dimensional look up table encompassing the list of colors, and smoothing the set of nodes.

Color table manipulations for contour reduction

A method and apparatus for improving color matching between original color images and reproductions thereof. Incorporated into the improved color matching technique is an improved out-of-gamut mapping strategy which does not affect in-gamut colors but which ensures that colors outside of the input device gamut will be mapped to the boundary of the output device gamut while preserving hue and minimizing the combined chrominance-luminance error.

Out-of-gamut color mapping strategy

A technique for calibrating non-reference printers to a reference printer in a network system by determining a set of four 1-D look-up tables for each non-reference printer. Each set of four 1-D look-up tables is constructed from a corresponding set of transfer functions, where each transfer function in a given set is a composite of a 1-D characteristic function for a particular primary color of the reference printer and a 1-D inverse characteristic function for that particular primary color of the corresponding non-reference printer. The characteristic functions are determined by performing a specific color space transformation analysis on each non-reference printer and on the reference printer.

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San Jose, CA, United States of America

Joseph S Shu