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US 2014/0368886 A1Published application
Black trapping methods, apparatus and systems for binary images
AssigneeXerox Corporation
InventorsXing Li, Zhenhuan Wen
Life of this patent
Estimating the term…
Abstract
Provided are black trapping methods, apparatus and systems for binary images. According to one exemplary method, black trapping color image data is performed by incorporating a set of trapping condition logical operations. Specifically, edge checking is based on estimated contone color values and density checking based on a binary bitmap.
Claims22
A method of performing black trapping on a color image data representation for rendering comprising:
- a) determining if the pixel of interest is a natural extension of a halftone pattern associated with the halftone bitmap;
- b) estimating a continuous tone value associated with black pixels within a predetermined window of pixels associated with the pixel of interest;
- c) determining if the pixel of interest is associated with an edge based on the continuous tone values associated with black pixels estimated in step b);
- and
- d) if the pixel of interest is a natural extension of a halftone pattern associated with the halftone bitmap and the pixel of interest is associated with an edge, modifying to non-black halftone pixel bitmap plane at the pixel of interest location.
2 more elements
A printing apparatus comprising:
- an image marking device for rendering a color image on a media substrate;
- and
- a controller configured to receive a halftone pixel bitmap representation of an image for rendering on the image marking device, the controller configured to execute instructions to perform a method of black trapping, the method comprising:
- receiving a halftone pixel bitmap representing the color image, the halftone pixel bitmap including a black pixel bitmap plane and one or more non-black halftone pixel bitmap planes;
- a) determining if the pixel of interest is a natural extension of a halftone pattern associated with the halftone bitmap;
- b) estimating a continuous tone value associated with black pixels within a predetermined window of pixels associated with the pixel of interest;
- c) determining if the pixel of interest is associated with an edge based on the continuous tone values associated with black pixels estimated in step b);
- and
- d) if the pixel of interest is a natural extension of a halftone pattern associated with the halftone bitmap and the pixel of interest is associated with an edge, modifying a non-black halftone pixel bitmap plane at the pixel of interest location.
6 more elements
A method of performing black trapping on a color image data representation for rendering comprising:
- receiving a halftone pixel bitmap representing the color image, the halftone pixel bitmap including a black pixel bitmap plane and colorant halftone pixel bitmap planes;
- selecting a pixel of interest associated with the halftone pixel bitmap
- a) determining if the pixel of interest is a natural extension of a halftone pattern associated with the halftone bitmap;
- b) determining if the pixel of interest is associated with an edge;
- c) determining if the density of black pixels substantially near the pixel of interest is greater than a predetermined threshold;
- and
- d) if the pixel of interest is a natural extension of a halftone pattern associated with the halftone bitmap, a pixel of interest is associated with an edge and the density of black pixels is greater than the predetermined threshold, modifying a non-black halftone pixel bitmap plane at the pixel of interest location.
4 more elements
A printing apparatus comprising:
- an image marking device for rendering a color image on a media substrate;
- and
- a controller configured to receive a halftone representation of an image for rendering on the image marking device, the controller configured to execute instructions to perform a method of black trapping on the halftone representation of the image, the method comprising:
- receiving a halftone pixel bitmap representing the color image, the halftone pixel bitmap including a black pixel bitmap plane and colorant halftone pixel bitmap planes;
- selecting a pixel of interest associated with the halftone pixel bitmap
- a) determining if the pixel of interest is a natural extension of a halftone pattern associated with the halftone bitmap;
- b) determining if the pixel of interest is associated with an edge;
- c) determining if the density of black pixels substantially near the pixel of interest is greater than a predetermined threshold;
- and
- d) if the pixel of interest is a natural extension of a halftone pattern associated with the halftone bitmap, a pixel of interest is associated with an edge and the density of black pixels is greater than the predetermined threshold, modifying a non-black halftone pixel bitmap plane at the pixel of interest location.
7 more elements
Dependencies are inferred from the claim text.