Systems and methods for line width control and pixel retagging

• US 8,467,089 B2
• Filed: 11/24/2008
• Issued: 06/18/2013
• Est. Priority Date: 11/24/2008
• Status: Active Grant

• Current Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Inventors: Loce, Robert P., Xu, Beilei, Schweid, Stuart A.
• Primary Examiner(s): REINIER, BARBARA DIANE
• Application Number:
  US12/276,810
• Publication Number:
  US 20100128314A1
• Time in Patent Office: 1,667 Days
• Field of Search: None
• US Class Current: 358/1.9
• CPC Class Codes: G06K 15/02 using printers
• CPC Class Codes: G06T 2207/20192 Edge enhancement; Edge preservation
• CPC Class Codes: G06T 2207/30176 Document
• CPC Class Codes: G06T 5/73 Deblurring; Sharpening
• CPC Class Codes: H04N 1/4092 Edge or detail enhancement

Abstract

A system and method for processing a digital image for rendering are provided. The method includes performing one or more Line Width Control (LWC) operations on digital image data including pixels having pixel values representing gray levels and tag states providing information for specialized rendering techniques thereby changing one or more pixel values resulting in one or more inaccurate pixel tag states, identifying and reassigning one or more inaccurate pixel tag states for improving the rendering of the resultant digital image. An apparatus, such as an image processing system, capable of performing line width control and tag reassignment is also provided.

Claims

1. A method for processing a digital image for rendering, the method comprising:

receiving digital image data including pixels having pixel values representing gray levels, at least some of the pixels having tag states;

performing one or more Line Width Control (LWC) operations on the digital image data moving at least one edge of an image object and changing one or more pixel values resulting in one or more inaccurate pixel tag states;

performing pixel evaluation identifying one or more pixels having inaccurate tag states; and

revising one or more inaccurate pixel tag states for improving the rendering of the digital image.

2. The method of claim 1 further comprising rendering a portion of the image using halftoning and rendering a portion of the image having anti-aliased pixel tag states using anti-aliased rendering.

3. The method of claim 1 wherein the revising includes reassigning pixel tag states for pixels having neighbor pixel (NP) pixel values changed by the one or more LWC operations.

4. The method of claim 3 wherein the revising includes reassigning pixel tag states for pixels having nearest neighbor pixel (NNP) pixel values changed by the one or more LWC operations.

5. The method of claim 1 wherein the revising includes reassigning pixel tag states to anti-aliased pixel tag states when pixels neighboring anti-aliased pixels and having foreground or background pixel values that are changed to intermediate pixel values in the one or more LWC operations.

6. The method of claim 1 wherein the revising includes reassigning pixel tag states to provide accurate distance to edge information for pixel tag states having inaccurate distance to edge information resulting from changes to an image edge made in the one or more LWC operations.

16. The method of claim 1 wherein the revising comprises at least one of reassigning pixel tag states to anti-aliased pixel tag states and reassigning pixel tag states from tag states which are anti-aliased pixel tag states to tag states which are not anti-aliased pixel tag states.

17. The method of claim 1 wherein the revising comprises at least one of reassigning pixel tag states to “

1-in”

pixel tag states or from “

1-in”

pixel tag states, and reassigning pixel tag states to “

1-out”

pixel tag states or from “

1-out”

pixel tag states.

18. The method of claim 1 further comprising:

wherein the performing pixel evaluation includes determining that a pixel has a pixel value that is within a range of pixel values for gray edge pixels, and determining that the tag state for the pixel is not an anti-aliased value; and

wherein the revising includes changing the tag state for the pixel to an anti-aliased tag state value.

19. The method of claim 1 further comprising:

wherein the performing pixel evaluation includes determining that a pixel has a pixel value that is not within a range of gray edge pixel values, and determining that the tag state for the pixel is an anti-aliased value; and

wherein the revising includes changing the tag state for the pixel to a tag state which is not an anti-aliased tag state.

20. The method of claim 1 further comprising:

wherein the performing pixel evaluation includes determining that a pixel has a pixel value that is not within a range of gray edge pixel values, and determining one of the pixel has a pixel value that is within a range of foreground pixel values and the pixel has a pixel value that is not within a range of foreground pixel values; and

wherein the revising includes one of changing the tag state for the pixel having a pixel value that is within a range of foreground pixel values to a foreground tag state and changing the tag state for the pixel having a pixel value that is not within a range of foreground pixel values to a background tag state.

7. A method of digital image Line Width Control comprising:

receiving digital image data including pixels having pixel values representing gray levels, at least some of the pixels having tag states;

performing a Line Width Control (LWC) operation on the digital image data changing one or more pixel values resulting in one or more inaccurate pixel tag states;

performing pixel evaluation and tag state reassignment reassigning anti-aliased pixel tag states for one or more pixels having inaccurate pixel tag states; and

outputting the digital image data having accurate pixel tag states for the rendering of the digital image.

8. An apparatus for processing images, comprising;

an image processing system performing a Line Width Control (LWC) operation on digital image data including pixels having pixel values representing gray levels, at least some of the pixels having tag states, the LWC operation moving at least one edge of an image object and changing one or more pixel values resulting in one or more inaccurate pixel tag states, the image processing system performing pixel evaluation and tag state reassignment identifying one or more pixels having inaccurate tag states and reassigning the tag states for the one or more pixels having inaccurate pixel tag states.

9. The apparatus of claim 8 further comprising the image processing system rendering a portion of the image in a first rendering operation utilizing pixel tag state information and rendering a portion of the image in a second rendering operation not utilizing pixel tag state information.

10. The apparatus of claim 8 further comprising the image processing system rendering a portion of the image using halftoning and rendering a portion of the image having anti-aliased pixel tag states using anti-aliased rendering.

11. The apparatus of claim 8 wherein the image processing system performing pixel evaluation and tag state reassignment reassigns pixel tag states for pixels having neighbor pixel (NP) pixel values changed by the LWC operation.

12. The apparatus of claim 11 wherein the image processing system performing pixel evaluation and tag state reassignment reassigns pixel tag states for pixels having nearest neighbor pixel (NNP) pixel values changed by the one or more LWC operations.

13. The apparatus of claim 8 wherein the image processing system performing pixel evaluation and tag state reassignment reassigns pixel tag states to “

1-in”

or from “

1-in”

, or reassigns pixel tag states to “

1-out”

or from “

1-out”

.

14. The apparatus of claim 8 wherein the image processing system performing pixel evaluation and tag state reassignment reassigns pixel tag states to anti-aliased pixel tag states when pixels neighboring anti-aliased pixels and having foreground or background pixel values that are changed to intermediate pixel values in the LWC operation.

15. The apparatus of claim 8 wherein the image processing system performing pixel evaluation and tag state reassignment reassigns pixel tag states to provide accurate distance to edge information for pixel tag states having inaccurate distance to edge information resulting from changes to an image edge made in the LWC operation.