Method of selective edge softening and rendering for the suppression of halo

• US 20040085557A1
• Filed: 10/27/2003
• Published: 05/06/2004
• Est. Priority Date: 12/06/1999
• Status: Active Grant

• Current Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Inventors: Loce, Robert P., Cuciurean-Zapan, Clara
• Granted Patent: US 7,227,670 B2
• Time in Patent Office: Days
• US Class Current: 358/1.9
• CPC Class Codes: G06K 15/1826 Object trapping
• CPC Class Codes: G06T 2207/20192 Edge enhancement; Edge preservation
• CPC Class Codes: G06T 2207/30144 Printing quality
• CPC Class Codes: G06T 2207/30176 Document
• CPC Class Codes: G06T 5/30 Erosion or dilatation, e.g. thinning
• CPC Class Codes: G06T 5/70 Denoising; Smoothing
• CPC Class Codes: G06T 5/73 Deblurring; Sharpening
• CPC Class Codes: H04N 1/4092 Edge or detail enhancement
• CPC Class Codes: H04N 1/58 Edge or detail enhancement; Noise or error suppression, e.g. colour misregistration correction H04N1/62 takes precedence

Abstract

Selective edge softening and selective edge dithering is introduced into an image representation to improve local control where halo problems are expected. Selective areas of dilation are isolated and separately dithered or halftoned, the result of which is then swapped back into or substituted for the stored original image. In this manner misregistration and color plane-to-plane interactions can be compensated for in plural image forming station architecture systems. The same technique is also valuable in monochrome systems as an aid to overcoming edge displacement and slow toner problems when the selective edge softening is selectively applied to edges which are in particular perpendicular to the fast scan direction.

Claims

1. A method for improving the printing of an image, said method including:

receiving a source image of original pixel data;

trapping the source image of original pixel data;

tagging data in the trapping step; and

dithering the data tagged in the trapping step.

2. The method of claim 1, wherein the trapping is performed upon source image black data.

3. The method of claim 1, wherein the trapping is performed upon source image color data separation.

4. The method of claim 3, wherein the trapping is performed upon a image shape data color separation only if there is another color separation to be developed.

5. The method of claim 1, wherein the dithering is a high frequency halftone type.

6. The method of claim 1, wherein the dithering is a halftone type which is different from the system halftone ultimately applied to the rest of the source image.

7. The method of claim 1, wherein the dithering is a diffused type halftone.

8. The method of claim 1, wherein the dithering is a stochastic type halftone.