Color error diffusion with color bleed control

• US 20050212816A1
• Filed: 03/29/2004
• Published: 09/29/2005
• Est. Priority Date: 03/29/2004
• Status: Active Grant

• Current Assignee: Sharp Laboratories of America Incorporated (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Laboratories of America Incorporated (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Chang, Ching-Wei
• Granted Patent: US 6,977,663 B2
• Time in Patent Office: Days
• US Class Current: 345/616
• CPC Class Codes: H04N 1/52 Circuits or arrangements for halftone screening

Abstract

A method for controlling color bleed in relation to a system-invoked halftone color-image process which involves and includes the practice of error diffusion. The proposed method involves (a) selecting a location in the system which is downstream therein relative to where error diffusion takes place, (b) at that location, performing diffusion-accumulated error calculation, (c) at another location in the system which is downstream from where error calculation takes place, applying error filtering to define a numerically weighted pixel-neighbor distribution pattern for such calculated accumulated error, where the numbers associated with that pattern add to a defined distribution-weight totality number, and (d) then preparing, for use in a next-pixel error-diffusion event, a chosen distribution-weight totality number which is less than the defined distribution-weight totality number.

Claims

1. A method for controlling color bleed in relation to a system-invoked halftone color-image process which involves the practice of error diffusion, said method comprising

selecting a location in the system which is downstream therein relative to where such error diffusion takes place,

at that selected location, performing diffusion-accumulated error calculation,

at another location in the system which is downstream from where said performing takes place, applying error filtering to define a numerically weighted pixel-neighbor distribution pattern for such calculated accumulated error, where the numbers associated with that pattern add to a defined distribution-weight totality number, and

then preparing, for use in a next-pixel error-diffusion event, a chosen distribution-weight totality number which is less than the defined distribution-weight totality number.

2. The method of claim 1, wherein the mentioned chosen distribution-weight totality number is 15/16 of the mentioned defined distribution-weight totality number.

3. The method of claim 1, wherein said applying is done using a Floyd and Steinberg error filter.

4. The method of claim 3, wherein the mentioned chosen distribution-weight totality number is 15/16 of the mentioned defined distribution-weight totality number.

5. The method of claim 1, wherein said applying is done using an error filter which is one of a (1) Floyd and Steinberg filter, (2) a Jarvis, Judice and Ninke filer, and (3) a Stucki filter.

6. The method of claim 1, wherein color error diffusion takes the form of vector error diffusion.

7. The method of claim 6, wherein said applying is done using an error filter which is one of a (1) Floyd and Steinberg filter, (2) a Jarvis, Judice and Ninke filter, and (3) a Stucki filter.

8. The method of claim 6, wherein the mentioned chosen distribution-weight totality number is 15/16 of the mentioned defined distribution-weight totality number.

9. The method of claim 6, wherein said applying is done using a Floyd and Steinberg error filter.

10. The method of claim 9, wherein the mentioned chosen distribution-weight totality number is 15/16 of the mentioned defined distribution-weight totality number.