Method and system for improved copy quality by generating contone value based on pixel pattern and image context type around pixel of interest

• US 8,023,150 B2
• Filed: 03/08/2010
• Issued: 09/20/2011
• Est. Priority Date: 11/10/2005
• Status: Expired due to Fees

• Current Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Inventors: Tse, Francis Kapo, Wu, John W., Lee, Chia-Hao, Nagarajan, Ramesh, Cassidy, John Christopher
• Primary Examiner(s): Rogers; Scott A
• Application Number:
  US12/719,233
• Publication Number:
  US 20100157374A1
• Time in Patent Office: 561 Days
• Field of Search: 358/1.9, 358/2.1, 358/3.01, 358/3.06, 358/3.08, 358/3.21, 358/3.23, 358/462, 382/173, 382/176, 382/205, 382/224, 382/229, 382/237, 382/254, 382/261
• US Class Current: 358/2.1
• CPC Class Codes: H04N 1/40075 Descreening, i.e. converting a halftone signal into a corresponding continuous-tone signal; Rescreening, i.e. combined descreening and halftoning

Abstract

A method and system reconstructs a contone image from a binary image by first tagging pixels to identify one of a multiplicity of image content types. The tag information and the pattern of bits surrounding the pixel to be converted to a contone value are used to reconstruct a contone image from a binary image. The pattern of bits in the neighborhood is used to generate a unique identifier. The unique identifier is used as the address for a lookup table with the contone value to be used wherein each lookup table corresponds to an image context type.

Claims

1. A system to generate a continuous tone image from tagged binary encoded image, comprising:

a pattern identifier generator to generate a pattern identifier value based upon a pattern of pixels around a pixel of interest;

an image type selector to generate an image type signal identifying an image context type in a pre-determined neighborhood of pixels around a pixel of interest; and

a contone value generator, operatively connected to said pattern identifier generator and said image type selector to receive said pattern identifier value and said image type signal, to generate a contone value from the received pattern identifier value based upon the received image type signal.

2. The system as claimed in claim 1, wherein said contone value generator includes a plurality of look-up tables, each look-up table having a plurality of contone values stored therein, each contone value corresponding to a pattern identifier value, each look-up table corresponding to an image context type.

3. The system as claimed in claim 2, wherein said image type signal enables a look-up table associated with the image context type corresponding to the received image type signal.

4. The system as claimed in claim 1, wherein said contone value generator includes a memory having a plurality of contone values stored therein, each combination of a pattern identifier value and an image context type being mapped to a stored contone value.

5. The system as claimed in claim 1, wherein said contone value generator includes a logic circuit to generate a plurality of contone values, the generated contone value corresponding to a pattern identifier value and an image context type.

6. A method to generate a continuous tone image from tagged binary encoded image, comprising:

electronically generating, using an electronic device, a pattern identifier value based upon a pattern of pixels around a pixel of interest;

electronically generating, using an electronic device, an image type signal identifying an image context type in a pre-determined neighborhood of pixels around a pixel of interest; and

electronically generating, using an electronic device, in response to receiving said pattern identifier value and said image type signal, a contone value from the received pattern identifier value based upon the received image type signal.