Image processing apparatus and image processing method for performing error diffusion processing for each region of an image

Patent metadata

Field	Value
Publication number	US-8947735-B2
Application number	US-201113208716-A
Country	US
Kind code	B2
Filing date	Aug 12, 2011
Priority date	Aug 25, 2010
Publication date	Feb 3, 2015
Grant date	Feb 3, 2015

Abstract

When the pixel of interest exists at a pixel position where reference of an error buffer is necessary, a quantization error generated in a region having undergone error diffusion processing is obtained from the error buffer. A quantization error generated in error diffusion processing in a region containing the pixel of interest is obtained from an error memory. Diffusion errors are calculated from the quantization errors using an error diffusion matrix. The value of the pixel of interest and the diffusion errors are added, and the addition value is quantized into the quantization value of the pixel of interest. The difference between the quantization value and the addition value is calculated as a quantization error to be stored in the error memory. When the pixel of interest exists at a pixel position where write in the error buffer is necessary, the quantization error is stored in the error buffer.

First claim

What is claimed is:

1. An image processing apparatus for performing error diffusion processing for each region of an image divided into a plurality of regions so that each region has an overlapping processing region, comprising:
a first error holding unit constructed to hold quantization errors which occurred in the error diffusion processing for a region different from a region of interest containing a pixel of interest;
a second error holding unit constructed to hold quantizat…

Assignees

• Kodama Shigeo
• Ishikawa Hisashi
• Canon Kk

Inventors

• Kodama Shigeo
• Ishikawa Hisashi

Classifications

• H04N1/4052 Primary

  Electricity · mapped topic