Title:
HALF TONE IMAGE RECORDER
Document Type and Number:
Japanese Patent JP3031590
Kind Code:
B2
Abstract:
PURPOSE: To simplify a circuit and to improve picture quality by distributing level difference, which is generated in the case of quantizing the density level of a notice picture element, to peripheral picture elements and deciding the destination of distribution corresponding to residual between the total sum of distributed levels and the level difference by using any random number.
CONSTITUTION: Difference from source data generated in the case of quantization is defined as an error component. When error to be generated is defined as ε, this εis distributed respectively to respective picture elements on the upper left side and just upper right side of image data in the direction of a preceding line and the picture element on the left side of a notice processing line at a certain distribution rate. When the error is completely distributed from an (i+1)th line to the picture elements of an i-th line with this distribution, the notice picture element is moved to the i-th line, and quantization is performed. An error component ε' to be generated is distributed respectively to respective picture elements on the lower left side, just down side, right side of the i-th line at a certain distribution rate. The arithmetically remained component is distributed by designating one of four points while using any random number. Next, the attention line is moved to an (i+2)th line and similar processing is performed. These two processes are performed to the end of input image data.
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Inventors:
Hiroshi Maeda
Toshio Yamagishi
Norihide Kunikawa
Toshihiro Okahashi
Toshio Yamagishi
Norihide Kunikawa
Toshihiro Okahashi
Application Number:
JP21131292A
Publication Date:
April 10, 2000
Filing Date:
August 07, 1992
Export Citation:
Assignee:
Sharp Corporation
International Classes:
H04N1/40; H04N1/405; (IPC1-7): H04N1/40; H04N1/405
Domestic Patent References:
| JP257365A |
Attorney, Agent or Firm:
Yoshio Kawaguchi (1 person outside)