Title:
POLE PIXEL DETECTION DEVICE
Document Type and Number:
Japanese Patent JP3245586
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To accurately detect a pole pixel that corresponds to a halftone dot included in an image by comparing the center pixel existing in a prescribed local area of the image and the center pixel existing in a local area greater than a prescribed local area and around the center pixel of the prescribed local area with the density level of a prescribed peripheral pixel to detect the 1st and 2nd pole pixels and defining the OR of the 1st and 2nd pole pixels as a pole pixel.
SOLUTION: A local area is defined as a rectangular mask of a small (3×3) pixel size and also as a rectangular mask of a larger (5×5) pixel size. In regard to these two rectangular masks, the center pixels Lc are defined as the 1st and 2nd pole pixels when the density levels of the pixels Lc are higher than those of the prescribed peripheral pixels L1-L8 by the prescribed threshold. Then the OR of the 1st and 2nd pole pixels is defined as a pole pixel. Thus, the pole pixels can be accurately detected to the halftone dots included in a wide range of the number of lines.
Inventors:
OUCHI SATOSHI
IMAO KAORU
IMAO KAORU
Application Number:
JP2000215968A
Publication Date:
January 15, 2002
Filing Date:
March 27, 1990
Export Citation:
Assignee:
RICOH KK
International Classes:
G06T5/00; G06T7/40; H04N1/40; (IPC1-7): H04N1/40; G06T7/40; //G06T5/00
Other References:
【文献】特許2777379(JP,B2)
Attorney, Agent or Firm:
Hideo Takino