Facsimile and static presentation processing – Facsimile – Specific signal processing circuitry
Patent
1989-03-06
1990-09-18
Britton, Howard W.
Facsimile and static presentation processing
Facsimile
Specific signal processing circuitry
358455, 358454, 382 22, H04N 140
Patent
active
049582380
ABSTRACT:
There is provided an image processing apparatus which handles an image as a digital signal, comprising: an input device to input image data indicative of a concentration of an image; a binarization circuit to binarize the input image data; a positive
egative state detection circuit to detect whether error data generated when the image data is binarized by the binarization circuit is in a positive state or a negative state; and a selector to select whether the error data generated upon binarization is to be corrected or not, on the basis of the positive or negative state of the error data. The input device has a generator to read an original and generate an analog image signal and a converter to convert the analog image signal into the digital image data. The error data is the difference between the input image data and the binary data produced by the binarization circuit. With this apparatus, an image of a good picture quality can be obtained by improving the error diffusion method as a halftone processing method. Even when portions of high and low concentrations in an original are very close to each other, the blanking phenomenon, wherein no dot is printed in the low concentration area near the boundary between those portions, and the consequent problem that the reproduced image lacks its proper content can be prevented.
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Katayama Akihiro
Ohsawa Hidefumi
Britton Howard W.
Canon Kabushiki Kaisha
Vu Kim Yen
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