Facsimile and static presentation processing – Facsimile – Specific signal processing circuitry
Patent
1990-03-30
1993-12-07
Peng, John K.
Facsimile and static presentation processing
Facsimile
Specific signal processing circuitry
358475, 358464, 358460, 358461, 382 50, H04N 140
Patent
active
052687732
ABSTRACT:
A document image signal processor of gray level for use in a facsimile. The document image signal processor establishes a local window and a broad window from document image signals scanned by a CCD image sensor. An average level and a level difference between a maximum and a minimum level of the image signals are extracted from the local window. A maximum threshold of the background of the document image is extracted from the broad window. Thus, the image signals can be binarized with an adaptive threshold. Accordingly, the inventive image signal processor provides improved image, although the document image is collected (scanned) from a material whose brightness distribution is considerably ununiform. The document image signal processor includes a line-memory for reading/writing the document image signal, a local window register for forming a local image window, a broad window register for forming a broad image window register, an address and clock generator for generating address and control clocks, and an adaptive threshold logic unit for producing black/white decision logic of the center pixel.
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Kim Dong-Yool
Kim Young-Chul
Koide Hideki
Lee Hong-Jik
Park Yong-woo
Bushnell Robert E.
Peng John K.
Samsung Electronics Co,. Ltd.
Tong Nina
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