Facsimile and static presentation processing – Facsimile – Specific signal processing circuitry
Patent
1990-05-14
1992-06-23
Coles, Sr., Edward L.
Facsimile and static presentation processing
Facsimile
Specific signal processing circuitry
358474, H04N 110
Patent
active
051248107
ABSTRACT:
An image reading apparatus for reading an image on a sheet. The apparatus comprises an image reading part for scanning a predetermined area, including the sheet, one scanning line by one scanning line for producing an output image signal. A white reference image part is provided within the predetermined area so as to be scanned by the image reading part. A black reference image part is provided within the predetermined area so as to be scanned by the image reading part. A white reference memory is supplied with the output image signal from the image reading part for storing the output image signal supplied thereto, and a black reference memory is supplied with the output image signal from the image reading part for storing the output image signal supplied thereto. An image correction part is supplied with the output image signal from the image reading part and further with a first reference signal and a second reference signal from the white and black reference memories for producing a corrected image signal. A controller controls the reading operation of the white reference memory and the black reference memory. In the image forming apparatus, the effect of shading is eliminated, the quality of image recording is improved, and the size of the sheet on which the image to be read can be detected.
REFERENCES:
patent: 4601058 (1986-07-01), Seto
patent: 4614976 (1986-09-01), Ogata
patent: 4660082 (1987-04-01), Tomohisa et al.
Coles Sr. Edward L.
Grant II Jerome
Ricoh & Company, Ltd.
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