The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 31, 1994
Filed:
Jan. 03, 1992
Masaaki Ito, Yokohama, JP;
Ricoh Company, Ltd., Tokyo, JP;
Abstract
A white reference data generating unit which generates white reference data used in a shading correction process includes a line memory for storing white reference data, a determination circuit for determining whether or not the image data supplied from an image sensor is equal to or less than a predetermined threshold level, a updating circuit for updating the white reference data stored in the line memory to new white reference data calculated based on the white reference data stored in the line memory and input data while each line on a white reference plate is scanned, and a selector for supplying the image data, as the input data, to the updating circuit when the determination circuit determines that the image data is greater than the threshold level, and for supplying difference data, as the input data, to the updating circuit when the determination circuit determines that the image data is equal to or less than the threshold level, the difference data being obtained by subtracting a predetermined value from the white reference data stored in the line memory.