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:
Dec. 27, 1994
Filed:
Sep. 29, 1993
Osamu Takase, Yokohama, JP;
Ricoh Company, Ltd., Tokyo, JP;
Abstract
An image reading apparatus includes a photoelectric conversion element which has a plurality of cells, the plurality of cells including shielded cells which are optically shielded so that each shielded cell outputs only the dark signal, a dark signal data generating system for generating dark signal data for each cell of the photoelectric conversion element, the dark signal data corresponding to a ratio of an image signal output from each cell under a no-exposure condition to a first reference dark signal which is obtained based on the dark signals output from the shielded cells under the no-exposure condition, a dark signal data memory for storing the dark signal data for each cell, a dark signal component generating system for generating a dark signal component for each cell, the dark signal component corresponding to a product of the dark signal data for each cell multiplied by a second reference dark signal which is obtained based on the dark signals output from the shielded cells under the exposure condition, and a subtracter for subtracting the dark signal component from an image signal obtained for each corresponding cell under the exposure condition.