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:
Jun. 14, 1994
Filed:
Mar. 17, 1992
Shinya Takenaka, Osaka, JP;
Sumitomo Electric Industries, Ltd., Osaka, JP;
Abstract
In the white level detection circuit for an optical image reader, for a low value portion in an image, the white level signal corresponding to an image signal of a high value background portion which precedes to the low value portion is held steady. Accordingly, even if the low value image portion has a long duration, the white level signal may be kept at a proper value for the image signal corresponding to the low value image signal. For the high value background portion, the white level signal that immediately follows a variation of the image signal can be obtained. Therefore, a proper white level signal can be generated for the background portion. Various processing applied to the image signal on the basis of the white level signal may be performed in a satisfactory manner. As a consequence, the read performance of the optical image reader may be remarkably improved.