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:
Aug. 19, 1997
Filed:
Mar. 06, 1990
Masafumi Yamanoue, Yao, JP;
Sharp Kabushiki Kaisha, Osaka, JP;
Abstract
The shading correction is performed with respect to a signal 'A' indicative of the image density read by an optical read device in accordance with a reference signal 'B'. Both the signals 'A' and 'B' consist of n bits. An inputted signal having an initial value 'A' is doubled by a multiplier when A=B and B.noteq.0. A subtracter subtracts the reference signal 'B' from a signal 'X' outputted from the multiplier and discriminates whether or not a signal 'X-B' is negative. An S/P conversion register doubles an integrated value 'S' having an initial value '0' and changes the integrated value from 'S' to '2S' when the signal 'X-B' is negative. In contrast, when the signal 'X-B' is not negative the S/P conversion register adds '1' to '2S' and changes the integrated value from 'S' to '2S+1'. The signal 'X' outputted from the multiplier is again inputted into the multiplier when the signal 'X-B' is negative. Alternatively, the multiplier receives the signal 'X-B' outputted from the subtracter when the signal 'X-B' is not negative. The, above procedure is repeated n times. The last integrated value outputted from the S/P conversion register is equal to or approximately equal to a value obtained by an expression 'S=A(2.sup.n -1)/B', and therefore, the former can be regarded as a shading correction signal.