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. 01, 2001
Filed:
Jul. 24, 1998
Kazuhito Ohashi, Shizuoka-ken, JP;
Noriyoshi Chizawa, Mishima, JP;
Masafumi Kamei, Numazu, JP;
Takashi Sugiura, Mishima, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
This invention provides an image reading method and apparatus which can prevent a large difference from being produced between the color tones of the read image and the original image. A plurality of signals output from an image sensor (,) are A/D-converted into a plurality of digital signals by A/D conversion circuits (,), a predetermined one of the A/D-converted digital signals is compared with a predetermined reference level by a comparator (,), a low-pass filter (,) removes any high-frequency component from the comparison result, and the output from the low-pass filter (,) is controlled to be input to the A/D conversion circuits (,) as a reference voltage for determining the input range of each A/D conversion circuit (,).