Image reading device

Abstract

Abstract PURPOSE:To perform the setting of a pattern having a (gamma) correction characteristic over a wide range, by attaching plural reference planes with various kinds of density on a density reference board which performs an optical scanning to obtain a density reference signal at the time of a (gamma) correction, prior to the read of an original picture. CONSTITUTION:On the edge part of a contact glass 1 at the rear plane of an original scale 9, a density reference board 10 in which both white density and nonuniformity are managed, is provided, and the optical scanning is applied on the density reference board 10 prior to the read scanning of an original 2, and a data obtained by a line image sensor 8 at that time is used as a density reference value at the time of the (gamma) correction of a bit of digital picture information in which the original 2 read thereafter is multivalue-quantized. As the density reference board 10, a white board, but on which three reference planes with different reflecting density (a), (b), and (c), are attached, is provided, and the sample obtaining time of the density reference signal from a scanner reference position is change corresponding to selection of strong, medium and weak.

Inventors

• 👤 Takeshi Yoshimura
• 👤 剛 吉村

Bibliographic Details