Image reading device

Abstract

Abstract PURPOSE:To compensate the variance of the sensitivity due to a change of the quantity of light or the like, by storing a read picture signal outputted from an image pickup element and compensating the signal level on a basis of stored contents to give a uniform lightness to a pressing face of an input original along the scanning direction of the image pickup element. CONSTITUTION:An original 1 is guided by rollers 2 and is allowed to pass between a pressing plate 4 and a target glass 5 in a prescribed speed, and an original pressing face 4a of the plate 4 is illuminated uniformly by a light source 3 such as a fluorescent lamp. A detection signal DS is generated from an original sensor 8 before the original 1 reaches a scanning and reading position P, and the picture signal of the original 1 is applied to an image pickup element 7 through an image pickup optical system 6 at the position P, and the picture signal is read by the element 7, and a read picture signal V0 from a DC reproducing circuit 10 is applied to a reading circuit. This signal V0 is stored in a storage device of the reading circuit, and the signal V0 is inputted and compensated in a compensating circuit on a basis of contents stored in the storage device, and thus, a uniform lightness is given to the pressing face 4a along the scanning direction of the image pickup element.

Inventors

• 👤 Shingo Yamaguchi
• 👤 山口　晋五

Bibliographic Details