Image read apparatus

Abstract

An image read apparatus which is capable of implementing two-dimensional image reading with high resolution and high picture quality by using a linear image sensor. A vertical scanning mechanism inputs light imaged by a lens from a required sub-image of the read manuscript to a linear image sensor successively, before a sample and hold circuit samples part of an image signal outputted from the linear image sensor. An amplification factor control circuit changes an amplification factor which amplifies or attenuates the image signal in answer to a negative feedback input signal outputted from the sample and hold circuit. The change of the amplification factor causes the light component of the two-dimensional image signal other than the image to be removed due to a change of the amplification factor to be read. Thus, the sampled part of the image signal from the linear image sensor causes the amplification factor of the image signal to be subjected to the negative feedback. The negative feedback essentially removes or minimizes negative influences which affect the image signal caused by light-and-shade change of the frequency corresponding to the lamp line. The image read apparatus is consequently capable of implementing correction without reference to exposed time of the linear image sensor.

Dependencies are inferred from the claim text.