An image reading apparatus reads an optical image which is projected onto a predetermined plane by a slide projector. The image reading apparatus includes a scanner for optically scanning the optical image formed by the slide projector and for generating image information, a filter for eliminating a...http://www.google.com.tw/patents/US5103320?utm_source=gb-gplus-share專利 US5103320 - Image reading apparatus with correction of two-dimensional shading
