| 摘要 |
To read a document accurately and produce an image signal faithfully representing the document, an image reading method and apparatus adopts various means, of "latching an average light-shielded signal in a digital form", "using an average light-shielded signal resulting from averaging output signals of a plurality of light-shielded pixels as a black reference signal", "replacing that part of an image signal in which an average light-shielded signal is larger than an effective pixel signal in level with a signal of a zero level", "driving CCD sensors at such timing as to allow effective pixel signals output from the CCD sensors to be continuous in time" and "setting DC offset voltages of signals output from CCD sensors to a predetermined clamp potential.
|
