| 摘要 |
A preprocessing circuit of a line sensor which includes a plurality of photoelectric elements arranged in the form of a single array and divided into a plurality of blocks is provided. The preprocessing circuit includes a differential input/differential output preamplifier having a pair of input terminals and a pair of output terminals. A pair of read output data is collected by the preamplifier from a pair of photoelectric elements which are located substantially symmetrically with respect to the center of the line sensor while the line sensor is being scanned electronically. A pair of outputs from the preamplifier is selected such that there remain an output signal of a predetermined polarity. And, a peak value of the output of a predetermined polarity is sampled and held and it is adjusted in accordance with a dark level correction data stored in a memory for each of the photoelectric elements. The memory also stores a gain correction data for each of the photoelectric elements, which is used for correcting the gain of the output signal. Then, the output signal is converted into a digital signal.
|
