Method of and system reading out image signal

摘要

A digital image signal is read out at a predetermined picture element density by causing a light beam to repeatedly scan a recording medium bearing thereon an image in a main scanning direction at a predetermined main scanning speed while moving the recording medium in a sub-scanning direction substantially perpendicular to the main scanning direction at a predetermined sub-scanning speed, thereby two-dimensionally scanning the recording medium with the light beam, photoelectrically detecting signal light emitted from the recording medium upon exposure to the light beam to obtain an analog image signal, sampling the analog image signal at a predetermined intervals, and quantizing the sampled values. A digital image signal at a desired picture element density different from the predetermined picture element density is read out by changing the sub-scanning speed to m(>0) times the predetermined sub-scanning speed, and changing the intervals at which the analog image signal is sampled to intervals n(>0) times the predetermined intervals.