Scanning device with variable scanning density

摘要

In this device, an original is scanned along each of a multiplicity of parallel line paths by means of a light beam with fixed light spot size at constant speed in order to generate an image signal, and the scanning is successively shifted to the next line path in each case. The image signal is scanned is order to generate an image interrogation signal. Each line path is divided into a multiplicity of line sections in such a manner that each section results in a multiplicity of line interrogation signals, and the line paths are combined to form a multiplicity of groups of adjoining line paths so that image interrogation signals are derived from a multiplicity of patterns of lines and columns. The total value of the image interrogation signals for each pattern is arithmetically divided by the number of the signals in accordance with a control signal, in order to obtain an average value by this means.