Variable density scanner

摘要

In a variable density scanner a light beam of a fixed spot size is scanned on an original along each of a plurality of parallel line paths at a constant speed to generate a video signal and successively shifted to the next line path. The video signal is sampled to generate a video sample. Each of the line paths is divided into a plurality of line segments so that each segment derives a plurality of video samples and the line paths are formed into a plurality of groups of adjacent line paths so that the video samples are derived from a plurality of patterns of rows and columns. The total value of the video samples of each pattern is arithmetically divided by their number in response to the control signal to derive an average value.