PATTERN CHECK DEVICE

A pattern checking device receives scanning data obtained by raster scanning objects within predefined window regions with a photoelectric converter, converts the scanned data into pixel binary data, and evaluates the binary data in accordance with predetermined criteria to produce an output signal indicative of the evaluation. The evaluation is performed in at least two steps. In the first step, a primary decision circuit compares individual data from each window region in a group to upper and lower thresholds, and outputs primary decision result signals for each window region. In the second step, a secondary decision circuit compares all the primary decision result signals for all the window regions in the group with previously stored decision data for the group, and outputs a pattern check signal indicating whether the pattern appearing in the group of window regions constitutes a good pattern.