Abstract: A multiplicity of special points are identified and recorded as a photoelectrical scanning process. Each special point is marked as an annular pattern on a pattern sheet. The ground of the pattern sheet, the annular pattern and the interior of the annular pattern may have various optical densities and color properties and through detection of such optical properties with at least one light receiving head the exact center of the interior of the annular pattern is detected. This method will be highly useful in automatically drilling holes for mounting component parts in a printed circuit board as a process in the manufacture of printed circuit boards.