| 摘要 |
PURPOSE:To position an image precisely at a high speed by detecting a coupld of two points of central symmetry on an external form line where neither a noise nor absence is present on a majority decision basis, and calculating the center positionof the symmetry. CONSTITUTION:Distances l1(x1) from respective points on an x1 axis to the 1st black picture elements in a (y) scanning directions and distances l2(x2) from respective points on an x2 axis to the 1st black picture elements in the opposite scanning direction of the (y) axis are found successively. Then, the difference s(x) between l1(x1) and l2(x2) is calculated while a relative shift quantity (t) is varied. Then, the frequency n(s) of s(x) is calculated for each (t). Then, to corresponding to the maximum value no(t) of the frequency is calculated. Lastly, a center x1 coordinate (u+to) and a center (y) coodinate [v+s(to)]/2 are calcu lated from to and (u). |
