| 摘要 |
<p>The method is characterised in that a rectangle R is built up, cut up into 2c vertical strips of equal width, taken as a unit, intersected by I horizontal lines on which are thus delimited, by the various vertical strips, equal segments of unit length, two numbers s2 and sn are chosen defining a white threshold and a black threshold respectively, points Sb, S'b, Sn, S'n are placed on each of the segments AM and A'M such that ASb = A'S'b = sb/2 and MSn = MS'n = sn/2, first and second points P and Q are made to correspond to the numerical values p and q figuring in the table, at the intersection of a line k and of the columns b and b + 1, and all the zones containing the segments PQ delimited between the first and second points are coloured black, and the remainder white. <IMAGE></p> |
