Device for finding centroid coordinates of figures

A device for finding the centroid coordinates of a figure comprising;

• a main body having a roller capable of running in a single direction;
• a measuring lever pivotably supported by the main body so as to be rotatable right or left from the running direction of the main body in a horizontal plane, the measuring lever having a tracer to trace a contour of the figure to be measures;
• input means for successively reading coordinates where the tracer is positioned and input the coordinates to the main body;
• and
• the main body including a display and a calculating circuit;
• wherein
• the calculating circuit being constructed to compute the values My.sub.i, Mx.sub.i and F.sub.i from the successively input coordinates (x.sub.i, y.sub.i) (i=1 , . . . , n where (x.sub.n, y.sub.n)=(x.sub.1, y.sub.1)) according to the following equations:
• My.sub.i =(x.sub.i+1 -x.sub.i)(y.sub.i+1.sup.2 +y.sub.i+1 y.sub.i +y.sub.i.sup.2)/6
• Mx.sub.i =(y.sub.i -y.sub.i+1)(x.sub.i+1.sup.2 +x.sub.i+1 x.sub.i +y.sup.2)/6
• F.sub.i =1/2(x.sub.i +x.sub.i+1)(y.sub.i+1 -y.sub.i),
• the calculating circuit adding the values of My.sub.i, and Mx.sub.i and F.sub.i to the values My.sub.i-1, Mx.sub.i-1 and F.sub.i-1, respectively as the measuring lever is tracing, and after the contour of the figure is traced, divides the values My.sub.n and Mx.sub.n by the value of F.sub.n respectively to obtain the coordinates of the centroid of the figure, and
• the display displaying the differences of the current coordinates of the measuring lever from the coordinates of the centroid of the figure.