DETECTOR OF BOUNDARY POSITION AND ANGLE OF EDGE IMAGE

摘要

PURPOSE:To photoelectrically detect the boundary position and inclination of an edge image at the same time by adding, subtracting and dividing the output signals of central and sectorial photosensitive elements. CONSTITUTION:A circular central photosensitive element A0 and sectorial photosensitive elements A1-A4 arranged on a concentric circle constitute a detector and the areas of the elements A0-A4 are made equal to one another. When the boundary of an edge image is positioned on the center of the element A0, the output signal (I1+I2+I3+I4) of adding means C0 is in proportion to the sum of the light regions of the elements A1-A4 and the output signal I0 of amplifying means B0 is in proportion to four times the light regions of the element A0, being equal to the output signal of the adding means C0. Therefore, the output signal of subtracting means D0 becomes equal to zero. That is, by detecting a zero signal, the position of the boundary can be positioned on a center. Since, at the same time, an output signal in direct proportion to an inclination relative to a reference line is obtained from dividing means E1, the inclination can be known by multiplying the half of the sectorial angle of the sectorial element.