Dichotomous scan system for detection of overlapped objects

摘要

Apparatus and method are disclosed for detection of overlapped objects moving along a defined path. A light radiation source directs a light beam toward the path. As an object moves into the light beam, reflected light is received by two light sensors. An edge of an overlapping object moving along the defined path substantially blocks the light reflected from the underlying object from being received by one light sensor. The edges of an overlapping object are detected when a there is a difference in the amount of reflected light received by the light sensors and there exists a substantial rate of change in the amount of reflected light (indicative of a true edge of an overlapping object as opposed to warps, wrinkles, creases, etc. on the surface of an object) received by either light sensor due to the substantial blockage of reflected light by the edge.