| 摘要 |
<p>An apparatus and a method for counting objects, such as printed copy being advanced along a path in an overlapping manner, is arranged to direct two beams of infra-red radiation on to a predetermined region in the path of advancement of the copy. The two beams are distinguishable one from the other and are directed from positions respectively upstream and downstream of said region. Two detectors (24,25) are disposed above said region, to receive radiation respectively from two distinct areas, both within said region but spaced in the direction of the path of advancement of the objects. Suitable processing of the detector outputs, to determine the gradients of the said areas, allows the generation of a count signal as the leading edge of an object passes through said region.</p> |
