| 摘要 |
<p>Apparatus particularly suitable for the counting of folded printed matter being advanced along a line in an overlapping manner has two radiation sources (11 and 12) directing radiation on to the matter from opposite directions but at similar angles to the line of advancement. The radiations may be electromagnetic or sonar, but are distinguishable in time, or in frequency, or in polarisation. Reflected radiation is received by a receiver (16) the output of which is suitably processed to allow discrimination of whether radiation from both sources (11 and 12) is being received, or radiation from only one source, which will happen when the leading edge of an advancing object arrives at the zone at which radiation reflection takes place. Such discrimination then allows a count of the number of objects advanced to be obtained.</p> |
