| 摘要 |
<p>An instrument for counting the number of elements in a stack is moved over the side of the stack and an image of a portion (S) of the stack is formed on a linear photocell array (16). The photocell array is continually scanned and its electrical scan output signal is fed to a correlator which carries out an auto-correlation function whilst the instrument is initially stationary, and then a cross-correlation function as the instrument is moved, to furnish a time varying signal having a characteristic periodicity representing successive elements in the stack. The repeating cycles in this signal are counted to provide a count of the number of elements in the stack.</p> |
