| 摘要 |
<p>An optical scanner includes a light source (39) which directs a beam of light at a web of moving paper whereby the beam of light is transmitted through the web of moving paper. The transmitted beam (43) is split by a beam splitter (19) to provide a first split beam (44) travelling in a machine direction and a second split beam (45) travelling in a cross-machine direction. The split beams are received by charge-coupled device linear arrays (15, 19) which provide analog signals having magnitudes proportional to the magnitude of light intensity of the split beams. The analog signals are fed to analog-to-digital converters which provide digital data at the output. The digital data is then used to compute paper formation descriptors including paper mass variation, floc size statistics and histogram, Fourier power spectra and paper anisotropy.</p> |
