| 摘要 |
<p>An apparatus for measuring parameters, such as moisture content or basis weight, of a fibrous web, e.g., paper or non-wovens, comprises optical elements (52,54,58,64,66,68) and a wavelength selection device (56) for selectively directing a beam of electromagnetic radiation comprising wavelengths in the near infrared (NIR) to mid infrared (MIR) spectral range through the web (70); an element, such as a beam stop (72), arranged in the path of the electromagnetic radiation emerging from the web, for separating directly transmitted from scattered radiation; a collector (74) for collecting the scattered radiation; and at least one detector (78) for detecting the scattered radiation collected by the collector.</p> |
