NON-SCANNING, ON-LINE MULTIPLE WAVELENGTH SHEET MONITORING SYSTEM

摘要

A non-scanning sheet monitoring system is described which uses a plurality of compact, low part count sensor units (5) to measure a plurality of wavelengths from a plurality of measurement locations (3). Each sensor unit includes a plurality of radiation detectors (6, 7), each detector used to detect a different radiation wavelength. A source of radiation (8) may be associated with each sensor unit, a single source of radiation (8) may be used to illuminate the sheet for multiple sensor units, or passive radiation may be used. The sensor units may be arranged along a single line, or may be staggered in position.