Abstract

Sensors are needed by the food industry to facilitate remote sensing of moisture during food production processes such as baking and drying. These sensors should provide high sensitivity, have a fast and reversible response, be suitable to high-temperature environments and applicable to gas-phase systems, have a reasonably long service life, and be inexpensive. Optical sensors have inherent advantages for remote sensing and continuous monitoring. Optical sensors using absorption-based dye-doped fibers,¹ NIR spectroscopy,^2,3 and fluorescence measurements⁴ have been reported. However optical sensors suitable for high-temperature humidity detection are not seen in commercial instruments and have not been extensively reported in the literature.

© 1995 Optical Society of America