A Review of Image Analysis Based Methods to Evaluate Fiber Properties

This review focuses on fiber analysis methods, where the fibers are carried in suspension. They are photographed in a flow cell and their properties are evaluated by digital image analysis. Three fields of fiber analysis are covered: Fiber morphology, pulp surface chemistry, and chemically induced swelling respectively dissolving behaviour of pulp. For fiber morphology commercial analyzers were compared. On an absolute level the measurement differences between the analyzers varied from 15% to 40%, for some morphological parameters up to 70%. Still fiber length, width, and curl results are highly correlated, so relative comparison is possible. An increasing number of publications have recently been devoted to image analysis based evaluation of surface chemistry respectively chemically induced fiber swelling and dissolving. Considering that research effort it can be expected, that numerous innovations in both fields commercial fiber analyzers as well as new machine vision based fiber analysis techniques, can be expected in the next years.