TRANSVERSE DIMENSIONS OF WOOD PULP FIBERS BY CONFOCAL LASER SCANNING MICROSCOPY AND IMAGE-ANALYSIS

Cross-sectional images of wood-pulp fibres were generated using optical sectioning by a confocal laser scanning microscope. The technique has a distinct advantage over mechanical sectioning with a microtome, as it simplifies specimen preparation. Cross-sectional images were obtained for unbleached softwood kraft pulp fibres using epifluorescence mode. The accuracy of cross-sectional images was verified by imaging fluorescent microspheres. An image analysis procedure, in which the boundaries of fibre cross-sections were defined with a maximum-gradient edge-finding technique, was developed for measuring fibre cross-sectional area and wall thickness rapidly and accurately. The measurements were insensitive to the confocal microscope's asymmetric resolution, signal deterioration through the specimen thickness, overall image quality and operator bias.