The measurement of the diameters and lengths of Man-Made Vitreous Fibr
es (MMVFs) used in insulation materials is important to the glass and
mineral wool industry. Such measurements are needed for quality contro
l purposes. To obtain reliable quality estimators, the measurement of
several hundreds of fibres is necessary, traditionally carried out by
human operators. Manual measurements are reliable if performed by skil
led operators, but are always slow and repetitive. In this paper, two
methods for performing these measurements are presented. These methods
are based on the automated image analysis of Scanning Electron Micros
copy (SEM) images. For each of the two proposed methods, we present in
succession the sample preparation and the image analysis algorithms u
sed for the segmentation of the fibres and for their measurement.