The report reviews the ways to characterise the morphology of free and embedded particles.
For such a purpose quantitative image analysis is the principal and the most adequate method for fine characterisation. The different steps involved are described subsequently.
The main imaging techniques used for particle visualisation are recalled: they are selected according to the particle size range, desired level of details and eventual supplementary information that the imaging device can produce (transparency, chemical composition, etc.).
Images being 2D projection on a plane of 3D reality, the basic image treatment aims at the segmentation to retrieve particle silhouettes. There is no fixed procedure, each being case-dependent.
Sizing principles are presented: they enable to determine the projected equivalent diameter, the length and the breath of the particle silhouette and its perimeter.
The 2D shape descriptors are based on both contour and silhouette, on silhouette only or on contour only. The different types are reviewed. Tools to produce some information on the 3D-morphology of particles are then presented.
When particles are embedded, further morphological information can be obtained, related to the anisotropy of the sample and/or orientation of particles in the sample.
Statistical elements, in terms of the number of particles to analyse as well as ways to treat the large sets of parameters necessary to quantify the shape are outlined.