Wear particles are produced whenever moving surfaces interact. The analysis of wear particles is now widely applied for non-intrusive examination of the condition of machinery, and can provide useful information for machine maintenance. There have been many attempts to automate the analysis of wear particles in recent years, as visual analysis is often time consuming, expensive and inconsistent, In this study, laser scanning confocal microscopy (LSCM) has been further developed and applied to obtain three-dimensional images of wear particles. LSCM includes a transmission sensor to acquire transmission and reflected (confocal) images simultaneously. The transmission sensor can provide far better images for boundary analysis, therefore, appropriate images containing both boundary and surface data are available. Software for the image analysis of boundaries and surfaces has been developed in this study. (C) 1997 Elsevier Science S.A.