3D Modeling from AFM Measurements

There exist many techniques for the measurement of micro and nano surfaces and also several conventional ways to represent the resulting data, such as pseudo color or isometric 3D. This paper addresses the problem of building complete 3D micro-object models from measurements in the submicrometric range. More specifically, it considers measurements provided by an atomic-force microscope (AFM) and investigates their possible use for the modeling of small 3D objects. The general approach for building complete virtual models requires to measure and merge several data sets representing the considered object observed under different orientations, or views. A straightforward application of this scheme fails when acquisition methods for micro-objects, due to physical constraints, cannot provide the required positioning information for aligning the different views. The presented approach proposes to use an a posteriori software registration procedure that aligns views by registering common overlapping parts. It relies on the sole intrinsic properties of the object geometry and does not require additional measurements The actual registration process proceeds in two steps: a first rough interactive alignment of the views, followed by their automatic matching. Such generated 3D models offer new possibilities for the analysis of micro-objects by visualization or measurement in 3D space. First experiments are presented which demonstrate, among others, the successful alignment of three AFM views of a Ni-polymer substrate (used to fix particles) by geometric matching. The final goal of this work is to build complete virtual models of submicroscopic objects, for instance quartz particles measuring about 1-3 μm.