In this paper, we present a system developed to identify metal nanoparticles at different orientations, using digital image processing and analysis. The correct identification is important in nanotechnology, where it is possible to build structures for different purposes at the nanometric level. The recognition system computes automatically different characteristics such as: nanoparticle area, polygons, symmetry and molecular arrays (twins) in order to recognize different nanostructures. All these characteristics are obtained through the use of morphological, texture (co-occurrence matrix) and region analysis. Complexity issues, advantages, and results are presented and discussed.