Measuring the Three-Dimensional Morphology of Crystals Using Regular Reflection of Light

In this paper we present a new technique for measuring the three-dimensional (3D) morphology of faceted crystals. This new technique is based on the observation that a significant amount of regular reflection of light happens from flat crystal faces. Innovative lighting and camera arrangement is used to obtain the photograph of the crystal where a face is highlighted by huge contrast from the background. Such photographs are used to identify the location of the face corners using an in-house method as well as with the well-known Harris corner detector. The in-house method is found to be of comparable efficiency as the Harris detector. Using a simple algorithm, the 3D face coordinates are generated from the two-dimensional face coordinates. Finally, the 3D coordinates of the corners are used to reconstruct the crystal. A consistency check is employed during the reconstruction step which corrects for any missing corner or inconsistent data.