Investigation of sedimentary rocks and grains in the round: Micron-scale SEM-BEX 360° and 3D imaging

The aim of the current paper is to demonstrate the use of a novel prototype horizontal rotation stage, within a scanning electron microscope (SEM). Here we utilise sedimentary rock chips and grains, with images collected every 10 ° of rotation, to produce a continuous overlapping field of view 360° montage. The same procedure can also be used to collect elemental X-ray maps. The collected images and maps can be simply combined into an image stack and saved as a movie format of the rotating specimen through 360°. More significantly, individual images and elemental maps can be reconstructed using photogrammetry imaging software, producing three-dimensional (3D) models with mesh worked surfaces and rendered texture (colour or greyscale) based on SEM image and X-ray data. This produces photorealistic smoothly transitioning movies with 360° fields of view around each object and can also be saved for stereo-viewing using a virtual reality (VR) headset. This new technique generates highly detailed information on the 3D structural and compositional relationships between components at the submicron to millimetre scale. The technique has widespread applications, including imaging other geological materials, biological mineralised tests and material science specimens such as metals, ceramics and building materials.