Digital Data in Biodiversity Research Conference

Digitizing collections is a major challenge for natural science institutions. Thanks to various techniques developed over the years, most collection specimens can now be efficiently digitized. However, arthropods present a unique challenge due to their complex textures and structures, which can be tiny, transparent, hairy, shiny or dark. Consequently, existing workflows are limited to the scientific study of specimens requiring measurements, such as morphometric geometry. In response to this challenge, Sphaeroptica was developed with the aim of returning to the fundamental principles of photogrammetry. Sphaeroptica serves as a 3D viewer of a sphere of oriented 2D images, enabling users to visualize specimens and perform geometric measurements. It effectively displays complex structures such as chaetae and setae, using high-resolution stacked images instead of an approximate, simplified 3D model. Metric comparison of measurements obtained with Sphaeroptica on several case studies shows that differences with those measured on high-resolution 3D models derived from microcomputed tomography images are less than 1%, making Sphaeroptica's workflow suitable for accurate measurements of small and complex specimens such as arthropods.