Brecko, J.,  Pollet, Y.,  Henrard, A.,  Laebens, T.,  Mathys, A.,  Dekoninck, W.,  Pauwels, OSG.,  Jordaens, K.,  De Meyer, M.,  Vandenspiegel, D. & Semal, P. 2026. ‘Le focus stacking en un clin d'oeil : accélérer la numérisation 2D+ des collections d'histoire naturelle’. Conférence Internationale Francophone d’Entomologie, CIFE XI – L’entomologie face à la globalisation et à l’approche une seule santé. Book of abstracts. Liège.

Conference abstract

A decade after the introduction of a low-cost 2D+ digitization method for natural history specimens using focus stacking, this technique is now widely used to document the morphological characteristics of small specimens, particularly in entomology and other invertebrate collections. The main limitation remains the time required for image acquisition and the reconstruction of extended depth-of-field views, which can take several minutes per acquisition-reconstruction cycle. This study re-examines and significantly improves the initial workflow by identifying key bottlenecks—specifically camera stabilization, specimen lighting, camera movement, and image processing. It proposes a new digitization protocol that leverages mirrorless cameras by combining built-in features like "focus bracketing" with continuous movement along a camera rail, prime lenses with manual focus, LED dome lighting, and focus-stacking software utilizing GPU hardware acceleration. This new protocol reduces digitization time by up to 100-fold—dropping from several minutes to just a few seconds per final image—without compromising image quality. We also evaluate the integration of AI-based background removal tools and advanced visualization and measurement software, such as Stackoptica and Depthoptica, which enable pseudo-3D measurements from 2D+ images. The result is a faster, more scalable, and more precise digitization protocol that paves the way for high-resolution, high-throughput digitization of natural history specimens.