Producción CyT
Congreso
Autoría
Escobar Guardia A.
;
Gavazza A
;
Pavé R
;
Argoitia A
;
Caraballo, Diego A.
;
SCHIERLOH, LUIS PABLO
Fecha
2024
Editorial y Lugar de Edición
FFyB-UBA
Resumen
Información suministrada por el agente en
SIGEVA
Introduction and objective: Until recently, 3D-modelling of small (0.1-10cm3) (bio)structures must be performed using expensive image acquisition systems (microCT or light sheet microscopy) that were not available in most health educational or clinical centres in our region. With the advance of 3D-photogramming softwares and the general accessibility to high resolution digital cameras with macro lens, any interested professional can, with minimal financial and learning efforts, rapidly obtain u...
Introduction and objective: Until recently, 3D-modelling of small (0.1-10cm3) (bio)structures must be performed using expensive image acquisition systems (microCT or light sheet microscopy) that were not available in most health educational or clinical centres in our region. With the advance of 3D-photogramming softwares and the general accessibility to high resolution digital cameras with macro lens, any interested professional can, with minimal financial and learning efforts, rapidly obtain useful surface 3D-maps for downstream applications in (bio)printing projects [1]. Herein we describe the design, construction and concept's proof of a cost-effective step-motorised 3D-mapping stage for digital photogrammetry of small bony structures.Methodology: We adapted a classic version of a photogrammetry 3D scanner model by OpenScan (CC BY-NC-N). Our setup includes the scanner stage and a dedicated photography light enclosure. The frame’s parts were fabricated with a FDM 3D printer using standard PLA. The electronics include an inexpensive Arduino UNO R3 board that controls two stepper motors (28byj-48) in a half-step configuration. During testing, a scanning routine is executed to capture object-surrounding images accurately, ensuring consistent lighting conditions. Construction decisions prioritised stability and precision while minimising costs. The estimated cost was ≈U$S 60 including materials and 3D-printer usage. Results and discussion: As a proof of concept about prototype’s usability, we performed a collaborative work with a mammal research group that needed to establish discrepancy criteria among two close mastiff bat species (genus Molossus) that were genetically defined but morphologically overlapped (aka: "cryptic species") [2]. Given the size and complexity of the comparing objects (≈1.5cm3 sized skulls) and the subtle shape variation to be expected, this kind of problem implies a challenging scenario for testing our prototype’s pros and cons. After scanning 10 skulls (n=5 of each species, <100 images/3D-map), models obtained with Meshroom 2023.3.0 software were manually landmarked (3D Slicer 5.6.2 - SlicerMorph software, 30 landmarks/skull) and the dataset was analysed by 3D-Geometric morphometrics. Briefly, the generalised procrustes analysis (GPA) followed by principal component analysis (PCA) let us establish a significant global shape variation among both species and to identify the most discriminant cranial sub-structures.Conclusions: In the pursuit of digital 3D-models of small structures with enough resolution for (bio)printing aims, the current use of expensive hardware is now starting to be replaced by cost-effective digital photogrammetry. In this challenging context, our proposal can become a valuable accessory tool for simplifying and standardising the images sampling procedures. Furthermore, the mathematical scaffold behind the 3D-Geometric morphometrics theory employed herein can also be applied when the shape of the targeted (or fabricated) (bio)object needs to be carefully characterised. References[1]. Barbero-García et al 2017. “Low-Cost Smartphone-Based Photogrammetry for the Analysis of Cranial Deformation in Infants”. World Neurosurg 102:545-554. http://dx.doi.org/10.1016/j.wneu.2017.03.015[2]. Chambi-Velazquez et al 2024. “Revisiting Molossus (Mammalia, Chiroptera: Molossidae) diversity. Exploring southern limits and revealing a novel species in Argentina”. Vertebrate Zoology. Submission #122822. In press.
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Palabras Clave
3D-PRINTDIGITAL PHOTOGRAMETRYGEOMETRIC MORPHOMETRICSSMALL BONY STRUCTURES