Physik | Technik
Yanick Bader, 2004 | Lausen, BL
This paper presents a workflow for creating 3D printed models intended for science education from scanning electron microscope (SEM) images using photogrammetry. The workflow involves sample preparation, SEM image acquisition using a Zeiss GeminiSEM 450 and photogrammetric reconstruction with Agisoft Metashape. The resulting digital models were post-processed with various software for 3D printing. The method produces high-quality models with micron-scale resolution, which can improve understanding of microscopic structures. A survey investigating the educational impact of hands-on learning in a lung dissection context showed increased student motivation, enjoyment and understanding compared to traditional learning methods.
Introduction
Traditional 2D images and text can limit the understanding of complex structures, especially at the microscopic level. To address this issue, accurate and engaging 3D educational models can be created by combining scanning electron microscopy (SEM), photogrammetry, and 3D printing. SEMs are suitable for photogrammetry due to their large depth of field, high resolution, and ability to image various materials. The aim of this work is to answer the following question: How can Structure from Motion (SfM) photogrammetry be used to create 3D printed educational models from scanning electron microscope (SEM) images?
Methods
The process started with preparing specimens for SEM imaging, ensuring they were vacuum-safe and conductive for high-quality imaging. A special mount was developed to improve visibility. Images were captured using a GeminiSEM 450 with settings optimized for depth of field and contrast. To achieve the best possible photogrammetric reconstruction, images were taken in a dome-shaped pattern. Agisoft Metashape was used to create digital 3D models from the SEM images. The models were embedded into a stand to make them usable as educational tools. They were simplified, corrected for errors, and had support structures added for printing. A Formlabs 3B+ resin printer was chosen for its ability to print delicate features. To assess the educational potential of 3D models, a study was conducted on a similar hands-on activity, specifically lung dissection. The study aimed to determine whether hands-on learning improves student motivation, enjoyment, and understanding of the lung compared to traditional methods.
Results
The workflow was tested on two Drosophila melanogaster flies, resulting in the successful creation of a model of the full head and eye. The models accurately captured fine details such as hair and the facets of the eyes, which were then reconstructed, and 3D printed. A survey conducted among students showed that over 80% agreed that dissection increased their motivation, enjoyment, and understanding of lung anatomy compared to traditional methods. Similarly, a high percentage indicated that interactive techniques, such as 3D models, enhance learning.
Discussion
The possibility of generating 3D models from SEM images using photogrammetry has been demonstrated, which opens opportunities for scientific education and visualization. Although these models are not suitable for quantitative analysis, they still offer valuable insights into microscopic structures. During image acquisition, the tilt range was found to be a limitation, but pre-tilting and raised mounting can improve coverage. Automation would significantly enhance efficiency. Accuracy assessment can be performed by comparing models to reference scans. The use of resin printers for small and intricate models in 3D printing worked flawlessly. The survey emphasizes the educational potential of such models and supports the value of developing 3D models using this workflow, as they can offer a similar hands-on learning experience.
Conclusions
Photogrammetry can create visually appealing 3D models from SEM images, even without precise calibration. Although this approach limits direct quantitative measurements, these models offer valuable insights into microscopic structures, making them ideal for scientific education and visualization. This technique is most effective for samples with round features that are easily prepared for high vacuum conditions. Further research is necessary to optimize image parameters for maximum efficiency and model quality. The use of Augmented and Virtual Reality (AR/VR) could improve the accessibility and interactivity of the models.
Würdigung durch den Experten
Dr. Dimitri Vanhecke
Die Arbeit von Yanick Bader umfasst eine Pipeline zur Erzeugung originalgetreuer 3D-Objekte (entweder virtuell oder real) aus Mikroskopaufnahmen. Die Arbeit kann zu Bildungszwecken, zur Analyse von Prototypen oder zur Gewinnung von Erkenntnissen, z. B. in einer VR-Umgebung, eingesetzt werden. Der Beitrag von Herrn Bader war beträchtlich. Er fand Zugang zu einem Elektronenmikroskop. Er erlernte den Umgang mit dem Gerät, einschliesslich der Vorbereitung biologischer Proben, verarbeitete die Daten zu einem 3D-Datensatz und druckte diesen mit einem 3D-Drucker aus.
Prädikat:
sehr gut
Sonderpreis der Schweizerischen Physikalischen Gesellschaft (SPG)
Gymnasium Liestal
Lehrer: Dr. Jann Frey
