protype - microphotogrammetry

building 3d models at a microscopic scale using phtogrammetry

project goal

I explored photogrammetry, the process of building a 3D model from photos taken from different viewpoints in Project 10: Instagrammetry. Here, I was curious whether I could apply this process that typically operates on a macroscopic scale to bring microscopic structure into 3D.

methods

When using a traditional stage microscope, the viewplane is 2D. Though translation in 2D can theoretically be used to create a 3D model, being able to rotate the perspective of the camera in addition to translating can substantially boost the quality of the model. Additionally, traditional microscopes illuminate the subject from below the objective, requiring the sample to be transluscent.

For these reasons, I used an inexpensive handheld microscope. This microscope is also digital, which made it easy to capture images. I took a set of 45 images in a roughly a 1 cm2 region. I once again used Metashape for the photogrammetry processing.

The 45 images used to construct a 3D model. Each image covers an area of 6 mm x 8 mm.

results

3D model of a feather section. Note the scale is approximately 1 cm.
On an iPhone in the Safari browser, click on the image to view the model in AR.

conclusion

The model does a good job at reconstructing the ridges between the barbs. When looking at the original microscope images, it seems the detail of the barbules is lost. Potentially this could be improved with higher quality settings in the photogrammetry processing, higher resolution images, or more images.

what will i do next
  • Properly calibrate scale of images so that precise scale of the object can be computed.
  • Collect more images and use a higher processing quality in the photogrammetric reconstruction.