Other "Scapes" Mapped & Modeled!

Example of Coastal Wetland margin forest sUAS aerial mapped and 3D modeled using SfM. Interface shows Pix4D 3D space in which users can manipulate/rotate the rendered scene.

Example of Tropical Reef scuba mapped and 3D Modeled using Structure from Motion (SfM). This is Racha Reef in Thailand scuba surveyed by my colleague K. Jaroensutasinee prior to and just following a Cyclone that significantly damaged the reef. In the image you see the Pix4D SfM interface along with the scuba survey camera positions.

This was a project to evaluate the validity/accuracy of sUAS aerial mapping/modeling vs. Ground survey techniques using a Total Station. We found the sUAS aerial mapping and Structure from Motion processing produced an orthomosaic of good detail and an accompanying Digital Surface Model that compared well with Total Station transect elevation accuracy.

Following are some interesting examples of "Scale Independent" Structure from Motion (SI SfM). Check my SfM section for a more detailed description of what SfM is and how it works!

I've used sUAS/drones for Hectare scale landscape mapping, and underwater cameras for Tropical Reef survey/mapping. But I've discovered SfM also works for much smaller-scale phenomena. So I experimented with using my iPhone, microscopes and even scanning electron microscopes to create orthomosaics of a variety of scapes at widely differing scales.

This is an example of what you can do with a smartphone. I simply "flew over" the object as I would a landscape with a drone. I made regular "lawn mowing-style" passes over the coral and input the imagery into Pix4D. It rendered a 3D model in less than a minute. This 3D file can be output to a 3D printer to make tiny Brain Coral replicas... Cool!

This example, like that of the Brain Coral above, is accomplished by using an iPhone to fly over and around a seashell. Images input to Pix4D SfM software..... the SfM process simply sorts out the "structure" from the relative positions of the camera as it calculates its movement over the object. Again, the 3D file may be output for use in other processing.

This is an example of using a microscope to image an area of a slide by moving the slide stage and capturing successive images. The process is similar to the flights over landscapes using sUAS, and my smaller scape examples using the iPhone (above).

This is really unexpected.... I asked a colleague in our Physics Department to capture successive images of nano-scopic carbon threads. He used the same technique of "lawn-mower" style overflights of the area of interest. The result is that we could image/mosaic a very large (relative) area of the nano-scopic scene and easily trace the dimensions of the carbon threads. The results of this work supported an undergraduate Honors Thesis. David Uhl (now MS candidate in Physics) did the work and wrote it up. Very unique SfM results!

I did a comparison of mosaics: one was hand-stitched using Photoshop (many hours and not really accurate) and the other SfM (completed in less than 2 minutes).