2021 GSA Introduction to Structure from Motion

Instructors: J Ramon Arrowsmith & Chelsea Scott, Arizona State University ; Christopher Crosby, UNAVCO

Endorsed by: OpenTopography, UNAVCO

Course Description:
Structure from Motion (SfM), a photogrammetric technique that uses overlapping images to construct 3D surface models, is quickly emerging as a valuable research and education tool in geodesy, geomorphology, structural geology, and related disciplines. Images can be collected with a standard consumer-grade camera, making SfM a low-cost tool that complements other 3D imaging technologies, such as terrestrial and airborne laser scanning (lidar). SfM can be collected from a handheld camera or an airborne platform such as an aircraft, tethered balloon, kite, or UAS (unmanned aerial system), enabling 3D imaging of features ranging in size from decimeters to several kilometers. This one-day course will provide faculty, students, and professionals with an introduction to SfM technology, data collection and processing, and examples of science and educational applications. A combination of lectures and hands-on demonstrations of SfM equipment and data processing will be used.

Software:
- Agisoft Metashape Professional 1.7.4: Proprietary SfM software available for Windows, MacOS, and Linux. A license will not be necessary for the course as we will use Metashape in demo mode, but please have the software installed on your machine before the short course begins.

Optional Software (will be demo'd but not required for hands-on activities):
- CloudCompare 2.11.x Anoia: Open source point cloud software available for Windows, MacOS, and Linux. Please have the software installed on your machine before the short course begins. If you happen to have an older computer you may need to install a previous version of CloudCompare available under "Older stuff" on the downloads page.
- Virtual Outcrop Geology Group LIME
- Stereonet 11

YOUTUBE PLAYLIST OF RECORDED PRESENTATIONS direct links to videos via the logos below.

Agenda:

• 9:00 am Welcome and course introduction (Crosby)
• 9:20 am Introduction to SfM and scientific motivations (Arrowsmith)
  - Introduction to SfM Photogrammetry
  - Coordinate systems and other basic concepts
• 10:15 am Break
• 10:30 am Faraglione, Vulcano Island, Sicily, Italy demo (Scott)
  - 2018 Faraglione, Vulcano Island, Sicily, Italy (simple demo) dataset in OpenTopography
  - Faraglione sample image set
  - Faraglione SfM products
  - UNAVCO Agisoft Metashape processing guide
• 11:15 am Overview of SfM data acquisition concepts & other topics (Crosby)
• 12:00 Lunch break
  - Take pictures and/or organize some data of your own (all)
  - Optional: Discussion in breakouts
• 12:45 pm Wrap up your lunch and begin running models (all)
• 1:15 pm Participants share models, group discussion of what worked and what didn't (all)
• 1:45 pm Discussion of Mecca Hills Painted Canyon project (Scott)
  - Painted Canyon dataset in OpenTopography & Painted Canyon exercise page
  - 3D mapping on point clouds and textured meshes in LIME/V3GEO
  - CloudCompare and Stereonet
  - LIME software demonstration video
• 2:30 pm Final discussion
• 3 pm adjourn
• post-3 pm Short course leaders available for additional informal discussion.

Other sample Datasets & Resources:
- Georeferencing in Metashape: Tutorial & Mafala Bolo, Ethiopia sample data
- GETSI curriculum: Analyzing High Resolution Topography with TLS and SfM
- Topographic differencing: Measuring change at Earth’s surface: On-demand vertical and three-dimensional topographic differencing implemented in OpenTopography & OpenTopography topographic differencing resources
- CloudCompare tutorial playlist by James Dietrich