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Photogrammetry: A Quick Primer
This document provides an overview of photogrammetry, which is the process of using photographs to measure and survey objects and landscapes. It discusses different types of photogrammetry like stereography and structure from motion (SfM). SfM uses photographs to build 3D models and can be used with images from any camera. The document also outlines common uses of photogrammetry in fields like geology, archaeology, and engineering. It provides guidance on capturing images for photogrammetry projects of objects, buildings, and interiors.
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Photogrammetry: A Quick Primer
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- 5. Photogrammetry: Using photographsto survey & measure distances between objects Photogrammetry = Umbrella Term Over Things like: • Stereography/Stereoscopy • Stereoplotting (elevation contours on terrain maps) • Structure From Motion (SfM) • = Using photographs to build a 3D Model • SfM = Umbrella Term Over Things like: • “Stereographic Reconstruction” (How Vricon describes their stuff) • Simultaneous Localization & Mapping (SLAM) • Visual Odometry (when Robots SLAM)
- 6. • Structure fromMotion (SfM) • Can use images from any cameras, in any order, at any scale (but typically applied esp to close range) • = crowdsourcable • At 1:1 level = highest photogrammetry resolution possible • Industry preferred term in BIM, GEOINT, Exploration & Museum sciences Simultaneous Location & Mapping (SLAM) • Performs SfM by use of metadata context vs. edge recognition • Can only use ordered images from same camera • Lower resolution because of mathematical approximation • Best used for kilometer+ swathes (order + geospatial metadata help build, but don’t require precision) • VR/AR community fondness for term (because real time capture predicates use of same camera, low resolution necessary in current engines)
- 7. Photogrammetry vs. SpatialMapping in VR/AR Thing to be aware of: Spatial Mapping focus isn’t on image capture, but bounding box/volume recognition Uses cameras + near-infrared depth sensors for limited structured light scanning (SLS) Examples: Spatial Mapping in Hololens
- 8. A Brief Noteon the Infrared Spectrum
- 9. What is PhotogrammetryUsed For? Aerial • Terrain Mapping • Creating Virtual Landscapes Terrestrial /1:1 • Rapid Replication of Objects/Artifacts • Creating Virtual Landscapes Time/Space Replicator
- 10. Who Uses Structurefrom Motion & Derivatives? GEOINT Exploration & Surveying Architecture & Infrastructure Leisure Building Information Modelling (BIM) Roadworks Structural Engineering Agricultural Technology (Agrotech) Geology Geosciences Oil & Gas Aerospace Conservation Anthropology Marine Sciences Meteorology Gaming Museums & Education Virtual Tourism Tourism (organizational) National Policy & Security Digital Archaeology (the group who’s had their fingers in the 2D + 3D pies in all of these categories the longest) Film Autonomous Vehicles
- 11. Quick How ToGuide: • What You’ll Need • Camera (even phone camera is fine these days) • Software • Best: • BIM Industry standard is Agisoft • 2nd place: Autodesk Remake (formerly Autodesk 123D Catch & Autodesk Memento) • RealityCapture • Lots of open source versions • Samantha (->Zephyr) • Assorted MatLab pull-a-part-ables • Patience
- 12. For An Object BasicObject Basic Object with Higher Res Detail Exs. From Bentley Photogrammetry Workflows
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- 14. If there’s notmuch texture/uniform texture: • use a calibration mechanism • ensure photo order to provide additional context
- 15. For A BuildingExterior: For just the front facade
- 16. Going Round Corners(More is Better)
- 17. Height Helps (Butagain, aren’t necessary, can fudge from human height)
- 18. For A RoomInterior (the hardest)
- 19. If Using Drones: •Maintaining photo sequence is crucial
- 20. For planes + •Known/Precision overlap required
- 21. Once you’ve capturedyour images • Get rid of any blurry or zoomed ones (these are non-helpful) • Pop them into suitable software • Push them through the automated workflow (or torture yourself in Matlab, your choice) • Export in your desired format • Yay!
- 22. How does Photogrammetryfit in with the rest of the possibilities for Diagnostic Imaging?
- 23. Towards Ubiquitous Sensing •But photogrammetry is only the beginning….. • 3D Social Multimedia • Diagnostic devices constantly getting cheaper • (Visible Image camera as example) • Rising demand for 3D Content • -- Everyone constantly mapping the world in 3D • Throw in machine learning analytics • =Ubiquitous, Omniscient 3D Sensing & Mixed Reality Space • =The Science Fiction Future will be upon us…. Shout out to my recent invited paper on this re: National Security preparation for this…