Photogrammetry is more than a $5 word – it’s a method of digitizing the world around you.
Put simply, photogrammetry is the process of taking overlapping photographs of an object, structure, or space, and converting them into 2D or 3D digital models. You can accurately measure the digital models with X, Y, and Z coordinates (Z coordinates being the third dimension).
Photogrammetry is often used by surveyors, architects and engineers to create topographic maps, or blueprints based on real-life scenes.
For example, if you wanted to run a construction or renovation project on a large plot of land, you could photograph the area from a UAV and start with a digital model of the landscape – dirt mounds and all – as your blueprint.
Previously, assessing construction site materials was done by taking manual measurements on-site. With photogrammetry technology, surveyors and construction site managers can more accurately assess, track, and order materials. This helps reduce cost and maximizes safety by avoiding unnecessary time in hard-hats.
HITT, a construction company based in Virginia, used photogrammetry to create 3D models of dirt mounds and other materials on a construction site for a new 12-building campus spanning 200 acres. They were able to plan delivery schedules for various materials, and more accurately track the amount of material needed – thus decreasing cost for the project.
Another company, IMCO General Construction, uses photogrammetry to collect field data from a bird’s eye view. The company collects photos from a UAV, and can then better track assets and progress for their water, energy, and transportation projects.
To complete a photogrammetry project successfully, all you really need is a camera. Generally speaking, the higher quality camera you use, the better resolution your 3D model or point cloud will have – but you can use any photo taking device from your iPhone to a GoPro to a DSLR camera.
Photos can be taken from the ground, or from above. Many UAV’s come with a camera attached to them for easy aerial image capturing. If your drone doesn’t come equipped with a camera, you can always attach a GoPro to the drone yourself.
Tips & Tricks for taking photos
Be sure to set your camera to take overlapping photos of your object or construction site. For the best accuracy, you want each photo to overlap about 50% with the previous photo. Setting this up is fairly trivial – just set your camera to time lapse mode so it takes one picture every 2-3 seconds.
Watch this quick 6 minute video on how to take photos to make the best possible virtual representations of reality here:
For flying UAV’s to take aerial photos
If you’re new to flying drones, don’t worry – 3DR’s SiteScan software will pilot the drone for you in the the best flight pattern for your site.
If you’re looking to pilot the drone yourself, just be sure to choose a flight path that allows you to get plenty of overlap in your photos of the landscape or building site.
How to Process Your Photo Data
Clearly photogrammetry can be a useful tool for surveying, construction, and renovation projects. But once you’ve captured the photos, how do you actually develop them into a point cloud that you can edit, measure, and model?
Reality capture software like ReCap 360 Pro can help you process your photograph data into virtual 3D models that you can measure, edit. ReCap 360 Pro is like the staging area where you prep your point cloud and cut it into more easily processed chunks, ultimately preparing it for more advanced modeling.