What is Photogrammetry anyway?
It’s quite simple. Think of the digital maps we use today.
Those have been created thanks to the science and technology of photogrammetry, more precisely satellite and aerial (via drone, UVA, aircraft) photogrammetry.
Potogrammetry is a technique used to create measurements from photographs. As explained in one of our previous blog posts “Photogrammetry in the Visual Effects industry”, it is the technical art of extracting reliable information from photographic images of real-world objects or terrain features to create 3D digital models out of the generated precise measurements.
Wait, how many types of photogrammetry are there?
There are three types of photogrammetry: satellite, aerial, and terrestrial. In the Visual Effects industry, aerial and terrestrial are the two main types.
Both satellite and aerial photogrammetry provide a view from above and are used to study or survey specific land areas. While the two can produce digital images, their methods of creating images are quite divergent, as is their application.
Usually, it is easier for companies to opt for either aerial or terrestrial photogrammetry for their surveying, mapping, or creation of 3D models needs.
What’s the use of Drone Photogrammetry?
A drone is a practical, simple to use, and cost-efficient tool, which explains its popular usage for a variety of applications across different industries. Since its inception, it has been mostly used for surveying, mapping, and creating 3D models.
Photogrammetrists opt for drone photogrammetry when they need to scan large physical objects such as buildings or construction sites, or large land areas, which will then convert to 3D models—quite a common technique in the VFX industry.
Drone photos are geo-tagged, which means that the information pertaining to the latitude, longitude, and altitude from the drone’s GPS and onboard sensors are embedded in the metadata of the image.
This explains why drone photos are great for photogrammetry.
How to create accurate 3D models out of drone photos?
To obtain the best results, you will need a 60-80% overlap on each of your aerial photos. You have to take as many photos as needed from different angles and at the optimal altitudes and height, typically 150-200 feet. You will also need a flight planning app for optimum flight consistency.