Photogrammetry is the science and technology of obtaining reliable information about physical objects and the environment through the process of recording, measuring, and interpreting photographic images. Photogrammetry is not a new technology, its principles date back to Leonardo da Vinci’s research on perspective in 1480. For centuries, photogrammetry has played a critical role in our understanding of objects far away from the Earth’s surface. Its uses have recently expanded to industries such as construction, engineering, architecture, agriculture, and more.
What is Photogrammetry?
Photogrammetry reconstructs objects or environments through the use of photographs. Site photos are taken from the air or ground with a high-quality camera, capturing images from different locations and angles. The data captured provides enough spatial detail to allow for accurate calculations. Once the visual data is gathered, the photos are stitched together to create real-world topographical maps, meshes, and 3D models. The technique can be used for construction engineering, military intelligence, agricultural assessment, and more.
The Meaning of Photogrammetry
When you break down the word photogrammetry – “photo” refers to light, “gram” means drawing and “metry” refers to measurements. Photogrammetry uses photos to gather measurements from which drawings, maps, and models can be created.
Taking aerial photos is one of the most common approaches to mapping out an area. Aerial photographs capture point-in-time visual records of specific land areas. The process entails mounting a camera on an aircraft or drone. Engineers determine the flight path and the number of photos the camera will take, based on the desired output and resolution. Aerial photogrammetry can capture hundreds of photos of a large-scale real-world environment, like a subdivision or city, in hours.
Depending on the goals of a project, teams can use aerial or drone-based photogrammetry to create photorealistic or thomosaic maps, capture valuable volumetric data or generate interior models for virtual home tours on real estate sites. Aerial photogrammetry tends to work best for large-scale, exterior projects.
Terrestrial photographic images are taken from a fixed position on the ground. Data about the camera’s position, such as its coordinates, are collected at the time the photo is taken. Terrestrial photogrammetry requires manual resources, and it may take longer to cover a large portion of land. When collecting photos, images need to overlap with each other, so they can be effectively stitched together to generate reliable site data.
Terrestrial photogrammetry is used to capture fine architectural details, and are often collected with a laser scanner. A laser scanner captures photos of an environment and overlays the images on top of a point cloud, allowing for very accurate representation of the physical features of a site.
The Basics of Photogrammetry
Triangulation is the principle used by photogrammetry to produce three-dimensional coordinates. By mathematically intersecting converging lines in space, the precise location of a point can be determined.
Photogrammetry for Engineering
The engineering industry has used photogrammetry to obtain accurate building measurements for many years. By using the 3D rendered images from laser scanners or drones, engineers can evaluate as-built site details and the progress of construction work. 3D rendered images can be used to create a 3D model or 3D mesh for evaluation and planning.
Industries Using Photogrammetry
There are advances daily in the applications for photogrammetry. High resolution cameras, drones and LiDAR laser scanners continue to advance this technology and offer services for many industry needs.
For more information on photogrammetry, contact TruePoint Laser Scanning at firstname.lastname@example.org or 419-843-7226.