Is photogrammetry a 3D scan?

Photogrammetry and 3D scanning are related techniques, but they are distinct processes.

Photogrammetry:

• Photogrammetry is a method of extracting 3D information from 2D images, typically photographs.
• It involves analyzing multiple images of a scene or object taken from different viewpoints. The software identifies common features in these images and uses them to triangulate the 3D positions of points in the scene.
• Photogrammetry can be applied to various scales, from small objects to large landscapes.

3D Scanning:

• 3D scanning, on the other hand, is a process of directly capturing the geometry and appearance of a physical object to create a 3D model.
• This can be done using various technologies such as laser scanning, structured light scanning, or time-of-flight sensors.
• Unlike photogrammetry, which relies on images, 3D scanning captures point cloud data directly from the surface of the object.

Differences:

• While both techniques result in 3D models, the methods of data acquisition are different. Photogrammetry uses images, while 3D scanning uses direct physical measurements.
• Photogrammetry is often more suitable for large-scale scenes or objects where capturing images is more practical than scanning every detail directly.
• 3D scanning can provide highly accurate and detailed models, especially for smaller objects or those with intricate features.

In summary, while both photogrammetry and 3D scanning are used to create 3D models, they employ different approaches for data acquisition. Photogrammetry relies on images and triangulation, while 3D scanning directly captures the physical geometry of an object using various scanning technologies.