Photogrammetry is a method of using photos to define points accurately within a 3D space. It can be used to determine measurements, defining the camera’s position, and building 3D sites and objects. Videogrammetry is the same process, but works with video.
Both photo- and videogrammetry look to match key features among either a series of images (photogrammetry), or a series of video frames (videogrammetry). For creating 3D sites and objects, a large number of key features are matched to form a collection of dense points.