The general objective is to capture the position of every point in the scene by using at least two cameras with different angles. Dynamic scenes such as people or animals in motion can be captured with a complex multi-camera setup. The resulting form of the subject is then calculated via a specialized software like Agisoft PhotoScan, Autodesk 123D Catch, or Autodesk Memento. Compared to 3D scanning, photogrammetry can capture all data at once, which makes scanning more convenient. However, this requires studio setup and the results are still not as detailed as 3D scans.
Types of Photogrammetry
Photogrammetry is usually divided into aerial and close range. A large part of modern maps was created using aerial photogrammetry where a camera is mounted in an aircraft pointed vertically towards the ground. Such data can be used for creating digital models or 3D representations of a terrain’s surface with a method known as a digital elevation model (DEM), digital terrain model (DTM), or digital surface model (DSM).
A close-range photogrammetry typically uses hand-held or tripod-mounted cameras to measure and model complex architectural and engineering structures, set pieces, forensic scenes, human figures, just to name a few examples.
How Photogrammetry Works
The use of different angles allows for similarity-based mathematical analysis to be performed to reconstruct real-life objects and structures into a faithfully reproduced 3D space. The fact that each point has to be matched with the same point shot from different angle means that opaque and non-specular surfaces cannot be mapped using this method.
This stitching process works like a generation of panoramic photographs from multiple images. Once aligned, the resulting point cloud is used for generating a mesh composed of millions for triangles and high-resolution textures that can be applied to previously generated meshes. The final scene can be rendered in a common 3D engine such as Unity. Such scene can be enhanced with dynamic lighting, audio effects, particle effects, or moving objects such as clouds in the background.
Photogrammetric Processing Software
Photogrammetric processing software ranges from stand-alone solutions to cloud-based platforms that are able to reduce otherwise very high hardware requirements for efficient processing.
Agisoft PhotoScan is developed Agisoft LLC located in St. Petersburg in Russia. This stand-alone software is the leader in photogrammetric digital image processing and generation of spatial 3D data. The software comes in two different editions – Standard and Professional. Both editions support photogrammetric triangulation, generation and editing of a dense point cloud, generation and texturing of the 3D model, spherical panorama stitching, and fisheye camera lenses. The Professional Edition additionally comes with support for spherical and cylindrical cameras, classification of dense point cloud, DEM, python scripting, network processing, and many others.
3DF Zephyr Pro
3DF Zephyr allows for automatic and easy reconstruction of 3D models from photos without the need for manual editing or special equipment. The software is easy-to-use and able to export high-resolution videos without any external application. It comes in Lite, Pro, and Aerial version, with the Lite version costing just $199.
Autodesk 123D Catch
Autodesk 123D Catch is compatible with Windows Phone devices, iPhone, iPad, Android, or any regular camera. It lets users create scans of real-life objects with extraordinary ease and turn these scans into realistic 3D models that can be viewed or shared with other people.
Autodesk Memento is an end-to-end solution for converting any captured reality input (photos or scans) into high definition 3D meshes that can be cleaned up, fixed, and optimized for the Web, mobile or 3D printing / fabbing.
Pix4D is a complete image processing software mapping & modeling solution capable of converting thousands of images into georeferenced 2D mosaics and 3D models.
EnsoMOSAIC 3D is a digital photogrammetric software for stereoscopic 3-dimensional data acquisition from EnsoMOSAIC aerial images and for processing large XYZ point clouds.