Photogrammetry

Photogrammetry is a surveying technique based on angle measurements, frozen during image acquisition, and whose values can be reconstructed by making full use of knowledge of the exact geometry of the images and the optics used to acquire them. For a long time, however, these calculations were carried out optically and mechanically, making the equipment used extremely expensive and therefore reserved for highly specialized companies.

The use of increasingly powerful computing resources has progressively enabled us to reconsider all the image processing stages, and many photogrammetric products can now be fully automated: digital surface models (DSMs) and orthophotographs in particular. As image acquisition has also made great strides under the impact of the development of consumer cameras and self-piloting drones, all photogrammetric knowledge now needs to be capitalized on in software, and a whole new generation of software packages has come onto the market, not from the traditional producers of photogrammetric equipment. These tools enable technicians with very little knowledge of photogrammetry, or even topometry, to carry out processing very efficiently, making this technology much more democratic. So, while laser scanners have created a whole new clientele for point clouds, another way of obtaining point clouds has emerged that is highly competitive, based on very inexpensive hardware and software. It's a whole new set of technologies that needs to be analyzed, while at the same time studying certain advances in computer vision that are fundamental to understanding the situation we've reached. Now that all the technical hurdles have been removed, many new prospects are opening up.