How does it work?
Each photo mission is prepared to the custom specifications discussed with the client in advance. Multiple flight lines are generated over the proposed site, designed for high overlap between flight lines and successive images. Ground control points (GCPs), if needed, are acquired for the project (we recommend using GCPs for all projects that will be used in a CAD/GIS environment), requiring an on-site visit with a dGPS.
The mission is flown with high-resolution cameras mounted in a vertical position, pointing straight down. Once the vertical images are all captured, we return to base and begin post-processing.
The images are geotagged and sent through an advanced Surface-From-Motion (SFM) system. This system analyzes each pixel in each individual image and is able to calculate very precise camera positioning using a variety of techniques, such as Automatic Aero-Triangulation (AAT) and Bundle Block Adjustment. Using this precise camera calibration data, a rough 3D point cloud is generated and the individual camera positions are displayed, allowing for a visual quality check of the project. If everything looks good, we introduce the previously-collected ground control point data to improve accuracy and densify the 3D point cloud, which is used to generate a DSM and the subsequent orthophoto.