Camera calibration maps a lens’s focal length and distortions and is an important step in any photogrammetric process such as ortho-photo or digital elevation model (DEM) production. This does not change any physical characteristics of the lens, rather it records the existing distortions and exact focal length used by our photogrammetric software.
At Focal Flight, a calibration of each vertical camera is performed on a regular basis. We also offer calibration services to other aerial photo companies and use a 4 x 6-meter calibration target array. The targets are photographed from 11 different positions in two different orientations. This type of calibration is a “Brown Model” calibration that generates the following parameters used by our photogrammetric software:
- C – Calibrated focal length, or principal distance
- XP – Principal point offset in an x-image coordinate
- YP – Principal point offset in a y-image coordinate
- K1, K2, & K3 – 3rd, 5th, and 7th order term of radial distortion correction
- Coefficients of decentering distortion