Airborne orthorectification projects
Depending on the characteristics of the camera system and the desired quality level of the final orthophotos, a rectification project can require a large amount of effort or nearly no operator work at all.
Some of factors affecting the project workflow include:
•How good is the raw positioning?
•How good is GPS/IMU trajectory?
•Is the image timing accurate?
•How stable and well known is the camera?
•Is the internal geometry of the camera known beforehand?
•Is the camera misalignment known beforehand?
•How good are the raw images visually?
•Have light conditions been uniform during the flight session?
•Is there a color cast or other coloring problems in the images?
•What are the requirements for the final orthophotos?
•Reasonable positional quality only or best achievable positional quality?
•True orthophotos or normal orthophotos?
•Does the orthophoto mosaic need to be visually high quality without any detectable seamlines?
This chapter outlines two possible strategies for an orthorectification workflow. These two strategies represent two extreme cases: the minimum effort and the maximum effort possibility. You will probably choose a strategy which is somewhere in between these two extremes.