We are using ODM to reconstruct pointcloud every week but sometimes we have a “problem”. Vertical face are not sufficiently densified. In order to improve this we decided to test two other flight scenario.
Usually we are flying single grid nadir but here we test the following configurations:
Cross pattern 5° angle, camera always looking in the flight direction, i.e. changing direction for each segment
Cross pattern 5° angle, camera always looking in the same direction, i.e. one time looking forward, one time looking backward
The second scenario provided us a distored pointcloud:
The reference point cloud shows more and larger holes in the steep face, so more off-nadir images required, as evidenced by the slight improvements in the later flights, and I think the flight path needs to be extended back out from the face a bit too, in order to get better coverage of the face and produce a more complete point cloud.
Thank you for your tests and hints. We will try next flight with 15° angle
Regarding the distorded aspect do you have any idea ? (If you look at my picture you see a cross section of flight 1 and flight 2 output which are not coincident)
How can we “be sure” when we design a flight plan that reconstruction will be ok ? With nadir images we never had such case.