Capturing images for photogrammetry

  1. The overlap between the 2 consecutive photos should be at least 75% side and 75% front.
  2. The flight altitude should be as constant as possible.
  3. The camera position angle varies respect to the type of target scanned subject. The optimal result is acquired with the angle:
    • 90o (nadir or top-down images), suitable for terrains and piles, orthophoto creation;
    • 45o for the objects that are very steep or perpendicular to the ground such as buildings;
  4. For the objects of more complex geometry or homogeneous, flat surface:
    • increase the overlap between photos up to 85%;
    • increase the camera altitude;
    • use georeferencing for higher accuracy;
    • set camera exposure settings as accurately as possible so not to blow out any highlight or shadow detail.
  5. Large and tall constructions (such as buildings, towers, monuments, etc.) should be captured in few stages:
    • 45 o angled flight with consistent overlap.
    • 90 o (nadir) flight with consistent overlap.
    • orbital flights around objects that require more detail.
  6. In case of presence of a uniform or reflective surface on the terrain, increase the altitude and ensure capturing as many textured features as possible. Water, snow, sand, tin roofs and other uniform or reflective surfaces have too little key points for matching, thus they are almost impossible to reconstruct.
  7. Plan the flight in respect with the terrain. It is recommended:
    • to avoid capturing the sky, i.e. the photos should preferably contain the view of the terrain.
    • to avoid the presence of holes on the reconstructed object, make sure that the texture of the surface is rough enough.
    • If multiple flights are to be made, ensure the consistent overlap between adjacent picture rows.
    • Building facades should be captured at 45 o or less if needed.