Taking images with 3D reconstruction in mind is quite different from just taking images of an infrastructure and will need some practice before you nail it.
We have created a small guide to help you understand the concepts and requirements.
Most importantly is the following:
- There must be overlap between the images and all images must be connected (No holes between areas for a single inspection)
- Overlap is recommended to be 60-80% for best quality
- The angles between each image must not be larger than 15 degrees. Meaning that a minimum of 6 images should be taken around corners of a building of 90 degrees.
- The difference in distance to the object must not be larger than 1½-2. If using different lenses/cameras, the same apply for the GSD between images. Meaning that if you want to take image from e.g. 10 meters away and 30 meters away, you need to have intermediate images. Starting from 10 meters, then 15 meters, then 22,5 meters and finally 30 meters.
- Images must be in good consistent quality. Not over/under-exposed and blurry. Lock the exposure if possible to ensure that colors are not changing to much.
- Do not change zoom level between images. Use a fixed focal length in case you have zoom available.
- Include as much ground as possible and have both the structure and background in focus.