This article describes:
- Camera. Use a digital camera with reasonably high resolution. The resolution affects the quality of the processing result.
- Camera position:
- Avoid large camera inclinations from the horizontal plane (more than 45 degrees). Otherwise, the image frame space will not be used effectively concerning the target object.
- The camera track should be parallel to the surface of the object during shooting.
- Flying closer to the object of interest will improve the quality of the reconstructed surface and texture.
- The number of photos. More than required is better than not enough. Excessive images can be disabled during processing.
- Markers. If the drone does not have a high-precision receiver onboard, it is recommended to add markers measured with topographic instruments when preparing for data capture. The markers can be used for alignment optimization and referencing tasks.
- Weather. It is recommended to plan the data capture process for a cloudy day. Direct sunlight leads to patches on most of the surfaces; the light patches which have moved across the target object during the shooting process will create difficulties for reconstruction algorithms.
How to shoot a building?
- Capturing scenarios. The following figures illustrate CORRECT capturing scenario:
The following figures illustrate INCORRECT capturing scenario:
- How to shoot the corners of a building? At the corners of a facade, when moving from one wall to another, it is recommended to take photos with more-than-average overlap to ensure the maximum number of connecting points for the walls forming the corner.
- Avoid reflections and highlights. If the facade material is characterized by a large reflection coefficient (siding, polished stone, steel, etc.), it is recommended to use a circular polarizing filter to avoid reflections and highlights.
- Identical details on the object. The pictures below show the left and right parts of a building, respectively. Increasing the number of unique elements (it might be worth adding markers to the facade) and maintaining a high overlap ratio will help to fix the issue when the different parts of a building look similar as in the photos below:
How to shoot an isolated object?
- Capturing scenarios. The following figures illustrate incorrect and correct capturing scenarios for such isolated objects as statues and monuments:
- Apply masks. To achieve good reconstruction results, it is recommended to Mask all irrelevant elements on the source photos (background, accidental foreground, moving objects, etc.).