## 5 Photogrammetry: Knowledge Base
### Terrestrial (Ground) Photogrammetry: Realization Phase  
It is possible to determine dimensions, positions and properties of objects and phenomena from photographic images produced by ground photogrammetry. Capturing is done from a stable position on the ground. Secured elements of the internal and external orientation of the images allow determining the 3D position of each point [36].  
After the 3D laser scanning phase, terrestrial photogrammetry of the Kunerad manor house was started (December 2019). Capturing was performed on a DSLR CANON EOS 60D with an APS-C sensor, the resolution of 18 Mpx, and EPS 18-75 mm lens. The output format was RAW format for subsequent postprocessing to achieve image consistency (exposure, shadows, overexposure or underexposure). By the combination of requirements for accuracy and spatial arrangement from the project definition, the maximum distance of 5 m from the object was specified. At the maximum resolution and distance, a pixel size value of 2 mm was determined. This parameter guaranteed sufficient additional points to the laser scan point cloud.  
From the basic setting parameters, the ISO value was fixed at 100 throughout the shooting, the aperture was F8.0, and the shutter speed changed during the position and orientation of the camera.  
The ISO 100 value guaranteed that the sensor would not be too sensitive to light, and at the higher value the remaining two parameters would not be compensated for and the images would not produce higher noise intensity, which would result in a significant deterioration of the 3D model [37]. The aperture number was based on the spatial arrangement, as mentioned above. The relationship between the depth of field and the distance to the object was also considered, which means that the shortest distance from the object could be at a maximum 2.5 m. The hyperfocal distance, based on the well-known parameters of the camera, lens, and distance, was 1.93 m, which ensured that all images would be sufficiently focused.  
Due to weather conditions, the capturing was performed during cloudy weather and in almost no wind. These conditions ensured that the lighting of the object would be diffuse, without significant sharp shadows. During the photo shoot, image checks were performed, because, as already mentioned, the photo shoot took place during the winter and in the proximity of the building. Moreover, there was snow on the building in certain places. Snow in combination with daylight affected the camera's basic parameters. Therefore, it was necessary to change these values and at the same time to follow mentioned recommendations when taking photos [38].  
From the point of view of photography limitations, the same problem occurred as for the laser scanning, when both reconstruction and cleaning work took place during the process. It was necessary to avoid the mechanisms present during the capturing and at the same time monitor them so that they were not captured in the images.  
The combination of data from laser scanning and ground photogrammetry was ensured by targets that were on the object and in its proximity range.  
The total number of images created during the day with the emphasis on even coverage of the object was 1500. Photography was performed both by hand and using a monopod. Figure 7 shows the detail from ground photogrammetry.  
Figure 7: Detail from terrestrial (ground) photogrammetry.