Data acquisition in this context refers to photography applied to each monument. Visible points of reference were identified on each monument around which each photograph was taken in a rule-of-three manner employing a minimum 60% overlap with the preceding photograph. Using the below image as an example, the red dot represents the central focus point of the photograph. Three separate angles were taken of this point; front facing and two side facing. The front facing image makes it easy to establish the focus point for later inclusion of a marker while the two side profiles would facilitate estimation of depth during rendering.
These focus points were identified along a chosen path and given intervals. Each path was along the circumference of each model where possible. In order to ensure the necessary 60% overlap in each photograph, the selection of specific points or areas of interest will help streamline the process. These points of reference are known as markers and should be selected carefully.
Data acquisition varied on a case by case basis as preliminary assessments were carried out to establish best practice for each stone or monument. In the case of St. Peter’s, the monument had to be captured in separate elements and processed in batches due to the size and/or location of the monument in relation to surrounding features or architecture.