Page 21 - 3DF Zephyr

globally, which means that it's usually faster than the incremental one and potentially be less prone to drifting error. The incremental engine on the other hand, albeit slower, tends to be able to include more cameras in the final solution. In a nutshell, you'd better exploit the global pipeline if you are processing a huge dataset (more than 1000 pictures). Bundle Adjustment: it is a nonlinear minimization procedure that corrects points and cameras positions while minimizing the reprojection error of each point: it is performed at the end of each merge and a further Bundle Adjustment run at the end the procedure. If you are working with huge datasets you'd better choose local and restrained option. Photo Ordering: this parameter suggests the software which was the photographic capture applied on field and therefore the sequence of the pictures taken . That way can speed up the near images detection process. By using sequential option the photos have been taken following a numerical order (photo 1 near photo 2 - photo 2 near photo 3 and so on), while circular option indicates a loop sequence. If you are aware that the photos have been taken with a specific order, you can streamline the process by choosing among those two options, otherwise you can consider the sparse option. The last option is called approximate grid and it was designed for data acquisition collected from drones or UAV systems, and it is exploited when capture is sequential and has a high percentage of overlap between the pictures (70% - 80%). A further description of those parameters is available here: http://www.3dflow.net/3df-zephyr-parameters-tuning-guide/ You may also switch to the "Custom" mode by selecting "Custom" from the "settings" dropdown menu. This mode allows to fine tune in detail every single reconstruction parameter. Remember that you can load an XML file or reset to default by right-clicking and selecting the desired option. Please also note that a hint regarding the selected parameter is shown at the bottom of the window.