A toolkit for the dynamic study of air sacs in siamang and other elastic circular structures
Fig 5
DLC labeling approach for DLC+.
The five points to be tracked on the air sac outline are depicted. Note that two outline ends, which we call fixed points, are clearly defined. The other three points are defined relative to these fixed points. Firstly, it is the middle point between the start and end point (vertically defined by being on the edge of the air sac). The two other points are again the middle of the start or end and the adjacent middle point. In this way, we ensure that DLC can always determine the points, even when some are not determinable, without relating them to the two fixed start and end points. As such, some points are only relationally but nevertheless systematically definable. Photos taken by Wim Pouw and Mounia Kehy.