# What is the triangulation angle?

I start to work in the field of computer vision and read a paper in which the author states "When suitable correspondences between salient image structures have been established, the 3D uncerntainty of these structures mainly depends on the triangulation angle between the oberservations and the 3D structures". So what is the triangulation angle? In the wikipedia article on triangulation (http://en.wikipedia.org/wiki/Triangulation_%28computer_vision%29) there is a really nice pictures that explains the triangulation but which angle in this picture is the trinagulation angle?

The angle between the projections of the target point, along the host surfaces, is technically called Triangulation Angle.