Figure 2.

Principle of the camera-based optical tracking technique. (a) The three coordinates represent the three lenses integrated in the camera bar. The camera bar is looking at point P(x, y, z), where P₁, P₂, and P₃ are the intersections on the image plane. (b) The top view demonstrates the similar triangles used to calculate the position information. The depth d of point P can be determined via triangulation. Reprinted from [20] with permission.