Accuracy study of a binocular-stereo-vision-based navigation robot for minimally invasive interventional procedures

Figure 4 Measurement of insertion parameters and deviation distance. A: Insertion depth and angle were measured on preoperative planning image. Insertion depth (b) was the distance from entry point (dotted arrow) to target (solid arrow). Insertion angle (a) was the angle of insertion trajectory and horizontal line; B: Euclidian error was the vertical dimension (d) from the center of target (solid arrow) to real needle (triangular arrow).