Fig. 11.

Tracker-on-C for video overlay. a Summary of projection errors for planning data and DRR overlay. b Overlay of segmented vertebrae, registration fiducials, and planned trajectories for T5 and T7 pedicle screws on the video image of a thorax phantom. (The software implementation allowed free adjustment of alpha blending values such that 3D models could be overlaid on the video images with variable opacity—from fully opaque to transparent.) c Virtual field light overlay on the video image of the thorax phantom. d DRR overlay on the video image of the thorax phantom. Any or all of these three video overlay functionalities can be combined within an augmented scene derived from the tracker video stream