Tracked ultrasound calibration
Significant research has been dedicated to using US in a quantitative manner. Toward this goal, the main problems are to assemble individual 2D US images into 3D volumes and then to relate the position of surgical tools with respect to the reconstructed US volume. Solution of both problems requires tracking the 2D US probe in 3D space with respect to a stationary frame of reference. Typically, tracking is achieved by rigidly attaching 3D localizers to the US probe. The missing link, however, is the spatial transformation between the US image pixels and the tracking body attached to the US probe, which requires calibration. Hence, calibration is ubiquitously present in all systems where 2D ultrasound is used for quantitative image guidance. Clearly, the accuracy of calibration is the most significant factor in the accuracy of these systems.