Estimation of soft-tissue model parameters using registered pre- and postoperative facial surface scans.

Computer-based techniques for the simulation of craniofacial surgical procedures and for the prediction of the surgical outcome have been shown to be very useful. However, the assessment of the accuracy of the simulated surgical outcome is difficult. In this paper, a technique is described which allows to compare the simulated surgical outcome and the actual surgical result. The simulated postoperative patient's appearance is compared to a second surface scan which is obtained postoperatively. The pre- and postoperative surface scans, which are different due to the surgery, are registered employing a robust registration method which minimizes distances of corresponding points. Parameters of the soft-tissue model can be adapted with respect to minimized differences of corresponding points of the simulated postoperative and the actual postoperative surface of a patient's face.