**Appendix A. Optimization Step of the Automatic Registration Algorithm**

The automatic registration is based on the minimization of the cost function *J* given in Equation (9). This is done in the third step of the algorithm (Figure 1). In this appendix, we give more information about this important step of the algorithm, with a focus on the constraints (Appendix A.1) and on the minimization method (Appendix A.2).
