Registration accuracy for 9- and 6-DOF registration of LAT and PA views of the body phantom over 1000 simulation trials with randomly perturbed initialization. Details of the steps to generate the random initialization and its range were explained in section 2.3.1. In each case (a)–(d), the error in each of nine system parameters is shown along with the resulting PDE before and after the registration. Box and whisker plots denote the first/third quartiles and min/max values, respectively, with the median marked by the horizontal line and outliers by crosses. For 6-DOF registration, the error in (x, y, z)s is the same as the initialization error since these parameters were not solved.