Kulshreshth Arun K, Alpers Andreas, Herman Gabor T, Knudsen Erik, Rodek Lajos, Poulsen Henning F
Department of Computer Science, The Graduate Center, CUNY, NY 10016, USA and Center for Fundamental Research: 'Metal Structures in Four Dimensions', Risø DTU, Technical University of Denmark, DK-4000 Roskilde, Denmark.
Inverse Probl Imaging (Springfield). 2009 Feb 1;3(1):69. doi: 10.3934/ipi.2009.3.69.
An iterative search method is proposed for obtaining orientation maps inside polycrystals from three-dimensional X-ray diffraction (3DXRD) data. In each step, detector pixel intensities are calculated by a forward model based on the current estimate of the orientation map. The pixel at which the experimentally measured value most exceeds the simulated one is identified. This difference can only be reduced by changing the current estimate at a location from a relatively small subset of all possible locations in the estimate and, at each such location, an increase at the identified pixel can only be achieved by changing the orientation in only a few possible ways. The method selects the location/orientation pair indicated as best by a function that measures data consistency combined with prior information on orientation maps. The superiority of the method to a previously published forward projection Monte Carlo optimization is demonstrated on simulated data.
提出了一种迭代搜索方法，用于从三维X射线衍射（3DXRD）数据中获取多晶内部的取向图。在每一步中，基于取向图的当前估计，通过正向模型计算探测器像素强度。识别出实验测量值最超过模拟值的像素。只有通过改变估计中所有可能位置的相对小子集中某个位置的当前估计，才能减小这种差异，并且在每个这样的位置，只有通过以几种可能的方式改变取向，才能实现识别像素处的增加。该方法通过一个测量数据一致性并结合取向图先验信息的函数，选择被指示为最佳的位置/取向对。在模拟数据上证明了该方法相对于先前发表的正向投影蒙特卡罗优化方法的优越性。
