11. The method of claim 8 , wherein training the first machine learning system comprises: e) obtaining training input data; f) generating a diffraction signal with the first machine learning system using the training input data; g) determining if one or more termination criteria are met; and h) if the one or more termination criteria are not met, iterating steps f) to h).
12. The method of claim 11 , further comprising: when iterating steps f) to h), adjusting the machine learning system or using new training input data in step g).