Adaptive total variation based autofocusing strategy in ptychography

In ptychography, the axial diffraction distance between specimen and detector is extremely important since the precision of this a prior parameter can strongly affect the quality of reconstruction. However, in experiments, applying a simple evaluation model for image quality assessment (IQA) will result in low accuracy with various specimens in the autofocusing methods. In this paper, we propose an autofocusing strategy with adaptive Lp-norm based total variation (TV) model, which achieves high accuracy of the convergence. It has been verified in optical experiments that our method is applicable to various types of specimens. Besides, the method can work efficiently and stably with poorly estimated specimen-detector distance.