Precise and unbiased estimation of astigmatism and defocus in transmission electron microscopy

► Unbiased and precise defocus and astigmatism estimation with related uncertainties. ► The background in the PSD is suppressed by adaptive filtering. ► Robust template matching in polar representation detects also very low astigmatism. ► Outlier rejection of detected rings based on equidistance of CTF zeros in q2-space. ► Thon ring averaging (with Cs influence) can enhance the SNR of the rings in 1D PSD.