A practical method to determine the effective resolution in incoherent experimental electron tomography

It is not straightforward to determine resolution for a 3D reconstruction when performing an electron tomography experiment. Different contributions such as missing wedge and misalignment add up and often influence the final resolution in an anisotropic manner. The conventional resolution measures can not be used for all of the reconstruction techniques, especially for iterative techniques which are more commonly used for electron tomography in materials science. Here we define a quantitative resolution measure that determines the resolution in three orthogonal directions of the reconstruction. As an application we use this measure to determine the optimum number of simultaneous iterative reconstruction technique (SIRT) iterations to reconstruct the gold nanoparticles, based on a high angle annular dark field STEM (HAADF-STEM) tilt series. -- Research highlights: → We developed a model-based resolution measure for experimental electron tomography. → It measures the resolution along the main directions in the reconstruction. → It is applied to nano-size gold particles reconstructed with SIRT and WBP. → The method is space invariant and independent of the particle size. → The method yields the optimal number of 'SIRT iterations'; 20 in our case.