Inner-Loop Free ADMM for Cryo-EM

Lauréne Donati (1) , Emmanuel Soubies (1) , Michael Unser (1)

1 Biomedical Imaging Group [Lausanne]

Thanks to recent advances in signal processing, the interest for fast l1-regularized reconstruction algorithms in cryo-electron mi-croscopy (cryo-EM) has intensified. The approaches based on the alternating-direction of multipliers method (ADMM) are particularly well-suited due to the prime convergence speed and flexibility of use of this algorithm. Yet, the standard ADMM scheme still relies on a nested conjugate gradient (CG) to solve the linear step in its alternating-minimization procedure, which can be costly when handling large-scale problems. In this work, we present an inner-loop-free ADMM algorithm for 3D reconstruction in cryo-EM. By using an appropriate splitting scheme, we are able to avoid the use of CG for solving the linear step. This leads to a substantial increase in algorithmic speed, as demonstrated by our experiments.

Mots clés: Cryo-EM reconstruction; inverse problem; regularization; alternating-direction of multipliers method (ADMM); splitting; inner-loop-free; convergence speed

Domaines: Traitement des images [eess.IV]; Traitement du signal et de l'image [eess.SP]; Traitement du signal et de l'image [eess.SP]

Lauréne Donati, Emmanuel Soubies, Michael Unser. Inner-Loop Free ADMM for Cryo-EM. ISBI 2019 - IEEE International Symposium on Biomedical Imaging, Apr 2019, Venise, Italy. ⟨hal-02048101⟩