An encryption-decryption framework for validating single-particle imaging

TL;DR

This paper introduces an encryption-decryption framework for validating single-particle imaging reconstructions without ground truth, enabling better assessment of data quality and resolution in XFEL experiments.

Contribution

It presents a novel validation framework that quantifies reconstruction consistency and relates data sufficiency to resolution, improving upon Fourier Shell Correlation methods.

Findings

Quantifies orientation disconcurrence and disagreement between reconstructions.

Defines data sufficiency criteria related to spatial resolution.

Reformulates XFEL-SPI resolving power using information theory.

Abstract

We propose an encryption-decryption framework for validating diffraction intensity volumes reconstructed using single-particle imaging (SPI) with x-ray free-electron lasers (XFELs) when the ground truth volume is absent. This framework exploits each reconstructed volumes' ability to decipher latent variables (e.g. orientations) of unseen sentinel diffraction patterns. Using this framework, we quantify novel measures of orientation disconcurrence, inconsistency, and disagreement between the decryptions by two independently reconstructed volumes. We also study how these measures can be used to define data sufficiency and its relation to spatial resolution, and the practical consequences of focusing XFEL pulses to smaller foci. This framework overcomes critical ambiguities in using Fourier Shell Correlation (FSC) as a validation measure for SPI. Finally, we show how this encryption-decryption framework naturally leads to an information-theoretic reformulation of the resolving power of XFEL-SPI, which we hope will lead to principled frameworks for experiment and instrument design.