Unsupervised segmentation and clustering workflow for efficient processing of 4D-STEM and 5D-STEM data

TL;DR

This paper presents a clustering framework for segmenting 4D and 5D-STEM data, enabling efficient analysis, data compression, and high-quality mapping of structure, orientation, and strain.

Contribution

A novel unsupervised clustering method using local diffraction-pattern similarity for segmentation and data reduction in 4D-STEM datasets.

Findings

Produces cluster-averaged diffraction patterns with improved signal quality.

Reduces data volume by orders of magnitude for faster analysis.

Successfully applied to in situ liquid-cell gold nanoparticle growth data.

Abstract

Four-dimensional scanning transmission electron microscopy (4D-STEM) enables mapping of diffraction information with nanometer-scale spatial resolution, offering detailed insight into local structure, orientation, and strain. However, as data dimensionality and sampling density increase, particularly for in situ scanning diffraction experiments (5D-STEM), robust segmentation of structurally consistent behavior across sequential measurements becomes essential for efficient and physically meaningful analysis. Here, we introduce a clustering framework that identifies crystallographically distinct domains from 4D-STEM datasets. By using local diffraction-pattern similarity as a metric, the method extracts closed contours delineating spatially contiguous regions. This approach produces cluster-averaged diffraction patterns that improve signal quality while reducing data volume by orders of magnitude, enabling rapid and accurate orientation, phase, and strain mapping. We demonstrate the applicability of this approach to in situ liquid-cell 4D-STEM data of gold nanoparticle growth. Our method provides a scalable and generalizable route for spatially coherent segmentation, data compression, and quantitative structure-strain mapping across diverse 4D-STEM modalities. The full analysis code and example workflows are publicly available to support reproducibility and reuse.