Multimodal Image Registration of Raman Spectral Maps in Two Dimensional Materials by Strain and Doping Analysis

TL;DR

This paper presents a method for registering hyperspectral Raman images of 2D materials by analyzing strain and doping variations, enabling multimodal microscopy data correlation despite the lack of keypoints.

Contribution

It introduces a novel registration technique using strain analysis from Raman spectra and Hough transformations to align images from different microscopy modalities.

Findings

Effective registration of Raman hyperspectral images achieved.

Strain-based keypoints improve multimodal image alignment.

Enables pixel-by-pixel correlation across microscopy methods.

Abstract

It is common to measure a single sample using multiple different microscopy methods that have variable scales, rotation and translation. Registering hyperspectral images of two dimensional materials is particularly difficult due to the lack of keypoints on unprepared substrates. Identifying variations in the strain of these samples can assist in the registration of these samples by creating keypoints to correlate images. Registration of these images allow for multimodal analysis from these various instruments by aligning multiple images into a single coordinate space. This is done by Hough transformations and arbitrary resolution definitions to generate a new coordinate frame where spatial information may be preserved and correlated on a pixel by pixel basis. Such multimodal image alignment may be used to correlate data from various instruments. Strain information is extracted from the Raman spectra and the resulting hyperspectral image is used to register the Raman information with the other modes of microscopy.