Reconstruction of partially sampled multi-band images - Application to STEM-EELS imaging

Etienne Monier (1, 2) , Thomas Oberlin (1, 2) , Nathalie Brun (3) , Marcel Tencé (3) , Marta de Frutos (3) , Nicolas Dobigeon (1, 2)

1 IRIT-SC - Signal et Communications
2 Toulouse INP - Institut National Polytechnique (Toulouse)
3 LPS - Laboratoire de Physique des Solides

Electron microscopy has shown to be a very powerful tool to map the chemical nature of samples at various scales down to atomic resolution. However, many samples can not be analyzed with an acceptable signal-to-noise ratio because of the radiation damage induced by the electron beam. This is particularly crucial for electron energy loss spectroscopy (EELS) which acquires spectral-spatial data and requires high beam intensity. Since scanning transmission electron microscopes (STEM) are able to acquire data cubes by scanning the electron probe over the sample and recording a spectrum for each spatial position, it is possible to design the scan pattern and to sample only specific pixels. As a consequence, partial acquisition schemes are now conceivable, provided a reconstruction of the full data cube is conducted as a post-processing step. This paper proposes two reconstruction algorithms for multi-band images acquired by STEM-EELS which exploits the spectral structure and the spatial smoothness of the image. The performance of the proposed schemes is illustrated thanks to experiments conducted on a realistic phantom dataset as well as real EELS spectrum-images.

Mots clés: spectrum-image; partial sampling; inpainting; Scanning Transmission Electron Microscope STEM; Electron Energy Loss Spectroscopy EELS; multi-band imaging; image reconstruction

Domaines: Traitement du signal et de l'image [eess.SP]

Etienne Monier, Thomas Oberlin, Nathalie Brun, Marcel Tencé, Marta de Frutos, et al.. Reconstruction of partially sampled multi-band images - Application to STEM-EELS imaging. 2018. ⟨hal-01552138⟩