The refractive-index gradient vector field approach establishes a connection between a tomographic data set of differential phase contrast images and the distribution of the partial spatial derivatives of the refractive index in an object. The reconstruction of the refractive index in a plane requires the integration of its gradient field. This work shows how this integration can be efficiently performed by converting the problem to the Poisson equation, which can be accurately solved even in the case of noisy and large datasets. The performance of the suggested method is discussed and demonstrated experimentally by computing the refractive index distribution in both a simple plastic phantom and a complex biological sample. The quality of the reconstruction is evaluated through the direct comparison with other commonly used methods. To this end, the refractive index is retrieved from the same data set using also (1) the filtered backprojection algorithm for gradient projections, and (2) the regularized phase-retrieval procedure. Results show that the gradient vector field approach combined with the developed integration technique provides a very accurate depiction of the sample internal structure. Contrary to the two other techniques, the considered method does not require a preliminary phase-retrieval and can be implemented with any advanced computer tomography algorithm. In this work, analyzer-based phase contrast images are used for demonstration. Results, however, are generally valid and can be applied for processing differential phase-contrast tomographic data sets obtained with other phase-contrast imaging techniques.

Gasilov, S., Mittone, A., Brun, E., Bravin, A., Grandl, S., Mirone, A., et al. (2014). Tomographic reconstruction of the refractive index with hard X-rays: An efficient method based on the gradient vector-field approach. OPTICS EXPRESS, 22(5), 5216-5227 [10.1364/OE.22.005216].

Tomographic reconstruction of the refractive index with hard X-rays: An efficient method based on the gradient vector-field approach

Bravin A
Membro del Collaboration Group
;
2014

Abstract

The refractive-index gradient vector field approach establishes a connection between a tomographic data set of differential phase contrast images and the distribution of the partial spatial derivatives of the refractive index in an object. The reconstruction of the refractive index in a plane requires the integration of its gradient field. This work shows how this integration can be efficiently performed by converting the problem to the Poisson equation, which can be accurately solved even in the case of noisy and large datasets. The performance of the suggested method is discussed and demonstrated experimentally by computing the refractive index distribution in both a simple plastic phantom and a complex biological sample. The quality of the reconstruction is evaluated through the direct comparison with other commonly used methods. To this end, the refractive index is retrieved from the same data set using also (1) the filtered backprojection algorithm for gradient projections, and (2) the regularized phase-retrieval procedure. Results show that the gradient vector field approach combined with the developed integration technique provides a very accurate depiction of the sample internal structure. Contrary to the two other techniques, the considered method does not require a preliminary phase-retrieval and can be implemented with any advanced computer tomography algorithm. In this work, analyzer-based phase contrast images are used for demonstration. Results, however, are generally valid and can be applied for processing differential phase-contrast tomographic data sets obtained with other phase-contrast imaging techniques.
Articolo in rivista - Articolo scientifico
Tomography; refractive index; X-rays;
English
5216
5227
12
Gold Open Access
Gasilov, S., Mittone, A., Brun, E., Bravin, A., Grandl, S., Mirone, A., et al. (2014). Tomographic reconstruction of the refractive index with hard X-rays: An efficient method based on the gradient vector-field approach. OPTICS EXPRESS, 22(5), 5216-5227 [10.1364/OE.22.005216].
File in questo prodotto:
File Dimensione Formato  
Gasilov_OptExp_2014.pdf

accesso aperto

Tipologia di allegato: Publisher’s Version (Version of Record, VoR)
Dimensione 500.31 kB
Formato Adobe PDF
500.31 kB Adobe PDF Visualizza/Apri

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/348046
Citazioni
  • Scopus 17
  • ???jsp.display-item.citation.isi??? 12
Social impact