Spatially resolved and observer-free experimental quantification of spatial resolution in tomographic images

Area of Science:

• Imaging Science
• Metrology
• Chemical Engineering

Background:

• Accurate quantification of spatial resolution is crucial for tomography system performance evaluation.
• Existing methods often involve subjective observer interpretation or lack spatial specificity.
• A need exists for objective, spatially resolved, and quantitative assessment of tomography system resolution.

Purpose of the Study:

• To develop and validate a novel, observer-independent framework for quantifying the spatial resolution of tomography systems.
• To create a spatially resolved map of spatial resolution within the tomography system's imaging space.
• To assess the performance of a chemical species tomography system using the proposed method.

Main Methods:

• A "black box" approach stimulating the system with a sharp edge input.
• Analysis of reconstructed images using Fourier decomposition of spatial frequency components.
• Determination of local limiting spatial resolution via a cut-off threshold, enabling spatial mapping.

Main Results:

• A spatial resolution map with 28 regions was generated for a chemical species tomography system.
• Local spatial resolution varied by 57% across the imaging space.
• Some regions showed performance up to 4 times better than literature values, suggesting an underlying mechanism related to beam array geometry.

Conclusions:

• The proposed framework provides an objective and spatially resolved method for tomography system spatial resolution quantification.
• Findings highlight significant spatial variations in performance, impacting system design and evaluation.
• A geometrically regular beam array is hypothesised to enhance reconstruction objectivity and performance.