InSpectr: Multi‐Modal Exploration, Visualization, and Analysis of Spectral Data

Abstract

This paper addresses the increasing demand in industry for methods to analyze and visualize multimodal data involving a spectral modality. Two data modalities are used: high‐resolution X‐ray computed tomography (XCT) for structural characterization and low‐resolution X‐ray fluorescence (XRF) spectral data for elemental decomposition. We present InSpectr, an integrated tool for the interactive exploration and visual analysis of multimodal, multiscalar data. The tool has been designed around a set of tasks identified by domain experts in the fields of XCT and XRF. It supports registered single scalar and spectral datasets optionally coupled with element maps and reference spectra. InSpectr is instantiating various linked views for the integration of spatial and non‐spatial information to provide insight into an industrial component's structural and material composition: views with volume renderings of composite and individual 3D element maps visualize global material composition; transfer functions defined directly on the spectral data and overlaid pie‐chart glyphs show elemental composition in 2D slice‐views; a representative aggregated spectrum and spectra density histograms are introduced to provide a global overview in the spectral view. Spectral magic lenses, spectrum probing and elemental composition probing of points using a pie‐chart view and a periodic table view aid the local material composition analysis. Two datasets are investigated to outline the usefulness of the presented techniques: a 3D virtually created phantom with a brass metal alloy and a real‐world 2D water phantom with insertions of gold, barium, and gadolinium. Additionally a detailed user evaluation of the results is provided.

GEMSe: Visualization‐Guided Exploration of Multi‐channel Segmentation Algorithms

“…However, data from single scanning modalities may return unclear or ambiguous responses, or may not deliver all information that is needed. Material scientists, for example, often require the exact topological details of a specimen along with minuscule structural deficiencies as well as information on its chemical composition [AFK*14]. To address these demands, the analysis strategies are increasingly adapted to measuring the same scene or specimen using multiple techniques, resulting in a so‐called multi‐modal dataset, where multiple measurement values are available per dataset location.…”

open_iA: A tool for processing and visual analysis of industrial computed tomography datasets

“…• InSpectr (A. Amirkhanov, Fröhler, Kastner, Gröller, & Heinzl, 2014) makes it possible to analyze spectral data, e.g., from X-Ray fluorescence spectral tomography, alongside with data from computed tomography for the same specimen. • Dynamic Volume Lines (Weissenböck, Fröhler, Gröller, Kastner, & Heinzl, 2019) facilitate the comparison of multiple slightly varying volumetric datasets, by mapping them to 1D and applying a nonlinear scaling to highlight regions with large differences.…”

A Systematic Review of Experimental Studies on Data Glyphs

“…Many cells remain empty, and there are several sparsely populated ones. One of the first things to notice is that there is no single study on circular orientation encodings, although they are used in visualization applications: representatives of this category are the compound glyph used in network graphs [12], pie chart glyphs for analyzing multi-dimensional data (e.g., global material composition [101], or biological binding properties [102] ), or as provided in visualization toolkits (e.g., JIT 2 ). Perhaps this type of encoding is a-priori deemed inferior based on Cleveland and McGill's [98] work that ranks orientation low for quantitative data representation.…”