Spectral Imaging applications for industrial settings: On-Site, At-Line, and In-Sight (invited talk)
Diana Guimarães1, Diana Capela1,2, Rafael Cavaco1, João Carvalho1,2, Joana Teixeira1,2, Tomás Lopes1,2, Pedro Jorge1,2, Nuno Silva1,2
1Center for Applied Photonics, INESC TEC, Rua do Campo Alegre 687, Porto, 4169-007, Portugal; 2Departamento de Física e Astronomia, Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre 687, Porto, 4169-007, Portugal
Spectral imaging has evolved from a laboratory curiosity into a powerful tool with growing relevance in industrial environments. Rather than capturing traditional RGB-visual images, spectral imaging techniques acquire rich spectral data at each pixel, generating detailed chemical and elemental maps across a sample. Techniques such as Laser-Induced Breakdown Spectroscopy (LIBS), X-ray Fluorescence (XRF), Raman spectroscopy, and Hyperspectral Imaging (HSI) can be used for this purpose, offering complementary insights or validating information regarding sample composition. While LIBS excels at detecting light elements with high spatial resolution, XRF delivers quantitative bulk analysis, Raman reveals surface-level molecular structures, and HSI captures subtle material variations based on molecular signatures, enabling rapid scanning of large surface areas.
When integrated, they enable smarter decision-making in areas ranging from resource exploration to production-line quality control.
In this talk, we explore how our lab implements these advanced spectral techniques, across industrial contexts: directly on-site for raw materials exploration in mining environments; at-line for heavy metal screening in recycled wood processing and quality inspection in the cork industry; and now in-sight, where digital and augmented reality frameworks are used to offer enhanced interpretation and decision support for lithium exploration.
Advancing Polymer Characterization with Simultaneous Optical Photothermal IR and Raman Microspectroscopy
Miriam Unger1, Heinz W. Siesler2
1Photothermal Spectroscopy Corp. GmbH, Germany; 2University of Duisburg-Essen, Department of Physical Chemistry
This presentation highlights advances in vibrational spectroscopic imaging, with a focus on the application of the optical photothermal infrared (O-PTIR) technique for the high-resolution analysis of polymer microstructures. O-PTIR enables submicron lateral resolution and allows for the simultaneous acquisition of IR and Raman spectra from the exact same sample location — overcoming the diffraction-limited resolution of conventional FT-IR imaging and the spatial mismatch issues in separate Raman and IR measurements.
We demonstrate the capabilities of this technique through the spectroscopic imaging of synthetic polymers and phase-separated biopolymer blends. These blends are increasingly important due to the rising demand for biodegradable alternatives to conventional plastics. However, the physical properties of biopolymers often require optimization through blending, which can lead to phase separation. Mapping this spatial segregation is essential for understanding and improving material performance.
By combining submicron IR and Raman imaging in a single, co-localized measurement, O-PTIR provides deeper insight into the structural and chemical heterogeneity of polymeric systems. The instrumentation and methodology presented mark a significant step forward in characterizing complex materials at previously inaccessible spatial scales.
LED vs. Halogen Illumination for Hyperspectral Imaging of Space-Derived Waste Materials
Roberta Palmieri1, Giuseppe Bonifazi1, Idiano D'Adamo2, Silvia Serranti1
1Department of Chemical Engineering, Materials and Environment, Sapienza University of Rome, 00184 Rome, Italy; 2Department of Computer, Control and Management Engineering, Sapienza University of Rome, 00185 Rome, Italy
Waste management is fundamental for minimizing environmental impact and preserving resources, and circular economy models are essential in this context. Accurate material identification and classification are necessary for optimizing recycling processes. Moreover, sorting materials effectively enhances both the efficiency and sustainability of recycling systems.
Recently, space agencies have increased interest in waste minimization and in recycling materials generated in space, since the accumulation of space debris poses significant risks to ongoing and future space missions. Space waste is primarily composed of materials such as polymers, metals, foams, technical textiles, and electronic components, which, at the end of their useful life, contribute to the growing mass of debris in Earth orbit. This highlights the pressing need for efficient and sustainable waste management systems, grounded in circular economic principles, to address the escalating problem of space-generated waste. Such systems are essential not only for mitigating the risks they pose to future missions but also for reducing the environmental footprint of space activities. Identification, classification and/or sorting of these materials is critical for developing efficient recycling technologies, enabling the selection of appropriate equipment to handle different waste types, such as plastics, metals, and complex composite materials. Given the challenges of performing material analysis in space, where traditional sample preparation techniques are often impractical, Hyperspectral Imaging (HSI) in the Near Infrared (NIR) range presents a powerful, non-invasive solution. HSI allows for quick, accurate analysis of materials in real-time without requiring physical contact or sample preparation.
This study explores the use of two distinct illumination sources, LED and Halogen Light, for hyperspectral data collection to classify space-derived waste materials such as foams, technical textiles, and plastics, while also comparing their performance. These materials, commonly found in space applications, contribute significantly to the space debris problem, making their accurate classification a priority for future space waste management strategies. Data were captured using a NIR Spectral Camera™ (Specim, Finland) and an ImSpector N17E™ imaging spectrograph. The raw spectral data were processed with advanced algorithms to reduce noise and improve differentiation, facilitating the analysis of different waste types.
Principal Component Analysis (PCA) and Partial Least Squares Discriminant Analysis (PLS-DA) were applied to explore the data and then classify the materials based on spectral signatures. The research explores the potential of using LED and Halogen illumination to effectively support material classification through HSI, with each light source offering unique advantages depending on the specific application: LED lighting is particularly beneficial in scenarios that demand energy efficiency and stability, while Halogen illumination is more suitable in contexts where a broader spectral range is crucial for accurate material differentiation.
This research is carried out within the framework of the "Sustainable Technologies for Circularity Valorization" (SUSTAIN) project, a spin-off and phase 2 continuation of the "Hyperspectral Based Sensing Architectures for Resource Circularity" (H-SPACE) initiative, funded under the Italian PNRR program, aiming to develop technologies that improve space waste management and promote to the circular economy in space.
The findings suggest that HSI, combined with tailored illumination, holds significant potential for advancing space waste recycling by enabling precise and efficient classification of materials. This approach not only supports the sustainable management of space-derived waste but also lays the groundwork for future innovations in hyperspectral imaging, contributing to a more sustainable and resource-efficient future for space industries.
Molecular Imaging of Biofilms by Label-Free QCL-Based Mid-IR Reflection Microspectroscopy
Bei Shi Lee1, Matthias Godejohann2, Mengyang Liu3, Rainer Leitgeb3, Wolfgang Drexler3, Michael Berney1,4, Richard Haindl3
1Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Zurich, Switzerland; 2MG Optical Solutions GmbH, 86919 Utting/Ammersee, Germany; 3Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria; 4Albert Einstein College of Medicine, Bronx, USA
The progress of vibrational microspectroscopy systems has developed rapidly with the availability of compact, reliable laser sources such as Interband Cascade Lasers (ICL), Quantum Cascade Lasers (QCL) and extremely broad tuning External Cavity Quantum Cascade Lasers (EC-QCL). The are commercially available since more than twenty years. Since about a decade EC-QCL based microspectroscopy systems deliver disruptive results in digital pathology for the diagnose of cancerous tissue in measurement times up to 170 times Faster than Fourier-Transform Infrared spectrometer microscopes (µFTIR). The throughput of QCL-IR far-field microscopes fit into the common time slots of clinical routines, while the measurement times of µFTIR do not fulfil this requirement.
Here we present a feasibility study of simultaneously imaging the morphology and the related metabolism of microbiological specimen clusters on different materials under changing environmental conditions. This includes drying of bacterial cultures and its reaction to different treatments. The measurement time of less than one minute is short enough to regard the sample as stable during measurement.
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