Material Sensing with Spatial and Spectral Resolution Based on an Integrated Near-Infrared Spectral Sensor and a CMOS Camera

Measuring the composition of materials at a distance is a key requirement in industrial process monitoring, recycling, precision agriculture, and environmental monitoring. Spectral imaging in the visible or near-infrared (NIR) spectral bands provides a potential solution by combining spatial and spe...

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Main Authors: Ben Delaney, Sjors Buntinx, Don M. J. van Elst, Anne van Klinken, René P. J. van Veldhoven, Andrea Fiore
Format: Article
Language:English
Published: MDPI AG 2025-05-01
Series:Sensors
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Online Access:https://www.mdpi.com/1424-8220/25/11/3295
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author Ben Delaney
Sjors Buntinx
Don M. J. van Elst
Anne van Klinken
René P. J. van Veldhoven
Andrea Fiore
author_facet Ben Delaney
Sjors Buntinx
Don M. J. van Elst
Anne van Klinken
René P. J. van Veldhoven
Andrea Fiore
author_sort Ben Delaney
collection DOAJ
description Measuring the composition of materials at a distance is a key requirement in industrial process monitoring, recycling, precision agriculture, and environmental monitoring. Spectral imaging in the visible or near-infrared (NIR) spectral bands provides a potential solution by combining spatial and spectral information, and its application has seen significant growth over recent decades. Low-cost solutions for visible multispectral imaging (MSI) have been developed due to the widespread availability of silicon detectors, which are sensitive in this spectral region. In contrast, development in the NIR has been slower, primarily due to the high cost of indium gallium arsenide (InGaAs) detector arrays required for imaging. This work aims to bridge this gap by introducing a standoff material sensing concept which combines spatial and spectral resolution without the hardware requirements of traditional spectral imaging systems. It combines spatial imaging in the visible range with a CMOS camera and NIR spectral measurement at selected points of the scene using an NIR spectral sensor. This allows the chemical characterization of different objects of interest in a scene without acquiring a full spectral image. We showcase its application in plastic classification, a key functionality in sorting and recycling systems. The system demonstrated the capability to classify visually identical plastics of different types in a standoff measurement configuration and to produce spectral measurements at up to 100 points in a scene.
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spelling doaj-art-c55e91eeaf2b4f8b838b78bd03f4e32e2025-08-20T02:23:09ZengMDPI AGSensors1424-82202025-05-012511329510.3390/s25113295Material Sensing with Spatial and Spectral Resolution Based on an Integrated Near-Infrared Spectral Sensor and a CMOS CameraBen Delaney0Sjors Buntinx1Don M. J. van Elst2Anne van Klinken3René P. J. van Veldhoven4Andrea Fiore5Department of Applied Physics, Eindhoven Hendrik Casimir Institute, Eindhoven University of Technology, P.O. Box 513NL, 5600 MB Eindhoven, The NetherlandsDepartment of Applied Physics, Eindhoven Hendrik Casimir Institute, Eindhoven University of Technology, P.O. Box 513NL, 5600 MB Eindhoven, The NetherlandsDepartment of Applied Physics, Eindhoven Hendrik Casimir Institute, Eindhoven University of Technology, P.O. Box 513NL, 5600 MB Eindhoven, The NetherlandsDepartment of Applied Physics, Eindhoven Hendrik Casimir Institute, Eindhoven University of Technology, P.O. Box 513NL, 5600 MB Eindhoven, The NetherlandsDepartment of Applied Physics, Eindhoven Hendrik Casimir Institute, Eindhoven University of Technology, P.O. Box 513NL, 5600 MB Eindhoven, The NetherlandsDepartment of Applied Physics, Eindhoven Hendrik Casimir Institute, Eindhoven University of Technology, P.O. Box 513NL, 5600 MB Eindhoven, The NetherlandsMeasuring the composition of materials at a distance is a key requirement in industrial process monitoring, recycling, precision agriculture, and environmental monitoring. Spectral imaging in the visible or near-infrared (NIR) spectral bands provides a potential solution by combining spatial and spectral information, and its application has seen significant growth over recent decades. Low-cost solutions for visible multispectral imaging (MSI) have been developed due to the widespread availability of silicon detectors, which are sensitive in this spectral region. In contrast, development in the NIR has been slower, primarily due to the high cost of indium gallium arsenide (InGaAs) detector arrays required for imaging. This work aims to bridge this gap by introducing a standoff material sensing concept which combines spatial and spectral resolution without the hardware requirements of traditional spectral imaging systems. It combines spatial imaging in the visible range with a CMOS camera and NIR spectral measurement at selected points of the scene using an NIR spectral sensor. This allows the chemical characterization of different objects of interest in a scene without acquiring a full spectral image. We showcase its application in plastic classification, a key functionality in sorting and recycling systems. The system demonstrated the capability to classify visually identical plastics of different types in a standoff measurement configuration and to produce spectral measurements at up to 100 points in a scene.https://www.mdpi.com/1424-8220/25/11/3295spectral sensingmaterial classificationnear infraredintegrated photonics
spellingShingle Ben Delaney
Sjors Buntinx
Don M. J. van Elst
Anne van Klinken
René P. J. van Veldhoven
Andrea Fiore
Material Sensing with Spatial and Spectral Resolution Based on an Integrated Near-Infrared Spectral Sensor and a CMOS Camera
Sensors
spectral sensing
material classification
near infrared
integrated photonics
title Material Sensing with Spatial and Spectral Resolution Based on an Integrated Near-Infrared Spectral Sensor and a CMOS Camera
title_full Material Sensing with Spatial and Spectral Resolution Based on an Integrated Near-Infrared Spectral Sensor and a CMOS Camera
title_fullStr Material Sensing with Spatial and Spectral Resolution Based on an Integrated Near-Infrared Spectral Sensor and a CMOS Camera
title_full_unstemmed Material Sensing with Spatial and Spectral Resolution Based on an Integrated Near-Infrared Spectral Sensor and a CMOS Camera
title_short Material Sensing with Spatial and Spectral Resolution Based on an Integrated Near-Infrared Spectral Sensor and a CMOS Camera
title_sort material sensing with spatial and spectral resolution based on an integrated near infrared spectral sensor and a cmos camera
topic spectral sensing
material classification
near infrared
integrated photonics
url https://www.mdpi.com/1424-8220/25/11/3295
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