Measuring Absolute Radiance by Calibrating a Hyperspectral Camera Economically: Code and Data

This deposit contains the complete source code and data (v1.0.0) necessary to reproduce Figures 2–11, 14 and 15 and Tables 1–3 from the associated publication: Kong, X., Lin, C.-W., & Hanselaer, P. (2026). Measuring absolute radiance by calibrating a hyperspectral camera economically. Color Research & Application, 51(2), e70043. DOI: 10.1002/col.70043. A commercial hyperspectral camera (Specim IQ) is characterised (repeatability, linearity with integration time, dark current, flat field behaviour and wavelength calibration with a helium lamp) and calibrated for absolute spectral radiance with a Bentham SRS8Q calibration source and a factory-calibrated JETI Specbos 1211L spectroradiometer as ground truth. The calibration is validated with an OLED panel (OLEDWorks Brite 3 FL300) and a Macbeth ColorChecker, and compared with a TechnoTeam LMK 6-5 colour camera. The measurements were carried out between 2021 and 2023 at the Light&Lighting Laboratory, KU Leuven (Ghent, Belgium). Files SpecimIQ-Absolute-Radiance-Calibration-1.0.0-code.zip (1.1 MB): MATLAB code, processed data, spectroradiometer and colour camera data, regions of interest and reference results. README.md – full documentation LICENSE and CITATION.cff – licence and citation information runAllAnalyses.m – raw hyperspectral images → processed data runAllFigures.m – processed data → figures and tables verifyReproduction.m – compares the results with the reference results src/ – MATLAB code, one folder per topic of the paper repeatability/ – Section 3.1: analyzeRepeatability, plotFigure2, plotFigure3 linearity/ – Section 3.2: analyzeLinearity, plotFigure4 darkCurrent/ – Section 3.2: analyzeDarkCurrent, plotFigure5 flatFieldBehavior/ – Section 3.3: analyzeFlatFieldBehavior, plotFigure6, plotFigure7 wavelengthCalibration/ – Section 3.4: analyzeWavelengthCalibration, plotFigure8, createTable1 radianceCalibration/ – Section 3.5: analyzeRadianceCalibration, plotFigure9, plotFigure10, plotFigure11 oledValidation/ – Section 4.1: analyzeOledValidation, plotFigure14, createTable2 colorCheckerValidation/ – Section 4.2: analyzeColorCheckerValidation, plotFigure15, createTable3 common/ – camera constants, reading the raw cubes and the data files, settings colorimetry/ – spectral interpolation, XYZ, u′v′, CIELAB, comparison with the ground truth plotting/ – figure style and saving data/ rawData/ hyperspectralImages/ – put the eight topic folders of the rawData zip here spectroradiometer/ – spectral radiance (ground truth) colorCamera/ – colour camera region means regionsOfInterest/ – pixel areas used in Sections 3.5 and 4 externalData/ – CIE 1931 2° colour-matching functions processedData/ – output of the analyze scripts, input of the figure scripts tests/referenceResults/ – reference results of this release (used by verifyReproduction) output/ – generated figures and tables (created by runAllFigures) SpecimIQ-Absolute-Radiance-Calibration-1.0.0-rawData.zip (1.4 GB, 9.9 GB unzipped): 92 raw Specim IQ captures (ENVI format, 512 × 512 pixels × 204 bands) in eight topic folders. Zenodo cannot preview this zip because it contains more than 1000 files; its structure is shown below. repeatability/ – Section 3.1, captures 313–373 linearity/ – Section 3.2, captures 460, 463, 466, 469, 472, 475, 476 darkCurrent/ – Section 3.2, captures 374–382 flatFieldBehavior/ – Section 3.3, captures 222, 224–227 wavelengthCalibration/ – Section 3.4, captures 253–255 radianceCalibration/ – Section 3.5, captures 240–242 oledValidation/ – Section 4.1, captures 397, 398 colorCheckerValidation/ – Section 4.2, captures 809, 819 Each capture is stored in <topic>/<captureNumber>/ with the original folder structure of the camera: capture/<captureNumber>.hdr – ENVI header (wavelengths, integration time) capture/<captureNumber>.raw – raw digital counts, 512 × 512 × 204, uint16, BIL order capture/DARKREF_* and WHITEREF_* – references recorded by the camera (not used) metadata/ and manifest.xml, *.png – camera metadata and preview image Getting Started & Reproduction Instructions Download the code package and refer to the comprehensive README.md file for detailed, step-by-step instructions, including: Run the runAllFigures master script to generate all figures and tables (about 1 minute). Run verifyReproduction to compare the results with the reference results. Optional: unzip the raw data, move the eight topic folders into /data/rawData/hyperspectralImages/ and run runAllAnalyses to reproduce everything from the raw images (about 10–15 minutes). System Requirements MATLAB R2021a or newer (tested with R2024a), or GNU Octave 8.4 (tested). No toolboxes are needed for the figures and tables. Only the Lilliefors normality test (Section 3.1) uses the Statistics and Machine Learning Toolbox; it is skipped if the toolbox is not installed. Reproducibility All analyses were recomputed from the raw data in one MATLAB code base and checked against the original analysis outputs and the published values. The calibration factors agree with the original analysis to 10 significant digits, Table 3 is reproduced exactly and Table 2 within rounding. A few small discrepancies with the published article remain; none of them changes the conclusions. They are listed in the section Reproducibility Notes of the README.md. How to Cite Please cite both the associated publication and this dataset deposit: Kong, X., Lin, C.-W., & Hanselaer, P. (2026). Measuring absolute radiance by calibrating a hyperspectral camera economically. Color Research & Application, 51(2), e70043. DOI: 10.1002/col.70043. Kong, X., Lin, C.-W., & Hanselaer, P. (2026). Measuring absolute radiance by calibrating a hyperspectral camera economically: Code and data (Version v1.0.0) [Dataset]. Zenodo. https://doi.org/10.5281/zenodo.13136174. Xiangzhen Kong and Ching-Wei Lin contributed equally to this work and should be regarded as co-first authors. Licensing & Source Code: MIT License (MATLAB .m files). Data and Documentation: CC BY 4.0 License (raw and processed data, README.md). This license applies to the files of this deposit only; the published article is © 2026 Wiley Periodicals LLC. Third-party data: the CIE 1931 2° colour-matching functions in /data/externalData/ are published by the CIE (DOI: 10.25039/CIE.DS.xvudnb9b) and are included under the license of the CIE. Source: The code package is the v1.0.0 release of the official GitHub repository: https://github.com/kongfundamentals/SpecimIQ-Absolute-Radiance-Calibration. Contact For questions about the code, the data or other measurements of the project, please contact either of the co-first authors, Xiangzhen Kong ([e-mail]) or Ching-Wei Lin ([e-mail]).