## 2 Materials and Methods
### HSI Data Acquisition  
In this study, the HSI samples were acquired with a line scan push broom camera, the Specim IQ [20], equipped with a VNIR (400-1000 nm) CMOS sensor with the following specifications: a spectral resolution (FWHM) of 7 nm, a spatial sampling of 512 pixels, 204 spectral bands, a pixel size of 17.58 \(\upmu\)m \(\times\) 17.58 \(\upmu\)m, and 12-bit data output (Figure 1). This configuration achieves a peak quantum efficiency greater than 45%, a full-well capacity > 32 k e\({}^{-}\) and a signal-to-noise ratio greater than 400:1. After the scan, the final image has 512 \(\times\) 512 pixels of spatial resolution. This model is equipped with a 21 mm focal length F/2.2 objective with a FOV of 0.55 \(\times\) 0.55 m, at a distance of 1 m. Although portable, the system presents specifications and performance similar to laboratory cameras. Moreover, the computational power installed in the system (NVIDIA Tegra K1 GPU and Kepler Mobile CPU) allows the processing of the raw data and visualization of the samples' reflectance spectra on the camera-integrated display. This is particularly helpful in evaluating data immediately after the acquisition.  
When the camera is switched on, the system performs an automatic internal verification of the current spectral range calibration. If the date of the last check is older than 30 days, the system requests a new validation check. The procedure, as described by the manufacturer [21], involves scanning the white reference and the calibration tile simultaneously (Figure 2). After the data acquisition, the system compares the obtained reflectance values with the internal calibration data and warns if there is any deviation that requires a factory calibration. This procedure ensures that data cubes are acquired within the intended spectral range and that the reflectance for each spectral band is adequately computed. For this study, a validation check was performed, and no deviations were detected.  
During the scans, whether for calibration check or data acquisition, the targets were simultaneously illuminated using two ARRI Arrillite 750 Plus projectors, each equipped with a 750 W G9.5 2-pin HPL OSRAM halogen lamp, positioned behind the camera as shown in Figure 2, to ensure uniform lighting. The projectors were placed at a distance of approximately 1.5 m to prevent overheating of both the camera and samples. A stable illumination was achieved after approximately 4 min of preheating (see Supplementary Materials for details).  
For each data acquisition, the samples and the white reference (Figure 3) The data is saved in ENVI format, consisting of a flat-binary raster file accompanied by an ASCII header file [22]. For processing, the ENVI files are converted into corresponding datacubes, represented as 3D arrays (xy\(\lambda\)), with 512 \(\times\) 512 spatial pixels (xy), and 204 spectral bands (\(\lambda\)). Each \"hyper-pixel\" at spatial coordinates (x, y) is a vector with 204 components, one for each band, representing the intensity of the spatial pixel across all bands (Figure 4).  
Figure 1: Detail of the experimental apparatus: (a) Hyperspectral camera, (b) BSF meal sample, and (c) white reference, over a Teflon\({}^{\text{\textregistered}}\) sheet (black sheet).  
Figure 2: Experimental setup during the Specim IQ spectral range calibration check: (a) White reference and (b) calibration tile (SN: 190-110766), provided by the manufacturer (bottom left corner); (c) camera; (d) projectors with halogen lamps.