Active Hyperspectral Imaging with a Fabry–Pérot Interferometer-Based Tunable Light Source

Many conventional hyperspectral imagers lack customizability, as their integrated optical systems and fixed imaging settings prevent wavelength selection and result in unnecessary data collection. To overcome these limitations, custom hyperspectral imaging (HSI) setups are necessary. In this study, we introduce and evaluate a custom HSI setup built around a tunable light source (TLS) developed by the Technical Research Centre of Finland (VTT). The TLS separates wavelengths with a piezo-actuated Fabry-Pérot Interferometer (PFPI), allowing the user to select wavelengths within the 450–850 nm range, with a full width at half maximum (FWHM) of 20–30 nm. Almost any imaging device, including the monochromatic machine vision sensor used in this work, can be paired with TLS. To evaluate the TLS’s performance, linear and nonlinear samples are imaged using the TLS custom imaging setup and a commercially available spectral imager Specim IQ, that employs a conventional spectral imaging approach as a comparison point. The spectral unmixing algorithm is used to analyze the hyperspectral data. The results indicate that the TLS is suitable for close-range hyperspectral imaging. While the custom setup necessitates additional effort, it enhances adaptability, is programmable, and reduces redundant data collection and imaging time.