# Regulated Power Supply with High Power Factor for Hyperspectral Imaging Applications
## 5 Conclusions  
This paper shows the performance of a custom regulated power supply integrated into an HS acquisition system considering different light-intensity profiles for three types of lamps and two illumination modes. Detailed results are provided for steady period and light stability, showing better performance of the 150 W custom power supply (PPS) and TechniQuip's commercial power supply (CPS-2) with respect to the MI-150 fiber optic illuminator (CPS-1) in terms of light stability; however, steady period is minimized considering the fiber optic illuminator. Moreover, the automatic extraction of the spatial ROI for the transmittance mode together with the automatic extraction of the light-intensity values within the steady period are also presented. Figure 17: Light stability (SNR) across spectral bands for the different type of power supplies (PPS, CPS-1, and CPS-2). **(a)** Reflectance mode. **(b)** Transmittance mode. This work analyzes the effects of different power supplies when applied to hyperspectral illumination. It has been shown that the quality of the power supply affects the quality of the resulting light at different wavelengths, but little research has been performed on the effect of the design of the power supply on the resulting illumination. The results of our experiments indicate a significant influence of the power supply on the stability of light as measured by the SNR. This effect becomes particularly pronounced when analyzing the SNR across different spectral bands. Power sources with the highest PF and THD, specifically CPS-2 and PPS (as shown in Table 2), also exhibited the best light stability across the spectral range of the camera (Figure 17). However, other factors may also affect SNR, highlighting the need for further research to clarify the extent to which PF and THD affect light stability across various wavelengths. Considering these findings, future research should aim to identify which components of the power supply contribute to either positive or negative impacts on the SNR at various wavelengths. Specifically, it should focus on AC/DC converters used in lamp power supplies, which are known for exhibiting significant non-linearity. Additionally, future research should benchmark the performance of different real-world power supplies against an ideal power supply, i.e., one that provides a pure sine wave with minimal series impedance. This comparison would offer a more reliable reference for future studies in this area. Furthermore, it is necessary to understand the importance of SNR in specific HSI applications, identifying scenarios where high SNR is required and selecting an appropriate power supply accordingly. To effectively address specific challenges in HSI, such as classification or segmentation, additional experiments are necessary. This can be achieved by creating datasets consisting of the same objects illuminated using different power supply configurations. Then, the impact of different illumination conditions on the specific problems being studied could be evaluated. The effects of different lighting conditions will be considered for future research. Finally, while this study was concentrated on evaluating light stability in the VNIR spectral range, future research should expand to include higher spectral regions (beyond 1000 nm), which are crucial for a wide range of HSI applications. The following supporting information can be downloaded at [[https://www.mdpi.com/article/10.3390/app15031093/s1](https://www.mdpi.com/article/10.3390/app15031093/s1)]([https://www.mdpi.com/article/10.3390/app15031093/s1](https://www.mdpi.com/article/10.3390/app15031093/s1)). Figure S1: Schematic of the step-down converter with output voltage sampling and input current sampling compensation. Table S1: Results for the steady time and SNR for the different types of power supplies (PPS, CPS-1, and CPS-2), in reflectance and transmittance mode. Conceptualization, J.M.C.-P., S.O., H.F. and G.M.C. ; methodology, J.M.C.-P., R.L., S.O. and H.F.; validation, R.L. and S.O.