ArticleHardwareX2026
A low-cost three-wavelength illumination system for camera-based photoplethysmography imaging.
Article in HardwareX, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.
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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
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Authors and funding
4 authors.
Funding
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Abstract
This paper presents the design and implementation of a low-cost, reliable three-wavelength (3-λ) illumination device intended for photoplethysmography imaging (PPGI) measurements. The proposed system employs high-power light-emitting diodes operating in the green (520 nm), red (625 nm), and near-infrared (855 nm) spectral regions, enabling non-contact cardiovascular monitoring with flexible spectral configuration. The illumination module integrates seven green LEDs, eleven red LEDs, and fifteen infrared LEDs, a distribution selected to compensate for wavelength-dependent camera sensitivity while providing sufficient radiant intensity and spatial uniformity at low power consumption and cost. Each wavelength channel is independently driven using dedicated single-channel linear LED drivers with pulse-width modulation control, allowing precise adjustment of illumination intensity. System operation is managed by a microcontroller-based control platform, which ensures accurate timing, synchronization, and stable operation required for PPGI applications. The compact and modular design supports straightforward integration with camera-based imaging systems, while optional wireless control enhances usability in laboratory environments. Overall, the proposed illumination device represents a robust and cost-effective solution for experimental and applied PPGI measurements in research-oriented non-contact biosensing systems.
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