In the field of optical sensor technology, research is being conducted into approaches for detecting and visualizing veins from a low-cost perspective as an alternative to cameras, ultrasound or near-infrared imaging. As the simplest and cheapest option, ordinary LEDs can be considered for this purpose, which can both emit light and measure it. By illuminating the area to be examined, different structures can be detected based on the intensity of the reflected light, which depends on the different degrees of absorption of the tissue types. Furthermore, research is being conducted on intensity-based distance measurement and coupling with optical fibers.