Low-cost fluorescence-based temperature sensing system for neonatal care

A remotely-measured fluorescence-based temperature measurement system designed for neonatal care is built and presented using a low-cost, off-the-shelf camera-phone image sensor. The fluorophore-based sensor salve removes the need of attaching thermistor probes using adhesives to the neonate's skin; and therefore reduces the risk of epidermal stripping, microbial infections, etc. The system performs low-cost yet precise remote ratiometric measurements of our thermometric fluorescent salve using only a 10-bit, 120-FPS CMOS imager. An FPGA handles control and capture of image data in the region of interest with frames synchronized with a pulsing illuminator. A minimalistic algorithm using basic pixel-summations and division to compute a ratio is presented, suitable for implementation on a minimal embedded system. The resolution of the system is reported to be at least 0.18 degrees Celcius.