> optical frequency comb
"113 km absolute ranging with nanometer precision" (2024) https://arxiv.org/abs/2412.05542 :
> two-way dual-comb ranging (TWDCR) approach
> The advanced long-distance ranging technology is expected to have immediate implications for space research initiatives, such as the space telescope array and the satellite gravimetry
From https://news.ycombinator.com/item?id=42330179 .. https://www.notebookcheck.net/University-of-Tokyo-researcher... :
> multispectral [UV + IR] camera ... optical, non-contact method to detect [blood pressure, hypertension, blood glucose levels, and diabetes]." [ for "Non-Contact Biometric System for Early Detection of Hypertension and Diabetes" https://www.ahajournals.org/doi/10.1161/circ.150.suppl_1.413... ]
>> "Tongue Disease Prediction Based on Machine Learning Algorithms" (2024) https://www.mdpi.com/2227-7080/12/7/97 :
>>> new imaging system to analyze and extract tongue color features at different color saturations and under different light conditions from five color space models (RGB, YcbCr, HSV, LAB, and YIQ). [ and XGboost ]
Note that the precision is very good, however the accuracy is nowhere near as close (fractions of a metre) in the atmosphere, due to the variable refractive index of air. Long term averages can help, of course.