LEUVEN (Belgium), July 14, 2020 — CrowdScan, a spin-off from imec and the University of Antwerp, has developed a system that measures the density of a crowd in real-time using a wireless sensor network. 

Based on six years of research at the University of Antwerp and imec, CrowdScan has developed a system to measure crowd densities without using camera images, mobile phone data or other privacy-sensitive information. By transmitting low-energetic radio waves (868 MHz), CrowdScan measures the average signal attenuation of a wireless sensor network relative to the empty environment.  

https://www.imec-int.com/en/articles/university-of-antwerp-and-imec-launch-crowdscan-a-new-spin-off-to-measure-crowds-without-compromising-personal-privacy-