A Study on Passive Crowd Density Estimation using Wireless Sensors

For automatic monitoring systems and user oriented services, crowd density estimation becomes an important research topic. There are existing methods like the camera based crowd density estimation or the RFID based counting systems. However, these methods need deployment cost and enough spaces to set the sensors. In this paper, we therefore present a passive estimation system that could be easily installed on existing infrastructures. To be precise, we use RSSI (Received Signal Strength Indicator) and LQI (Link Quality Indicator) that can be attained by popular wireless networks. Furthermore, we develop a prototype system which combines visual marker detection to locate the place, Web services to collect/distribute sensor data, and augmented reality visualization to enhance the estimated crowdedness.