# Geometric and Physical Constraints for Drone-Based Head Plane Crowd Density Estimation

> Research article (2019 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), 2019) · cited 64× · AI/ML

**Wikidata**: [openalex:W2978859332](https://www.wikidata.org/wiki/openalex:W2978859332)  
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