In 2008/2009 I managed and worked on an applied research project (funded by Regione Emilia Romagna (PRIN project), ImageLab, and Bridge 129 S.p.a.), focused on monitoring the safety of workers in construction sites, specifically addressing the problem of detecting in an automatic manner the workers that are not wearing the hard hat (i.e. the protective helmet).
The goal was two fold: first to provide a useful tool for reducing the bad habit to go bare-head in construction sites, second to reduce the cost of insurances covering construction site hazards.
The project yielded a very good application release candidate, devised to work with high resolution PTZ cameras patrolling the whole construction site. Have a look to these demo videos: the red box around the head means detection of bare-head. People far away are not detected because of the small resolution.
You can see in the next videos the snapshot that have been collected after a few hours of test on real construction sites. The first clip shows people detected without hard-hat, while the second shows the good ones, with hard-hat.
Anyone interested? Contact me!