High-speed imaging of droplet spread after a cough

We propose to capture high-speed camera imagery of a cough and use astronomical image analysis techniques to track the droplets. This will inform a mathematical model of how droplets spread through the air and onto surfaces, with application to the transmission of Covid-19 and other infectious diseases.

We have already been conducting experiments in droplet spread using human-safe fluorescein dye. We produce coughs using either an artificial model or a human volunteer who holds some of the dye in their mouth. The droplets fall on printed targets. The targets are photographed under UV light so that the droplets fluoresce. These images are then processed by software based on astronomical imaging pipelines, which aligns and rectifies the targets, and automatically detects the thousands of droplets along with statistics like size, location, and brightness. One paper is already published (https://www.journalofhospitalinfection.com/article/S0195-6701(21)00044-X/abstract) and another is submitted. More are planned.

The research group is composed of respiratory specialists from Portsmouth Hospital Trust, medical faculty from UoP and Brunel University, as well as members of the Institute of Cosmology and Gravitation who provide expertise in image analysis and data processing. We also have collaborators in the Bristol aerosol research group plus contacts in the dental and ophthalmology communities. We are currently funded by the ICG’s ins, and have an STFC IPS bid in for a commercial partnership with AerosolShield Ltd.


We wish to trial a new method for much more detailed tracking of droplet spread. High-speed cameras are available which can capture thousands of frames a second. This should be sufficient to track the droplets as they first emerge after a cough, or as they hit a surface and fragment. We believe that the combination of high-speed imagery and fluorescent dye to improve the droplet visibility is unique. We will attempt to use two cameras so that we can track the droplets in 3D by computer analysis.

Because this has not been tried before, we cannot guarantee success - however, this could be quite rewarding. After acquisition of the video, we will include this data in an upcoming Data Dive run by the ICG, a few-day event where physics PhD and staff from our local university partners are invited to help us explore interesting data sets.