Imaging System for the quantification of contamination on a surface
STS worked with NPL (National Physical Laboratory) to develop and commericialise a system that they had developed to prototype stage for the identification of contamination on surfaces and in particular on people. This system originally called "Fives" was designed to quantify amounts of airborne contaminants that would be deposited on a person under a range of different conditions. In particular this system had application in chemical warfare, agricultural pesticides and aerosolised contaminants.
Of special interest to the designers was the ability to test the integrity of suits and clothing designed to protect the user from contaminants, here the integrity of closures,zips and masks are crucial in ensuring a suitable level of protection is given. By exposing mannequins dressed in protective clothing to a simulated contaminant containing a fluorescent powder the system could not only identify the presence of the material from an image but also quantify the amount deposited on the "person" from the image alone.
This technique uses a video capture method to take a rapid picture of the person and to then allow to correct the image for body curvature when calculating the deposited material. All of this is done using UV light sources in a dodecahedral frame to illuminate the contaminated person when the images are taken. By using reference pictures the system can identify the area of interest and calculate the deposition.
Although extremely skilled scientists the staff at NPL did not have the commercial ability to take this product to market. STS were able to take this project on secure some additional grant funding and to take the product to market within 12 months. An initially crude set up was refined to produce the substantial UV dodecahedron required and the UV lighting upgraded to produce more light with a more controllable output. This update was crucial as the amount of sensitivty acheivable by the system relied not only on the sensitivity of the camera but also on the intensity of the fluorescence achieved - which is directly affected by the amount of excitation light the particles are exposed to.
The system was also piece-meal and whilst the scientists at NPL understood what was required this was not a user friendly interface, STS therefore undertook a complete rewrite of the software interface so that the package could be used in the field. Various camera and equipment upgrades were also carried out eventually concluding with a system fit for purpose. This was verified and then corroborated by the purchase of systems by the HPA (now Public Health England) and to units of the US Army CBRN reserch sections who used them for cheical warfare suit testing.
