Non-invasive
When doctors need to monitor a young child’s breathing, bands are strapped around the child’s chest, which are then attached to computers. This can be stressful and anxiety-inducing for a child, but researchers at the University of the West of England, working with Bristol University and consultants at local hospitals may soon change that. They are working on a non-invasive respiratory monitor.

Professor Melvyn Smith, Director of the Machine Vision Lab at the University of West of England explains, ‘Typically in the past, people have used a contact device, it’s like a strap that they apply to the torso of the patient, and try and measure the volume changes and the rate of change in the chest and abdomen. It’s not very satisfactory because you only get point measurements where the device is, and it can move around.’

Muscular dystrophy
‘The non-invasive techniques that have been tried are unsatisfactory’ says Professor Smith, ‘because while they signal a patient is breathing, they won’t measure the quality of the breathing.’ Clinicians are particularly interested in how this may help children with muscular dystrophy, ‘but with any patient that’s very poorly, you need to be aware of how weak the breathing has become and how healthy the breathing process is,’ explains Smith. ‘The breathing of an opera singer is very different from the breathing of a patient like this. The breathing may be shallow or the muscles may not be working efficiently. That’s where the modelling part comes in, that might involve monitoring the movement of the chest and abdomen and relating them to each other.’

Photometric stereo
They are going to use a technology which they have already developed for other projects called Photometric Stereo. ‘It involves using specialist illumination,’ says Smith. ‘We acquire images underneath this illumination, and then we use the shading of the object that appears in the image to recover detail on shape.’ The data, revealed through a combination of camera and lighting, is processed and analysed to give a 3D image, while real-time imaging allows them to see and measure the movement of chest and abdomen in real-time. A year from now, ‘we aim to have a working demonstrator and show that it works,’ says Smith.