Moving story

From The Lord of The Rings to Beowulf, film-goers have grown used to the spectacle of ultra-realistic digital characters and humans seamlessly sharing the screen. And while the skills of the film industry’s most creative minds can never be underestimated, some of cinema’s most impressive special effects would not have been possible without technology developed by UK motion capture specialist Oxford Metrics Group(OMG).

Recently announcing a 50 per cent rise in profits to £3m over the past year, the company has become the undisputed world leader in motion capture technology and with applications for its technology in the computer game, life sciences, and defence industries, there is a lot more to its systems than the glamour of the big screen.

The story began when the company’s founder and chief executive, bio- mechanics specialist Julian Morris, decided to leave academia for business and joined UK technology firm Oxford Instruments. ‘They were looking for new diversification, and at the time there were no systems available for measuring human movement so I said why don’t we develop a system for doing this.’

The core elements of what has become OMG’s Vicon motion-capture system were born: a series of retro-reflective markers for attaching to the body, video cameras for detecting the motion of these markers in two dimensions and a mathematical process for reconstructing this data into a 3D movement.

In 1984, shortly after beginning work on the project, a reorganisation at Oxford Instruments prompted Morris and a number of his colleagues to exercise management buyout options and start their own business. It was, he said, a nice position for a new company to be in. ‘We had a running start. We didn’t have to get venture capital or anything like that because at the early stages we were very close to having customers.’

These early customers were children’s hospitals, which were carrying out research into the movement of children with cerebral palsy in an effort to determine whether corrective surgery could enable them to walk more effectively. This grew to be the first coherent market and is still a significant part of the business today, said Morris. ‘Almost any children’s hospital will have a gait lab with a Vicon system.’

Although the medical market was, and still is, sizeable, Morris quickly realised that the technology had potential in a variety of other applications. For instance, early on, the company began looking at using the technology to analyse the movement of the dummies used in automotive crash testing. ‘Anywhere that film was being used instead of video and where we could replace manual analysis with some degree of automation — those were the opportunities,’ said Morris.

But it was not until the mid-90s — with the advent of computer games featuring realistic human characters — that the big commercial opportunities began to appear and Morris realised that his technology was exactly what the gaming industry had been waiting for. ‘It turned out that the animators wanted exactly the same thing as the medical specialists: information about how the joints moved, in order to do their animations and then stick a skin on top of that.’

Today, OMG numbers some of the world’s largest game makers, including EA and Nintendo among its customers.

The increasing use of animation in film also provided a new market for the technology and, although the principles of the modern system are essentially the same as those behind its medical forbears, advances in computer processing and digital imaging have given today’s system some incredible capabilities.

According to Morris, Beowulf, which was launched last year, represents perhaps one of the most extreme deployments of the technology so far.

In some of the film’s crowd scenes, where up to 12 actors had to be captured, the system used about 200 specially developed cameras to simultaneously track about 1,500 markers attached to the different actors’ bodies and faces.

Making sense of all of this data was, said Morris, a huge challenge. ‘Each of the cameras collects 2D information relating to the markers that they can see and a massive software task is then required to associate the markers seen by the different cameras. The cameras all feed into PCs where the 2D co-ordinates are all bought together to estimate the 3D positions of the points that generated the images. From that we need to work out which marker is which and finally drive a skeleton, which is used to create the animation.’

In the process of developing the algorithms used to reconstruct the 3D and to determine the precise position of the cameras, OMG almost stumbled upon its other great contribution to the film industry; an Emmy award-winning piece of software called Boujou that is able to look at a normal video scene without any special markers and work out how the camera is moving and what its position is relative to whatever it’s looking at.

‘That knowledge of how the camera was moving was something the film industry needed to know very badly for computer graphics,’ said Morris. ‘If it was adding a computer graphic to a real scene, the viewpoint of the real image and viewpoint of computer graphic have to be precisely the same, otherwise one tends to appear to wander around relative to the other.’

Once again realising that its technology has applications beyond its initial target audience, OMG has now set up a new division, called YOTTA, which uses vans equipped with cameras to recognise and locate objects of interest beside the road (such as road signs, street signs or markings) and generate a detailed geographic database.

Morris said the company is now working with various local authorities across the UK that hope to use the system to replace traditional methods of surveying.

In an application that perhaps moves furthest away from OMG’s original incarnation as a medical devices company, a variant of this imaging technology may even be used on board military UAVs. ‘We have MoD contracts in two areas’, said Morris, ‘one in automatic target recognition and the other in image-based tracking.’

He said that such systems which, by recognising objects on the ground, are able to generate their own maps and navigate without the need for GPS, are of great interest to the military, which is keen to develop methods of UAV navigation that cannot be affected by ground-based signal jammers.

For a company that started out more than 20 years ago working in children’s hospitals it has, said Morris, been an eventful and unexpected journey: ‘I never imagined it would have so many applications. It’s been a very curious evolution.’