Software to deliver HDR images to non-LED TVs

Research at Warwick University could speed up delivery of the next generation of TV image quality.

Warwick scientists are working with IBM in Austin, Texas, to enable existing TV sets to display high-dynamic-range (HDR) images that display light and contrast in a way much closer to how the human eye sees them than ordinary photo or video.

Only TVs with LED backlighting can display true HDR footage, which can be up to 30 times brighter and 10 times darker than normal images, but very few compatible models are yet on the market.

The technology will allow non-LED sets to display an approximation of HDR imaging by decoding the large amount of data involved and displaying it using a technique called ’tone mapping’.

‘The problem with [HDR video] is that it’s huge − it’s 42GB per minute of footage,’ project leader Prof Alan Chalmers told The Engineer.

‘So, what we’ve developed and filed a patent for is the compression algorithm that takes the content and compresses it down to manageable sizes.’

Chalmers’ team is now working on the decoding software that will allow people to view the compressed data on a normal screen.

The team plans to release the software for free over the internet, but for ordinary TVs it will need a processor embedded into each set. The scientists hope to produce this technology for new models, as well as for retrofitting old ones.

‘A key part of what we’re doing is proving that our algorithm is robust and gives the compression ratio we need in order to be valid for all possible footage,’ said Chalmers.

‘The second thing is then to be able to decode and view in real time – preferably 30 frames a second. Getting that kind of performance requires a lot of computational ’oomph’ and that’s really why IBM is a great partner for us, because it’s got the right cell processor.’

The project, which is partially funded by £93,000 in EPSRC follow-on funding, is due to end in February 2011, although the software could be available to download as early as September.

HDR is a measure of the light captured per pixel of an image, as opposed to the number of pixels, as with high-definition (HD) TV. An HDR camera can effectively capture 20 times the range of light of a standard camera – roughly equivalent to the human eye’s capabilities.

Very few true HDR LED TVs are currently available to buy – the SIM2 Solar 47 being the prime example – partially because the intellectual property behind the technology is owned by Dolby, which has been slow to licence it.

While Warwick’s work won’t replicate the exact level of quality as a true HDR TV, it could mean consumers will see much improved images on screens more quickly.

Another factor that might slow down the spread of this kind of video is the lack of HDR cameras, and therefore footage. Warwick has the first and only available device in the world, built by SpheronVR – although HDR is commonly used in computer games.