Embedded Systems – Instant replay

Embedded Systems – Instant replayA US firm has found a way to take the controversy out of sporting decisions. Roy Rubenstein blows the whistle on a hand-held referee’s aid
Picture the scene – a jubilant goalscorer is being chased by his team mates and the dreaded linesman’s flag goes up. Joy turns to anger and suddenly it’s the referee the players are after. Coolly, he looks at his handheld unit, freezes the play the instant the pass was made, and with confidence disallows the goal. A few heads are shaken but the crowd accepts the decision, after all they have just examined the same clip on their own handheld units.
Sounds fanciful? Not according to US firm Scanz Communications which is working with Cadence Design Systems to develop just such a handheld appliance. The first implementation will be for sports referees, followed by one for spectators (see box). Handheld unit at a glance The unit aimed at spectators will have a much smarter look than the officiating device and will have two main controls. The first will allow the user to fast forward and rewind the images, and run them both slowly, quickly and at normal speed. The other control will be a zoom facility, magnifying a region of the screen by up to three times. No pricing information is available but the target is the same “as a mobile phone or a PDA”. Scanz Communications will first show the consumer handheld at the US Consumer Electronics Show early next year.  
 
According to Sheldon Saltman, Scanz’s president, the handheld device will not just allow you to see video of key match actions but will also play feeds of highlights from other matches taking place. “It is appropriate for any league in the world, any type of sport,” said Saltman.
Moreover, Scanz is looking at other markets for its handheld design. The company is investigating its use in security applications in shopping malls and gaming venues such as casinos. Here there can be as many as 3,000 people being watched by up to 800 hidden cameras. Should something suspicious be noted in the control room, captured images can be relayed to staff on the spot via the handheld images.
Before beginning the design, Cadence’s first task was working with Scanz to better understand the end applications. “There are several market opportunities and the key is to determine what is unique and what is common to particular venues,” said Jim Douglas, v-p and general manager of Cadence’s embedded systems design group. What followed was a clear system definition and the thrashing out of the functional requirements.
Cadence has chosen to use standard discrete devices rather than a system-on-a-chip for the sport official’s device: “The time-to-market pressures are too great and there are not the required volumes for these first systems,” explained Douglas.
The unit’s components comprise an MIPS4121 microprocessor from NEC, 64Mbyte of RAM (“we could go even greater as we do more media applications”), an MPEG-1 decoder and a 5.8GHz wireless communications chip capable of handling 10Mbit/s data rates.
An MPEG-1 decoder was chosen as it is the simplest MPEG compression standard to provide moving image quality for the unit’s 3.8in. TFTcolour screen. The combination of the MIPS CPUand the MPEG-1 decoder results in up to 30 frames/s – each 320×240 – being displayed. The CPUalso runs a real-time operating system, enabling the processing of multiple video feeds – capturing one while another is being displayed, for example.
The system level considerations include ensuring the unit works across a wide range of temperatures expected at sporting venues, creating a rugged design – referees are known to take a tumble – and ensuring that the unit has sufficient power to ensure high quality images in a variety of lighting conditions.
Another system design challenge is determining the physical layout of the wireless transmitters at venues like football grounds or casinos. “The key is to ensure that there are no physical obstructions when communicating the captured data to the handhelds,” said Douglas.
For Douglas the main challenge of the handheld design has been the media processing part of the design. “The wireless comms part – with the chip and the error correction software – is not difficult,” he said. “But with the live tests – running the screens through and getting the quality you want, in and out, is tough. This is where the hardware and the software guys start screaming at each other.”
Scanz and Cadence expect to have working prototypes in a fortnight’s time and will start field trials with video feeds transmitted at a sporting venue in the summer. The devices will then be used by officials for Arena (indoor) football and Canadian football from July.
So when will the NFL adopt the technology? Scanz’ Saltman would not be drawn. However, he stressed that the NFL has voted back the use of instant replays in sports officiating. “Looking at a big screen slows the game down,” said Saltman. “This compares with the immediacy and portability of our unit, enabling you the viewer to see what the official sees.”


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