ADRIAN PENNINGTON /
07.01.2007
Originally featured on BroadcastEngineering.com
Virtual graphics
Innovative systems bring OB and live sports up to speed.

For many broadcasters, live sports coverage ranks as their premium content, a source of event television for capturing and retaining audiences. For this reason, outside sports broadcast is one of the most pressured production environments and the frontline for new technology.

While the development and integration of an HD outside broadcast chain (super slow-motion cameras, RF links and multichannel audio) has been the main technology driver for the last few years, the most innovative changes are now taking place within on-screen graphics.

Producers often find greater benefits from using creative graphics than from adding another camera channel. They can also deliver new game perspectives and presentations with 3-D analysis tools and data aggregators.

Expectations have also grown. At one time, a graphic change consisted of moving a flat caption to fit the top left-hand screen. Now instant replay-powered viewers expect instantaneous 3-D representations of the game.

Many of the new breed of graphics systems stem from advances in image-tracking technology. Yet their deployment means nothing without editorial control. The key brief from broadcasters to graphics providers is that the technology enables new stories to be told. Graphics should elucidate a decision or pattern of play, or add dynamism to dull periods.

Perfect playback

Irish pay-TV broadcaster Setanta Sports will begin broadcasting select English Premiership football matches later this year, in direct competition with incumbent broadcaster Sky Sports. To optimize its coverage, Setanta intends to play back any incident from the perfect angle and to revolutionize game analysis.

Setanta appointed Alston Elliot to design templates and manage its graphics output. The southern England-based firm designs and supplies on-air graphics to a variety of broadcasters for snooker, rugby and association football but is primarily known for innovating cricket packages for Sky Sports and M-Net in South Africa.

The company operates 60 Vizrt licenses for playout, with three installed in each of five mobile units. The firm has devised its own software to run its templates and interface with an input and logging software.

For Sky Sports cricket, for example, the company supplies a graphics van to the main OB supplier, usually CTV. An Alston Elliot-trained operator will sit alongside the commentary position and manually input data, such as direction of runs and shot type, and update the score. In conjunction with the OB director, the operator will suggest or select graphics or captions at various stages in play. Clearly, getting a statistic wrong would constitute a serious error. For darts coverage, the scoring is even faster and mathematically more complex, so the operator's job is even more pressured.

Multilingual, multilateral

Turin, Italy-based Delta Tre supplies and manages graphics for the UEFA Champions League and UEFA European Championships. It also provided the host graphics feed for the HBS production of the 2002 and 2006 World Cup games.

The company operates 14 graphics trucks across Europe for coverage of every live Champions League match and management of live statistics and score lines for UEFA's official Web site. Although the on-air design and layout was produced by a specialist agency, Delta Tre takes the brief and builds and implements the templates using its software. It also provides multilingual versions of the multilateral feed.

The company had to retune its software engine D3D to complement the HD acquisition during the last two World Cups. The increased aspect ratio requires the software to render up to four times as many polygons without dropping any frames. The computational power needed for live 3-D rendering made it impractical until NVIDIA developed its range of GPUs. NVIDIA's 4500 Quadro cards now power the Delta Tre engine.

In order to satisfy the demand for separate language feeds and different styles of graphics, the company also developed remote graphic insertion. With a single operator using a laptop at the event and sending data via ISDN, graphics can be added to a clean feed at an International Broadcast Centre on another continent, but still follow the lead of the host broadcaster's selected graphics.

The company will introduce a real-time tracking device that monitors where, how far and at what speed players have traveled at the Manchester United vs. Roma Champions League Quarter Final. The image recognition system, which was partly devised by Delta Tre, comprises two banks of eight cameras that overlap to cover all zones on the pitch. An operator takes an image of the player at the start, assigns that to the area where they are standing, and then the cameras automatically follow the player's movement, updating information constantly and live throughout the entire game.

Side by side

Swiss manufacturer Dartfish developed two applications from sports coaching simulations. The BBC used both SimulCam and StroMotion in its coverage of downhill skiing and figure skating during the 2006 Olympics.

SimulCam is based on the idea that whenever two athletes are competing at different times, but over the same terrain, their filmed performances can be composited into a single video that shows both competitors seemingly competing. Software automatically compensates for the differences in camera angle (pan, tilt and zoom) between the two recorded performances and then blends the two performances together.

StroMotion reveals the evolution of an athlete's movement by compounding static images into a frame-by-frame sequence. Footage is loaded into a PC-based module for automatic computation of camera movement. It then builds a panoramic image that covers the camera's range during the shot, removes the moving object from the sequence and reinserts it as a series of animated images to illustrate movement. Rendering takes just three minutes.

Fast tracks

Technology from Virtual Spectator offers a rival application to Dartfish. For North One's host broadcast of the World Rally Championship (WRC), a system installed in a mobile production unit will provide a 3-D overlay of a competitor's vehicle while live shots of another car are broadcast. The WRC format permits cars to race at intervals against the clock, not against each other, so this application can bring additional dynamism to the competition.

Onboard GPS systems store information about the car's route, which is downloaded to the application to simulate speed, pitch and significant movement. As with the WRC video games, the position and altitude of the cars can be viewed from any angle, including driver's-eye view.

New views

Piero's sports graphic system enables broadcasters to present play from angles that are not captured by cameras. The system began as a BBC research and development exercise for BBC Sport, relying initially on a camera head equipped with sensors to measure the pan, tilt and zoom of the camera and lens. BBC Outside Broadcasts developed methods to relay this data back to the studio along with the accompanying video.

BBC R&D also developed a method to measure the camera position, orientation and field of view by tracking lines on the pitch. By knowing the shape and dimensions of the pitch and its white line markings, the software can calculate how the camera moves frame by frame and distort the graphical image accordingly. The foreground image is overlaid on the background graphic by chroma key.

These two approaches — virtual graphics calculated by camera sensor and by line tracking — have been adopted and refined by Red Bee Media. The company commercialized the product in 2006, making its first sale to the BBC and subsequently Sky Italia, TV Globo, Al Jazeera and Hong Kong's iCable.

Although the camera sensor application is usually sited in an OB truck and requires a trained operator, the line tracking module (Piero Sketch), with a slightly cut down library of effects, can be operated by studio pundits via touch screen. However, it still requires an operator to set up and drive the system.

Red Bee has experienced cost savings through using the virtual graphics solution. The system's discrete PC-based module cuts operational overheads, so it can work directly from a server or Digital Betacam deck for archive footage. Additionally, because it's not tied to any particular camera, it can extrapolate information from any angle.

The system is already in regular use for association football matches. And Red Bee has also optimized the product at 720p for American NFL football in a bid to crack the U.S. market.

A tennis application will follow, featuring hot spots that highlight player travel during a point. Red Bee tweaks each system for specific needs. Piero, for example, can extract images of real players and seamlessly place them in a CG stadium.

Forward looking

The Hawk-Eye image tracking system, technology developed by The Television Corporation, automatically inputs data, such as speed of delivery or ball trajectory. It is also a staple part of official tennis umpiring, and it has been proposed for goal-line decisions during association football. Already a familiar part of cricket coverage, it has also recently been adapted for snooker, where it enables commentators to highlight what a player should have done with a particular shot.

Hawk-Eye incorporates both image analysis and radar technology. For cricket, six fixed Java Advanced Imaging (JAI) monochrome cameras, running at 120fps, are placed on the ground. They track the ball's entire trajectory, from the point where it is released from the bowler's hand to the point where the ball is considered dead. This is updated 100 times per second. The cameras are used in two sets, and a multichannel frame grabber handles each set. The captured images are then processed to produce a 3-D image, which can predict future motion with an accuracy of 5mm.

Hawk-Eye is part telestrator and part replay machine. It is offered to the director in the same way a videotape operator would suggest clips. It's a specialist tool set-up, calibrated and operated by the company, and it allows operators to exchange data at events with graphics providers.

IT specialist BBG Sports tested a rival system for cricket during Channel 9's Ashes coverage in Australia last winter. Hot Spot deploys two Emerald IR thermal imaging cameras, devised by Paris-based Cedip Infrared Systems, to remotely sense and measure the tiny amount of heat generated by a collision (friction), such as ball on pad. A black and white negative image shows the ball's precise point of contact.

In-line viewing

Orad recently branched into applications for live OB. Last year, it introduced CyberSport for key event analysis. It features live insertion of tied-to-the-field 2-D/3-D animations, as well as sport-specific plug-ins that interface the system into statistical databases for football, swimming or athletics.

The software includes an embedded four-zone chroma keyer developed specifically to cope with harsh outdoor lighting. Even in extreme weather conditions in which part of the playing field is cloudy and the other is sunny, a different chroma key zone can be dynamically applied to each area, ensuring high-quality graphic overlays.

CyberSport also supports multicamera productions. For example, during an association football game, in addition to the main tracked camera, two cameras on the 16m-line can be tracked, providing a perfect angle for displaying an offside line. The system can be integrated with EVS servers or Forum — Orad's six-channel, slow-motion video server — to provide replay features, such as drawing dynamic offside lines, measuring ball speed or highlighting a certain event using a digital magnifying glass.

TrackVision, the company's football enhancement tool, features similar technology. Over live video streams, it can draw a 9m distance indicator for free kick events, as well as precisely measure and display the distance to goal.

Virtual advertising

The logical end game of virtual graphics packages is advertising. The ability to insert brand logos virtually onto the field of play or dynamically update billboards around a stadium provides broadcasters and rights holders with genuine revenue opportunities. Greater take-up is currently being seen from smaller IPTV service providers rather than large broadcasters.


Adrian Pennington writes about broadcast technology.



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