pritch Posted February 5, 2011 Share Posted February 5, 2011 So, last night, I was watching the rugby, and I happened to notice that, at the start of the second half, the BBC showed the scores on the surface of the pitch; I'm fairly sure that I've seen players walking over the top of the scores too, so it's obviously something more clever than just on-screen graphics, and I was wondering how they actually do it? Is it chroma key, against the green? Is a rugby pitch even a uniform enough colour of green for that to work? If it is chroma key, how do they get it to work for the Irish matches, without the green shirted Irish players disappearing? Link to comment Share on other sites More sharing options...
kerry davies Posted February 5, 2011 Share Posted February 5, 2011 You mention that match and anyone Irish again and I swear I'll ....Scotland have kicked off before I did. Link to comment Share on other sites More sharing options...
timd Posted February 5, 2011 Share Posted February 5, 2011 Interesting problem, actually. Could be a chroma job, but instead of replacing the green just using it to work out a pitch layer, overlay score and then overlay everything not caught in the filter. Just a thought, would like to know how it's actually done. Link to comment Share on other sites More sharing options...
jason5d Posted February 5, 2011 Share Posted February 5, 2011 I suspect they are using software with a built in alpha channel Link to comment Share on other sites More sharing options...
dosxuk Posted February 5, 2011 Share Posted February 5, 2011 It's basically a chroma key, but done through a special computer, rather than in a vision mixer. You just need to tell the computer what range of colour the grass / court / track is (and can be recalibrated quickly). As for making sure the green shirts don't disappear - it's just about setting the parameters correctly. They used to all need to be generated on site using one set of equipment per angle required, and a pile of sensors on each camera used so that the computer knew the pan, tilt, zoom and focus of the camera (which all have to be wired back) and could then overlay the graphics while moving the camera. Nowadays since computing power has become high enough, you can teach the computer how to work out the camera positioning by the location of features, such as lines on the pitch. This is more flexible, but less reliable - there's often restrictions on how many of the defining features that must remain in shot, otherwise the computer can get lost. MOOV are one of several companies which provide the equipment - http://www.moov.tv/portfolio/vr_showcase-1.htm Link to comment Share on other sites More sharing options...
pritch Posted February 5, 2011 Author Share Posted February 5, 2011 James: Thanks for that, really interesting! The things they can do these days, eh? Kerry: Sorry to mention it; although the score was beautifully presented on the pitch by the BBC graphics bods, I did have one major gripe with it, which is that the numbers underneath the three feathers were somewhat lower than the numbers underneath the rose. Oh well. Next year, perhaps? Link to comment Share on other sites More sharing options...
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