Chroma Keying for Football Ind | Forum

Chroma Keying for Football Indoor

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I would like to know if I could use your Chroma Keyer to do this job:

I want to overlay cupra logo on the gray / black floor and when players run over that areas it is masked by them.

Chroma Keying for Football Indoor

I used the adjuster to convert the image to use green channel.

Chroma Keying for Football Indoor

Inverting your Basic Chroma Keyer Matte output to mask the players this is the best I got

Chroma Keying for Football Indoor

You can see I have issues with hairs, referees pants, socks and boots because they have very similar colors.

It would be great to be able to select a list of colors where you want to overlay any graphic so the keyer can ignore the rest of colors out of that list.

Please let me know if you find a better way than mine to do this.

Sergio Gómez

JohanF

You can’t use chroma key here because there is no chroma (color) to key! With the ground being dark/grey, there’s just no color separation to the people on the ground. What you’re doing now is essentially a luma key, which works for some things but also has some clear problems. The pants on the referee also have no color, just like the floor. Since it is also the same shade as the ground, how could any keying algorithm know to separate it from the ground? Typical keyers don’t use Ai/machine learning, so they have no awareness of what is actually going on in the video, it’s just using math in clever ways to separate a foreground object from the background. I don’t think there’s a good solution for this. If the ground as black, I don’t see a way to make it work, unless you can get the players and referee to only wear brighter clothing.

Sergio Gómez

Thank you for your comments JohanF,

I was trying luma keyer and the results were worse, so I converted to green with the adjuster module with better results but not enough

Last weekend there was Moto GP broadcast and they were overlaying graphics on the road and it was very well integrated as you can see below.

Chroma Keying for Football Indoor

I wonder how they do it!

JohanF

@Sergio Gómez: You’re still doing luma keying, but just using the green channel and the advanced keyer. It’s hard to tell without seeing moving images, but it looks like the effect in the screen grab could be accomplished (with some tweaking) in Aximmetry. The main difference between the screenshot and your footage is that there actually is some luma contrast between the ground and the motorcyclists. It also looks like the text overlay is semi translucent and blended over the ground, so even if the foreground isn’t keyed out perfectly it won’t be very noticeable when it overlaps the text element.

Chroma Keying for Football Indoor

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