I don't know what might been happening with my camera calibration.
I tried for about 8 hours with several different calibration videos, but couldn't make it work.
Some of the cameras always tilt in a stranger way or end up upsidedown. I tried to manually ajust the height and scale using the first camera parameters, but it doesn't look good. In one instance, the ajusted distance of camera 4 went as high as 6251m.

I'll run another tests tomorrow. Any suggestions on how to overcome these problems?

you are probably not getting the target(maglite flash light) for camera 4, or losing lots of frames for this camera. There are lots of advice in this forum that says that when recording the calibration video , it`s ok to have the light track for at least 3 of the 4 or 6 cameras. I wouldn`t recommend that. My advice is to have the flash light track for all the cameras, you can loose few frames for different cameras, that will be supported(filled) by the rest of the cameras. In brief, the track flash light should be seen by all the cameras. Before recording your calibration video, practice the movement of the flash light with the screen in front of you so you can see what you`re doing , until you can see that you have the flash light in all cameras. Like I said , it`s ok to lose few frames for some cameras, but in general the flash light should be seen for all the cameras and for the majority of the frames , 95% of the frames for everycamera, but if you can get 100% of the frames for all your cameras, that would be nice,and also disable AUTO DETECT INITIAL CAMERA POSITION and AUTO ADJUST CAMERA FOV, then place the cameras manually roughly with the scene tools, you know orbit , zoom, move and pan, then you shouldn`t have any problems. Hope this help

I don't know if the problem is an occluded LED but if so, it's a good idea to mark off boundaries on the floor to give you a guide during calibration recording. When I was using PS3 Eye, I would mark the corners and center of my capture space. And yes, it helps to practice a routine--after recording a calibration video, check the video results immediately to see if you have valid data in every camera view. Once you get this down, you should be able to record flawless calibration data everytime.

It the above doesn't help, there are other things you can look at that may cause errors in calibration. Look for shiny reflective surfaces, like windows, computer screens, polished floors--it's possible that the light is being reflected on a surface and confusing the tracking system. If such surfaces are present, you should cover them up or find a new location to shoot in.

Sometimes the problem may not be caused by a reflection at all--one time, calibration was thrown off for me by a screen saver running on a computer screen in the background. Turning off the computer monitor solved that problem.

G.

_________________
Greenlaw
Artist/Partner - Little Green Dog | My Demo Reels (2013,) (2015,) (2017,) and (2019)

Watch a one minute excerpt on Vimeo now!

Also, be aware that it's not necessary for the calibration pattern to cover the entire capture space. When I was doing this, my pattern was actually a bit smaller than the capture space--it just needs to be big enough for all the cameras to see and get good tracking and alignment results from. This old calibration video I shot is a good example of the pattern I use:

Four Camera Calibration Video

This video was created using 1.0 but the procedure should still be valid for 2.0. Hope this helps.

G.

_________________
Greenlaw
Artist/Partner - Little Green Dog | My Demo Reels (2013,) (2015,) (2017,) and (2019)

Watch a one minute excerpt on Vimeo now!

Outstanding answers, thanks you guys.

Did some new tests today. In the latest one, I could get all green points, a great definied "cage", but for some reason, my camera 1, which was 1,80m, was placed at Ipi, at 0,6m...

Moderators, can I upload the scene here (dropbox link) so that you could tell me what I'm doing wrong?

wicq, I really can't see how to not occclude the light of one of the cameras since, I'll always face back some of them. Perhaps, I could try attaching it to a stick...
Was hoping to be able to solve it with the default set up, but will have to disable auto detect camera and Fov, to see if I can make it work in the next try.

Greenlaw, you solved one of the problems. My floor was actually reflecting some of the light back, bouncing it up. Thanks!

I'll have access to the studio on Wednesday. Hope to finally get it right.

Btw, wicq. In case I ajust the cameras manually, I shouldn't apply darkening or extra darkening on the ipi recorder, right?

kyle, for tracking video of course you have to chose darkening(extra darkenning is not necesary) and don`t say "in case I manually adjust cameras position". I strongly recommend you to adjust the cameras manually. I know that I said "roughly", but you can do it with preccission, not need to be perfect , and you can helo yourself by having the model in the middle .well I read over here that AUTO DETECT INITIAL CAMERA POSITION doesn`t work when using 5 or 6 cameras, and that`s true because I wanted to track the calibration video for the 6 cameras with that option checked and I only get 4 cameras to be near to where they should be, not perfetc at all , but you could see that they where near, the other 2 were in any random spot.then I did it again with both the FOV and AUTODECT checked and I got nothing, the 6 cameras went to hell.Ok now I dont know how is the lighting in your room,but I`ve seen a couple of users that has tons of light in the ceiling for tracking video(one of then has a very reflective floor).That`s just unecesary in so many levels.The light that should be seen is the maglite flash light, not a grill full of lights. I only use one plain and sheep yellow light bulb that is in the middle of the room, those old light bulbs that are yellow light(althought for ps3 cameras it looks white) so lighting is not something you have to worry about when recording the calibration video. Like I said one plain light in the middle of the ceiling , choose darkening and that`s all.About not been able to have the light track for all the cameras because you occlude one of the cameras, mmm Maybe you can use an stick , but if you can get a transparent one that will help you a lot because at some point the stick itself will occlude the light. ok yeah of course having reflective floor is not a good idea at all.try also to cover all the relfective things you have in your room with blanckets or towels. One thing to worry about lighting is when you record perfomances videos, in this case you should set lighting the way brighteness, contrast and a general look is the same for all the cameras. you can do that by adding lights in different places and watch at the same time the screen so you see that for all the views you have a general look for all the cameras. that is difficult , but once you have something you feel it`s ok ,you can help the cameras to match each other by moving different things in every camera properties like for example gain and exposure, But all this info is for when you get to the part when recording acting videos. First , get your calibration video to work ,and then lets talk about acting videos.

Sure!

Please also read carefully the Calibration section in user's guide. There may be some tips you've just skimmed over, or some that were added after you'd last read this section.

Thanks for the answer, vmaslov. I actually found two things that I might be doing wrong, after re-reading the wiki info.
Firstly, I did all my tests with the lights off.

And the other one is that most of the time, my light is tracked, but with a red square around it.In the end, I get the "green cage" that I was supposed to get, but that might be something to look out for.
In this case, what should I do to avoid it?

The lights off are dangerous from the point of your safety. This does not confuse marker tracker.
The bounding box of the light marker may be red during the marker tracking process, because the data defining its color are not fully computed yet. You should only look at the colors of marker points after the tracking is complete. If at least 90% of them are green - that is usually OK.

It would be easier to find where your problems lie if we had your calibration video. If you want to avoid publicity, you can send a link to our tech support email.