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PostPosted: Thu Mar 22, 2018 7:37 pm 

Joined: Thu Mar 22, 2018 7:35 pm
Posts: 2
Hey guys, I need to know which background color is better?


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PostPosted: Fri Mar 23, 2018 2:18 am 
iPi Soft

Joined: Wed Jan 11, 2012 6:12 am
Posts: 2039
Location: Moscow, Russia
You do not need specific background as our software evaluates background before recording so it can distinguish moving objects (actors) in video. The main thing it should be contrast with actor skin and clothes otherwise the software can confuse parts of actor body with background.
Also, for tracking with RGB cameras proper lighting has much value. It should be bright, even and non-directional. So that colors are clearly visible from each camera and there are practically no shadows.


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PostPosted: Fri Mar 23, 2018 6:00 pm 

Joined: Thu Mar 22, 2018 7:35 pm
Posts: 2
vmaslov wrote:
You do not need specific background as our software evaluates background before recording so it can distinguish moving objects (actors) in video. The main thing it should be contrast with actor skin and clothes otherwise the software can confuse parts of actor body with background.
Also, for tracking with RGB cameras proper lighting has much value. It should be bright, even and non-directional. So that colors are clearly visible from each camera and there are practically no shadows.


Thanks, what about height of cameras? the higher the better?


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PostPosted: Sun Mar 25, 2018 8:39 am 
iPi Soft

Joined: Wed Jan 11, 2012 6:12 am
Posts: 2039
Location: Moscow, Russia
It is usually good when camera heights vary, and have one very high camera for better feet tracking. You can find our recommendations for camera placement in our docs:
http://docs.ipisoft.com/User_Guide_for_Multiple_PS_Eye_Cameras_Configuration#Scene_Set-up


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PostPosted: Mon Mar 26, 2018 10:00 am 

Joined: Mon Nov 06, 2017 11:50 pm
Posts: 28
The background color is not required. But for the best results, go for the green or the blue background/backdrop. This may improve tracking!


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PostPosted: Tue Mar 27, 2018 8:25 am 

Joined: Mon Aug 03, 2009 1:34 pm
Posts: 2293
Location: Los Angeles
For PS3 Eye, you don't need a color background at all. I think some confusion may have arisen when I recorded iPi Mocap against a green background many years ago, but that color was completely incidental. We just happen to have a green screen stage in our garage, and the real benefit of the screen was that it covered up a ton of crap we had along the walls. The color of the background does not matter so long as there is good contrast between the performer and the environment.

It's probably easier to answer "What shouldn't the background be?"

Avoid shiny, reflective backgrounds like mirrors, and windows. Reflective images and light will confuse the tracker. This includes the floor. For example, if the light used for calibration is seen in a waxed floor surface, Mocap Studio will not know which 'dot' to follow. If you have shiny walls, shiny objects on the walls or windows, you may need to cover them up with a blanket or non-reflective material.

I don't shoot with PS3 Eye these days but some of this matters to Kinect too. I just close our window blinds. If you have a shiny floor, throw a rug on it. We have a rug on our shiny wooden floor that also serves to define the area we can perform within.

The color of your clothes should ideally contrast with the background, so if you're wearing black, any bright color in the background may help. If you're wearing red, a green background will give you good contrast. But covering up the background entirely is not necessary unless there is something about your environment that will conflict with tracking or performer contrast.

With PS3 Eye, the most important things to consider is contrast and even lighting. Avoid harsh, directional lighting that casts dark shadows on the performer and on the floor. It's best to use soft lighting (we use multiple soft boxes,) or multiple ceiling lights that cancel out hard shadows.

Hope this helps.

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PostPosted: Wed Mar 28, 2018 8:12 am 

Joined: Thu Sep 04, 2014 9:47 am
Posts: 871
Location: Florida USA
...

Depending on your available space for set up, and guessing you are referring to use of PS Eyes, a good consideration for a set up is how Organic Motions Open Stage set up is configured.

You can visualize it here: https://www.youtube.com/watch?v=PpvYR9yA0Jk

You will notice how the performer isn't fully illuminated and same method applies for iPi Recording, using enough light for the PS Eyes to see the colors worn by the performer(s).

You could of course use blue or green back drops, but white works just as well and reflects white light more diffusely, green, or blue will reflect green and blue bleed on to a performer and white usually won't conflict with any colors worn by the performers, not even the arm/face skin color and most likely easier and cheaper to find and use solid white sheets, or drop cloths.

Non-shiny flooring is agreed with, especially for calibration, but you don't need to use the green interlocking pads shown in the video either, a lighter colored flooring or carpeting works fine, although those locking padded tiles come in many lighter colors and reasonably priced on eBay to cover a 10 ft x 10 ft area, or larger if wanted.

Here is a single camera view from a while ago of the space I use: http://youtu.be/4Zt4nnDaXDg
I still use the same space, but now I don't use the lights during the day recordings and tweaked my Gain setting a bit lower for all cams to 16 and the Exposure to 60 and turn off Auto-gain, it removes the white film over the recording as seen in that video and puts more contrast on to the performer for better color saturation and I don't use arm cover shirt any longer either and much tighter T shirt used now also and I get very good tracking results with high energy dance motions in almost any positions they can perform.

I also sit right in the same room with the computer and performer while recording, I just wear clothing to blend in to the background more, sitting still while recording is going on, and have never had iPi tracking jump off on to me and not the performer and I am not in the scene during the background evaluation either.

This is my set up with 6 PS Eyes, it works well for me, but maybe not for all users, since most don't use a 3 sided windowed room, why I referred to more of a set up like used in the Organic Motion video.

Camera calibration and the iPi Actor skeletal set up is also very important for better tracking, so be sure those are very accurate and you should get pretty good tracking results, I also suggest at least using the Flex spine option, the stiff spine will affect the tracking on most human motion results, and with high energy motions like dancing or fighting, you can use the very flex spine option, as long as the motion is in constant motion, but you can switch between flex and very flex within the same take, but there is more steps involved to make it work optimally when the Refining stage is run.

Good Luck

...


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PostPosted: Wed Mar 28, 2018 10:41 am 

Joined: Mon Aug 03, 2009 1:34 pm
Posts: 2293
Location: Los Angeles
Oh, yeah, I meant to add that you don't even need a solid color background. iPi is good about canceling out most environment so long as there are not reflective surfaces or any property that will interfere with getting a clear performance video and calibration footage.

The only reason I had a solid background was to cover up the clutter along the walls. On the shelves, we kept a drum kit, tools, shiny plastic bins and other reflective items, so it was helpful to cover it with the screen and simplify the 'environment' for Mocap Studio.

In my experience, every environment will have different considerations. I would try recording in the space you have and see if it works. If it doesn't, you'll need to figure out why and adapt to conditions. If you need help, post some pics here.

BTW, within reason Recorder and Mocap Studio can be pretty flexible about the environment. Some users here have captured excellent mocap footage recording outdoors on overcast days or before the sunrises (to prevent hard shadows.) The same rules apply indoors or out, and if you follow them, you should get good results.

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Artist/Partner - Little Green Dog | Demo Reel (2017) | Demo Reel (2015) | Demo Reel (2013)

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Watch a one minute excerpt on Vimeo now!


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PostPosted: Wed Mar 28, 2018 5:29 pm 

Joined: Thu Sep 04, 2014 9:47 am
Posts: 871
Location: Florida USA
...

Agreed, you don't need a specific wrapping background color, but at least covering any clutter present as GL stated can do noting but help, especially if any objects in a cams view are the same color as the performers clothes.

If you do have a dedicated recording area where you can set it up with a cleaner background, and good equalized ambient lighting the outcome will track better.

I don't always cover everything in the area either and the tracker still stays locked on very well for the most part, if you are having severe tracking loss, something else may be affecting the tracking, like clothing color chosen, iPi Actor scale, (Actor height should not be too far off the performers actual height +/- 2 cm with Actor heels close to touching the floor), bone sizing of the skeleton should match up to all performers joints closely, as shown in the Pose Tab, or performers clothing to baggy, or Actor clothing scaling too large, iPi tracks better with RGB cameras when performers clothing is a more tight fit with iPi Actor clothes scaled to match, especially on fast, or extreme motions.

If all that is set right and calibration is good, with good lighting, you should be getting pretty good results with any fairly clean neutral background color with contrasting performer clothing.

...


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PostPosted: Wed Mar 28, 2018 5:51 pm 

Joined: Mon Aug 03, 2009 1:34 pm
Posts: 2293
Location: Los Angeles
This discussion reminded me of an early iPi Desktop Motion Capture test I did way, waaay back when Logitech web cameras were the preferred device. I set up a mocap session in a common area at Rhythm & Hues, and I was sure I thought of every possible 'gotcha' I could encounter in that environment.

But when I got home, the calibration was all bad because there was an active computer monitor in the background with a bouncing Windows logo screen saver that kept distracting the tracker. D'oh!

Anyway, when you're starting out, expect to make a lot of dumb mistakes. Hopefully, you won't make too many of them twice, and before long the recording sessions will go should go smoothly and efficiently. :)

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Greenlaw
Artist/Partner - Little Green Dog | Demo Reel (2017) | Demo Reel (2015) | Demo Reel (2013)

Image
Watch a one minute excerpt on Vimeo now!


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