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Floor evaluation missing with Kinect
https://forum.ipisoft.com/viewtopic.php?f=2&t=6884		 Page 1 of 2
Author:  argus1000 [ Tue Mar 05, 2013 10:16 am ]
Post subject:  Floor evaluation missing with Kinect
Hi,

When I use Ipisoft version 2 with 2 Kinects, the program misses (overlooks) the "Floor evaluation" step. When I press the "Refit pose" button, the character's feet are all askew. The result is that the feet in my final capture are off the mark; they don't stay put. I know such a step as "Floor evaluation" exists because I have seen it in other people's tutorials. Is there something I'm missing?
Author:  andrew [ Tue Mar 05, 2013 11:48 am ]
Post subject:  Re: Floor evaluation missing with Kinect
Hello!

Quote:
I know such a step as "Floor evaluation" exists because I have seen it in other people's tutorials. Is there something I'm missing?


Floor evaluation is performed only for calibration projects if we're speaking about two Kinects. For performance projects there is no need to evaluate floor - all data about cameras positions is obtained from scene file.

Quote:
When I press the "Refit pose" button, the character's feet are all askew


Starting from version 2.2.1.145 iPi Mocap Studio becomes more sensitive to initial actor's position when pressing "Refit Pose" button. Thus it's required to align actor's model with point cloud more accurate using Move tool.

We know about this issue and will try to improve this aspect in one of the future updates.
Author:  Greenlaw [ Tue Mar 05, 2013 2:05 pm ]
Post subject:  Re: Floor evaluation missing with Kinect
Hi,

I've had a few cases where the program seems to miss the floor. In other words, the position of the two Kinects will appear to be correct relative to their own 'floor' but this floor might be well below the actual scene floor and rotated at some random orientation. When this occurs, re-running Calibration sometimes corrects the error but usually not. Typically, I find that I need to use a different calibration video when I see this problem. (I've gotten in the habit of recording two or three calibration videos because of this error, typically one before recording action and one after recording actions.)

I might still have some 'bad' files lying around. I'll check and if I find one, I'll send one in if you're curious.

Looking back, I think these calibration errors occurred when I recorded during the daytime. I think outdoor lighting from the windows may interfere with one or both Kinects, especially if it's a sunny day. I'm getting much more predictable and accurate results recording at night under 'dim' non-directional room lighting.

G.
Author:  andrew [ Tue Mar 05, 2013 11:07 pm ]
Post subject:  Re: Floor evaluation missing with Kinect
Hello Greenlaw!

Yes, direct sun light should be avoided due to high intensity in IR spectrum range.

Also please note, that for floor detection background data is used. Thus there is no sense in shooting many calibration videos without background re-evaluation for each.

At last, starting from 2.1.1.18 version iPi Recorder has significant improvement in background evaluation: for each depth sensor background is evaluated separately when other sensor(s) is (are) switched off, therefore avoiding interference of sensors to each other. This "trick" significantly improves the quality of background data which should help in floor detection.
Author:  Greenlaw [ Wed Mar 06, 2013 12:14 am ]
Post subject:  Re: Floor evaluation missing with Kinect
Quote:
Yes, direct sun light should be avoided due to high intensity in IR spectrum range.

Also please note, that for floor detection background data is used. Thus there is no sense in shooting many calibration videos without background re-evaluation for each.


Thank you for confirming this! Yes, I found that during daylight I needed to re-evaluate the background before shooting any new calibration and sometimes before shooting action videos. My assumption was that this is because the outdoor lighting could change the appearance of the room, even when the window blinds are closed and sometimes within minutes if it's early in the morning.

This problem generally occurs during the morning hours to noon but mostly goes away later in the afternoon, and does not occur at all in the evening when room lighting is consistent. After I noticed this pattern, I began to shoot only at night--and if I absolutely needed to shoot during the day then I will run Background Evaluation frequently.

This is not a complaint--just providing information to other users who may be running into trouble. :)

Quote:
At last, starting from 2.1.1.18 version iPi Recorder has significant improvement in background evaluation: for each depth sensor background is evaluated separately when other sensor(s) is (are) switched off,


Yes, I noticed that! Thanks for adding this feature.

BTW, in my case, the second sensor seems to require a brief (1 second?) 'warm up' step as it fills the IR image entirely with 'yellow' and then starts capturing proper depth--is this normal? It doesn't seem to matter which sensor is #2 but it's always the second sensor in the process. Because of this, I was also wondering if recording from sensor #2 should be delayed a second to allow this 'warm up' to finish? Just to be safe, I've been running Background Evaluation with longer duration.

G.
Author:  andrew [ Wed Mar 06, 2013 12:44 am ]
Post subject:  Re: Floor evaluation missing with Kinect
Quote:
BTW, in my case, the second sensor seems to require a brief (1 second?) 'warm up' step as it fills the IR image entirely with 'yellow' and then starts capturing proper depth--is this normal? It doesn't seem to matter which sensor is #2 but it's always the second sensor in the process. Because of this, I was also wondering if recording from sensor #2 should be delayed a second to allow this 'warm up' to finish? Just to be safe, I've been running Background Evaluation with longer duration.


It's ok. We also have similar behavoiur with some of our sensors including ASUS Xtions. iPi Recorder takes this fact into account. But longer duration of Background Evaluation can slightly improve quality of resulted data. Thus you're almost correct in your preferences!
Author:  Greenlaw [ Wed Mar 06, 2013 1:58 am ]
Post subject:  Re: Floor evaluation missing with Kinect
Okay, thanks! Not going to worry about it then. :)

G.
Author:  argus1000 [ Thu Mar 07, 2013 11:21 am ]
Post subject:  Re: Floor evaluation missing with Kinect
Thanks Andrew and Greenlaw for your expert consideration, but my problem was simpler than expected. My 2 Kinect cameras were at an angle bigger than 90 degrees, so the whole calibration and capture was somewhow askew. Since then, I put my cameras at 75 degrees distance from each other, and everything (the feet included) is perfectly stable. The captures are perfect. Who would've thought?
Author:  Greenlaw [ Thu Mar 07, 2013 11:27 am ]
Post subject:  Re: Floor evaluation missing with Kinect
Oh, yeah--I ran into that and just recently too but forgot about it until you mentioned it. :P

Tip: When calibrating for two Kinects, move and rotate the calibration board in a random motion and especially move it from front to back. The front to back motion makes it clear to the system that it's solving a 90 or a 180 degrees setup. Until recently, I only rotated the board from side-to-side and this made the system guess incorrectly almost every time. Now, with the random motions with front and back movements, it works perfectly almost every time.

G.
Author:  argus1000 [ Sun Mar 10, 2013 12:07 pm ]
Post subject:  Re: Floor evaluation missing with Kinect
When I said my captures were perfect, I wasn't telling the whole truth. Sure, changing the camera placement did good things for the feet position, but still they leave to be desired. If you watch the video below, you'll find that, when the character does his salute (extends his right arm), about three fifths into the video, both his feet go into the ground. This is a recurrent problem with Ipisoft captures when characters do a major move, like getting out of bed, etc... I appreciate that Andrew said he is working on it. My capture was imported and rendered in Daz Studio.

http://youtu.be/343zEEFenHQ
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