You may not be running the latest drivers.
There is a Logitech QuickCam 11.9 (not avail for download, only thru Logitech Updater (LU) for users with a previous QuickCam release installed.
You don't want to put the cameras thru a hub. Ideally, maybe 2 inputs on the front of your computer, 2 on the back, or get a USB card.
I'll copy in a few notes I made while reading that may be useful to you:
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2) Use a faster codec. Best codec is MJPEG codec. We recommend
http://www.morgan-multimedia.com/technicalsV3.htm - it is inexpensive ($30) and comes with 2 month free trial. In MJPEG, each video frame is compressed separately using the JPEG still image compression standard. No frame differencing or motion estimation is used to compress the images. This makes it very fast and very high-quality, at the expense of bigger file size (which is not a problem for motion capture). ???? WILL IT WORK WITH 64 BIT wIN7???
XVID is also a great codec but it is designed for smaller file size, not for fast compression. You may increase the speed of XVID compression by tweaking the Quality option. At 320x240, most modern PCs should be fast enough to compress 4 video streams at 30 frames per second using XVID quality 1 (max) in real time. At 640x480, you may need to change quality setting to 4 or so. You may also need to tweak "Other options...->Encoding->Multiple threads" and "Other options...->Common->Force optimizations".
3) iPi Recorder is known to work much faster on Windows XP, as compared to Vista. HOPE IT WORKS OK ON WIN7?
4) Make sure you turn OFF the RightLight, Anti-flicker and similar options for your cameras.
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Please re-shoot calibration video at 30 frames per second using new iPi Recorder (version 1.0.1.36 Beta). Our recent research shows that our previous recommendation of recording calibration video at 10 FPS was wrong. Higher framerate results in better synchronization and much better calibration reliability and accuracy
It is also important that in new calibration video you move pointer more randomly (like in circles and spirals) and cover bigger space. Imaging yourself a jedi practicing some fancy martial arts moves with a lightsaber in slow-mo. Irregular/random marker trajectories help to improve accuracy of calibration.
By the way, you may find the following video useful:
http://www.youtube.com/watch?v=8Pyly9BdcO4It demonstrates calibration of a more traditional marker-based OptiTrack system. While they have their own specifics (for example, they have high-framerate cameras so fast calibration wand movement is not a problem for their system), the video still demonstrates some common principles, like covering the entire capture volume and doing circular movements to make calibration patterns more random.
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----------------- change contrast to get better capture
I have had that problem before the best way to end up with a good camera calibration is to play with the contrast of the video once it is recorded, I also had a lot of noise on some recordings, "reflections, lights, floor reflecting the calibration object", then I grabbed the calibration video, placed it inside a video editing software and made it as dark as possible working with the contrast, then when I was basically unable to see with my naked eye the spot, I saved it and did the calibration.
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I recommend that next time you also incorporate the following improvements into your calibration sequence:
1) Don't move the marker too fast, to avoid motion blur.
2) Cover your capture volume more uniformly.
3) Record calibration video at 640x480 at 30 FPS
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Yes, using bright-color gloves should significantly improve reliability of tracking. Please do not forget to enable support for gloves (turn off "Hands color same as face color" checkbox).
For best results, you need bright ambient lighting. That is, illumination should surround actor. In photographic terms, you should use soft lights / aim for high-key lighting:
http://en.wikipedia.org/wiki/Soft_lightshttp://en.wikipedia.org/wiki/High-key_lighting---
We strongly recommend turning OFF the Logitech RightLight when recording for motion capture.
Logitech communicate mp using RightLight1 Technology which doesn't have control parameter, so it cannot be set on or off. The on off parameter appear only in webcam with RightLight2 like QuickCam Pro 9000.
Please note that there was a version of Logitech's driver software that didn't allow for manual control of exposure for more than 2 cameras connected at a time. There was an update that fixed this.
Without this manual control, your frame rates can vary based on how bright/dark something is, so you definitely want to set up the software for manual control for all four cameras.
