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RSS >  mouse drifting from center
rhubarb #1 22/05/2010 - 11h50

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Registered on : 17/05/2010

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I have built a 3 point cap using IR LEDs and a MS VX1000 webcam with IR filter removed. It works very well except 1 issue:-

If I turn my head and return then the view (in Condor) doesnt quite return to center. so I have to recenter freetrack and Condor every 30secs or so using a programmed key.

The problem does not seem to have anything to do with Condor as I can reproduce it using only freetrack:-

If I center freetrack and then look over my shoulder and then return to center. The freetrack skull returns to center but the mouse does not. After a couple of repeats the difference is large. My neck tells me that the Skull is right and the mouse has drifted.

Note that this problem only occurs in mouse *relative* mode (mouse absolute mode seems to work fine). But I have not found settings that work well with mouse absolute and Condor (havent looked hard yet). Also mouse absolute mode is a PITA cos I have to keep switching it off everytime I need to press buttons in the GUI - so would rather avoid using it.

So why is the mouse not comming back. I thought it might be because I have max mouse speed set in the Control Pannel (I use the trackpad on my laptop). So I set this to sloooowest (uggh!) but this had no effect on the head tracking issue.

I have tried adjusting a few things in freetrack but have not been able to solve the problem. It seems to me that if freetrack *can* return the mouse to center in absolute mode then it should also be able to do it in relative mode too.

(ps I understand that in relative mode the freetrack center does not have to be the center of the screen)

Peter
nadrealista #2 23/05/2010 - 15h59

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Registered on : 13/01/2010

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The reason might be loosed tracking by moving LED out of camera's FOV or low radiation angle of LEDs.

I suggest to make corresponding axe (YAW?) more sensitive in your profile. In that case, you will not exceed camera's or LED's "working angle".
rhubarb #3 23/05/2010 - 19h33

Class : Apprenti
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Registered on : 17/05/2010

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Hi
thanks for the suggestions. But the LEDs are not going out of the webcam's field of vision. The crosses in the FreeTrack Camera view stay locked on solidly to the LEDs the whole time

Also since mouse absolute  mode (as opposed to mouse relative mode) works fine I dont think the problem is with the LED tracking.

At some point freetrack is telling the mouse to move (as I move my head). but there seems to be a problem getting the mouse to come back to its center

(also I am not accidentaly touching the laptop's trackpad which would of course upset everything)

Peter
rhubarb #4 28/05/2010 - 11h57

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Registered on : 17/05/2010

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I have also observed that if I turn my head very slowly then the skull still follows the head movement correctly but the mouse pointer does not move or follows in small spurts

this causes  clear deviation between the skull and mouse

this happens only in mouse relative mode (absolute mode is OK)

this problem is probably related to my mouse drifting problem described above

I have not managed to test freetrack yet on another laptop in order to rule out my hardware. (The trackpad/mouse pointer on my HP pavillion dv4000 does behave oddly sometimes)

Peter

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