laboratory coordinate system

Provide a complete, user friendly and highly configurable tool to automatically process experimental motion data from different laboratories for their use into neuromusculoskeletal software.
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Aseel Ghazwan
Posts: 22
Joined: Thu Sep 17, 2015 2:54 am

laboratory coordinate system

Post by Aseel Ghazwan » Wed Aug 10, 2016 3:02 pm

Hi,
As shown in the figure below, which demonstrates the laboratory and FP coordinate system. Should I define the laboratory coordinate system as: (YZX), then I have to set the motion direction as “backward”? Also for the selection of 90left OR 90right is that according to the direction of motion?
GCS.jpg
GCS.jpg (17.18 KiB) Viewed 880 times
Another question, here the laboratory coordinate system is (YZX), while the OpenSim coordinates (XYZ), so I have to rotate the laboratory coordinates to OpenSim. Alice Mantoan mentioned that Rotations to OpenSim are automatically computed, could you please clarify this point in details.

Thanks in advance,
Aseel.
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Alice Mantoan
Posts: 29
Joined: Fri Feb 24, 2012 11:51 am

Re: laboratory coordinate system

Post by Alice Mantoan » Sun Aug 21, 2016 7:18 am

Dear Aseel,

sorry for the delay but I was on holiday without the Internet.

Regarding the first question, you are right: just define the lab coordinate system as YZX and set the motion direction to "backward".
Then, as stated in the User Manual, at the red Warning box also available at the following link:
http://rehabenggroup.github.io/MOtoNMS/ ... he-program

" you can choose among the following additional options: backward, 90left, 90right. All of them are defined with respect to the positive direction of your laboratory CS. ".

So, it is not according to the direction of motion, but, conversely, according to the positive direction of your lab reference system.

Lastly, knowing the orientation of your lab reference system from the acquisition.xml file, and the OpenSim global reference system, it is possible to compute the transformation that rotates the data from the first to the second one. We only make the assumption that the orientation of the input data matches one of the available choices for the motion direction.
If you want to give a look to the code, you can refer to the following MATLAB functions:
  • - MOtoNMS/src/shared/globalToOpenSimRotParametersCreator.M
    - MOtoNMS/src/shared/RotateCS.m
    - MOtoNMS/src/shared/defineMotionDirectionRotParamOpenSim.m
    - MOtoNMS/src/shared/rotatingMotionDirection.m
Though in delay, hope this can still help you for your work.
Best regards,
Alice
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