1 Topic by saki

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Hello, I am a ballet instructor and I would like to use Kinovea for gait and movement analysis.

Is there a feature to automatically or semi-automatically display joint positions and the Center of Mass from an uploaded video?

Specifically, I want to see how the Center of Mass shifts as the arms and legs move. If this is possible, could you please guide me on how to set it up?

2 Reply by joan

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There is no integrated automated way. There is a very manual way where you add a human model drawing object and track it over time but you would have to place joints manually because with full body tracking there is always something occluding some points.

The more automated way is via Sports2D here: https://github.com/davidpagnon/Sports2D

Kinovea can read the files from Sports2D if they are created with the right options, I'm planning on improving this integration more in the future. In the meantime if more people could try Sports2D and report their experience it would be helpful. I think the installation process could be streamlined for non-developers and non-researchers. Right now I think you need to either use google Colab or install python and call it from the command line. Check this tutorial: https://www.youtube.com/watch?v=Er5RpcJ8o1Y

edit: inside Kinovea only the built-in human model has the center of mass, the model used to import Sports2D data files doesn't calculate the center of mass, something to add in the future.

3 Reply by saki

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Dear Kinovea Support Team,

thank you for your reply.
And I am writing to ask for assistance regarding the "Center of Mass" feature.

As shown in the attached photo, I have placed tracking points on each joint of the Human Model. While the joints are successfully tracking the person's movement, the Center of Mass (COM) marker does not move or follow the body's motion.

I have looked through the configuration menus, but I cannot find the specific option to enable the dynamic link between the tracked joints and the Center of Mass.

Could you please guide me on how to make the Center of Mass move in sync with the tracked joints?

Thank you for your help

4 Reply by joan

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Thanks. Sorry I was confused for a bit because the human model tool is not actually configured to be trackable.

If I understand correctly what you have done is created separate tracking points for each joint and also added a human model object on top. Indeed the "linking" doesn't work like that, sorry for the confusion. If you test with a simple line or angle drawing you can see how it is supposed to work: you add the line or angle object, right click, and select the menu "Tracking > Start tracking". This will create all the individual tracks for the points automatically. This doesn't work with the human model because its points are not marked as trackable, mainly because it creates a big mess which is almost impossible to work out manually.

If you want to try anyway, I uploaded a version of the human model tool that has all the points trackable here:

https://kinovea.org/tools/extra/human-m … 0model.xml

Download this and replace the file in under: DrawingTools\Custom\10 - Human model.xml

If you use the installer version the file is under "Program files\Kinovea\DrawingTools\Custom" folder and if you use the portable (.zip) version, the file is in the "DrawingTools\Custom" folder. You need to close and restart Kinovea for this to take effect.

After that you can start tracking the human model. The tracking tab on the annotation pane on the right hand side has more options for the size of the search box and tracking parameters. Now any movement of the points should update the center of mass.

I know it's not a great solution that's why I want to integrate Sports2D more tightly.