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ChildMindInstitute / tingle-pilot-study

Pilot study for Tingle wrist-worn position-tracking device intended for use with body-focused repetitive behaviors such as trichotillomania.
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📚 Data Dictionary #23

Open shnizzedy opened 6 years ago

shnizzedy commented 6 years ago

Describe data for clarity and sharing

shnizzedy commented 6 years ago

@curtpw ― Do you want to add any details (units of measurement, anything about the specific sensors) to the data dictionary in the README?

Everyone ― Please review the data dictionary in the README for errors and exclusions.

curtpw commented 6 years ago

It is worth keeping gimbal lock in mind when it comes to pitch and roll values. Gimbal lock (360 --> 0 and vice versa) will be 180 degrees away (as far away as possible) when your arm is pointed straight out in front of you with your thumb pointed towards the sky. Neural network classification is extremely good at incorporating gimbal lock but that is not true of all machine learning or regression techniques.

binarybottle commented 6 years ago

Thank you for the reminder, @curtpw. Why not use quaternions?

WIkipedia: "The representations of rotations by quaternions are more compact and quicker to compute than the representations by matrices. In addition, unlike Euler angles they are not susceptible to gimbal lock. For this reason, quaternions are used in computer graphics,[12] computer vision, robotics, control theory, signal processing, attitude control, physics, bioinformatics,[13][14] molecular dynamics, computer simulations, and orbital mechanics."