3D Motion Capture Flashcards
What is motion capture ?
The recording of peoples movement
Why does Qualisys use more than 2 cameras ?
Because the data collected by the system is limited if one of the cameras becomes obstructed therefore 3 or more are commonly used. So tracking can continue even if blocked from one cameras view.
How does data collection work in Qualisys ?
Cameras automatically register points in space. IR light is sent from the cameras and the detection of the returning light is converted into a co-ordinate in 3D space. Each marker needs co-ordinates.
What is the volume of interest ?
The area that the motion capture will view. Cameras are as far away as possible to increase overlap.
Why is calibration completed ?
To ensure accuracy of marker data by telling the computer exactly where the cameras are within space. Calibration is only valid if cameras haven’t moved so calibration takes place regularly.
What is used to complete calibration ?
An L frame. The L frame sets the origin and so then all movement is relative to this spot.
Can also use a calibration wand.
What must a participant do before motion capture ?
Remove reflective or baggy clothing by either taping over the reflective parts or wearing cycling shorts.
What are the benefits of motion capture ?
Accurate calculation of marker positions
Improve athletic performance
Determining Risk /Injury
Tracking Progression
What is the difference between 2D and 3D motion capture ?
2D - only uses one camera
3D - uses more than one camera.
What exercises were completed during the motion capture labs ?
Countermovement jump
Squat
Gait
Static Bike Cycling
What are some of the limitations of 3D motion capture ?
Time consuming to attach markers
Require skilled personnel
Markers difficult to place correctly on bone
Expensive for smaller projects
Requires specific room requirements
Why is a countermovement jump important ?
Often used to evaluate lower limb power/ athleticism
Allows people to measure neuromuscular fatigue.
Why is gait important ?
Improper Gait can cause other issues and requires balance and muscle co-ordination.
