Yeok-c/Vicon

A package to read in Vicon data for analysis

Vicon

A package to read in Vicon data for analysis. This package can be used to read in a CSV file generated from the Vicon motion capture system

IMPORTANT NOTE

There is a strange bug when reading in the file. It will throw and error if you try to read in the raw file. To solve this problem. Open up the CSV file in libreoffice or Excel and resave the file. Make sure its a CSV file.

Notes

• subject prefix removed from marker name i.e (subject:RKNEE -> RKNEE)
• New devices connected to the Vicon should extend the Device class

Installation

This package relays on a submodule that needs to be installed

git clone https://github.com/nag92/Vicon.git
cd Vicon
git submodule init
git submodule update

Playing the markers

file = "path to CSV file"
data = Vicon.Vicon(file)
markers = data.get_markers()
markers.smart_sort() # sort the markers into bodies by the names 
markers.play()

Get rigid body

Rigid bodies are organized by marker then frame. The markers are of type Point.

file = "path to CSV file"
data = Vicon.Vicon(file)
markers = data.get_markers()
markers.smart_sort() # optional param to remove subject name
shank_frame = markers.get_rigid_body("name of body") # returns an array of markers 
## Get the X corr of a marker 2 in frame 100
x = shank_frame[2][100].x

Get rigid body transform

Rigid bodies are organized by marker then frame. The markers are of type Point.

file = "path to CSV file"
data = Vicon.Vicon(file)
markers = data.get_markers()
markers.smart_sort() # optional param to remove subject name

# Do severial bodies, use the marker location on the rigidbody
frames["hip"] = [core.Point(0.0, 0.0, 0.0),
                 core.Point(70.0, 0, 0.0),
                 core.Point(0, 42.0, 0),
                 core.Point(35.0, 70.0, 0.0)]

frames["RightThigh"] = [core.Point(0.0, 0.0, 0.0),
                        core.Point(56.0, 0, 0.0),
                        core.Point(0, 49.0, 0),
                        core.Point(56.0, 63.0, 0.0)]

frames["RightShank"] = [core.Point(0.0, 0.0, 0.0),
                        core.Point(56.0, 0, 0.0),
                        core.Point(0, 42.0, 0),
                        core.Point(56.0, 70.0, 0.0)]

markers.auto_make_transform(frames)


# Get just one transform and the RMSE error 
# Can be used to get the transformation between ANY two sets of markers 
 m = markers.get_rigid_body("ben:hip")
 f = [m[0][frame], m[1][frame], m[2][frame], m[3][frame]]
 T, err = Markers.cloud_to_cloud(hip_marker, f)

Get model outputs

only works with lowerbody model currently

from Vicon import Vicon
file = "path to CSV file"
data = Vicon.Vicon(file)
model = data.get_model_output()
model.left_leg().hip.angle.x

Get force plates

from Vicon import Vicon
file = "path to CSV file"
data = Vicon.Vicon(file)
fp = data.get_force_plate(1).get_forces() # pass in 1 or 2 to get the foce plates