Event Onset

Create an Event Label using two Threshold crossings and a local minimum.

Create an event label at the last minimum value before a threshold crossing, or at the last baseline threshold crossing before a threshold crossing. The event created is the “minimum” event or “baseline” event that is closest to the threshold crossing.

The threshold crossing is a fairly high value (or metric) that the user is confident is beyond the Event of interest
The baseline crossing is a low threshold value (or metric) which is typically the point at which a velocity signal(for example) just starts moving.
The last local minimum before the threshold crossing (higher threshold).
The event from the baseline crossing and local minimum that is closest to the higher threshold crossing is set as the ONSET Event.

If multiple components are chosen (X Y and Z), the command will look for when any component passes the threshold and when any component reaches the baseline or a local minimum.

\\ Event_Onset\\ /Signal_Types=The type of signal to be evaluated\\ /Signal_Names=The name of the signal to be evaluated\\ /Signal_Folder=The name of the signal folder\\ /Event_Name=The name to be given to the threshold event\\ /Select_X=(True or False)Use this component of the signal\\ /Select_Y=(True or False)Use this component of the signal\\ /Select_Z=(True or False)Use this component of the signal\\ /Threshold=The first threshold value. E.g. the point at which we start going backwards through the signal\\ /Threshold_Instance=The instance of the first threshold crossing\\ /Baseline=A baseline value. If the signal crosses this point before the local minima, the event will be placed at this frame\\ /Frame_Window=The range of frames of data that must satisfy the threshold crossing. Used by the "Ensure" variable\\ /Frame_Offset=The frame offset from the threshold crossing where the event label is to be placed\\ /Ascending=(True or False) Determine the threshold when the signal is passing up through the threshold\\ /Descending=(True or False) Determine the threshold when the signal is passing down through the threshold\\ /Start_At_Event=The search begins from the start event\\ /End_At_Event=The search ends at the end event\\ ;\\

Example 1

Identifies movement onset based on the speed of the hand.

\\ Event_Onset\\ /Signal_Types=DERIVED\\ /Signal_Names=HANDSPEED\\ /Signal_Folder=PROCESSED\\ /Event_Name=ON\\ /Select_X=TRUE\\ /Select_Y=FALSE\\ /Select_Z=FALSE\\ /Threshold=0.2\\ /Threshold_Instance=0\\ /Baseline=0.05\\ /Frame_Window=8\\ /Frame_Offset=0\\ /Ascending=TRUE\\ /Descending=FALSE\\ /Start_At_Event=GO\\ /End_At_Event=VEL_MAX\\ ;\\

Note that both the Threshold and Baseline parameter accept either a number or a METRIC

Example 2

\\ Event_Onset\\ /SIGNAL_TYPES= LINK_MODEL_BASED\\ /SIGNAL_NAMES= Left_GRF\\ ! /SIGNAL_FOLDER= ORIGINAL\\ /EVENT_NAME= SCOTT2\\ ! /SELECT_X= TRUE\\ ! /SELECT_Y= FALSE\\ ! /SELECT_Z= FALSE\\ /THRESHOLD= 25\\ ! /THRESHOLD_INSTANCE= 0\\ ! /BASELINE= 0\\ ! /FRAME_WINDOW= 8\\ /ASCENDING= TRUE\\ ! /DESCENDING= FALSE\\ ! /START_AT_EVENT=\\ ! /END_AT_EVENT=\\ ;\\

]]

Result:
Visual3D will find when the signal crosses the threshold (25N) and look backwards in time (along the light blue) and find EITHER:
- When the signal reaches the baseline of 0 N (this is indicated by the first instance of SCOTT2)
-OR-
- When the signal reaches the local minima (this is indicated by the second instance of SCOTT2)

HAS-Motion Software Documentation

Table of Contents

Event Onset

Example 1

Example 2