Table of Contents
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)  |