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--- visual3d:documentation:emg:processing:onset [2024/07/16 16:55] – removed sgranger
+++ visual3d:documentation:emg:processing:onset [2024/07/17 15:45] (current) – created sgranger
@@ Line 1: / Line 1: @@
+====== Onset ======
+||
+Computing the onset of an EMG signal can be quite tricky. In this example, we describe a pipeline for a straightforward estimation of EMG onset based on the the [[Visual3D:Documentation:Pipeline:Signal_Commands:Teager_Kaiser_Energy|Teager-Kaiser Energy]] Operator and [[Visual3D:Documentation:Pipeline:Event_Commands:Event_Threshold|Event_Threshold]]. This is not a definitive definition, but simply a starting point for the user.
+{{:Teager_Kaiser.jpg}}
+\\
+<code>
+!Apply a high pass and low pass filter assuming that the surface emg signal contains information
+!from 20 to 500 Hz
+Highpass_Filter
+/SIGNAL_TYPES=ANALOG
+/SIGNAL_NAMES=EMG_C
+! /SIGNAL_FOLDER=ORIGINAL
+! /RESULT_SUFFIX=
+/RESULT_FOLDER=PROCESSED
+! /FILTER_CLASS=BUTTERWORTH
+/FREQUENCY_CUTOFF=20
+/NUM_REFLECTED=0
+/TOTAL_BUFFER_SIZE=100
+! /NUM_BIDIRECTIONAL_PASSES=1
+;
+!Apply the Teager-Kaiser Operator
+Teager_Kaiser_Energy
+/SIGNAL_TYPES=ANALOG
+/SIGNAL_NAMES=EMG_C
+/SIGNAL_FOLDER=PROCESSED
+! /SIGNAL_COMPONENTS=
+! /RESULT_FOLDER=PROCESSED
+! /EVENT_SEQUENCE=
+! /EXCLUDE_EVENTS=
+;
+!Create events that define the resting baseline of the muscle
+Event_Explicit
+/EVENT_NAME=REST1
+/FRAME=1
+! /TIME=
+;
+Event_Explicit
+/EVENT_NAME=REST2
+/FRAME=150
+! /TIME=
+;
+!Compute the median and standard deviation of the TKO envelope during rest
+Metric_Median
+/RESULT_METRIC_NAME=_MED
+/APPLY_AS_SUFFIX_TO_SIGNAL_NAME=TRUE
+/RESULT_METRIC_FOLDER=EMG
+/SIGNAL_TYPES=ANALOG
+/SIGNAL_NAMES=EMG_C
+/SIGNAL_FOLDER=PROCESSED
+! /SIGNAL_COMPONENTS=ALL_COMPONENTS
+/EVENT_SEQUENCE=REST1+REST2
+/EXCLUDE_EVENTS=
+/GENERATE_MEAN_AND_STDDEV=FALSE
+! /APPEND_TO_EXISTING_VALUES=FALSE
+;
+Metric_StdDev
+/RESULT_METRIC_NAME=_SD
+/APPLY_AS_SUFFIX_TO_SIGNAL_NAME=TRUE
+/RESULT_METRIC_FOLDER=EMG
+/SIGNAL_TYPES=ANALOG
+/SIGNAL_NAMES=EMG_C
+/SIGNAL_FOLDER=PROCESSED
+! /SIGNAL_COMPONENTS=ALL_COMPONENTS
+/EVENT_SEQUENCE=REST1+REST2
+/EXCLUDE_EVENTS=
+/GENERATE_MEAN_AND_STDDEV=FALSE
+! /APPEND_TO_EXISTING_VALUES=FALSE
+;
+!Identify the event EMG_C_ON based on a threshold crossing
+!of the median + 3 * standard deviation
+Event_Threshold
+/SIGNAL_TYPES=ANALOG
+/SIGNAL_NAMES=EMG_C
+/SIGNAL_FOLDER=PROCESED
+/EVENT_NAME=EMG_C_ON
+/SELECT_X=TRUE
+! /SELECT_Y=FALSE
+! /SELECT_Z=FALSE
+! /SELECT_RESIDUAL=FALSE
+/THRESHOLD=METRIC::EMG::EMG2_MED+3*METRIC::EMG::EMG2_SD
+! /FRAME_WINDOW=8
+! /FRAME_OFFSET=0
+/ASCENDING=TRUE
+! /DESCENDING=FALSE
+! /ENSURE_RANGE_FRAMES_BEFORE_THRESHOLD_CROSSING=FALSE
+/ENSURE_RANGE_FRAMES_AFTER_THRESHOLD_CROSSING=TRUE
+! /START_AT_EVENT=
+! /END_AT_EVENT=
+/EVENT_INSTANCE=1
+;
+</code>