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visual3d:documentation:emg:filtering:integrate_emg [2024/06/14 17:11] – created sgrangervisual3d:documentation:emg:filtering:integrate_emg [2024/07/17 15:45] (current) – created sgranger
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-|**Language:**|** English**  • [[index.php?title=EMG_Integrate/fr&action=edit&redlink=1|français]] • [[index.php?title=EMG_Integrate/it&action=edit&redlink=1|italiano]] • [[index.php?title=EMG_Integrate/pt&action=edit&redlink=1|português]] • [[index.php?title=EMG_Integrate/es&action=edit&redlink=1|español]] ****|+====== Integrate EMG ======
  
-|===== Contents =====\\ \\ \\ \\ * [[#Integrate_EMG|1 Integrate EMG]]\\   * [[#Integrating_an_EMG_envelope_between_events|1.1 Integrating an EMG envelope between events]]|+===== Linear Envelope =====
  
-====== Integrate EMG ======+=== Computing the EMG Envelope using rectify and lowpass filter ===
  
-==== Integrating an EMG envelope between events ====+This section will compute the EMG Envelope using rectify and lowpass filter. Rectify takes the absolute value of every element of a signal. Visual3D calculates signal rectification using the following formula: x(ti)abs(x(ti))
  
-The result of integrating a signal is a single metric value per event rangeFor example, the commands below will integrate an EMG signal between events from **Start** to **End**+=== Lowpass Filter Cutoff === 
 + 
 +The default lowpass filter in Visual3D is a fourth order butterworth filter. 
 + 
 +Butterworth filters have an upper limit on the magnitude of the cutoff frequency. 
 + 
 +The maximum theoretical cutoff frequency is (sampling_rate*0.802/2). 
 + 
 +VIsual3D is a little more conservative than that because we have found the filter to be unreliable at the theoretical limits. 
 + 
 +The highest cutoff frequency that VIsual3D will allow you is 0.393sampling-rate. 
 + 
 +If your EMG signals are sampled at 1000 Hz, the highest cutoff frequency is 393 Hz. 
 + 
 +=== Example Script === 
 + 
 +The highpass filter is not part of the linear envelope, but is used to remove the [[Visual3D:Documentation:EMG:Processing:Detecting_Muscle_Onset|DC offset]].
  
 <code> <code>
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 /Signal_Folder=ORIGINAL  /Signal_Folder=ORIGINAL 
 ! /Result_Suffix=  ! /Result_Suffix= 
-/Result_Folder=PROCESSED +/Result_Folder=HIGHPASS
 ! /Filter_Class=BUTTERWORTH  ! /Filter_Class=BUTTERWORTH 
 /Frequency_Cutoff=50  /Frequency_Cutoff=50 
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-Apply low pass filter with 500 hz cutoff +Rectify the signals 
-Lowpass_Filter  +Rectify
-/Signal_Types=ANALOG  +
-/SIgnal_Names=EMG1+EMG2+EMG3  +
-/Signal_Folder=PROCESSED  +
-! /Result_Suffix=  +
-! /Result_Folder=PROCESSED  +
-! /Filter_Class=BUTTERWORTH  +
-/Frequency_Cutoff=500  +
-/Num_Reflected= 0  +
-/Total_Buffer_Size=100  +
-/Num_Bidirectional_Passes=1  +
-+
- +
-! RMS moving average with a 100ms window +
-Moving_RMS  +
-/SIGNAL_TYPES=ANALOG  +
-/SIGNAL_NAMES=EMG1+EMG2+EMG3  +
-/SIGNAL_FOLDER=PROCESSED  +
-! /RESULT_SUFFIX=  +
-/RESULT_FOLDER=RMS  +
-/NUM_WINDOW_FRAMES=1+0.1*PARAMETER::ANALOG::RATE  +
-;  +
- +
-! Integrates an EMG signal between events from Start to End  +
-Metric_Integrate +
-/RESULT_METRIC_NAME=_INT +
-/APPLY_AS_SUFFIX_TO_SIGNAL_NAME=TRUE +
-! /RESULT_METRIC_FOLDER=PROCESSED+
 /SIGNAL_TYPES=ANALOG /SIGNAL_TYPES=ANALOG
 /SIGNAL_NAMES=EMG1+EMG2+EMG3 /SIGNAL_NAMES=EMG1+EMG2+EMG3
-/SIGNAL_FOLDER=RMS +/SIGNAL_FOLDER=HIGHPASS  
-! /SIGNAL_COMPONENTS=ALL_COMPONENTS +! /RESULT_NAMES
-/EVENT_SEQUENCE=START+END +/RESULT_TYPES
-/EXCLUDE_EVENTS+/RESULT_FOLDER=RECTIFY  
-/GENERATE_MEAN_AND_STDDEV=FALSE +/RESULT_SUFFIX=
-/APPEND_TO_EXISTING_VALUES=FALSE+
 ; ;
-</code> 
  
 +! Apply a low pass filter
 +Lowpass_Filter  
 +/Signal_Types= ANALOG 
 +/Signal_Names= EMG1+EMG2+EMG3 
 +/Signal_Folder= RECTIFY 
 +! /Result_Suffix= 
 +/Result_Folder=LOWPASS
 +/Frequency_Cutoff=10 
 +/Num_Reflected=50
 +;
 +</code>
  
-Retrieved from "" 
  
  
visual3d/documentation/emg/filtering/integrate_emg.1718385094.txt.gz · Last modified: 2024/06/14 17:11 by sgranger