vraag 13

main.py

@@ -62,6 +62,14 @@ class SignalProcessing:
         b, a = butter(order, [low, high], btype='band')
         filtered_data = filtfilt(b, a, data)
         return filtered_data
+    
+    def lowpass_filter(self, data, cutoff):
+        nyquist = 0.5 * self.fs
+        normal_cutoff = cutoff / nyquist
+        order = 4
+        b, a = butter(order, normal_cutoff, btype='low')
+        filtered_data = filtfilt(b, a, data)
+        return filtered_data
 
     def power_spectral_analysis(self, data):
         N = len(data)
@@ -113,21 +121,25 @@ def plot_emg_data(file_path):
     filtered_ta = signal_processor.bandpass_filter(channel_tibialis_anterior, 25, 300)
 
     rectified_rf = np.abs(filtered_rf)
-    recitfied_ta = np.abs(filtered_ta)
+    rectified_ta = np.abs(filtered_ta)
+
+    envelope_rf = signal_processor.lowpass_filter(rectified_rf,5)
+    envelope_ta = signal_processor.lowpass_filter(rectified_ta,5)
+
 
-    freq_rf, fft_rf = compute_fft(rectified_rf, sampling_rate)
-    freq_ta, fft_ta = compute_fft(recitfied_ta, sampling_rate)
+    freq_rf, fft_rf = compute_fft(envelope_rf, sampling_rate)
+    freq_ta, fft_ta = compute_fft(envelope_ta, sampling_rate)
 
     plt.figure(figsize=(13,8))
 
     plt.subplot(2, 2, 1)
-    plt.plot(time_vector, filtered_rf)
+    plt.plot(time_vector, envelope_rf)
     plt.title('EMG Data - Rectus femoris')
     plt.xlabel('Time [Seconds]')
     plt.ylabel('Amplitude')
 
     plt.subplot(2, 2, 2)
-    plt.plot(time_vector, filtered_ta)
+    plt.plot(time_vector, envelope_ta)
     plt.title('EMG Data - Tibialis Anterior')
     plt.xlabel('Time [seconds]')
     plt.ylabel('Amplitude')