diff --git a/View/signal_processing_tab.py b/View/signal_processing_tab.py
index 665c742..d107ddf 100644
--- a/View/signal_processing_tab.py
+++ b/View/signal_processing_tab.py
@@ -730,82 +730,88 @@ class SignalProcessingTab(QWidget):
 
     def clear_noise_data(self):
 
-        stg.BS_noise_raw_data[self.combobox_acoustic_data_choice.currentIndex()] = np.array([])
-        stg.BS_noise_averaged_data[self.combobox_acoustic_data_choice.currentIndex()] = np.array([])
-        stg.SNR_raw_data[self.combobox_acoustic_data_choice.currentIndex()] = np.array([])
-        stg.SNR_cross_section[self.combobox_acoustic_data_choice.currentIndex()] = np.array([])
-        stg.SNR_stream_bed[self.combobox_acoustic_data_choice.currentIndex()] = np.array([])
-        stg.time_noise[self.combobox_acoustic_data_choice.currentIndex()] = np.array([])
-        stg.noise_method[self.combobox_acoustic_data_choice.currentIndex()] = 0
-        stg.SNR_filter_value[self.combobox_acoustic_data_choice.currentIndex()] = 0
+        if len(stg.filename_BS_raw_data) == 0:
 
-        stg.BS_raw_data_pre_process_SNR[self.combobox_acoustic_data_choice.currentIndex()] = np.array([])
-        stg.BS_raw_data_pre_process_average[self.combobox_acoustic_data_choice.currentIndex()] = np.array([])
+            pass
 
-        stg.BS_cross_section_pre_process_SNR[self.combobox_acoustic_data_choice.currentIndex()] = np.array([])
-        stg.BS_cross_section_pre_process_average[self.combobox_acoustic_data_choice.currentIndex()] = np.array([])
+        else:
 
-        stg.BS_stream_bed_pre_process_SNR[self.combobox_acoustic_data_choice.currentIndex()] = np.array([])
-        stg.BS_stream_bed_pre_process_average[self.combobox_acoustic_data_choice.currentIndex()] = np.array([])
+            stg.BS_noise_raw_data[self.combobox_acoustic_data_choice.currentIndex()] = np.array([])
+            stg.BS_noise_averaged_data[self.combobox_acoustic_data_choice.currentIndex()] = np.array([])
+            stg.SNR_raw_data[self.combobox_acoustic_data_choice.currentIndex()] = np.array([])
+            stg.SNR_cross_section[self.combobox_acoustic_data_choice.currentIndex()] = np.array([])
+            stg.SNR_stream_bed[self.combobox_acoustic_data_choice.currentIndex()] = np.array([])
+            stg.time_noise[self.combobox_acoustic_data_choice.currentIndex()] = np.array([])
+            stg.noise_method[self.combobox_acoustic_data_choice.currentIndex()] = 0
+            stg.SNR_filter_value[self.combobox_acoustic_data_choice.currentIndex()] = 0
 
-        if stg.noise_method[self.combobox_acoustic_data_choice.currentIndex()] == 0:
-            self.lineEdit_noise_file.clear()
+            stg.BS_raw_data_pre_process_SNR[self.combobox_acoustic_data_choice.currentIndex()] = np.array([])
+            stg.BS_raw_data_pre_process_average[self.combobox_acoustic_data_choice.currentIndex()] = np.array([])
 
-        elif stg.noise_method[self.combobox_acoustic_data_choice.currentIndex()] == 1:
-            self.lineEdit_val1.clear()
-            self.lineEdit_val1.setText("0.00")
+            stg.BS_cross_section_pre_process_SNR[self.combobox_acoustic_data_choice.currentIndex()] = np.array([])
+            stg.BS_cross_section_pre_process_average[self.combobox_acoustic_data_choice.currentIndex()] = np.array([])
 
-            self.lineEdit_val2.clear()
-            self.lineEdit_val2.setText("0.00")
+            stg.BS_stream_bed_pre_process_SNR[self.combobox_acoustic_data_choice.currentIndex()] = np.array([])
+            stg.BS_stream_bed_pre_process_average[self.combobox_acoustic_data_choice.currentIndex()] = np.array([])
 
-            self.lineEdit_profile_tail_value.clear()
-            self.lineEdit_profile_tail_value.setText("0.0000")
+            if stg.noise_method[self.combobox_acoustic_data_choice.currentIndex()] == 0:
+                self.lineEdit_noise_file.clear()
 
-            self.verticalLayout_groupbox_plot_profile_tail.removeWidget(self.canvas_profile_tail)
-            self.canvas_profile_tail = FigureCanvas()
-            self.verticalLayout_groupbox_plot_profile_tail.addWidget(self.canvas_profile_tail)
+            elif stg.noise_method[self.combobox_acoustic_data_choice.currentIndex()] == 1:
+                self.lineEdit_val1.clear()
+                self.lineEdit_val1.setText("0.00")
 
-        self.lineEdit_SNR_criterion.setText("0.00")
-        self.lineEdit_horizontal_average.setText("0.00")
+                self.lineEdit_val2.clear()
+                self.lineEdit_val2.setText("0.00")
 
-        # --- Clear SNR plot ---
-        self.verticalLayout_groupbox_plot_SNR.removeWidget(self.toolbar_SNR)
-        self.verticalLayout_groupbox_plot_SNR.removeWidget(self.scroll_SNR)
+                self.lineEdit_profile_tail_value.clear()
+                self.lineEdit_profile_tail_value.setText("0.0000")
 
-        self.canvas_SNR = FigureCanvas()
-        self.toolbar_SNR = NavigationToolBar(self.canvas_SNR, self)
-        self.scroll_SNR.setWidget(self.canvas_SNR)
+                self.verticalLayout_groupbox_plot_profile_tail.removeWidget(self.canvas_profile_tail)
+                self.canvas_profile_tail = FigureCanvas()
+                self.verticalLayout_groupbox_plot_profile_tail.addWidget(self.canvas_profile_tail)
 
-        self.verticalLayout_groupbox_plot_SNR.addWidget(self.toolbar_SNR)
-        self.verticalLayout_groupbox_plot_SNR.addWidget(self.scroll_SNR)
+            self.lineEdit_SNR_criterion.setText("0.00")
+            self.lineEdit_horizontal_average.setText("0.00")
 
-        # --- Clear BS plot ---
-        self.verticalLayout_groupbox_plot_pre_processed_data_2D_field.removeWidget(self.toolbar_BS)
-        self.verticalLayout_groupbox_plot_pre_processed_data_2D_field.removeWidget(self.scroll_BS)
+            # --- Clear SNR plot ---
+            self.verticalLayout_groupbox_plot_SNR.removeWidget(self.toolbar_SNR)
+            self.verticalLayout_groupbox_plot_SNR.removeWidget(self.scroll_SNR)
 
-        self.canvas_BS = FigureCanvas()
-        self.toolbar_BS = NavigationToolBar(self.canvas_BS, self)
-        self.scroll_BS.setWidget(self.canvas_BS)
+            self.canvas_SNR = FigureCanvas()
+            self.toolbar_SNR = NavigationToolBar(self.canvas_SNR, self)
+            self.scroll_SNR.setWidget(self.canvas_SNR)
 
-        self.verticalLayout_groupbox_plot_pre_processed_data_2D_field.addWidget(self.toolbar_BS)
-        self.verticalLayout_groupbox_plot_pre_processed_data_2D_field.addWidget(self.scroll_BS)
+            self.verticalLayout_groupbox_plot_SNR.addWidget(self.toolbar_SNR)
+            self.verticalLayout_groupbox_plot_SNR.addWidget(self.scroll_SNR)
 
-        self.combobox_frequency_profile.clear()
+            # --- Clear BS plot ---
+            self.verticalLayout_groupbox_plot_pre_processed_data_2D_field.removeWidget(self.toolbar_BS)
+            self.verticalLayout_groupbox_plot_pre_processed_data_2D_field.removeWidget(self.scroll_BS)
 
-        self.verticalLayout_groupbox_plot_profile.removeWidget(self.toolbar_profile)
-        self.verticalLayout_groupbox_plot_profile.removeWidget(self.canvas_profile)
+            self.canvas_BS = FigureCanvas()
+            self.toolbar_BS = NavigationToolBar(self.canvas_BS, self)
+            self.scroll_BS.setWidget(self.canvas_BS)
 
-        self.canvas_profile = FigureCanvas()
-        self.toolbar_profile = NavigationToolBar(self.canvas_profile, self)
+            self.verticalLayout_groupbox_plot_pre_processed_data_2D_field.addWidget(self.toolbar_BS)
+            self.verticalLayout_groupbox_plot_pre_processed_data_2D_field.addWidget(self.scroll_BS)
 
-        self.verticalLayout_groupbox_plot_profile.addWidget(self.toolbar_profile)
-        self.verticalLayout_groupbox_plot_profile.addWidget(self.canvas_profile)
+            self.combobox_frequency_profile.clear()
 
-        self.slider.setValue(1)
-        self.slider.setMaximum(10)
+            self.verticalLayout_groupbox_plot_profile.removeWidget(self.toolbar_profile)
+            self.verticalLayout_groupbox_plot_profile.removeWidget(self.canvas_profile)
 
-        self.slider.setValue(0)
-        self.slider.setMaximum(10)
+            self.canvas_profile = FigureCanvas()
+            self.toolbar_profile = NavigationToolBar(self.canvas_profile, self)
+
+            self.verticalLayout_groupbox_plot_profile.addWidget(self.toolbar_profile)
+            self.verticalLayout_groupbox_plot_profile.addWidget(self.canvas_profile)
+
+            self.slider.setValue(1)
+            self.slider.setMaximum(10)
+
+            self.slider.setValue(0)
+            self.slider.setMaximum(10)
 
     def open_dialog_box(self):