diff --git a/src/cristallina/plot.py b/src/cristallina/plot.py
index 6188ce0..526c08b 100644
--- a/src/cristallina/plot.py
+++ b/src/cristallina/plot.py
@@ -188,20 +188,23 @@ def plot_image_channel(data, channel_name, pulse=0, ax=None, rois=None, norms=No
     axis_styling(ax, channel_name, description)
     plt.legend(loc=4)    
 
-def plot_spectrum_channel(data, channel_name_x, channel_name_y, ax=None):
+def plot_spectrum_channel(data, channel_name_x, channel_name_y, average=True, frame=0, ax=None):
     """
     Plots channel data for two channels where the first is taken as the (constant) x-axis
-    and the second as the y-axis (here we take the mean over the individual pulses).
+    and the second as the y-axis (here we take by default the mean over the individual pulses).
     """
     try:
         mean, std = np.mean(data[channel_name_y].data), np.std(data[channel_name_y].data)
-        # data[channel_name].data
         mean_over_frames = np.mean(data[channel_name_y].data, axis=0)
     except TypeError:
         print(f"Unknown data in channel {channel_name_y}.")
         return
 
-    y_data = mean_over_frames
+    if average:
+        y_data = mean_over_frames
+    else:
+        y_data = data[channel_name_y].data[frame]
+        
 
     if ax is None:
         fig, ax = plt.subplots(constrained_layout=True)
diff --git a/src/cristallina/utils.py b/src/cristallina/utils.py
index 8b92eb9..d309070 100644
--- a/src/cristallina/utils.py
+++ b/src/cristallina/utils.py
@@ -92,6 +92,9 @@ class ROI:
     @property
     def rows(self):
         return slice(self.bottom, self.top)
+    @property
+    def LeftRightBottomTop(self):
+        return [self.left, self.right, self.bottom, self.top]
 
     @property
     def cols(self):
@@ -106,7 +109,7 @@ class ROI:
         return self.top - self.bottom
     
     def __repr__(self):
-        return f"ROI(bottom={self.bottom}, top={self.top}, left={self.left}, right={self.right})"
+        return f"ROI(bottom={self.bottom},top={self.top},left={self.left},right={self.right})"
 
     def __eq__(self, other):
         # we disregard the name
@@ -118,12 +121,16 @@ class ROI:
     
 ######################## Setting up paths ########################
 
-def heuristic_extract_pgroup():
-    """ The function tries to guess the current p-group from the directory name."""
-    cwd = os.getcwd()
-    if "/p" in cwd:
+def heuristic_extract_pgroup(path=None):
+    """ The function tries to guess the current p-group from the 
+        current working directory (default) or the contents of 
+        the given path.
+    """
+    path = path or os.getcwd()
+
+    if "/p" in path:
         # Cut the string and look at the next five letters after /p
-        p_number = cwd.partition("/p")[2][:5]
+        p_number = path.partition("/p")[2][:5]
 
         if not p_number.isdigit():
             raise KeyError("Automatic p-group extraction from the current working directory didn't work.")