diff --git a/src/ich/InSAR_canopy_height.py b/src/ich/InSAR_canopy_height.py
index 468d29de56055731d780e0fc3e1f7bd555fb4ade..66989fbd605a76703f8dfaa5d7e1d418578b6856 100644
--- a/src/ich/InSAR_canopy_height.py
+++ b/src/ich/InSAR_canopy_height.py
@@ -39,8 +39,8 @@ parser = argparse.ArgumentParser(description="Generate canopy height map from In
 
 parser.add_argument("-c", "--correlationFile", dest="corFile", help="Correlation file [0,1]")
 parser.add_argument("-l", "--cal_ht", dest="lidarFile", help="Calibration height file (e.g., LiDAR heights in meters)")
-parser.add_argument("-ll", "--lower_limit", dest="htl", default=None, help="Lower limit of canopy height (m)", type=int)
-parser.add_argument("-ul", "--upper_limit", dest="htg", default=None, help="Upper limit of canopy height (m)", type=int)
+parser.add_argument("-ll", "--lower_limit", dest="htl", default=0, help="Lower limit of canopy height (m)", type=int)
+parser.add_argument("-ul", "--upper_limit", dest="htg", default=0, help="Upper limit of canopy height (m)", type=int)
 parser.add_argument("-w", "--window", dest="window_size", default=10, help="Window size", type=int)
 parser.add_argument("-val", "--validation", dest="validation", default=0, help="Fraction to split for cross-validation", type=float)
 
diff --git a/src/ich/args_in.py b/src/ich/args_in.py
index bb11d9506d898a8bcc5568f9bd681d4d526a12db..dd96c8a9eddc4d2342aa6522a616fc47a22fdafb 100644
--- a/src/ich/args_in.py
+++ b/src/ich/args_in.py
@@ -77,7 +77,7 @@ def rvog_inverse(args):
         # Apply masks to filter out invalid or extreme values
         lidar_ht[lidar_ht == 0] = np.nan
 
-        if args.htl==None and args.htg==None:
+        if args.htl==0 and args.htg==0:
             """ Calculating the upper limit of the heights to be estimated from the LiDAR data 
             Ceiling the upper limit to the closest multiple of 5 for the height at 99.9 percentile """
             args.htl=0