Merge pull request OpenPIV#328 from nepomnyi/master

Normalized median filter is added to `windef.py`.

Author: alexlib

openpiv/validation.py

@@ -408,13 +408,22 @@ def typical_validation(
     #     plt.quiver(u,v,color='k')
 
 
-    flag_m = local_median_val(
-        u,
-        v,
-        u_threshold=settings.median_threshold,
-        v_threshold=settings.median_threshold,
-        size=settings.median_size,
-    )
+    if settings.median_normalized:
+        flag_m = local_norm_median_val(
+            u, 
+            v, 
+            ε=0.2, # use the recomended value at this point, later add user's input for this
+            threshold=settings.median_threshold,
+            size=settings.median_size
+        )
+    else:
+        flag_m = local_median_val(
+            u,
+            v,
+            u_threshold=settings.median_threshold,
+            v_threshold=settings.median_threshold,
+            size=settings.median_size,
+        )
 
     # u[flag_m] = np.ma.masked
     # v[flag_m] = np.ma.masked

openpiv/windef.py

@@ -129,11 +129,12 @@ class PIVSettings:
     min_max_v_disp: Tuple=(-30, 30)
     # The second filter is based on the global STD threshold
     std_threshold: int=10  # threshold of the std validation
-    # The third filter is the median test (not normalized at the moment)
+    # The third filter is the median test: pick between normalized and regular
+    median_normalized: bool=False # False = do regular median, True = do normalized median
     median_threshold: int=3  # threshold of the median validation
+    median_size: int=1  # defines the size of the local median
     # On the last iteration, an additional validation can be done based on
     # the S/N.
-    median_size: int=1  # defines the size of the local median