diff --git a/src/helpers/statistics.py b/src/helpers/statistics.py
index c92e061..176670e 100644
--- a/src/helpers/statistics.py
+++ b/src/helpers/statistics.py
@@ -1,4 +1,5 @@
 import numpy as np
+import math
 
 def imgStats(img):
     mean = np.zeros(3)
@@ -6,4 +7,20 @@ def imgStats(img):
     for i in range(img.shape[2]):
         mean[i] = np.mean(img[:, :, i])
         std[i] = np.std(img[:, :, i])
-    return mean, std
\ No newline at end of file
+    return mean, std
+
+def calcNormalFunc(mean, sd, len):
+    f = np.zeros(len, dtype=np.longdouble)
+    
+    # calculate PDF
+    for x in range(len):
+        exp = (-(x - mean) ** 2)/(2 * sd ** 2)
+        f[x] = 1 / math.sqrt(2 * np.pi * sd** 20 ) * (math.exp(exp))
+
+    # normalize PDF
+    max = np.amax(f)
+    min = np.amin(f)
+    for x in range(len):
+        f[x] = (f[x] - min) / (max - min)
+
+    return f
\ No newline at end of file