diff --git a/hyperit/hyperit.py b/hyperit/hyperit.py
index a7d9ed5..f973f26 100644
--- a/hyperit/hyperit.py
+++ b/hyperit/hyperit.py
@@ -568,7 +568,7 @@ def __filter_estimation(self, s1: np.ndarray, s2: np.ndarray) -> float | np.ndar
         elif self._measure == MeasureType.PhyID:
             return self.__estimate_atoms(s1, s2)
 
-        __initialise_estimator(s1, s2)
+        self.__initialise_estimator(s1, s2)
 
         return self.__estimate_it_epoch_average(s1, s2) if self._epoch_average else self.__estimate_it(s1, s2)