1 files changed, 10 insertions, 1 deletions
diff --git a/src/argaze/GazeAnalysis/VelocityThresholdIdentification.py b/src/argaze/GazeAnalysis/VelocityThresholdIdentification.py
index 7d6c7b2..7131373 100644
--- a/src/argaze/GazeAnalysis/VelocityThresholdIdentification.py
+++ b/src/argaze/GazeAnalysis/VelocityThresholdIdentification.py
@@ -133,7 +133,7 @@ class GazeMovementIdentifier(GazeFeatures.GazeMovementIdentifier):
         # Ignore non valid gaze position
         if not gaze_position.valid:
 
-            return None if not terminate else self.current_fixation
+            return GazeFeatures.UnvalidGazeMovement() if not terminate else self.current_fixation
 
         # Store first valid position
         if self.__last_ts < 0:
@@ -211,6 +211,9 @@ class GazeMovementIdentifier(GazeFeatures.GazeMovementIdentifier):
 
                 return self.current_fixation
 
+        # Always return unvalid gaze movement at least
+        return GazeFeatures.UnvalidGazeMovement()
+
     @property
     def current_fixation(self) -> FixationType:
 
@@ -218,9 +221,15 @@ class GazeMovementIdentifier(GazeFeatures.GazeMovementIdentifier):
 
             return Fixation(self.__fixation_positions)
 
+        # Always return unvalid gaze movement at least
+        return GazeFeatures.UnvalidGazeMovement()
+
     @property
     def current_saccade(self) -> SaccadeType:
 
         if len(self.__saccade_positions) > 0:
 
             return Saccade(self.__saccade_positions)
+
+        # Always return unvalid gaze movement at least
+        return GazeFeatures.UnvalidGazeMovement()