From fb1a05aa8c309263d22cbb79e47c8c6f38366790 Mon Sep 17 00:00:00 2001
From: Théo de la Hogue
Date: Wed, 21 Sep 2022 18:33:16 +0200
Subject: Checking GazePosition validity.

---
 src/argaze/GazeFeatures.py | 50 +++++++++++++++++++++++++++++++++-------------
 1 file changed, 36 insertions(+), 14 deletions(-)

(limited to 'src')

diff --git a/src/argaze/GazeFeatures.py b/src/argaze/GazeFeatures.py
index 1c5f537..be5c430 100644
--- a/src/argaze/GazeFeatures.py
+++ b/src/argaze/GazeFeatures.py
@@ -34,21 +34,26 @@ class GazePosition():
     def __array__(self):
         return numpy.array(self.value)
 
+    def valid(self):
+        return self.accuracy >= 0
+
     def draw(self, frame, color=(0, 255, 255)):
 
-        # Draw point at position
-        cv.circle(frame, self.value, 2, color, -1)
+        if self.valid():
+
+            # Draw point at position
+            cv.circle(frame, self.value, 2, color, -1)
 
-        # Draw accuracy circle
-        if self.accuracy > 0:
-            cv.circle(frame, self.value, round(self.accuracy), color, 1)
+            # Draw accuracy circle
+            if self.accuracy > 0:
+                cv.circle(frame, self.value, round(self.accuracy), color, 1)
 
-class GazePositionMissing(GazePosition, Exception):
-    """Exception to raise when gaze position is missing."""
+class UnvalidGazePosition(GazePosition):
+    """Unvalid gaze position."""
 
-    def __init__(self, message):
+    def __init__(self):
 
-        super(Exception, self).__init__(message)
+        super().__init__((math.nan, math.nan), accuracy=-1)
 
 class TimeStampedGazePositions(DataStructures.TimeStampedBuffer):
     """Define timestamped buffer to store gaze positions."""
@@ -126,7 +131,7 @@ class DispersionBasedMovementIdentifier(MovementIdentifier):
         dispersion: float = field(init=False)
         euclidian: bool = field(default=True)
 
-        centroid: GazePosition = field(init=False)
+        centroid: tuple = field(init=False)
 
         def __post_init__(self):
 
@@ -186,18 +191,30 @@ class DispersionBasedMovementIdentifier(MovementIdentifier):
 
             # select timestamped gaze position until a duration threshold
             (ts_start, gaze_position_start) = remaining_ts_gaze_positions.pop_first()
-            (ts_current, gaze_position_current) = remaining_ts_gaze_positions.pop_first()
+
+            # Invalid start position
+            if not gaze_position_start.valid():
+
+                self.__ts_gaze_positions.pop_first()
+                continue
 
             ts_gaze_positions = TimeStampedGazePositions()
             ts_gaze_positions[ts_start] = gaze_position_start
 
+            (ts_current, gaze_position_current) = remaining_ts_gaze_positions.pop_first()
+
             while (ts_current - ts_start) < self.__duration_threshold:
 
-                ts_gaze_positions[ts_current] = gaze_position_current
+                # Ignore non valid position
+                # TODO ? Consider invalid position to not break fixation ?
+                if gaze_position_current.valid():
 
-                if len(remaining_ts_gaze_positions) > 0:
+                    ts_gaze_positions[ts_current] = gaze_position_current
+
+                try:
                     (ts_current, gaze_position_current) = remaining_ts_gaze_positions.pop_first()
-                else:
+
+                except:
                     break
 
             # is it a new fixation ?
@@ -215,6 +232,11 @@ class DispersionBasedMovementIdentifier(MovementIdentifier):
 
                     # select next gaze position
                     ts_next, position_next = remaining_ts_gaze_positions.pop_first()
+
+                    # Invalid next position
+                    if not position_next.valid():
+                        continue
+
                     ts_gaze_positions[ts_next] = position_next
 
                     # how much gaze is dispersed ?
-- 
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