Adding NearestNeighboIndex analysis.

3 files changed, 74 insertions, 2 deletions

diff --git a/src/argaze/GazeAnalysis/NearestNeighborIndex.py b/src/argaze/GazeAnalysis/NearestNeighborIndex.py
new file mode 100644
index 0000000..104bb30
--- /dev/null
+++ b/src/argaze/GazeAnalysis/NearestNeighborIndex.py
@@ -0,0 +1,49 @@
+#!/usr/bin/env python
+
+""" """
+
+__author__ = "Théo de la Hogue"
+__credits__ = []
+__copyright__ = "Copyright 2023, Ecole Nationale de l'Aviation Civile (ENAC)"
+__license__ = "BSD"
+
+from typing import TypeVar, Tuple, Any
+from dataclasses import dataclass, field
+
+from argaze import GazeFeatures
+
+import numpy
+from scipy.spatial.distance import cdist
+
+@dataclass
+class ScanPathAnalyzer(GazeFeatures.ScanPathAnalyzer):
+    """Implementation of Nearest Neighbor Index (NNI) as described in Di Nocera et al., 2006
+    """
+
+    def __post_init__(self):
+
+        pass
+
+    def analyze(self, scan_path: GazeFeatures.ScanPathType, screen_dimension: tuple[float, float]) -> float:
+        """Analyze scan path."""
+
+        assert(len(scan_path) > 1)
+
+        # Gather fixations focus points
+        fixations_focus = []
+        for step in scan_path:
+            fixations_focus.append(step.first_fixation.focus)
+
+        # Compute inter fixation distances
+        distances = cdist(fixations_focus, fixations_focus)
+
+        # Find minimal distances between each fixations
+        minimums = numpy.apply_along_axis(lambda row: numpy.min(row[numpy.nonzero(row)]), 1, distances)
+
+        # Average of minimun distances
+        dNN = numpy.sum(minimums / len(fixations_focus))
+
+        # Mean random distance
+        dran = 0.5 * numpy.sqrt(screen_dimension[0] * screen_dimension[1] / len(fixations_focus))
+
+        return dNN / dran
diff --git a/src/argaze/GazeAnalysis/__init__.py b/src/argaze/GazeAnalysis/__init__.py
index cb18a08..f955856 100644
--- a/src/argaze/GazeAnalysis/__init__.py
+++ b/src/argaze/GazeAnalysis/__init__.py
@@ -2,4 +2,4 @@
 .. include:: README.md
 """
 __docformat__ = "restructuredtext"
-__all__ = ['DispersionThresholdIdentification', 'VelocityThresholdIdentification', 'TransitionMatrix', 'CoefficientK', 'LempelZivComplexity', 'NGram', 'Entropy']
\ No newline at end of file
+__all__ = ['DispersionThresholdIdentification', 'VelocityThresholdIdentification', 'TransitionMatrix', 'CoefficientK', 'LempelZivComplexity', 'NGram', 'Entropy', 'NearestNeighborIndex']
\ No newline at end of file
diff --git a/src/argaze/utils/demo_gaze_features_run.py b/src/argaze/utils/demo_gaze_features_run.py
index 50cf113..0e247e2 100644
--- a/src/argaze/utils/demo_gaze_features_run.py
+++ b/src/argaze/utils/demo_gaze_features_run.py
@@ -46,7 +46,7 @@ def main():
     aoi_scene_filepath = os.path.join(current_directory, 'demo_environment/aoi_scene.jpg')
     aoi_scene_image = cv2.imread(aoi_scene_filepath)
 
-    window_size = [aoi_scene_image.shape[1], aoi_scene_image.shape[0]]
+    window_size = (aoi_scene_image.shape[1], aoi_scene_image.shape[0])
 
     # Project AOI scene onto Full HD screen
     aoi_scene_projection = demo_scene.orthogonal_projection * window_size
@@ -106,6 +106,10 @@ def main():
     entropy_analysis = (-1, -1)
     enable_entropy_analysis = False
 
+    nni_analyzer = NearestNeighborIndex.ScanPathAnalyzer()
+    nni_analysis = 0
+    enable_nni_analysis = False
+
     gaze_movement_lock = threading.Lock()
 
     # Init timestamp
@@ -126,6 +130,7 @@ def main():
         nonlocal lzc_analysis
         nonlocal ngram_analysis
         nonlocal entropy_analysis
+        nonlocal nni_analysis
 
         # Edit millisecond timestamp
         data_ts = int((time.time() - start_ts) * 1e3)
@@ -230,6 +235,10 @@ def main():
 
                         raw_cK_analysis = raw_cK_analyzer.analyze(raw_scan_path)
 
+                    if enable_nni_analysis:
+
+                        nni_analysis = nni_analyzer.analyze(raw_scan_path, window_size)
+
                 # Append saccade to aoi scan path
                 aoi_scan_path.append_saccade(data_ts, gaze_movement)
 
@@ -294,6 +303,11 @@ def main():
                 display_hide = 'hide' if enable_entropy_analysis else 'display'
                 cv2.putText(aoi_matrix, f'Entropy: {on_off} (Press \'e\' key to {display_hide})', (20, 280), cv2.FONT_HERSHEY_SIMPLEX, 1, (0, 255, 255) if enable_entropy_analysis else (255, 255, 255), 1, cv2.LINE_AA)
 
+                # Write nni help
+                on_off = 'on' if enable_nni_analysis else 'off'
+                display_hide = 'hide' if enable_nni_analysis else 'display'
+                cv2.putText(aoi_matrix, f'Nearest neighbor index: {on_off} (Press \'i\' key to {display_hide})', (20, 320), cv2.FONT_HERSHEY_SIMPLEX, 1, (0, 255, 255) if enable_nni_analysis else (255, 255, 255), 1, cv2.LINE_AA)
+
                 # Check fixation identification
                 if gaze_movement_identifier[identification_mode].current_fixation != None:
 
@@ -401,6 +415,11 @@ def main():
                     cv2.putText(aoi_matrix, f'Stationary entropy: {entropy_analysis[0]:.3f},', (20, window_size[1]-280), cv2.FONT_HERSHEY_SIMPLEX, 1, (0, 255, 255), 1, cv2.LINE_AA)
                     cv2.putText(aoi_matrix, f'Transition entropy: {entropy_analysis[1]:.3f},', (20, window_size[1]-240), cv2.FONT_HERSHEY_SIMPLEX, 1, (0, 255, 255), 1, cv2.LINE_AA)
                     
+                # Write NNI
+                if enable_nni_analysis:
+
+                    cv2.putText(aoi_matrix, f'Nearest neighbor index: {nni_analysis:.3f}', (20, window_size[1]-320), cv2.FONT_HERSHEY_SIMPLEX, 1, (0, 255, 255), 1, cv2.LINE_AA)
+
             # Unlock gaze movement identification
             gaze_movement_lock.release()
 
@@ -462,6 +481,10 @@ def main():
 
                     enable_tm_analysis = True
 
+            # Enable NNI analysis with 'i' key 
+            if key_pressed == 105:
+
+                enable_nni_analysis = not enable_nni_analysis
 
             # Stop calibration by pressing 'Esc' key
             if cv2.waitKey(10) == 27: