make new indexes and added pfroc

src/sfransen/FROC/__init__.py

@@ -4,3 +4,4 @@ from .data_utils import *
 from .cal_froc_from_np import *
 from .blob_preprocess import *
 from .analysis_utils import *
+from .p_auc import *

src/sfransen/FROC/p_auc.py

@@ -0,0 +1,25 @@
+import numpy as np
+
+def partial_auc(sensitivity, fp_per_patient, low=0.1, high=2.5):
+    """
+    Calculates partial area-under-the-curve from FROC sensitivity/FPP curve.
+    """
+
+    # Remove all values above min and max FPP
+    clipped_sens, clipped_fpp = [0.], [0.]
+    max_sens_before_window = 0
+    max_fpp_before_window = 0
+    for sens, fpp in zip(sensitivity, fp_per_patient):
+        if fpp < low and fpp > max_fpp_before_window:
+            max_sens_before_window = sens
+
+        if fpp >= low and fpp <= high:
+            clipped_sens.append(sens)
+            clipped_fpp.append(fpp)
+
+    # Extend the window to the limits supplied by the user
+    clipped_sens = [max_sens_before_window] + clipped_sens + [clipped_sens[-1]]
+    clipped_fpp  = [low] + clipped_fpp + [high]
+
+    # Integrate y(x) with the trapezoid rule
+    return np.trapz(clipped_sens, clipped_fpp)