From c9271c233ab9d8571f1a3d2c222a6c74b3113338 Mon Sep 17 00:00:00 2001
From: nlitkowski <norbert.litkowski@gmail.com>
Date: Wed, 16 Feb 2022 00:36:06 +0100
Subject: [PATCH] Add loss and metrics

---
 src/loss.py    | 17 +++++++++++++++++
 src/metrics.py | 16 ++++++++++++++++
 2 files changed, 33 insertions(+)
 create mode 100644 src/loss.py
 create mode 100644 src/metrics.py

diff --git a/src/loss.py b/src/loss.py
new file mode 100644
index 0000000..242037b
--- /dev/null
+++ b/src/loss.py
@@ -0,0 +1,17 @@
+import tensorflow as tf
+from metrics import IOU
+
+
+class jaccard_loss(tf.keras.losses.Loss):
+
+    def __init__(self,
+                 smooth=100
+                 ):
+        super().__init__()
+        self.smooth = smooth
+
+    def call(self,
+             y_true,
+             y_pred):
+        iou = IOU(y_true, y_pred, self.smooth)
+        return (1 - iou) * self.smooth
diff --git a/src/metrics.py b/src/metrics.py
new file mode 100644
index 0000000..6f4a985
--- /dev/null
+++ b/src/metrics.py
@@ -0,0 +1,16 @@
+from keras import backend as K
+
+
+def IOU(y_true,
+        y_pred,
+        smooth=1e-7):
+    '''
+    Taken from https://github.com/keras-team/keras-contrib/blob/master/keras_contrib/losses/jaccard.py
+    '''
+    intersection = K.sum(K.abs(y_true * y_pred), axis=-1)
+    sum_ = K.sum(K.abs(y_true) + K.abs(y_pred), axis=-1)
+
+    jacc = (intersection + smooth) / \
+        (sum_ - intersection + smooth)
+
+    return jacc