From 9bc3a551d97aaf93d9b36f4b539653a6ed7df80a Mon Sep 17 00:00:00 2001
From: Glenn Jocher <glenn.jocher@ultralytics.com>
Date: Fri, 10 Apr 2020 17:24:49 -0700
Subject: [PATCH] histogram equalization added to augmentation

---
 utils/datasets.py | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/utils/datasets.py b/utils/datasets.py
index 8f1341e3..efd21f02 100755
--- a/utils/datasets.py
+++ b/utils/datasets.py
@@ -520,6 +520,11 @@ def augment_hsv(img, hgain=0.5, sgain=0.5, vgain=0.5):
     np.clip(img_hsv[:, :, 0], None, 179, out=img_hsv[:, :, 0])  # inplace hue clip (0 - 179 deg)
     cv2.cvtColor(img_hsv, cv2.COLOR_HSV2BGR, dst=img)  # no return needed
 
+    # Histogram equalization
+    if random.random() < 0.2:
+        for i in range(3):
+            img[:, :, i] = cv2.equalizeHist(img[:, :, i])
+
 
 def load_mosaic(self, index):
     # loads images in a mosaic