Merge pull request #234 from sanket2000sonavane/master

added link for face detector using opencv

Author: tuvtran

README.md

@@ -420,6 +420,7 @@ To get started, simply fork this repo. Please refer to [CONTRIBUTING.md](CONTRIB
   - [Mutiple Object Tracker](https://www.pyimagesearch.com/2018/10/29/multi-object-tracking-with-dlib/)
 - [Image Stitching with OpenCV and Python](https://www.pyimagesearch.com/2018/12/17/image-stitching-with-opencv-and-python/)
 - [Instance Segmentation with OpenCV](https://www.pyimagesearch.com/2018/11/26/instance-segmentation-with-opencv/)
+- [Face mask detector](https://www.pyimagesearch.com/2020/05/04/covid-19-face-mask-detector-with-opencv-keras-tensorflow-and-deep-learning/)
 
 ### Deep Learning: