Run the code like this:
OpenCV2 : python face_detect.py abba.png
OpenCv3: python facedetect_cv3.py abba.png
If you want to understand how the code works, the details are here:
Youtube_Channel :https://www.youtube.com/channel/UChukKWu0KrtXeZLlYjJshHg
Setup OpenCv2/OpenCv3 : https://www.youtube.com/watch?v=Oq18KACn8kA
Face detection using opencv HAAR Cascade : https://www.youtube.com/watch?v=F3rlb276wkk