python-opencv：module 'cv2.cv2' has no attribute 'CV_LOAD_IMAGE_GRAYSCALE'

原因分析： 

In OpenCV 3 for C++ you have to use cv::ImreadModes::IMREAD_GRAYSCALE which is located on

解决方法：

应该用：

cv2.IMREAD_GRAYSCALE

说明： 

...
IMREAD_ANYCOLOR = 4
IMREAD_ANYDEPTH = 2
IMREAD_COLOR = 1
IMREAD_GRAYSCALE = 0   #that will be it ;)
IMREAD_LOAD_GDAL = 8
IMREAD_UNCHANGED = -1
...
VERSION
    3.0.0-dev