python opencv cv2输出人脸检测等价比分，等价置信度

opencv3.4中，

rects,rl,wl = self.cascade.detectMultiScale3(img,scaleFactor=1.3,minNeighbors=4,minSize=(30, 30),flags=0,outputRejectLevels=True)

wl可作为分数

发现过程：https://github.com/opencv/opencv/blob/master/modules/objdetect/include/opencv2/objdetect.hpp

如果再opencv2.x版本中，想输出分数，采用同样的方法，查看objdetect.hpp文件的detectMultiScale封装形式，

https://github.com/opencv/opencv/blob/2.4/modules/objdetect/include/opencv2/objdetect/objdetect.hpp