I am try to get face detection working on using a python script and OpenCV but I keep getting this error:
Traceback (most recent call last)
File "face_detect.py", line 19, in <module>
cascade = cv.Load(options, cascade)
TypeError: OpenCV returned NULL
The code I used is here: https://github.com/mitchtech/py_servo_facetracker
I don know what is causing this error or how to fix it. Thanks in advance.
if you put on your goggles ;)
you'll see, that it's not
cascade = cv.Load(options, cascade)
in the original code, but :
cascade = cv.Load(options.cascade)
( and a remark: the old cv api got removed in newer opencv versions, you probably should avoid it in favour of cv2 )
I had the same issue. For me, the relative-path of the haarcascade was incorrect. It thought the data folder was one level up, instead it was two.
My changes
Original:
parser.add_option("-c", "--cascade", action="store", dest="cascade", type="str", help="Haar cascade file, default %default", default = "../data/haarcascades/haarcascade_frontalface_alt.xml")
Modified:
parser.add_option("-c", "--cascade", action="store", dest="cascade", type="str", help="Haar cascade file, default %default", default = "../../data/haarcascades/haarcascade_frontalface_alt.xml")
I met the same issue, and it seems like the file path of haarcascade_frontalface_alt.xml is not correct.
You should download haarcascade_frontalface_alt.xml to your computer from http://eclecti.cc/files/2008/03/haarcascade_frontalface_alt.xml.
So I fixed it by changing the file path of haarcascade_frontalface_alt.xml. Hope it will help!
