I am trying to make a basic program for a real time face detection Here s my code I am a newbie in OpenCV import numpy as np import cv2 cam cv2 VideoCapture 0 name detect face cascade cv2 CascadeClassifier haarcascade frontalface default xml cv2 namedWindow name cv2 WINDOW AUTOSIZE while True s img cam read gray cv2 cvtColor img cv2 COLOR BGR2GRAY faces face cascade detectMultiScale gray 1 3 5 print s for x y w h in faces img cv2 rectangle img x y x w y h 255 0 0 2 cv2 imshow name img k cv2 waitKey 0 if k 27 cv2 destroyWindow Detect break But when I run this code I get this error OpenCV Error Bad flag parameter or structure field Unrecognized or unsupported array type in cvGetMat file build buildd opencv-2 4 2 dfsg modules core src array cpp line 2482 Traceback most recent call last File mytry py line 27 in lt module gt cv2 imshow name img cv2 error build buildd opencv-2 4 2 dfsg modules core src array cpp 2482 error -206 Unrecognized or unsupported array type in function cvGetMat I am a newbie in OpenCV Please tell me what is wrong with the code why does this error arises what changes should I make

Real time face detection OpenCV, Python

Your line:

img = cv2.rectangle(img,(x,y),(x+w,y+h),(255,0,0),2)

will draw a rectangle in the image, but the return value will be None, so img changes to None and cannot be drawn.

Try

cv2.rectangle(img,(x,y),(x+w,y+h),(255,0,0),2)