在openCV代码中在脸部周围创建矩形时出错

Question

我试图在openCV中围绕面部创建一个矩形，但得到NameError。 我试图找到根本原因，但是没有成功。

import numpy as np
import cv2

CascadeClassifier = cv2.CascadeClassifier('/Users/adityaacharya/Desktop/openCV/aditya/cascades/haarcascades/haarcascade_frontalface_alt2.xml') 
cap = cv2.VideoCapture('http://root:admin@123@192.168.1.114/mjpg/video.mjpg')    

while(True):
    # Capture frame-by-frame
    ret, frame = cap.read()

    gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)

    faces = CascadeClassifier.detectMultiScale(gray, scaleFactor=1.5, minNeighbors=5)

    for (x, y, w, h) in faces:
        print(x,y,w,h)
        roi_gray = gray[y:y+h, x:x+w]#(ycord_start, ycord_end)
        roi_color = gray[y:y + h, x:x + w]

        img_item = 'image.png'
        cv2.imwrite(img_item, roi_gray)
    # Our operations on the frame come here
    color = (255, 0, 0)#BGE 0-255

    stroke = 2
    height = x + w    
    width =  y + h

    cv2.rectangle(frame, (x, y), (height, width))

    # Display the resulting frame
    cv2.imshow('frame',frame)
    if cv2.waitKey(20) & 0xFF == ord('q'):
        break

# When everything done, release the capture
cap.release()

cv2.destroyAllWindows()

在传递代码时，出现以下错误：

File "camera-test.py", line 33, in <module>   height = x + w         
NameError: name 'x' is not defined