无法在Python中使用OpenCV检测面部和眼睛 [英] Unable to detect face and eye with OpenCV in Python

问题描述

此代码用于使用网络摄像头检测面部和眼睛，但出现此错误

This code is to detect face and eyes using webcam but getting this error

Traceback (most recent call last):  
  File "D:/Acads/7.1 Sem/BTP/FaceDetect-master/6.py", line 28, in <module>  
    eyes = eyeCascade.detectMultiScale(roi)  
NameError: name 'roi' is not defined

但是当我使用此代码时，请务必检测图像中的脸部和眼睛，使其正常工作而不会出现任何错误

but when i use this code do detect faces and eyes in a image its working properly without any error

import matplotlib
import matplotlib.pyplot as plt
import cv2
import sys
import numpy as np
import os

faceCascade = cv2.CascadeClassifier('haarcascade_frontalface_default.xml')
eyeCascade= cv2.CascadeClassifier('haarcascade_eye.xml')

video_capture = cv2.VideoCapture(0)

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

    faces = faceCascade.detectMultiScale(frame)

    for (x, y, w, h) in faces:
        cv2.rectangle(frame, (x, y), (x+w, y+h), (0, 255, 0), 2)
        roi = frame[y:y+h, x:x+w]

    eyes = eyeCascade.detectMultiScale(roi)
    for (ex,ey,ew,eh) in eyes:
        cv2.rectangle(roi,(ex,ey),(ex+ew,ey+eh), 255, 2)

    cv2.imshow('Video', frame)

    if cv2.waitKey(1) & 0xFF == ord('q'):
        break

video_capture.release()
cv2.destroyAllWindows()

推荐答案

我认为这只是缩进的问题.

I think it is just a problem of indentation.

roi不在范围内.

for (x, y, w, h) in faces:
    cv2.rectangle(frame, (x, y), (x+w, y+h), (0, 255, 0), 2)
    roi = frame[y:y+h, x:x+w]

    # eyes detection runs for each face
    eyes = eyeCascade.detectMultiScale(roi)
    for (ex,ey,ew,eh) in eyes:
        cv2.rectangle(roi,(ex,ey),(ex+ew,ey+eh), 255, 2)

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