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此代码是使用网络摄像头检测面部和眼睛，但出现此错误

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，确实会检测图像中的面部和眼睛，它可以正常工作而没有任何错误

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()
4

1 回答 1

2

我认为这只是一个缩进的问题。

roifaces退出循环时超出范围。

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)
于 2016-09-07T11:32:14.680 回答