在 Python 中无法使用 OpenCV 检测面部和眼睛

Question

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

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检测图像中的面部和眼睛它工作正常没有任何错误

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()

Answer 1

我觉得只是缩进的问题

当您退出 faces 循环时，

roi 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)

在 Python 中无法使用 OpenCV 检测面部和眼睛

Unable to detect face and eye with OpenCV in Python

python

opencv

face-detection

nameerror

eye-detection