OPENCV调取摄像头检测人脸- python

代码如下：
其中摄像头用
1时：cap = cv2.VideoCapture(0)
2时：cap = cv2.VideoCapture(1)

import cv2

cap = cv2.VideoCapture(1)
face_cascade = cv2.CascadeClassifier(r'/home/liuyu/PycharmProjects/faceRecognition-master/haarcascade_frontalface_alt.xml')  # 加载人脸特征库
face_cascade.load('/home/liuyu/PycharmProjects/faceRecognition-master/haarcascade_frontalface_alt.xml')
while (True):
ret, frame = cap.read()  # 读取一帧的图像
gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)  # 转灰

faces = face_cascade.detectMultiScale(gray, scaleFactor=1.15, minNeighbors=5, minSize=(5, 5))  # 检测人脸
for (x, y, w, h) in faces:
cv2.rectangle(gray, (x, y), (x + w, y + h), (0, 255, 0), 2)  # 用矩形圈出人脸

cv2.imshow('Face Recognition', gray)
if cv2.waitKey(1) & 0xFF == ord('q'):
break
cap.release()  # 释放摄像头
cv2.destroyAllWindows()