python opencv 调用摄像头

import cv2

# 创建一个VideoCapture对象并从默认摄像头捕获视频
cap = cv2.VideoCapture(0)

# 检查是否成功打开摄像头
if not cap.isOpened():
    print("无法打开摄像头")
    exit()

# 循环读取视频帧
while True:
    # 读取一帧
    ret, frame = cap.read()

    # 检查是否成功读取视频帧
    if not ret:
        print("无法读取视频帧")
        break

    # 显示视频帧
    cv2.imshow("frame", frame)

    # 检查是否按下了ESC键
    if cv2.waitKey(1) == 27:
        break

# 释放资源
cap.release()
cv2.destroyAllWindows()