'CV2.VideoCapture' 对象没有属性 'isOpen'

是的，'cv2.VideoCapture' 对象没有 'isOpen' 属性。相反，我们应该使用 'isOpened()' 方法来检查视频捕获设备是否已正确打开。

以下是一个使用 'isOpened()' 检查摄像头是否打开的示例：

import cv2

cap = cv2.VideoCapture(0)

if not cap.isOpened():
    print("Cannot open camera")
else:
    while True:
        ret, frame = cap.read()
        if not ret:
            break
        cv2.imshow('frame', frame)

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

    cap.release()
    cv2.destroyAllWindows()

在这个示例中，我们首先检查摄像头是否被正确打开。如果摄像头没有正确打开，程序将输出“Cannot open camera”。如果摄像头被正确打开，程序将读取视频帧并显示在窗口中。

相关问题

'cv2.VideoCapture' object has no attribute 'isOpen'

是的，`cv2.VideoCapture`对象没有`isOpen()`方法。相反，我们应该使用`isOpened()`方法来检查视频捕获设备是否被正确打开。

以下是一个使用`isOpened()`方法检查摄像头是否打开的示例：

import cv2

cap = cv2.VideoCapture(0)

if not cap.isOpened():
    print("Cannot open camera")
else:
    while True:
        ret, frame = cap.read()
        if not ret:
            break
        cv2.imshow('frame', frame)

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

    cap.release()
    cv2.destroyAllWindows()

在这个示例中，我们首先检查摄像头是否被正确打开。如果摄像头没有正确打开，程序将输出“Cannot open camera”。如果摄像头被正确打开，程序将读取视频帧并显示在窗口中。

cv2.videocapture

cv2.VideoCapture is a function in the OpenCV library that is used for capturing video from a camera or a video file. It creates a video capture object that can be used to read frames from the video source. The function takes a parameter that specifies the index of the camera or the path of the video file to be opened.

Syntax:

cv2.VideoCapture(index or filename)

Example:

import cv2

# Open the default camera
cap = cv2.VideoCapture(0)

# Check if camera opened successfully
if not cap.isOpened():
    print("Error opening video stream or file")

# Read until video is completed
while cap.isOpened():
    # Capture frame-by-frame
    ret, frame = cap.read()

    if ret:
        # Display the resulting frame
        cv2.imshow('Frame', frame)

        # Press Q on keyboard to exit
        if cv2.waitKey(25) & 0xFF == ord('q'):
            break
    else:
        break

# Release the video capture object and close all windows
cap.release()
cv2.destroyAllWindows()

In this example, the function is used to open the default camera (index 0) and read frames from it. The frames are displayed using the cv2.imshow() function and the loop is exited when the user presses the 'q' key on the keyboard. Finally, the video capture object is released using the cap.release() function and all windows are closed using cv2.destroyAllWindows().