OpenCV视频采集结果

Question

我正在学习有关 OpenCV 视频捕获的教程，但返回了我不理解的值。这是我的脚本：

import cv2, time

video=cv2.VideoCapture(0)

check, frame = video.read()

print(check)
print(frame)

time.sleep(3)
cv2.imshow("Capturing", frame)

cvw.waitKey(0)
video.release()
cv2.destroyAllWindows

当我运行脚本时，这些是我的结果：

False
None
Traceback (most recent call last):
  File "capture.py", line 11, in <module>
    cv2.imshow("Capturing", frame)
cv2.error: OpenCV(4.2.0) /Users/travis/build/skvark/opencv-python/opencv/modules/highgui/src/window.cpp:376: error: (-215:Assertion failed) size.width>0 && size.height>0 in function 'imshow'

我不知道为什么要返回“False”和“None”。

感谢您的帮助

Answer 1

第一次阅读之前需要一些延迟。像这样插入延迟代码

import time
#if you use camera
#video=cv2.VideoCapture(0)
#if you use video file
video=cv2.VideoCapture('c:/1.avi')
time.sleep(3)
check, frame = video.read()

print(check)
print(frame)

Answer 2

使用以下代码连续读取相机的帧。

import cv2

cap = cv2.VideoCapture(0)

while(True):
    # Capture frame-by-frame
    ret, frame = cap.read()

    # Display the resulting frame
    if frame.size != 0:
        cv2.imshow('frame', frame)
    if cv2.waitKey(1) & 0xFF == ord('q'):
        break

# When everything done, release the capture
cap.release()
cv2.destroyAllWindows()

OpenCV视频采集结果

OpenCV video capture results

opencv

video-capture