waitKey(0) 和 waitKey(1) 的输出差异

问题描述

我刚刚开始使用 Python 的 OpenCV 库，但遇到了一些我不明白的事情.

I've just begun using the OpenCV library for Python and came across something I didn't understand.

cap = cv2.VideoCapture(0)

while True:
      ret, frame = cap.read() #returns ret and the frame
      cv2.imshow('frame',frame)

      if cv2.waitKey(1) & 0xFF == ord('q'):
          break

当我使用 cv2.waitKey(1) 时，我从我的笔记本电脑网络摄像头获得连续的实时视频源.但是，当我使用 cv2.waitKey(0) 时，我会得到静止图像.每次关闭窗口时，都会弹出另一个窗口，其中包含当时拍摄的另一张照片.为什么它不显示为连续供稿?

When I use cv2.waitKey(1), I get a continuous live video feed from my laptops webcam. However when I use cv2.waitKey(0), I get still images. Every time I close the window, another one pops up with another picture taken at the time.Why does it not show as a continuous feed?

推荐答案

来自 文档:

1.waitKey(0) 将无限显示窗口，直到任何按键(适合图像显示).

1.waitKey(0) will display the window infinitely until any keypress (it is suitable for image display).

2.waitKey(1) 将显示一帧 1 ms，之后显示将自动关闭.由于操作系统在切换线程之间有最短时间，因此该函数不会完全等待 1 毫秒，它会等待至少 1 毫秒，具体取决于您的系统上正在运行的其他内容当时的电脑.

2.waitKey(1) will display a frame for 1 ms, after which display will be automatically closed. Since the OS has a minimum time between switching threads, the function will not wait exactly 1 ms, it will wait at least 1 ms, depending on what else is running on your computer at that time.

因此，如果您使用 waitKey(0)，您会看到一个静止图像，直到您实际按下某些东西，而 waitKey(1) 函数将显示一个帧至少 1 毫秒.

So, if you use waitKey(0) you see a still image until you actually press something while for waitKey(1) the function will show a frame for at least 1 ms only.

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