OpenCV是一个非常强大的计算机视觉库，它为开发者提供了众多函数来处理图像和视频数据。cv2.waitKey(x)是其中一个非常常用的函数。它用于在显示图像时等待键盘输入，x代表等待的时间（单位是毫秒）。

当我们用OpenCV打开一个窗口并显示图像时，通常会使用cv2.imshow()函数来显示图像。但显示图像后，程序会立刻执行完毕并关闭窗口，无法让用户查看图像。为了解决这个问题，我们需要使用cv2.waitKey()。

cv2.waitKey()函数会等待指定的时间（x毫秒）或直到按下某个键。如果x设置为0，它会一直等待用户按键。这个功能非常适合需要用户交互的应用，比如图像编辑或者视频播放。它的返回值是按键的ASCII码，如果没有按键按下，返回-1。

常见的使用方式如下：

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