什么是OpenCV中的cvWaitKey()函数呢? [英] What does OpenCV's cvWaitKey( ) function do?
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问题描述
cvWaitKey的执行过程中会发生什么()
?什么是一些典型应用案例?只见它的 OpenCV的的参考,但该文件是不是它的确切目的明确。
What happens during the execution of cvWaitKey()
? What are some typical use cases? I saw it in OpenCV reference but the documentation isn't clear on its exact purpose.
推荐答案
cvWaitKey(X)/ CV :: waitKey(X)
做了两件事:
- 它等待的 X 毫秒为单位OpenCV的窗口上的一个键preSS(即从
创建简历:: imshow()
) 。请注意,它不会对标准输入控制台输入听。如果一个关键是在这段时间pssed $ P $,它返回键的ASCII code。否则,它返回1
。 (如果的 X 为零,它会无限期地等待关键preSS) - 它可以处理任何窗口的事件,如
CV创建窗口:: namedWindow()
,或显示与图片CV :: imshow()
。
- It waits for x milliseconds for a key press on a OpenCV window (i.e. created from
cv::imshow()
). Note that it does not listen on stdin for console input. If a key was pressed during that time, it returns the key's ASCII code. Otherwise, it returns-1
. (If x is zero, it waits indefinitely for the key press.) - It handles any windowing events, such as creating windows with
cv::namedWindow()
, or showing images withcv::imshow()
.
有关OpenCV的新手常犯的错误是调用 CV :: imshow()
通过视频帧的循环,而不遵循了每次抽奖CV :: waitKey(30)
。在这种情况下,没有出现在屏幕上,因为highgui从未给定的时间来处理来自 CV :: imshow()
。
A common mistake for opencv newcomers is to call cv::imshow()
in a loop through video frames, without following up each draw with cv::waitKey(30)
. In this case, nothing appears on screen, because highgui is never given time to process the draw requests from cv::imshow()
.
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