python - openCV:试图从相机代码中理解捕获视频
问题描述
下面是 openCV 文档中用于打开和关闭网络摄像头的简单代码,
import numpy as np
import cv2
cap = cv2.VideoCapture(0)
while(True):
# Capture frame-by-frame
ret, frame = cap.read()
# Our operations on the frame come here
gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
# Display the resulting frame
cv2.imshow('frame',gray)
if cv2.waitKey(1) & 0xFF == ord('q'):
break
# When everything done, release the capture
cap.release()
cv2.destroyAllWindows()
问题:
1) 上面代码中使用 numpy 库是什么,为什么需要它?
2)如何查看的返回值cv2.waitKey(0)
?