使用python启动网络摄像头并捕获图像

Question

I am trying to launch the webcam and capture an image using python I used the following code

 import cv as cv2
cv2.namedWindow("preview")
vc = cv2.VideoCapture(0)

if vc.isOpened(): # try to get the first frame
    rval, frame = vc.read()
else:
    rval = False

while rval:
    cv2.imshow("preview", frame)
    rval, frame = vc.read()
    key = cv2.waitKey(20)
    if key == 27: # exit on ESC
        break
cv2.VideoCapture.open(0)

cv2.destroyWindow("preview")

This launches the camera and closes when Esc is pressed but does not capture an image. Is there a command I'm missing to capture the image?

Answer 1

This code would work, I have simply added cv2.imwrite and save the frame you are already using. The command writes the image if you press escape:

import cv2
cv2.namedWindow("preview")
vc = cv2.VideoCapture(0)

if vc.isOpened(): # try to get the first frame
    rval, frame = vc.read()
else:
    rval = False

while rval:
    cv2.imshow("preview", frame)
    rval, frame = vc.read()
    key = cv2.waitKey(20)
    if key == 27: # exit on ESC
        cv2.imwrite("image.png", frame)
        break

cv2.destroyWindow("preview")

[Edit:] Make sure you are using cv2 and not cv, I have corrected your import statement. What version of OpenCV are you using?