如何从网络摄像头捕获单个图像并在 OpenCV 中进一步处理？

Question

I want my code to capture a single image from webcam and process it further, like later detect colours and sobel edges and a lot more. In short, I want to do image acquisition.

Answer 1

import cv2
cap = cv2.VideoCapture(0) # Usually if u have only 1 camera, then it's 0, if u have multiple camera then it's may be 0,1,2 ...
ret, frame = cap.read() # ret is True or False status which shows if you are success reading frame from web cam, frame is an array
# If u want to loop to read continously
ret = True
while ret:
    ret, frame = cap.read()
    if frame is None:
        continue # this will stop the loop if we failed to read frame, because ret will be False

If this is the answer that u wanted, then it have been asked multiple times. Make sure you have tried to search the answer before you asked

Answer 2

To use your webcam, you can use VideoCapture :

import cv2
cap = cv2.VideoCapture(0) # use 0 if you only have front facing camera
ret, frame = cap.read() #read one frame
print(frame.shape)
cap.release() # release the VideoCapture object. 

You start the webcam, read one image and immediately release it. The frame is the image and you can preprocess it however you want. You can view the image using imshow :

cv2.imshow('image', frame)
if cv2.waitKey(0) & 0xff == ord('q'): # press q to exit
    cv2.destroyAllWindows()

Answer 3

cam = cv2.VideoCapture(0)

image = cam.read()[1]

cv2.imshow("image", image)

cv2.waitKey(0)
cv2.destroyAllWindows()